User guide and maintenance manual
DOOSAN
Engine
P126
65.99897-8078A
Operation &
Maintenance Manual
GENERATOR DIESEL ENGINE
DE12T
POULS
P126TI-1
P126TI
P126TI- Ⅱ
PS-MMG0717-E1B
DE12T/P126TI
Operation and Maintenance Manual
FOREWORD
This maintenance manual is designed to serve as a reference for DOOSAN Heavy Industries Ltd's
(here after DOOSAN’s) customers and distributors who wish to gain basic product knowledge on
DOOSAN's DE series generator diesel engines (DE12T and POLUS P126TI)
These economical and high-performance diesel engines (6 cylinders, 4 strokes, in-line, direct injection
type) have been so designed and manufactured to be used for the generator application. They meet
all the requirements such as low noise, fuel economy, high engine speed, and durability.
To maintain the engine in optimum condition and retain maximum performance for a long time,
CORRECT OPERATION and PROPER MAINTENANCE are essential.
In this manual, the following symbols are used to indicate the type of service operations to be
performed.
Removal
Adjustment
Installation
Cleaning
Disassembly
Pay close attention-Important
Reassembly
Tighten to specified torque
Reassembly
Use special tools of manufacturer's
Directional Indication
Lubricate with oil
Inspection
Lubricate with grease
Measurement
During engine maintenance, please observe following instructions to prevent environmental damage;
z
Take old oil to an old oil disposal point only.
z
Ensure without fail that oil and diesel fuel will not get into the sea or rivers and canals or the ground.
z
Treat undiluted anti-corrosion agents, antifreeze agents, filter element and cartridges as special waste.
z
The regulations of the relevant local authorities are to be observed for the disposal of spent
coolants and special waste.
If you have any question or recommendation in connection with this manual, please do not hesitate to
contact our head office, dealers or authorized service shops near by your location for any services.
For the last, the content of this maintenance instruction may be changed without notice for some
quality improvement. Thank you.
Doosan Infracore Co., Ltd.
Jan. 2008
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
CONTENTS
1. Safety Regulations & Engine specifications
1.1. Safety Regulations
1.2. Engine Specification
1.3. Engine Assembly
1
7
8
2. Technical Information
2.1. Engine Model and Serial Number
2.2. Engines Characteristic
2.3. Troubleshooting
2.4. Operation Tip
12
13
35
45
3. Disassembly and Reassembly of Major Components
3.1. Disassembly
3.2. Inspection
3.3. Reassembly
47
61
79
4. Commissioning and Operation
4.1. Preparations
4.2. Breaking-in
4.3. Inspections after Starting
4.4. Operation in Winter Time
4.5. Tuning the Engine
4.6. Maintenance and Care
4.7. Cooling System
4.8. Adjustment of Valve Clearance
4.9. Fuel System
4.10. Injection Nozzle Maintenance
103
103
105
106
107
107
110
112
113
116
5. Maintenance of Major Components
5.1. Fuel Injection Pump
5.2. Cooling System
5.3. Lubricating System
5.4. Turbocharger
5.5. Air Intake System
5.6. V-belts
118
152
156
160
169
172
6. Special Tool List
174
z Appendix
176
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
1. Safety Regulations & Engine Specifications
1.1. Safety Regulations
1.1.1. General notes
Day-to-day use of power engines and the service products necessary for running
them presents no problems if the persons occupied with their operation, maintenance
and care are given suitable training and think as they work.
This summary is a compilation of the most important regulations. These are broken
down into main sections which contain the information necessary for preventing injury
to persons, damage to property and pollution. In addition to these regulations those
dictated by the type of engine and its site are to be observed also.
IMPORTANT:
If, despite all precautions, an accident occurs, in particular through contact
with caustic acids, fuel penetrating the skin, scalding from oil, antifreeze being
splashed in the eyes etc., consult a doctor immediately.
1.1.2. Regulations designed to prevent accidents
1) During commissioning, starting and operation
Before putting the engine into operation for the first time, read the operating
instructions carefully and familiarize yourself with the "critical" points, If you are
unsure, ask your DOOSAN representative.
z For reasons of safety we recommend you attach a notice to the door of the
engine room prohibiting the access of unauthorized persons and that you draw
the attention of the operating personal to the fact that they are responsible for the
safety of persons who enter the engine room.
z The engine must be started and operated only by authorized personnel. Ensure
that the engine cannot be started by unauthorized persons.
z When the engine is running, do not get too close to the rotating parts. Wear
close-fitting clothing.
z Do not touch the engine with bare hands when it is warm from operation risk of
burns.
z Exhaust gases are toxic. Comply with the installation instructions for the
installation of DOOSAN generator diesel engines which are to be operated in
enclosed spaces. Ensure that there is adequate ventilation and air extraction.
z Keep vicinity of engine, ladders and stairways free of oil and grease.
Accidents caused by slipping can have serious consequences.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2) During maintenance and care
z Always carry out maintenance work when the engine is switched off. If the engine
has to be maintained while it is running, e.g. changing the elements of changeover filters, remember that there is a risk of scalding. Do not get too close to
rotating parts.
z Change the oil when the engine is warm from operation.
CAUTION :
There is a risk of burns and scalding. Do not touch oil drain valve or oil filters
with bare hands.
z Take into account the amount of oil in the sump. Use a vessel of sufficient size to
ensure that the oil will not overflow.
z Open the coolant circuit only when the engine has cooled down. If opening while
the engine is still warm is unavoidable, comply with the instructions In the chapter
entitled "Cooling"
z Neither tighten up nor open pipes and hoses (lube oil circuit, coolant circuit and
any additional hydraulic oil circuit) during the operation. The fluid which flow out
can cause injury,
z Fuel is inflammable. Do not smoke or use naked lights in its vicinity. The tank
must be filled only when the engine is switched off.
z Keep service products (anti-freeze) only in containers which can not be confused
with drinks containers.
z Comply with the manufacturer's instructions when handling batteries.
CAUTION :
Accumulator acid is toxic and caustic. Battery gases are explosive.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3) When carrying out checking, setting and repair work
z Checking, setting and repair work must be carried out by authorized personnel
only.
z Use only tools which are in satisfactory condition. Slip caused by the worn openend wrench could lead to Injury.
z When the engine is hanging on a crane, no-one must be allowed to stand or pass
under it. Keep lifting gear in good condition.
z When checking injectors, do not put your hands under the jet of fuel.
z Do not inhale at atomized fuel.
z When working on the electrical system disconnect the battery earth cable first.
Connect it up again last in prevent short circuits.
1.1.3. Regulations Designed to Prevent Damage to Engine and Premature Wear
1) Never demand more of the engine than it was designed to yield for its intended
purpose.
z Detailed information on this can be found in the sales literature. The injection
pump must not be adjusted without prior written permission of DOOSAN.
2) If faults occur, find the cause immediately and have it eliminate in order to prevent
more serious of damage.
3) Use only genuine DOOSAN spare parts. DOOSAN will accept no responsibility for
damage resulting from the installation of other parts which are supposedly "just as
good".
4) In addition to the above, note the following points.
z Never let the engine run when dry, i.e. without lube oil or coolant. Use only
DOOSAN-approved service products (engine oil, anti-freeze and anticorrosion
agent).
z Pay attention to cleanliness, The Diesel fuel must be free of water. See
"Maintenance and care".
z Have the engine maintained at the specified intervals.
z Do not switch off the engine immediately when it is warm, but let it run without
load for about 5 minutes so that temperature equalization can take place.
z Never put cold coolant into an overheated engine. See "Maintenance and care".
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Do not add so much engine oil that the oil level rises above the max. marking on
the dipstick. Do not exceed the maximum permissible tilt of the engine. Serious
damage to the engine may result if these instructions are not adhered to.
z Always ensure that the testing and monitoring equipment (for battery charge, oil
pressure, and coolant temperature) function satisfactorily.
z Comply with instructions for operation of the alternator. See "Commissioning and
operation".
z Do not let the water pump run dry. If there is a risk of frost, drain the water when
the engine switched off.
1.1.4. Regulations designed to prevent pollution
1) Engine oil, filter element, fuel filter
z Take old oil only to an oil collection point. Take strict precautions to ensure that oil
does not get into the drains or into the ground.
z The drinking water supply may be contaminated.
z Oil and fuel filter elements are classed as dangerous waste and must be treated
as such.
2) Coolant
z Treat undiluted anti-corrosion agent and / or antifreeze as dangerous waste.
z When disposing of spent coolant comply with the regulations of the relevant local
authorities.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
1.1.5. Notes on safety in handling used engine oil
Prolonged or repeated contact between the skin and any kind of engine oil decreases
the skin.
Drying, irritation or inflammation of the skin may therefore occur. Used engine oil also
contains dangerous substances which have caused skin cancer in animal experiments.
If the basic rules of hygiene and health and safety at work are observed, health risks
are not to the expected as a result of handling used engine oil.
Health precautions :
z Avoid prolonged or repeated skin contact with used engine oil
z Protect your skin by means of suitable agents (creams etc.) or wear protective
gloves.
z Clean skin which has been in contact with engine oil.
- Wash thoroughly with soap and water, A nailbrush is an effective aid.
- Certain products make it easier to clean your hands.
- Do not use petrol, Diesel fuel, gas oil, thinners or solvents as washing agents.
z After washing apply a fatty skin cream to the skin.
z Change oil-soaked clothing and shoes.
z Do not put oily rags into your pockets.
Ensure that used engine oil is disposed of properly.
- Engine oil can endanger the water supply For this reason do not let engine oil get into the ground, waterways, the drains or the
sewers. Violations are punishable. Collect and dispose of used engine oil carefully.
For information on collection points please contact the seller, the supplier or the local
authorities.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
1.1.6. General repair instructions
1. Before performing service operation, disconnect the grounding cable from the
battery for reducing the chance of cable damage and burning due to short-circuiting.
2. Use covers for preventing the components from damage or pollution.
3. Engine oil and anti-freeze solution must be handled with reasonable care as they
cause paint damage.
4. The use of proper tools and special tools where specified is important to efficient
and reliable service operation.
5. Use genuine DOOSAN parts necessarily.
6. Used cotter pins, gaskets, O-rings, oil seals, lock washer and self-lock nuts should
be discarded and new ones should be prepared for installation as normal function of
the parts can not be maintained if these parts are reused.
7. To facilitate proper and smooth reassemble operation, keep disassembled parts
neatly in groups. Keeping fixing bolts and nut separate is very important as they
vary in hardness and design depending on position of installation.
8. Clean the parts before inspection or reassembly. Also clean oil ports, etc. using
compressed air to make certain they are free from restrictions.
9. Lubricate rotating and sliding faces of parts with oil or grease before installation.
10. When necessary, use a sealer on gaskets to prevent leakage.
11. Carefully observe all specifications for bolts and nuts torques.
12. When service operation is completed, make a final check to be sure service has
been done property.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
1.2. Engine Specification
Engine Model
DE12T
Items
P126TI
Water-cooled,
4 cycle in-line type
Turbo charged
Engine type
Water-cooled,
4 cycle in-line type
Turbo charged & intercooled
Direct injection type
Combustion chamber type
Cylinder liner type
Replaceable dry liner
Timing gear system
Gear driven type
No. of piston ring
Compression ring 2, oil ring 1
No. of cylinder-bore × stroke
(mm)
Total piston displacement
4 - 123 × 155
(cc)
Compression ratio
Engine dimension
(length × width × height)
Engine weight
11,051
17.1 : 1
(mm)
(kg)
1,365.5 × 870 × 1,046
1,383 × 870 × 1,207
930
910
Rotating direction (from flywheel)
Counter clockwise
Fuel injection order
1–5–3–6–2–4
Fuel injection timing (B.T.D.C static)
12°
12°
Injection pump type
Zexel in-line “P” type
Governor type
Injection nozzle type
(kg/cm )
Compression pressure
(kg/cm2)
Condition
Continuous
Prime
Stand by
Intake and exhaust valve clearance
(at cold)
(mm)
Open at
Intake valve
Close at
Exhaust valve
Mechanical governor
type(RSV)
Electric governor type(GAC)
Multi-hole type (5 hole)
Multi-hole type (5 hole)
2
Fuel injection pressure
Power (ISO 3046)
P126TI-Ι
Open at
220
1st: 160, 2nd: 220
28 (at 200 rpm)
50 Hz
(1,500 rpm)
60 Hz
(1,800 rpm)
–
–
205 PS
(151 kW)
226 PS
(166 kW)
245 PS
(180 kW)
270 PS
(199 kW)
50 Hz
(1,500 rpm)
280 PS
(206 kW)
328 PS
(241 kW)
370 PS
(272 kW)
60 Hz
(1,800 rpm)
336 PS
(247 kW)
378 PS
(278 kW)
405 PS
(298 kW)
356 PS
(262 kW)
392 PS
(288 kW)
18° (B.T.D.C)
34° (A.B.D.C)
46° (B.B.D.C)
Close at
14° (A.T.D.C)
Full forced pressure feed type
Oil pump type
Gear type driven by crankshaft
Oil filter type
Full-flow, cartridge type
Lubricating oil capacity (max./min.)
(lit)
Oil cooler type
23/20
Water cooled
Water pump
Gear driven impeller type
Cooling method
Pressurized circulation
Cooling water capacity (engine only) (lit)
19
Wax pallet type (83 ∼ 95 °C)
Thermostat type
Starting Motor voltage – output
–
0.3
Lubrication method
Alternator voltage – capacity
60 Hz
(1,800 rpm)
(V - A)
24 – 45
(V - kW)
24 – 6.0
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
1.3. Engine Assembly
1.3.1. Engine sectional view (Longitudinal)
1.
2.
3.
4.
5.
6.
7.
8.
9.
Cooling fan
Exhaust valve
Valve spring
Oil filter
Tappet
Push rod
Piston pin
Piston
Combustion chamber
10.
11.
12.
13.
14.
15.
16.
17.
18.
Crankshaft pulley
Vibration damper
Oil pump
Crankshaft
Oil pan
Connecting rod
Camshaft
Flywheel housing
Flywheel
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
1.3.2. Engine sectional view (Cross)
1.
2.
3.
4.
5.
6.
Intake manifold
Fuel filter
Oil cooler
Injection pump
Cylinder block
Oil filter
7.
8.
9.
10.
11.
12.
Injection nozzle assembly
Rocker arm
Cylinder head cover
Exhaust manifold
Piston ring
Turbocharger
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
1.3.3. Engine assembly views
1) DE12T
1.
2.
3.
4.
5.
6.
7.
8.
9.
Cooling fan
Cooling water pipe
Oil filler cap
Cylinder head cover
Turbocharger
Oil drain valve
Alternator
Oil pan
Starter
10.
11.
12.
13.
14.
15.
16.
17.
18.
Flywheel housing
Flywheel
Exhaust manifold
Injection nozzle assembly
Oil filter
Fuel filter
Oil cooler
Intake manifold
Injection pipe
19.
20.
21.
22.
23.
24.
25.
26.
27.
Thermostat
Injection pump
Oil level gauge
Mounting bracket
Vibration damper
Water pump
Fan drive
Crankshaft pulley
Breather
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2) P126TI
1.
2.
3.
Cooling fan
Cooling water pipe
Air pipe
→
Intake
(Air
cleaner
Turbocharger)
→
(Intercooler
manifold)
4.
5.
6.
7.
Air pipe
Turbocharger
Oil drain valve
Air pipe
(Intercooler
manifold)
8.
9.
Oil pan
Starter
→
10.
11.
12.
Flywheel housing
Flywheel
Exhaust manifold
19.
20.
21.
Thermostat
Injection pump
Oil level gauge
13.
Injection nozzle assembly
22.
Mounting bracket
14.
15.
16.
Oil filter
Breather hose
Oil cooler
23. Vibration damper
24. Water pump
25. Fan drive
17.
18.
Intake manifold
Injection pipe
Intake
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2. Technical Information
2.1. Engine Model and Serial Number
z The
engine
model
and
serial
number is located on the engine as
illustrated.
These
numbers
are
required when requesting warranty
and ordering parts. They are also
referred to as engine model and
serial number because of their
location.
z Engine serial No. (example 1 : DE12T)
EBHGA800001
Serial No.
Production Year(2008)
Engine Model Suffix
z Engine serial No. (example 2 : P126TI)
EDIGA800001
Serial No.
Production Year(2008)
Engine Model Suffix
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2. Engines Characteristic
z The Engines DE12T/ P126TI are in-line vertical water-cooled 6-cylinder fourstroke diesel engines with direct injection. DE12T is turbo-charged engine, and
P126TI model is turbo-charged and inter-cooled engine.
2.2.1. Oil gallery cooling type piston
z The OMEGA combustion bowl is a
unit
designed
to
perform
high
efficiency, low emission combustion.
As the rim around the combustion
bowl port of the upper of the piston
has been machined in a smaller
size
than
the
interior
of
the
combustion bowl, strong swirl is
produced in the combustion bowl
and strong squish flow makes the
fuel be mixed more sufficiently with
air.
z Due to the application of OMEGA
combustion system and optimal
utilization of intake and exhaust port
configuration within the cylinder
head, the POLUS P126TI and
DE12T (DE12 series) generator
diesel engines discharge very low
level of hazardous exhaust gases
such as smoke, nitrogen oxide,
hydrocarbon, or carbon monoxide
and thus ensure high performance
and low fuel consumption.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.2. Oil gallery cooling type piston (P126TI)
z Oil gallery cooling is used for the
piston of P126TI generator engine.
z When thermal loading is high,
piston cooling by means of an oil
gallery in the crown is normally
necessary
to
prevent
crown
cracking and ring sticking. The
design of the gallery, the design
and location of the oil spray nozzle
and the quantity of oil flowing in the
gallery are critical in order to
achieve the desired temperature
reduction.
z The cross section shape of the
gallery
should
be
designed
to
achieve sufficient oil movement to
maximize cooling efficiency.
2.2.3. Cylinder block
z The cylinder block is a single piece of alloy cast iron. To increase its stiffness, it is
extended to a level below the crankshaft center line. The engine has replaceable
dry cylinder liners and individual cylinder heads with struck-in valve seat rings and
replaceable valve guides,
2.2.4. Piston Con-rod / Crankshaft
z The forged crankshaft is a ingrate type (Counterweight is integrated with crank
shaft body). Radial oil seal on crankshaft and flywheel are provided to seal the
flywheel housing inside penetrations.
z The con-rods (connecting rods) are die-forged, diagonally split and can be
removed through the top of the cylinders together with the pistons. Crankshaft
and connecting rods run in steel-backed lead bronze ready-to fit type bearings.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.5. Engine timing
z Camshaft, oil pump and injection pump are driven by a gear train arranged at the
flywheel end.
2.2.6. Valves
z The overhead valves are actuated via chilled cast iron tappets, push rods and
rocker arms from the camshaft.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.7. Lubrication system
z The engine is equipped with force-feed lubrication.
z The pressure is produced by a gear pump whose drive gear is in direct mesh with
the crankshaft gear at the front end of cylinder block.
z The oil pump draws the oil from the oil sump and delivers it through the oil cooler
and oil filter to the main distributor gallery and from there to the main bearings,
big-end bearings and camshaft bearings as well as to the small-end bearings and
the rocker arms.
z The injection pump and the turbocharger are also connected to the engine
lubricating system.
z The cylinder walls and timing gears are splash-lubricated.
z Each cylinder has an oil jet provided for cooling the underside of the pistons.
z The lube oil is cleaned in a full-flow oil filter.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.8. Recommend of lubricating oil
z Initial factory fill is high quality break-in oil for API Service CD. During the break-in
period (50 hours), frequently check the oil level. Somewhat higher oil
consumption is normal until piston rings are seated. The oil level should be
maintained in the safe range between the Min. and Max. marks on the dipstick.
The safe range between the marks represents approximately 3 liters. To obtain
the best engine performance and engine life, grade of engine oil is recommended.
Engine oils are specified by API Service, letter designations and SAE viscosity
numbers. If the specified motor oil is not available, use a reputable brand of
engine oil labeled for API Service CD and SAE viscosity 30 or 15w40. Refer to oil
identification symbol on the container.
z Engine oil should be changed at the specified intervals. (800hr)
2.2.9. Oil cooler
z An oil cooler is provided between the oil filter and the cylinder block. This cooler is
a flat tube type with turbulence inserts and operated by the coolant.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.10. Fuel System
z The fuel is delivered by the fuel feed pump via the fuel filter to the injection pump
and from there to the injection nozzles.
z The fuel is sprayed into the cylinders through nozzles fitted in screw-fit injection
nozzle holders in the cylinder heads.
z Excessively delivered fuel and leak fuel from the nozzle flow through the return
pipe back to the tank.
z A strainer is arranged ahead of the fuel feed pump.
1.
1a.
2.
3.
4.
5.
6.
Fuel filter
Fuel water drain plug
Air bleeding screw (for fuel filter)
Injection nozzle
Overflow tube
Fuel pipe (filter → injection pump)
Overflow valve
7.
8.
9.
10.
11.
12.
13.
Delivery pipe
Fuel pipe (manual pump → filter)
Fuel tank
Fuel return pipe
Suction pipe
Feed pump
Injection pump
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.11. Injection pump
z The in-line injection pump is driven via gears from the crankshaft. It is connected
to the force feed lubricating system of the engine and consequently maintenancefree. The governor flange-mounted on the pump casing is a variable range
governor designed to keep the speed set by the speed control unit constant under
conditions of varying load.
z Governor system for fuel injection pump consists of “Integral Actuator” and
“ Speed Control Unit”.
1) Integral actuator
2) Speed control unit for governor system
The ESD5550 Series speed control unit is an all electronic device designed to
control engine speed with fast and precise response to transient load changes.
This closed loop control, when connected to a proportional electric actuator and
supplied with a magnetic speed sensor signal, will control a wide variety of engines
in an isochronous or droop mode. It is designed for high reliability and built
ruggedly to withstand the engine environment.
Simplicity of installation and adjustment was foremost in the design. Noninteracting performance controls allow near optimum response to be easily
obtained.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
The primary features of the ESD5550 Series speed control unit are the engine
STARTING FUEL and SPEED RAMPING adjustments. The use of these features
will minimize engine exhaust smoke experienced prior to attaining engine
operating speed.
Other features include adjustable droop and idle operation, inputs for accessories
used in multi-engine or special applications, protection against reverse battery
voltage, transient voltages, accidental short circuit of the actuator and fail safe
design in the event of loss of speed sensor signal or battery supply.
Engine model
P126TI
GAC governor model
ACE 175A
Speed control unit model
ESD5550
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.11. Fuel requirements
z DOOSAN marine diesel engines was designed to use Number 2-D diesel fuel or
equivalent that meets specification DIN 51601-DK. For maximum fuel economy,
Number 2-D fuel whenever possible. When temperatures are below -7 °C (20 °F),
use Number 1-D fuel. If Number 1-D fuel is not available, the mixture of one
kerosene to two gallons of Number 2-D fuel can be used. Once kerosene has
been added, the engine should be run for several minutes to mix the fuel.
2.2.12. How to select fuel oil
z Fuel quality is an important factor in obtaining satisfactory engine performance,
long engine life, and acceptable exhaust emission levels. DOOSAN engines are
designed to operate on most diesel fuels marketed today. In general, fuels
meeting the properties of ASTM Designation D975 (grades 1-D and 2-D) have
provided satisfactory performance.
z The ASTM 975 specification, however, does not in itself adequately define the fuel
characteristics needed for assurance of fuel quality.
z The properties listed in the fuel oil selection chart below have provided optimum
engine performance. Grade 2-D fuel is normally available for generator service.
Grade 1-D fuel should not be used in pleasure craft engines, except in an
emergency.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Fuel oil selection chart
General Fuel
Classification
Gravity, °API
#)
ASTM
Test
No. 1
ASTM 1-D
No. 2
ASTM 2-D
DIN 51601
D 287
40 ~ 44
33 ~ 37
0.815 ~ 0.855
D 93
100 (38)
125 (52)
131 (55)
Flash Point
Min. °F (°C)
Viscosity, Kinematic
CST 100 °F (40 °C )
Cloud Point °F #)
Sulfur Content
wt%, Max.
Carbon Residue
on 10%, wt%, Max.
D 445
1.3 ~ 2.4
1.9 ~ 4.1
1.8 ~ 10
D 2500
See Note 1)
See Note 1)
See Note 1)
D 129
0.5
0.5
0.15
D 524
0.15
0.35
0.1
Accelerated Stability
Total Insolubles
mg/100 ml, Max. #)
D 2274
1.5
1.5
D 482
0.01
0.01
D 613
45
45
> 45
350(177)
385(196)
45(218)
500 (260) Max.
550(288) Max.
375(191)
430(221)
510(256)
625(329) Max.
675(357) Max.
680(360)
0.05
0.05
Ash, wt%, Max.
Cetane Number, Min.
Distillation
Temperature, °F (°C)
IMP, Typican #)
10% Typical #)
50% Typical #)
90% +)
End Point #)
Water & Sediment
%, Max.
+)
D 86
D 1796
0.05
#) Not specified In ASTM D 975
+) Differs from ASTM D 975
NOTE:
The cloud point should be 6 °C (10 °F) below the lowest expected fuel
temperature to prevent clogging of fuel fitters by crystals.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.13. V-belt tension check and adjust
z By the finger-pressure the belt is
pressed by 10 mm ~ 15 mm between
the fan pulley and the alternator
pulley in normal condition. For the
adjustment of the tension, loosen
the adjusting bolts which support
the alternator, adjust the tension
and tighten the bolts again.
2.2.14. Turbocharger
z The exhaust gases of the engine are passed through the turbine rotor of the
turbocharger. Air compressor impeller mounted on the same shaft draws in fresh
air and delivers it at a higher pressure to the cylinders.
z The turbocharger is naturally air-cooled. Lubrication of the main bearing is by oil
under pressure from the engine lubricating system.
1. Compressor casing
2. Turbine casing
3. Compressor wheel
4. Impeller
5. Turbine
A. Air inlet
B. Gas outlet
C. Gas inlet
D. Oil supply
E. Oil return
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.15. Intercooler
z The intercooler is air to air type and has a large cooling fan capacity. The
intercooler life and
z performance depends on the intake air condition greatly. Fouled air pollutes and
clogs the air fins of intercooler. As a result of this, the engine output is decreased
and engine malfunction is occurred. So you always check whether the intake air
systems like air filter element are worn or polluted.
- Cleaning of intercooler fins: Every 600 hours.
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DE12T/P126TI
Operation and Maintenance Manual
2.2.16. Cooling system
The engine has a liquid-cooling system. The fresh water pump is a maintenance-free
by gear from the crankshaft.
Depending on the agreed extent of delivery and the design of the engine, the coolant
circuit can be equipped with temperature monitors which, in the event of loss of
coolant, shut the engine down.
z Check the coolant level of the expansion tank by removing the expansion tank
filler cap, and add coolant if necessary.
z When injecting antifreeze solution, first drain out the old coolant from the cylinder
block and radiator, and then clean them with cleaning solution.
z Be sure to mix soft water with antifreeze solution.
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DE12T/P126TI
Operation and Maintenance Manual
2.2.17. Coolant pressure cap
z Check the pressure valve opening
pressure using a expansion tank
cap tester. Replace the filler cap
assembly if the measured valve
does not reach the specified limit.
(pressure valve opening pressure:
0.9 kg/cm2)
NOTE:
Because it is dangerous to open the
pressure cap quickly when coolant
is hot, after lowering the inside
pressure of the tank by slowopening at first open it fully.
2.2.18. Cooling water
z Regarding the cooling water that is to be used for engine, the soft water not the
hard water must be used.
z The engine cooling water can be used diluting it with antifreezing solution 40%
and the additive for rust prevention (DCA4) 3 ~ 5 %.
z The density of above solution and additive must be inspected every 500 hours to
maintain it properly.
NOTE:
The proper density control of antifreezing solution and rust preventing
additive will be able to prevent the rusting effectively and maintain the stable
quality of engine.
For the improper control might give the fatal damage to the cooling water
pump and cylinder liners, detail care is needed.
z Since DE12T and POLUS P126TI (generator diesel engine of DE12 series)
cylinder liner is dry type, particularly the cooling water control should be applied
thoroughly.
z The density of antifreezing solution and additive for rust prevention is able to be
confirmed by the cooling water test kit. (Fleetguard CC2602M)
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DE12T/P126TI
Operation and Maintenance Manual
z How to use the cooling water test kit
(1) When the cooling water temp. of engine is in the range of 10 ~ 55 °C, loosen
the plug for cooling water discharge and fill the plastic cup about a half.
NOTE:
In taking the cooling water sample, if the water in auxiliary tank were taken, it
is hard to measure the accurate density. Take the cooling water sample
necessarily loosening the cooling water discharge plug.
(2) At the state of a test paper soaked in the sampled water, after taking the
paper out through water agitation, shake off the water.
(3) Wait for about 45 sec. till the color change of test paper.
NOTE:
However, it should not elapse longer than 75 sec, and if it did, the hue would
change.
(4) Make the numerical value by comparing the test paper which hue has
changed with the color list of label on storage bottle.
(5) By comparing the hue changed into yellowish green or so with the green color
indication of test paper storage bottle, confirm the density. (Then, the density
indication must be in the hue range of 33% to 50%).
(6) The brown at the middle of test paper and the lower pink color indication
represent the additive state for rust prevention, and the proper range is that
the meeting numerical value of brown (vertical) and pink color (horizontal)
locates in the range of 0.3 to 0.8 at the color list of label on the test paper
storage bottle.
(7) In case of less than 0.3, replenish the additive for rust prevention (DCA4), and
in case of more than 0.8, pour out the cooling water about 50% and then
readjust the density after refilling with clean fresh water.
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DE12T/P126TI
Operation and Maintenance Manual
z Amount of anti-freeze in winter
Ambient
temperature (°C)
Over -10
-10
-15
-20
-25
-30
-40
Cooling water (%)
Anti-freeze (%)
85
80
73
67
60
56
50
15
20
27
33
40
44
50
2.2.19. Fuel belt
z Use a fan belt of specified dimensions, and replace if damaged, frayed, or
deteriorated.
z Check the fan belt for belt tension.
If belt tension is lower than the specified limit, adjust the tension by relocating the
alternator. (specified deflection: 10 ~ 15 mm when pressed down with thumb)
2.2.20. Engine oil
z Check oil level with the oil level gauge and replenish if necessary.
z Check the oil level with the engine cooled. If the engine is warm, allow time for 5 ~
10 minutes for oil drain into the crankcase before checking oil level. The oil level
must be between Max and Min. lines on the gauge.
z Engine oil should be changed at the specified intervals. (800 hr)
Oil in the oil filter should be changed simultaneously.
-
First oil change : 50 hr operating
z The oil viscosity grades should be selected SAE NO.15W40 and API CD or CE.
2.2.21. Oil filter
z Check for oil pressure and oil leaks,
and repair or replace the oil filter if
necessary.
z Change
the
oil
filter
cartridge
simultaneously at every replacement
of engine oil.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.22. Fuel filter
z Drain
water
in
cartridge
with
loosening the cock under filter
manually (6) from time to time.
z The fuel filter should be replaced at
every 1,200 hours.
2.2.23. Air cleaner
z In case that elements are deformed,
damaged or if the air cleaner has a
crack, replace it.
z By
the
definite
interval,
the
elements must be cleaned and
replaced.
2.2.24. Valve clearance adjust procedure
z After letting the #1 cylinder's piston come at the compression top dead center by
turning the crankshaft, adjust the valve clearances.
z Loosen the lock nuts of rocker arm adjusting screws and push the feeler gauge of
specified value between a rocker arm and a valve stem and adjust the clearance
with adjusting screw respectively and then tighten with the lock nut.
z As for the valve clearance, adjust it when in cold, as follow.
Model
Intake Valve
Exhaust Valve
DE12T
P126TI
0.3 mm
0.3 mm
-
By cranking the engine, let #6 cylinder's valves overlap.
-
In time, adjust the valve clearance corresponding to “
-
Adjust the valve clearance corresponding to “
-
After reinsuring the valve clearances, retighten if necessary.
” of lower lists.
” of lower lists.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z No. 1 Cylinder is located at the side where flywheel was installed.
2.2.25. Cylinder compression pressure
z Stop the engine after warming up,
and
take
out
nozzle
holder
assembly.
z Install the special tool (compression
gauge adapter) at the nozzle holder
hole, and connect the compression
pressure gauge there.
Standard value
Limit value
Difference between
each cylinder
-
28 kg/cm2 over
24 kg/cm2
Within ± 10 %
Condition : Water temperature
20°C, Engine rotation 200 rpm
(10 rotation)
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.26 Injection nozzle
z Install a nozzle on the nozzle tester.
z If the inspected injection pressure is less than the specified value, adjust using the
adjusting shims.
Engine Model
DE12T
Injection nozzle pressure
220 kg/cm2
P126TI
1st : 160 kg/cm2
2nd : 220 kg/cm2
z Check the atomizing state and replace it if abnormal..
2.2.27. Fuel injection pump
z Check the housing crack, damage etc. and replace it if abnormal.
z Check if the idle operation and speed regulating lever's sealing is removed.
z The adjustment and testing of fuel injection pump should necessarily be done at
the test bench.
2.2.28. Battery
z Inspect for any leakage of electrolytic solution owing to battery crack, and replace
the battery in case of poor condition.
z Inspect for amount of electrolytic solution, and replenish if insufficient.
z Measure the gravity of electrolytic solution, if less than specified value (1.12 ~
1.28), replenish.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.29. Air removal of fuel system
The suction room of fuel injection pump has the function of air removal continuously
during the operation through a relief valve.
In case that the suction room lacks fuel at all, for instance, in case of new installation
of injection pump, after loosening the air removing screws of cartridge filter
respectively, remove the air by operating the manual pump of fuel supply pump until
bubble will disappear.
2.2.30. Fuel supply pump
Every time of engine oil replacement, the fuel strainer installed at the fuel supply
pump should be removed and cleaned.
2.2.31. Supercharger
The supercharger needs not arty special equipment
Every time of engine replacement, a leakage or clogging of oil pipes should be
inspected. Air cleaner should be maintained carefully for nut or foreign material not to
get in. Periodic inspection should be applied on the compressed air and exhaust gas
pipes, For leaking air will bring the overheat engine, an immediate repair must be
done. During the operation that is surrounded by the dust and oil mixed air, frequent
cleaning must be done on the impellers. Tear down the impeller casing (attention: be
careful not to bend) and must clean with non-acid solvent solution. If necessary, use
plastic scraper If impeller is severely polluted, dip the impeller into solution and may
be better to clean it with stiff brush.
Then one thing to beware is to dip only impeller part and so do not support by
impeller but bearing housing.
2.2.32. Starting motor
In case of engine maintenance, clean pinion and ring gear thoroughly putting in the
fuel, and coat them with grease.
Also, In case of washing car and so forth, inspect the wiring state being careful for
not to get
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.2.33. Electrical equipment
1) Alternator
The alternator is fitted with integral silicon rectifiers. A transistorized regulator
mounted on the alternator body interior limits the alternator voltage. The alternator
should not be operated except with the regulator and battery connected in circuit to
avoid damage to the rectifier and regulator.
The alternator is maintenance-free, nevertheless, it must be protected against dust
and, above all, against moisture and water.
Operate the alternator according to the instructions given in the chapter.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2) Starter motor
The sliding-gear starter motor is flanged to the rear of the flywheel housing on the
left-hand side. As parts of every engine overhaul, the starter pinion and ring gear
should be cleaned with a brush dipped in fuel and then a coat of grease should be
applied again.
Always protect starter motor against moisture.
WARNING:
Always disconnect the battery earth cable before starting work on the
electrical system. Connect up the earth cable last, as there is otherwise a risk
of short-circuits.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.3. Diagnosis and Remedy
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DE12T/P126TI
Operation and Maintenance Manual
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Condition
1) Starting difficult
(1) Compression pressure
2) Idle operation abnormal
Causes
Remedies
z
z
Valve's poor shut, stem distortion
Valve spring damage
Repair or replace
Replace valve spring
z
Cylinder head gasket's leak
Replace gasket
z
Adjust
z
Wear of piston, piston ring or
liner
Injection timing incorrect
Adjust
z
Air mixing at injection pump
Remove air
z
Valve clearance incorrect
Adjust
z
Valve tightness poor
Repair
z
Cylinder head gasket's leak
Replace gasket
z
Replace piston ring
z
Wear, stick, damage of piston
ring
Injection timing incorrect
Adjust
z
Fuel injection amount insufficient
Adjust injection pump
z
Adjust or replace
z
Nozzle injection pressure
improper or stuck
Supply pump's function lowered
Repair or replace
z
Fuel pipe system clogged
Repair
z
Air suction amount insufficient
Clean or replace air cleaner
z
Supercharger poor
Repair or replace
z
Disassemble engine
z
Compression pressure
insufficient
Injection timing incorrect
Adjust
z
Fuel injection amount insufficient
Adjust injection pump
z
Repair or replace
z
Injection pump timer's function
insufficient
Nozzle infection pressure,
infection angle improper
Supply pump's function lowered
Repair or replace
z
Air intake amount insufficient
Clean or replace air cleaner
z
Engine oil insufficient or poor
Replenish or replace
z
Cooling water insufficient
Replenish or replace
z
Fan belt loosened, worn,
damaged
Cooling water pump's function
lowered
Water temp. regulator's
operation poor
Valve clearance incorrect
Adjust or replace
3) Engine output insufficient
(1) Continuous output
insufficient
(2) Output insufficient
when in acceleration
z
Repair, replace
4) Overheating
z
z
z
z
Exhaust system's resistance
increased
Repair or replace
Replace
Adjust
Clean or replace
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
Condition
5) Engine noisy
(1) Crankshaft
(2) Con rod and
Con rod bearing
Causes
For noises arise compositely such as
rotating parts, lapping parts etc.,
there is necessity to search the
cause of noises accurately.
z As the wear of bearing or
crankshaft progress, the oil
clearances increase.
z Lopsided wear of crankshaft
z Oil supply insufficient due to oil
passage clogging
z Stuck bearing
z
z
z
z
z
(3) Piston, piston pin &
piston ring
(4) Others
z
z
z
z
z
z
z
z
z
z
z
z
6) Fuel Consumption
Excessive
Remedies
z
z
Lopsided wear of con rod
bearing
Lopsided wear of crank pin
Connecting rod distortion
Stuck bearing
Oil supply insufficiency as
clogging at oil passage
progresses
Piston clearance increase as the
wear of piston and piston ring
progresses
Wear of piston or piston pin
Piston stuck
Piston insertion poor
Piston ring damaged
Wear of crankshaft, thrust
bearing
Camshaft end play increased
Idle gear end play increased
Timing gear backlash excessive
Valve clearance excessive
Abnormal wear of tappet, cam
Supercharger inner part
damaged
Injection timing incorrect
Fuel injection amount excessive
Replace bearing &
grind crankshaft
Grind or replace
Clean oil passage
Replace bearing &
Grind
Replace bearing
Grind crankshaft
Repair or replace
Replace &
grind crankshaft
Clean oil passage
Replace piston &
piston ring
Replace
Replace piston
Replace piston
Replace piston
Replace thrust bearing
Replace thrust plate
Replace thrust washer
Repair or replace
Adjust valve clearance
Replace tappet, cam
Repair or replace
Adjust
Adjust injection pump
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Condition
7) Oil Consumption
Excessive
(1) Oil level elevated
Causes
z
z
z
z
z
(2) Oil level lowered
(3) Oil leak
z
z
z
z
z
z
z
z
Clearance between cylinder liner
& piston
Wear of piston ring, ring groove
Piston ring's damage, stick, wear
Piston ring opening's disposition
improper
Piston skirt part damaged or
abnormal wear
Oil ring's oil return hole clogged
Oil ring's contact poor
Looseness of valve stem & guide
Wear of valve stem seal
Cylinder head gasket’s leak
Looseness of connection parts
Various parts' packing poor
Oil seal poor
Remedies
Replace
Replace piston, piston ring
Replace piston ring
Correct position
Replace piston
Replace piston ring
Replace piston ring
Replace in set
Replace seal
Replace gasket
Replace gasket, repair
Replace packing
Replace oil seal
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.4. Engine Inspection
2.4.1. Stopping engine
Cut off the main circuit breaker of the generator control panel. After checking the
engine for any unusual condition at the idling speed, then press the stop button to stop
the engine.
2.4.2. General engine inspection cycle
Ο : Check & adjust
Inspection
Check for leakage(hoses, clamp)
Check the water level
Cooling Change the coolant water
System
Every Every Every Every Every
Daily 50hrs 200hrs 600hrs 800hrs 1,200hrs Remark
О
О
●
Adjust the V-belt tension
О
Clean the radiator
Check for leakage
Check the oil level gauge
О
О
Every
2,000hrs
О
●
1st
●
1st
Lubrication
System Change the lubricating oil
Replace the oil filter cartridge
Check the leakage for intercooler
(hoses, clamp)
Intake & Clean and change
Exhaust the air cleaner element
System Clean the inter-cooler air fins
● : Replace
О
О
О
О
clean
●
О
Every
2,000hrs
Clean the turbo-charger
Fuel
System
Check the leakage fuel line
Clean the fuel strainer
of fuel feed pump
Remove sediment from fuel tank
Drain the water in separator
Replace the fuel filter element
О
О
О
●
Check fuel Injection timing
О
Check the injection nozzles
О
Check the state of exhaust gas
Check the battery charging
Engine
Adjust
О
О
О
Check the compression pressure
Adjust Intake/Exhaust
valve clearance
When
necessary
When
necessary
О
О
1st
When
necessary
When
necessary
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2.4.3. Use of original parts for repair and replacement
For engine is being mechanically harmonized with many parts, only when the original
parts that the manufacture recommends to use is used, the engine trouble would be
preventively maintained and capable to keep up the maximum performances.
For the analogous parts not the original parts are poor in qualities and gives ill
performances, it may rather bring early engine failure.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3. Disassembly and Reassembly of Major Components
3.1. Disassembly
3.1.1. General precautions
z Maintenance operation should be carried out in a bright and clean place.
z Before disassembly, provide parts racks for storage of various tools and
disassembled parts.
z Arrange the disassembled parts in the disassembly sequence and use care to
prevent any damage to them.
3.1.2. Cooling water
z Remove the radiator cap. Open the
drain plug at the radiator lower part
to drain the coolant as the right
figure.
CAUTION :
When removing radiator filler cap
while the engine is still hot, cover
the cap with a rag, then turn it
slowly to release the internal steam
pressure This will prevent a person
from
scalding
with
hot
steam
spouted out from the filler port.
z Remove the drain plug from the
cylinder block and drain out the
cooling water into a container.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.3. Engine oil
z Take out the oil dip dipstick.
z Remove the oil drain valve of oil
pan and drain out the engine oil
into a prepared container.
3.1.4. Alternator belt
z Loosen the tension adjusting nut
installed on the alternator bracket,
and take off the alternator belt.
3.1.5. Cooling fan
z Remove the flange fixing bolts,
then take off the flange and cooling
fan.
3.1.6. Alternator
z Remove the alternator fixing bolt
and disassemble the alternator.
z Remove the tension adjusting bolt
and bracket.
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DE12T/P126TI
Operation and Maintenance Manual
3.1.7. Oil level gauge guide tube
z Loosen the flange nut installed on
the oil pan to remove the guide tube.
3.1.8. Fuel filter
z Remove fuel hoses connected to the
fuel injection pump, take off the
bracket fixing bolts, then disassemble
the fuel filter.
3.1.9. Breather
z Loosen the clamp screw to remove
the rubber hose.
3.1.10. Intercooler
z Tear down the various hoses and air
pipes from the inter cooler.
z Remove the intercooler fixing bolts
and tear it down.
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DE12T/P126TI
Operation and Maintenance Manual
3.1.11. Injection pipe
z Unscrew
the
hollow
screws
to
disassemble the fuel return pipe.
z Remove the nuts installed on the
fuel injection pump and nozzles,
then disassemble the injection pipe.
3.1.12. Intake manifold
z Remove the air hose connected to
the fuel injection pump.
z Loosen the intake manifold fixing
bolts, then disassemble the intake
manifold.
3.1.13. Turbo charger
z Release the clamp screw of the
rubber hose connected to the intake
manifold, and take off the intake
pipes both simultaneously.
z Unscrew the exhaust pipe bracket
fixing bolts, release the nuts installed
on
the
turbocharger,
then
disassemble the exhaust pipe.
z Remove
the
turbocharger
after
removing the oil supply pipe and
return pipe and releasing the fixing
nuts.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.14. Exhaust manifold
z Release the exhaust manifold fixing
bolts,
disassemble
the
exhaust
manifold, then remove the heat
shield and gasket.
NOTE :
Make sure to release the nuts one
after another because the exhaust
manifold will be removed if you
unscrew two nuts simultaneously.
3.1.15. Thermostat
z Remove the by-pass pipe connected
to the water pump, unscrew the
thermostat
fixing
bolts,
then
disassemble the thermostat housing.
z Disassemble the thermostat housing
and remove the thermostat.
z Disassemble the water pipe by
unscrewing
the
bolts
and
nuts
installed on the cylinder head.
3.1.16. Starter
z Unscrew the starter fixing bolts, then
disassemble the starter.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.17. Water pump
z Remove the water pipe connected to
the expansion tank.
z Remove the water pipe and hoses
connected to the water pump.
z Unscrew the water pump fixing bolts
and remove the water pump.
3.1.18. Injection pump
z Remove the oil supply pipe and
return pipe connected to the fuel
injection pump.
z Unscrew the bolts connecting the
coupling and drive shaft, loosen the
injection pump attaching bolts, then
disassemble the injection pump.
NOTE :
As far as possible, place the No.1
cylinder
in
'OT'
position
to
disassemble the injection pump.
z Release the pump fixing bracket
bolts to disassemble the bracket
from the cylinder block.
NOTE :
Do not interchange the shims as
they must be installed in their
original positions at reassembly.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.19. Oil filter
z Using
a
filter
remover
wrench,
remove the oil filter cartridge.
z Remove the pipe connected to the
oil cooler.
z Loosen the oil filter fixing bolts and
disassemble the oil filter head from
the cylinder block.
3.1.20. Fan drive pulley
z Remove the bolts and disassemble
the fan drive pulley.
3.1.21. Vibration damper
z Unscrew the pulley fixing bolts and
disassemble
the
pulley-vibration
damper assembly.
z Unscrew the vibration damper fixing
bolts and disassemble the damper
from the pulley.
3.1.22. Timing gear case cover
z Disassemble the oil seal using an oil
seal removing jig.
z Remove the cover fixing bolts and
disassemble the cover from the
timing gear case.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.23. Idle gear
z Unscrew the idle gear fixing bolts
and disassemble the thrust washer
and idle gear.
z Disassemble the idle gear pin using
a rubber hammer to prevent damage
to them.
3.1.24. Fuel injection pump drive assembly
z Unscrew the injection pump drive
shaft bearing housing fixing bolts
and remove the injection pump drive
assembly which the shaft, gear,
bearings,
and
housing
are
put
together.
3.1.25. Cylinder head cover
z Unscrew the cover fixing bolts and
disassemble the cover.
z Keep the bolts in an assembly state
so that the packings and washers
may not be lost, and keep the cover
packing as assembled with the cover.
3.1.26. Rocker arm assembly
z Unscrew the rocker arm bracket
bolts and remove the rocker arm
assembly.
z Take off the snap rings to remove
the washers and rocker arm, then
unscrew the bracket fixing bolts to
take off the bracket and springs.
z Take out the push rods.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.27. Injection nozzle
z Remove the oil seal holder fixing
bolts and tear down.
z Remove the oil seal and gasket from
the oil seal holder and scrap them
Do
not
perform
disassembly
operation unless coolant, gas, etc.
leak out.
3.1.28. Cylinder head
z Unscrew the cylinder head fixing
borts and take off the cylinder head.
z Remove the cylinder head gasket.
3.1.29. Valve and valve stem seal
z Compress the valve spring retainer
using a jig and take off the valve
cotter pins.
z Disassemble the valve springs and
retainers.
z Take off the valves.
z Remove and discard the valve stem
seal using a general tool as it should
not be re-used.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.30. Oil cooler
z Remove the water pipe connected to
the water pump.
z Remove the oil pipe connected to the
cylinder block.
z Unscrew the oil cooler cover fixing
bolts and disassemble the oil cooler
assembly from the cylinder block.
z Unscrew the oil cooler fixing bolts and
remove the oil cooler from the oil
cooler cover.
3.1.31. Oil pan
z Stand the engine with the flywheel
housing facing the bottom.
z Release the oil pan fixing bolts,
remove
the
stiffeners
then
disassemble the oil pan.
3.1.32. Oil pump and oil pipe
z Unscrew
the
oil
suction
pipe
bracket bolts, releasing the pipe
fixing bolts, then disassemble the
oil suction pipe assembly.
z Disassemble the oil pipe feeding oil
from the oil pump to the cylinder
block.
z Unscrew the oil pump fixing borts
and disassemble the oil pump.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.33. Relief valve
z Disassemble the relief valve.
3.1.34. Piston and connection rod
z Disassemble the pistons by two
cylinders
while
turning
the
crankshaft.
z Unscrew the connecting rod fixing
bolts and take off the pistons and
connecting rods in the direction of
piston
z Remove the piston pin snap rings,
take
off
the
piston
pin,
then
disconnect the connecting rod from
the piston.
z Disassemble the piston rings using
ring pliers.
z Use care not to interchange the
disassembled parts and keep them
in the sequence of cylinder No.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.35. Cylinder liner
z Disassemble the cylinder liner using
a liner puller.
3.1.36. Flywheel
z Position the engine so that the head
installing surface of the cylinder
block faces down.
z Unscrew the flywheel fixing bolts
and fit a dowel pin.
z Install flywheel disassembling bolts
in the bolt holes machined on the
flywheel,
and
disassemble
the
flywheel.
3.1.37. Oil seal
z Take off the rear oil seal using an oil
seal disassembling jig.
z If only the inside guide ring is
removed, use a special tool to take
off the outside seal.
3.1.38. Flywheel housing
z Loosen the housing fixing bolts
disassemble the flywheel housing.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.39. Cam shaft and tappet
z Remove the cam shaft gear.
z Take off the cam shaft gear thrust
washer.
z Take out the cam shaft using care
not to damage the cam shaft.
z Slide out the tappets by hand.
3.1.40. Crankshaft gear and oil pump idle gear
z Loosen the socket head bolts and
take out the oil pump idle gear.
z Use
a
puller
to
remove
the
crankshaft gear.
3.1.41. Timing gear case
z Unscrew the case fixing bolts and
disassemble the timing gear case.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.1.42. Crankshaft
z Remove the bolts from bearing
caps.
z Remove the main bearing cap fixing
bolts in the order of assembling.
(Remove them in the same way of
the cylinder head bolts.)
z Maintain the removed bearing caps
in the order of cylinders.
z Temporarily install the bolts at the
both side of crankshaft, and lift the
shaft with a rope.
NOTE :
Do not mingle with the metal
bearings
and
randomly.
To
bearing
prevent
caps
mixing,
temporarily assemble the metal
bearings
to
the
corresponding
bearing caps in turn.
3.1.43. Oil spray nozzle
z Unscrew the fixing bolt and remove
the oil spray nozzles.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.2. Inspection
3.2.1. Cylinder block
1) Clean the cylinder block thoroughly and make a visual inspection for cracks or
damage.
2) Replace if cracked or severely damaged, and correct if slightly damaged.
3) Check oil and water flow lines for restriction or corrosion.
4) Make a hydraulic test to check for any cracks or air leaks.
Hydraulic test :
Stop up each outlet port of water/oil passages in the cylinder block, apply air
pressure of about 4 kg/cm2 against the inlet ports, then immerse the cylinder
block in water for about 1 minute to check any leaks. (Water temperature: 70 °C)
3.2.2. Cylinder head
1) Inspection
z Carefully remove carbon from the lower lace of the cylinder head using
nonmetallic material to prevent scratching of the valve seat faces.
z Check the entire cylinder head for very fine cracks or damage invisible to
ordinary sight using a hydraulic tester or a magnetic flaw detector.
2) Distortion at the lower face
z Measure the amount of distortion
using a straight edge and a feeler
gauge at six positions (A ~ F) as
shown in the right figure.
z If the measured value exceeds the
standard value, retrace the head
with grinding paper of fine grain
size to correct such defect.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z If the measured value exceeds the
maximum allowable limit, replace
the cylinder head.
<Lower face warpage and height>
Standard
Limit
Warpage
0.2 mm or less
0.3 mm
Thickness : t
(reference)
114.95 ∼ 115.0 mm
113.9 mm
3) flatness
z Measure flatness of the intake/exhaust manifolds fitting surfaces on the cylinder
head using a straight edge and a feeler gauge.
Standard
Limit
0.05 mm
0.2 mm
4) Hydraulic test
z Hydraulic test method for the cylinder head is same as that for cylinder block.
3.2.3. Valve and valve guide
1) Valve
Clean the valves with clean diesel oil,
then inspect them as follows:
z Valve stem outer diameter
Measure the valve stem outer
diameter
at
3
positions.
(top,
middle, and bottom) If the amount
of wear is beyond the limit, replace
the valve.
z Valve seat contacting faces
If
valve
head
thickness
(H)
becomes less than 1.6 mm for
intake and 1.3 mm for exhaust,
replace the valve.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Valve head thickness
Measure the valve head thickness,
and
replace
the
valve
if
the
measured value is beyond the limit.
Dimension
Standard
Limit
Intake valve
1.5 mm
1 mm or less
Exhaust valve
1.5 mm
0.9 mm or less
Description
2) Valve guide
z Insert the valve into valve guide
and
measure
the
clearance
between valve and valve guide by
the shaking degree of valve. If the
clearance is bigger, measure the
valve and then replace the more
worn valve guide.
<Valve stem end play>
Intake
valve
Exhaust
valve
Standard
Limit
0.04 ∼ 0.07 mm
0.2 mm
0.06 ∼ 0.09 mm
0.25 mm
z Install the valve into the cylinder
head valve guide, then check and
see if it is centered with the valve
seat using a special tool.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3) Valve seat
z Contacting face amount
Measure
the
contacting
face
between the intake valve seat and
exhaust valve seat for valve seat
wear, and replace if the measured
value exceeds the specified limit.
z Install the valve into the valve seat
on the cylinder head, and check
the amount of depression of the
valve from the lower portion of the
cylinder head using a dial gauge.
< Valve depression >
Intake &
Exhaust
Standard
Limit
0 ∼ 0.03 mm
0.55 mm
If the amount of depression is beyond the specified limit, replace the valve seat.
z For removal of the valve seat,
apply arc welding work to two
points of valve seat insert, and pull
out the valve seat insert with inner
extractor.
z Undercool a new valve seat with dry ice for about 2 hours and press the valve
seat insert into position in the cylinder head using a special tool (bench press).
z Apply valve lapping compound to the valve head seating face on the valve seat
and lap the valve seat by turning it until it is seated in position, then wipe out the
lapping compound.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4) Valve spring
z Visual check
Visually check the exterior of the valve springs for damage, and replace if
necessary.
z Functional check
-
Measure free length and spring
tension with a valve spring
tester.
(Refer to appendix)
-
Measure the spring inclination
with a square.
-
Compare the measured value
with the standard value to
determine whether to replace
or repair.
Valve spring
inclination
Standard
Limit
1.0 mm
2.0 mm
3.2.4. Rocker arm shaft assembly
1) Rocker arm shaft
z Rocker arm shaft run-out
Place the rocker arm shaft on two
V blocks and inspect the shaft for
bend using a dial gauge.
If the amount of this run-out is
small, press the shaft with a bench
press
to
correct
the
run-out
Replace the shaft if the measured
value exceeds the limit.
Limit
0.2 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Rocker arm shaft diameter
P With an outside micrometer,
measure the rocker arm shaft
diameter at the point where the
rocker arms have been installed.
Replace the rocker arm if the
amount of wear is beyond the
specified limit.
Standard
Limit
φ23.978 ∼ φ23.959 mm
φ 23.75 mm
2) Rocker arm
z Visual check
Visually check the face of the
rocker arm in contact with the
valve stem end for scores and step
wear. If the wear is small, correct it
with an oil stone or grinding paper
of fine grain size. Rocker arm with
a considerable amount of step
wear should be replaced.
z Diameter of the rocker arm bushing
Measure the inside diameter of the
rocker arm bushing with an inside
micrometer or vernier calipers, and
compare the measured values with
the rocker arm shaft diameter. If
the clearance exceeds the limit,
replace either bushing or shaft,
whichever worn more.
< Clearance >
Standard
Limit
0.020 ∼ 0.093 mm
0.2 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3) Tappet and push rod
z Clearance
Measure the clearance of the tappet and tappet holes of the cylinder block. If the
value is beyond the specified limit, replace tappets.
Standard
Limit
0.035 ∼ 0.077 mm
0.15 mm
z Visual check of tappet
Visually check the face of the
tappets in contact with the cam for
pitting, scores or cracks, and
replace if severely damaged. If the
amount of cracks or pitting is small,
correct with an oil stone or grinding
paper.
z Outside diameter
With
an
measure
outside
the
micrometer,
tappet
outside
diameter If the measured value is
beyond the limit, replace tappets.
Tappet Dia.
φ 19.944 ∼ φ 19.965 mm
Standard
Limit
Tappet
0.035 ∼ 0.077 mm 0.15 mm
Clearance
z Push rod run-out
Limit
0.3 mm or less
Use a feeler gauge to measure the
push rod run-out.
Roll the push rod along a smooth
flat surface as shown in the figure.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.2.5. Cam shaft
1) Cam
z Cam lobe height
Standard
Cam lobe height
(C)
Intake
φ59.86 ∼ φ59.88 mm
Exhaust
φ59.86 ∼ φ59.88 mm
φ59.86 ∼ φ59.88 mm
Cam journal diameter (A,B)
Limit
φ49.5 mm
φ59.52 mm
Use a micrometer to measure the
cam
lobe
height
and
journal
diameter.
If the measured number is less
than
the
specified
limit,
the
camshaft must replaced.
z Cam surface
Inspect the cam face for scratch or
damage.
Slight step wear or damage on the
cam face may be corrected with oil
stone or oiled grinding paper. But,
replace if severely damaged.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2) Cam shaft
z Clearance between camshaft journal and camshaft bush
-
With an outside micrometer,
measure the camshaft journal
diameter.
-
Measure the inside diameter of
the camshaft bushing on the
cylinder block using a cylinder
bore indicator, and compare
the measured value with the
camshaft outside diameter to
determine the clearance.
< Clearance >
-
Standard
Limit
0.050 ∼ 0.128 mm
0.2 mm
Replace the bushing if the
measured value is beyond the
specified limit.
z Run-out
Support the camshaft on two V
blocks and check for run-out using
a dial indicator. Correct or replace
the cam shaft if the amount of runout is beyond the value indicating
need for servicing.
Standard
Limit
0.05 mm
0.2 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3) Cam shaft end play
z Push the thrust plate toward the
cam gear.
z With a feeler gauge, measure the
clearance between the thrust plate
and camshaft journal.
z If the end play is excessive,
replace the thrust plate.
Standard
Limit
0.13 ∼ 0.27 mm
0.30 mm
3.2.6. Crank shaft
1) Defect check
z Visually check the crankshaft journal and crank pins for scores or cracks.
z Using a magnetic particle test and color check, inspect the crankshaft for cracks,
and replace the crankshaft which has cracks.
2) Wear
z With
an
measure
outside
the
micrometer
diameter
of
the
crankshaft journals and pins in the
directions as shown, and compare
the measured values to determine
the amount of wear.
z If the amount of wear is beyond
the limit, have the crankshaft
ground
and
install
undersize
bearings. However, if the amount
of wear is within the limit, you can
correct the wear using an oil stone
or oiled grinding paper of fine grain
size. (Be sure to use grinding
paper which has been immersed in
oil.)
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Standard
Limit
Journal diameter
φ95.966 ∼ φ95.988 mm
φ94.966 mm
Pin diameter
φ82.966 ∼ φ82.988 mm
φ81.966 mm
* Undersize bearings available
‹ Standard
‹ 0.25 (Inside diameter is 0.25 mm lesser than the standard size.)
‹ 0.50 (Inside diameter is 0.50 mm lesser than the standard size.)
‹ 0.75 (Inside diameter is 0.75 mm lesser than the standard size.)
‹ 1.00 (Inside diameter is 1.00 mm lesser than the standard size.)
Undersize bearings are available in 4 different sizes as indicated above,
and the crankshaft can be reground to the above sizes.
NOTE :
When regrinding the crankshaft as
described below, the fillet section
'R' should be finished correctly.
Avoid sharp corners or insufficient
fillet.
* Standard values of 'R'
Crankshaft Pin 'R': 4.5
Crankshaft journal 'R': 4
3) Crankshaft run-out
z Support the crankshaft on V blocks.
z Turn the crankshaft with a dial
indicator placed on the surface
plate and take the amount of
crankshaft run-out.
Standard
Limit
0.05 mm
0.1 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.2.7. Crank shaft bearing and connection rod bearing
1) Visual check
Visually check the crankshaft bearing and connecting rod bearing for scores,
uneven wear or damage.
2) Oil clearance between crankshaft and bearing.
z Main bearing clearance
Install the main bearing in the
cylinder block, tighten the bearing
cap
to
specified
torque,
then
measure the inside diameter.
Torque
30 kg.m
Standard Dia.
φ96.06 ∼ φ96.108 mm
Compare the two values obtained
through
measurement
of
main
bearing inside diameter with the
outside diameters of crankshaft
journals
to
determine
the
oil
clearance.
< Main bearing oil clearance >
Standard
Limit
0.072 ∼ 0.142 mm
0.25 mm
z Connecting rod bearing clearance
Install the connecting rod bearing
in the connecting rod bearing cap,
tighten the connecting rod cap
bolts to the specified torque, then
measure the inside diameter.
Torque
28 kg.m
Standard
φ83.02 ∼ φ83.092 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Compare the two values obtained
through
measurement
of
connecting
rod
bearing
inside
diameter
with
the
outside
diameters of crankshaft pins to
determine the oil clearance.
Standard
Limit
0.049 ∼ 0.119 mm
0.20 mm
z If the clearance deviates from the specified range, have the crankshaft journals
and pins ground and install undersize bearings.
3) Bearing spread and crush
z Inspection
Visually
check
bearing
and
the
crankshaft
connecting
rod
bearing for scores, uneven wear or
damage.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Crankshaft bearing crush
Install the bearing and cap in the
cylinder block, retighten the bolts
to specified torque, unscrew out
one bolt completely, then measure
the clearance between the bearing
cap and cylinder block using a
feeler gauge.
0.15 ∼ 0.25 mm
Standard
z Connecting rod bearing crush
Install the bearing and cap in the
connecting rod big end, retighten
the
bolts
to
specified
torque,
unscrew out one bolt completely,
then
measure
the
clearance
between the bearing cap and
connecting rod big end using a
feeler gauge.
Standard
0.086 ∼ 0.116 mm
4) Crank shaft end play
z Assemble the crankshaft to the
cylinder block.
z With
a
dial
gauge,
measure
crankshaft end play.
Standard
Limit
0.15 ∼ 0.325 mm
0.5 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.2.8. Piston
1) Visual check
Visually check the pistons for cracks, scuff or wear, paying particular attention to the
ring groove.
2) Clearance between the piston and cylinder liner
z With
an
measure
outside
the
micrometer,
piston
outside
diameter at a point 18 mm away
from the lower end of piston skirt in
a direction at a right angle to the
piston pin hole.
Standard
φ122.854 ∼ φ122.886 mm
z Using a cylinder bore gauge,
measure
cylinder
liner
inside
diameter at 3 points (cylinder top
ring contacting face, middle, and
oil ring contacting face on BDC) in
a direction at an angle of 45°. Take
the mean value with the largest
and smallest values excepted.
Standard
Limit
φ123 ∼ φ123.023 mm
φ123.223 mm
z The clearance is computed by
subtracting
the
piston
outside
diameter from the cylinder liner
inside diameter. Replace either
piston or cylinder liner, whichever
damaged more, if the clearance is
beyond the specified limit.
<Clearance between piston and liner>
Standard
0.114 ∼ 0.169 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.2.9. Piston rings
1) Visual check
Replace the piston rings with new ones if detected worn or broken when the engine
is overhauled.
2) Piston ring gap
z Insert the piston ring into the upper
portion of the cylinder liner bore so
that it is held at a right angle to the
cylinder liner wall.
z Measure the piston ring gap with a
feeler gauge.
Standard
Limit
Top ring
0.30 ∼ 0.45 mm
1.5 mm
2nd ring
0.35 ∼ 0.50 mm
1.5 mm
Oil ring
0.30 ∼ 0.50 mm
1.5 mm
Replace piston rings with new
ones if the gap is beyond the limit.
3) Piston ring side clearance
z Fit the compression ring and oil
ring in the piston ring groove.
z With a feeler gauge, measure side
clearance
of
each
ring,
and
replace either the ring or piston if
the measured value is beyond the
specified limit.
Standard
Top ring
Limit
-
2nd ring
0.07 ∼ 0.102 mm 0.15 mm
Oil ring
0.05 ∼ 0.085 mm 0.15 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4) Piston ring tension
With a tension tester, measure piston
ring tension. Replace the piston ring if
the measured value is beyond the
limit.
Standard
2.27 ∼ 3.41 kg
2.0 ∼ 3.0 kg
4.03 ∼ 5.57 kg
Top ring
2nd ring
Oil ring
3.2.10. Piston pin
1) Wear
Measure the amount of wear on the
piston pin at the points as shown. If
the measured values are beyond the
limit (0.005 mm or greater), replace
the pin.
Standard
φ 44.995 ∼
φ 45.0 mm
Limit
φ 44.990 mm or less
2) Clearance
Measure the clearance between the
piston pin and connecting rod bushing,
and replace either of them, whichever
damaged more, if the measured value
is beyond the limit.
Standard
0.011 mm
3) Condition check
Check the engaged condition of the
piston and piston pin. If it is possible
to force the pin into the piston heated
with piston heater, the piston is
normal.
When replacing the piston, be sure to
replace the piston pin together.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.2.11. Connecting rod
1) Distorsion
Check
the
connecting
rod
for
distortion. As shown in the figure
below, install the connecting rod to
the connecting rod tester, and check
for distortion using a feeler gauge. If
the connecting rod is found distorted,
never re-use it but replace with a new
one.
2) Holes alignment (parallelism)
Measure
the
alignment
of
the
connecting rod small bushing hole
with connecting rod big end hole. At
this time also, use both connecting
rod tester and feeler gauge.
Standard
Limit
0.05 mm
0.1 mm or less
3) Wear
z Assemble the connecting rod to
the
crankshaft
connecting
rod
and
big
measure
end
side
clearance using a feeler gauge.
z Assemble the connecting rod to
the
piston
and
measure
connecting rod small end side
clearance.
z If
the
measured
values
are
beyond the limit, replace the
connecting rod.
Limit
0.5 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3. Reassembly
3.3.1. General precautions
z Wash clean all the disassembled parts, particularly oil and water ports, using
compressed air, then check that they are free from restrictions.
z Arrange the general and special tools in order for engine assembly operation.
z To wet each sliding part, prepare the clean engine oil.
z Prepare service materials such as sealant, gaskets, etc.
z Discard used gaskets, seal rings, and consumable parts, and replace with new
ones.
z Apply only the specified torque for bolts in the specified tightening order and
avoid over-tightening.
z Be sure to check that all the engine parts operate smoothly after being
reassembled.
z Check the bolts for looseness after preliminary reassembly.
z After completing the engine reassembly operation, check if there is missing parts
or shortage of parts.
z Keep your hands clean during the working.
3.3.2. Cylinder block
z Cover the floor of the workshop with wood plate or thick paper to prevent damage
to the cylinder head and place the cylinder block with the head fitting surface
facing downward.
3.3.3. Oil spray nozzle
z Tighten and assemble the oil spray
nozzle flange with fixing bolts using
the spray nozzle jig.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.4. Tappet and cam shaft
z Undercool a new bush with dry ice
for about 2 hours and press it into
position in the cylinder block using
a bench press. After the pressing
operation,
measure
the
inside
diameter of the cam bush to check
if it is not deformed.
z Apply engine oil to the entire face
of the tappets and slide them into
the tappet holes on the cylinder
block.
z Wet the cam bush inside diameter
and camshaft with oil, and carefully
assemble them while turning the
camshaft.
z Check to see that the camshaft
rotates smoothly.
3.3.5. Tappet
z Install the main bearing machined
with two holes in the cylinder block
so that the key is aligned with the
key groove, then apply oil to the
bearing surface.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Heat the crankshaft gear for at
least 10 minutes to 120°C, then
apply sealant (Loctite # 641) to the
inside wall of the heated crankshaft
gear evenly before inserting it to
the end of crankshaft.
z Semi-tighten a bolt at both sides of
the crankshaft, apply engine oil to
journals and pins, then assemble
the crankshaft with the cylinder
block by tightening the fixing bolts.
z Install the oiled thrust washers with
the oil groove facing outward.
z Install
the
bearing
and
thrust
washers to the bearing cap and
apply oil to the bearing and thrust
washers.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Install the bearing cap by matching
the cylinder block No. with the
bearing cap No.
z Apply oil to the entire part of the
bearing cap bolts, then tighten in
tightening sequence to specified
torque.
Torque
30 kg.m
z After semi-tightening both bolts
evenly, tighten them diagonally to
about 15 kg.m for the first stage
and 25 kg.m for the second stage
respectively,
then
tighten
them
completely to the specified torque
using a torque wrench.
z Tighten the bearing cap in the
sequence of 4-3-5-2-6-1-7.
z Check to see that the assembled
crankshaft turns smoothly.
3.3.6. Flywheel housing
z Temporarily install the guide bar on
the cylinder block.
z Apply gasket to the cylinder block.
z Using the dowel pin and guide bar,
install the flywheel housing and
tighten the fixing bolts in a diagonal
sequence to specified torque.
Torque
12 kg.m
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.7. Rear oil seal
z Apply lubricating oil to the outside
of the oil seal and flywheel housing
inside diameter and fit them over
the crank shaft, then assemble the
oil seal using an oil seal fitting jig.
3.3.8. Flywheel
z Install a guide bar into a bolt hole
on the crank shaft, and lift the
flywheel to align the dowel pin with
the pin hole on the flywheel for
temporary assembly operation.
z Install bolts in the remaining holes,
take out the guide bar, then install a
bolt in the hole where the guide bar
had been inserted.
z Tighten the fixing bolts using a
torque
wrench
in
a
diagonal
sequence to specified torque.
Torque
4 kg.m
3.3.9. Timing gear case
z Mount gasket using dowel pin on
the cylinder block.
z Install the timing gear case by
aligning the dowel pin with the
dowel pin hole on the timing gear
case.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.10. Fuel injection pump drive gear assembly
z Mount gasket by aligning the bolt
holes with the pin holes on the
bearing housing.
z Tighten up the fixing bolts in the
direction of fuel injection pump.
3.3.11. Oil cooler
z Install the oil pump idle gear onto
the No.7 bearing cap.
z Install a thrust washer over the
camshaft and assemble the cam
gear by aligning it with camshaft
key groove.
Torque
2.2 kg.m
z With the oil port on the idle gear pin
facing the cylinder block, install the
idle gear pin.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Install the idle gear by coinciding
the marks impressed on the crank
gear, cam gear, fuel injection pump
drive gear, and idle gear.
z Install a thrust washer on the idle
gear and tighten to specified torque.
Torque
6.2 kg.m
z Check and adjust the amount of
backlash between gears using a
feeler gauge.
Torque
0.15 ∼ 0.25 mm
3.3.12. Timing gear case cover
z Install dowel pin on the timing gear
case.
z Mount a gasket by aligning the
fixing bolt holes with those on the
gasket.
z Align the dowel pin with the cover
pin hole, then install the cover with
light tap.
z Tighten the fixing bolts beginning
with the oil pan fitting face.
3.3.13. Front oil seal
z Apply lubricating oil to the outside
of the oil seal and timing gear case
inside diameter and fit them over
the crankshaft, then assemble the
oil seal using an oil seal fitting jig.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.14. Cylinder liner
z Stand the cylinder block so that the
flywheel faces downward.
z Thoroughly clean the liner flange
fitting surface and bore inside with
compressed air to prevent the entry
of foreign substances.
z After the cleaning operation, make
the cylinder liner dried up and push
it into the cylinder block by hand.
z Wet the liner inside diameter with
engine oil.
3.3.15. Piston and connecting rod
z Use a piston heater to heat the
piston approximately 100 °C (212
°F) for 5 minutes.
z Align the piston pin hole with the
oiled connecting rod small end and
press the piston pin (by lightly
tapping with a rubber hammer) to
assemble the connecting rod with
the piston.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Noting the direction of the piston,
make the longer side (machined
with key groove on the bearing) of
the connecting rod big end and the
mark of impressed on the inside of
the piston face each other in
opposite directions. On the piston
head surface, the longer side of
connecting rod
big end
is in
opposite direction from the valve
seating surface as well as in the
same direction with the narrow
margin of combustion chamber.
z Install the snap rings and check to
see that it is securely assembled.
z Install the piston ring in the piston
using piston ring pliers.
z Identify the mark "Y" or "TOP" on
the ring end to prevent the top and
bottom of the piston ring from being
interchanged and make the marked
portion face upward.
z Adjust the angle among individual
piston ring gaps to 90° and fit a
piston assembling jig onto the
piston, Use care not to match the
ring gaps with the pin direction.
z Install the bearing by aligning it with
the connecting rod key groove and
apply oil to the bearing and piston.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Position the valve seating surface
toward the tappet hole and insert
the piston with hand.
Use care not to damage the
cylinder
liner
and
piston,
and
slightly lift and insert the piston into
the cylinder so that the ring may
not be damaged by the fillet of the
liner.
z Install the bearing in the connecting
rod cap and apply oil.
z Make sure that the manufacture
serial numbers impressed on the
connecting rod cap and connecting
rod big end are identical, and install
the connecting rod cap by aligning
it with dowel pin.
z Wet the fixing bolts with oil, semitighten them with hand, tighten
them to 15 kg.m for 1st stage and
22 kg.m for 2nd stage respectively,
and finally to specified torque.
Torque
28 kg.m
z Move the bearing cap with hand,
and release and reassemble it if no
movement is detected.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.16. Relief valve
z Assemble the relief valve.
3.3.17. Oil pump and oil pipe
z Install a dowel pin in the No.7
bearing cap, then assemble the oil
pump with specified torque.
Torque
4.4 kg.m
z Assemble the oil suction pipe with
the delivery pipe, then install the
bracket on the bearing cap.
3.3.18. Oil pan
z Mount gasket and put the oil pan
thereon.
z Place stiffeners and tighten bolts.
z Align the bolt holes with gasket
holes to prevent damage to the
gasket and tighten to specified
torque.
Torque
2.2 kg.m
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.19. Intake and exhaust valves
z Identify the marks of "IN" and "EX"
impressed
on
the
valve
head
before assembling the valve with
the valve head.
z With a valve stem seal fitting jig,
assemble the valve stem seal with
the valve guide.
z After installing valve springs and
spring retainer, press the retainer
with a jig, then install cotter pin.
z Tap the valve stem lightly with a
rubber hammer to check that the
valve is assembled correctly.
3.3.20. Nozzle tube
z Apply sealant (LOCTITE # 620) to
the nozzle tube and place the Oring over the cylinder head fitting
face on the nozzle tube, then
install the nozzle tube in the
cylinder head.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Install a guider of the nozzle tube
insert ass’y (Guider + Expander)
the cylinder head, then tighten the
nozzle fixing nuts.
z Apply engine oil to an expander
and install it onto the special tool
(guider).
z Tighten the bolts until the expander
is forced out of the cylinder head
bottom.
z After mounting the nozzle tube,
make a hydraulic test to check for
water leaks.
Test pressure
2 kg/cm2
3.3.21. Cylinder head
z Install the injection nozzle fixing
stud bolts and water pipe fixing
stud bolts.
z Clean the head bolt holes on the
cylinder block with compressed air
to remove foreign substances and
thoroughly clean the gasket fitting
face of the cylinder block.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Install head gasket, with 'TOP'
mark facing upward, on the cylinder
block by aligning the holes with
dowels.
z Check the inside of combustion
chamber for foreign substances,
and carefully mount the cylinder
head assembly in the block by
aligning the dowel pin with the
dowel pin hole. Be careful not to
damage the head gasket. If the
dowel pin is not in alignment, lift
the cylinder head again and then
remount it.
z Coat the head bolts with engine oil,
then
tighten
them
in
proper
sequence to the specified torque.
<Cylinder Head Bolts>
Type 1
Type 2
Specification
Torque
M14×1.5×153 M14×1.5×150
6 kg.m
24.5 kg.m
+180°+150°
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Coat the push rod with engine oil and insert it into the push rod hole.
z Adjust the valve clearance as following guide.
<Guide for valve clearance adjustment>
„
After letting the #1 cylinder's piston come at the compression top dead center by
turning the crankshaft, adjust the valve clearances.
„
Loosen the lock nuts of rocker arm adjusting screws and push the feeler gauge
of specified value between a rocker arm and a valve stem and adjust the
clearance with adjusting screw respectively and then tighten with the lock nut.
„
As for the valve clearance, adjust it when in cold, as follow.
Model
DE12T
P126TI
„
Intake Valve
Exhaust Valve
0.3 mm
0.3 mm
-
By cranking the engine, let #6 cylinder's valves overlap.
-
In time, adjust the valve clearance corresponding to “
-
Adjust the valve clearance corresponding to “
-
After reinsuring the valve clearances, retighten if necessary.
” of lower lists.
” of lower lists.
No. 1 Cylinder is located at the side where flywheel was installed.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Adjust valve clearance with a feeler
gauge and tighten the fixing nuts to
specified torque.
Torque
4.4 kg.m
3.3.22. Rocker arm assembly
z Apply lubricating oil to the rocker
arm bush and shaft, and assemble
the intermediate bracket with the
rocker arm using fixing bolts.
Torque
z Semi-install
4.4 kg.m
valve
clearance
adjusting bolts onto the rocker arm.
z Install
the
spring,
rocker
arm,
bracket, rocker arm, spring, washer,
and snap ring in the described
sequence.
z Install the rocker arm and bracket
in the same direction.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.23. Injection nozzle
z Install the dust seal with its round
portion facing downward.
z Mount a seal ring (0.5 mm) on the
seal ring seating surface of the
nozzle tube and assemble nozzle
holder assembly with the stud bolt
with
the
nozzle
pipe
installing
direction facing outward.
z Be sure to follow the specified
torque.
Torque
1.0 kg.m
3.3.24. Oil cooler
z Install the oil cooler onto the oil
cooler cover.
z Carefully
apply
the
gasket
to
prevent oil leakage.
z Do not damage the gasket and
install the cover onto the cylinder
block.
z Connect a connection pipe between
the water pump and oil cooler.
3.3.25. Oil filter
z Install the oil filter onto the cylinder
block, and tighten the fixing bolts.
z With the hollow screw, assemble
the oil pipe connected between the
oil cooler and cylinder block.
z Install a connection pipe between
the oil cooler and oil filter.
z Install the oil cooler connecting
pipe.
z Install packing and assemble the
cartridge using a filter wrench.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.26. Injection pump
z Install the injection pump bracket in
the cylinder block.
z After measuring the amount of runout with an alignment setting jig,
disassemble the bracket, adjust the
shims, then reassemble it.
Run out
0.2 mm or less
z Mount the top/bottom adjusting
shims in the bracket and then
mount the fuel injection pump.
z Tighten the fixing bolts in a diagonal
sequence to specified torque.
Torque
4.4 kg.m
z Turn the flywheel until No. 1 piston
is placed in the "OT" position of
notch marks on the flywheel, and
then
turn
again
the
flywheel
clockwise until showing the notch
mark
of
the
corresponding
to
right
the
figure
injection
timing is aligned with the pointer (↓)
on the flywheel housing.
DE12T P126TI
Fuel injection
timing
(B.T.D.C static)
12°
12°
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Turn the timer until the notch mark
of the indicator plate attached to
the fuel injection pump is aligned
with the notch mark of the timer.
z Tighten the Coupling fixing bolts
and nuts to specified torque.
Torque
6.0 kg.m
z Tighten the drive shaft connecting
flange fixing bolts to specified
torque
7.5 ∼ 8.5 kg.m
Torque
z Install the oil delivery pipe and
return pipe.
3.3.27. Vibration damper end pulley
z Install the vibration damper on the
crankshaft pulley.
z Install
the
crankshaft
pulley
assembly on the crankshaft, then
tighten the bolts and thrust washers.
Torque
13.4 kg.m
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.28. Fan drive pulley
z Install the fan drive pulley onto the
timing gear case cover.
3.3.29. Water pump
z Mount a new O-ring.
z Install the water pump drive pinion
over the PTO (power take-off)
spline.
z Connect water pipes and by-pass
pipe to the water pump.
z Connect
a water
pipe
to
the
expansion tank.
3.3.30. Power take-off
z Assemble the power take-off sub
assembly.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.31. Exhaust manifold
z Install the exhaust manifold gasket
over the stud bolts by aligning the
gasket with the exhaust port on the
cylinder head so that the face and
back
of
the
gasket
can
be
positioned correctly.
z Semi-assemble
manifold
and
the
install
exhaust
the
heat
resisting plate.
z First, install the nuts and then place
an additional nut on each of them
to prevent looseness.
3.3.32. Turbocharger
z Fit a new gasket over the stud bolts
of the exhaust manifold before
tightening those turbocharger fixing
bolts.
z Install the oil supply pipe and return
pipe.
z Semi-assemble the bracket to the
intake pipe, connect a rubber hose
between
the
turbocharger
and
intake pipe using rubber hose, then
assemble the bracket completely.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.33. Starter
z Assemble the starter in position on
the flywheel housing.
3.3.34. Intake manifold
z Fit a gasket on the intake manifold
before
assembling
the
intake
manifold.
3.3.35. Injection pipe
z Semi-assemble a nut at both ends
of the fuel high pressure pipe and
tighten them up one by one to
specified torque.
Torque
13.4 kg.m
z Tighten hollow screws to assemble
the fuel return pipe.
z Assemble the fuel return hose on
the fuel injection pump.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.36. Fuel filter
z Assemble the fuel filter with the
intake manifold.
z Assemble
the
fuel
feed
hose
according to the direction of an
arrow impressed on the fuel filter
head so that fuel can be fed in the
sequence of FUEL FEED PUMP →
FUEL
FILTER
→
FUEL
INJECTION PUMP.
3.3.37. Cylinder head cover
z Assemble the cover packing with
the cover, install the cover on the
head, then tighten the fixing bolts in
sequence to specified torque.
Torque
1.5 kg.m
z Assemble the breather hose with
PCV valve.
3.3.38. Alternator
z Install
the
alternator
mounting
bracket.
z Install the alternator with fixing bolts
to the mounting bracket.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3.3.39. Cooling fan
z Install the cooling fan and flange,
then tighten the fixing boltd.
3.3.40. V- Belt
z Install the V-belt on the crank pulley,
alternator pulley and fan drive
pulley.
z Adjust the V-belt tension using the
tension adjusting bolt.
3.3.41. Oil level gauge
z Assemble the oil level gauge and
guide tube on the oil pan.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4. Commissioning and Operation
4.1. Preparation
At the time of initial commissioning of a new or overhauled engine make sure to have
observed the "Technical Information for the installation DOOSAN generator engines".
z Oil filler neck on cylinder head cover
Before daily starting of the engine, check the fuel, coolant and oil level, replenish
if necessary.
The notches in the dipstick indicate the highest and lowest permissible oil levels
The oil required in the sump is specified in the "Engine Specification”.
NOTE:
The oil required to fill the oil fillers and pipes depends upon the engine and
use and must be determined individually at the time of initial commissioning.
(Make the Max and Min. marks of the determined quantity on the oil level
gauge.)
z Cleanliness
Ensure outmost cleanliness when handling fuels, lubricants and coolants.
4.2. Breaking-in
4.2.1. Operation of a new engine (Break-In)
Because the sliding surfaces of a new engine are not lapped enough, the oil film can
be destroyed easily by overload or overspeed and the engine life-time may be
shortened.
Therefore the following things must be obeyed by all means.
Up to the first 2,000 km (150 hours)
„ Engine should be run at fast idling until the temperature of the engine becomes
normal operating condition.
„ Overload or continuous high speed operation should be avoided.
„ High speed operation with no load should be prevented.
„ Abrupt start and stop of the engine should be avoided.
„ Engine speed must be under 70% of its maximum speed.
„ Maintenance and inspection must be accomplished thoroughly.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4.2.2. Check points for break-in
During the break-in (the initial running of the engine) period, be particularly
observant as follows:
1) Check engine oil level frequently. Maintain oil level in the safe range, between
the "min." and “max." marks on dipstick.
NOTE:
If you have a problem getting a good oil level reading on dipstick, rotate
dipstick 180° and re-insert for check.
2) Watch the oil pressure warning lamp. If the lamp blinks, it may be the oil pick-up
screen is not covered with oil. Check oil dipstick. Add oil to the oil pan, if required.
Do not overfill. If level is correct and the status still exists, see your DEALER for
possible switch or oil pump and line malfunction.
NOTE:
Oil pressure will rise as RPM increases, and fall as RPM decreases. In addition,
cold oil will generally show higher oil pressure for any specific RPM than hot
oil. Both of these conditions reflect normal engine operation.
3) Watch the engine water temperature gauge and be sure there is proper water
circulation. The water temperature gauge needle will fluctuate if water level in
expansion tank is too low.
At the end of the break-in period, remove break-in oil and replace the oil filter.
Fill oil pan with recommended engine oil. Refer to following table.
<Engine oil capacity>
Oil pan (only)
DE12T
23 liter
P126TI
23 liter
4.2.3. Operating after break-In
When starting a cold engine, always allow the engine to warm up gradually. Never
run the engine at full throttle until the engine is thoroughly warmed up. Be sure to
check the oil level frequently during the first 50 hours of operation, since the oil
consumption will be high until the piston rings are properly seated.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4.3. Inspections after Starting
During operation the oil pressure in the engine lubrication system must be monitored.
If the monitoring devices register a drop in the lube oil pressure, switch off the engine
immediately.
And the charge warning lamp of the alternator should go out when the engine is
running.
z Do not disconnect the battery or pole terminals or the cables!
z If, during operation, the battery charge lamp suddenly lights up, stop the engine
immediately and remedy the fault in the electrical system!
z Engine should be stopped if the color, the noise or the odor of exhaust gas is not
normal.
z Confirm the following things through warning lamps and gauge panel.
4.3.1. Pressure of lubricating oil
The normal pressure comes up to 1 kg/cm2 (1.0 bar) at idling and 3 ~ 5 kg/cm2 (3.0
~ 4.9 bar) at maximum speed. If the pressure fluctuates at idling or does not reach
up to the expected level at high speed, shut down the engine immediately and check
the oil level and the oil line leakage.
4.3.2. Temperature of cooling water
The cooling water temperature should be 78 ~ 85 °C in normal operating conditions.
Abnormally high cooling water temperature could cause the overheating of engine
and the sticking of cylinder components. And excessively low cooling water
temperature increases the fuel consumption, accelerates the wears of cylinder liners
and shortens the engine life-time.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4.4. Operation in Winter Time
Pay special attention to the freezing of cooling water and the viscosity of lubricating
oil.
4.4.1. Prevention against the freeze of cooling water
When not using anti-freeze, completely discharge the whole cooling water after
engine running. The freeze of cooling water causes the fatal damages of the engine.
Because the anti-freeze is used to prevent cooling water from freeze, consult "The
amount of anti-freeze".
4.4.2. Prevention against excessive cooling
Drop of thermal efficiency caused by excessive cooling increases fuel consumption,
therefore prevent the engine from excessive cooling. If the temperature of coolant
does not reach to normal condition (78 ~ 85 °C) after continuous operation, examine
the thermostat or the other cooling lines.
4.4.3. Lubricating oil
As cold weather leads to the rise of oil viscosity, engine speed becomes unstable
after starting. Therefore the lubricating oil for winter should be used to prevent this
unstability. Refer to “Lubricating System section”.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4.5. Tuning the Engine
The purpose of an engine tune-up is to restore power and performance that's been
lost through wear, corrosion or deterioration of one or more parts or components. In
the normal operation of an engine, these changes can take place gradually at a
number of points, so that it's seldom advisable to attempt an improvement in
performance by correction of one or two items only. Time will be saved and more
lasting results will be obtained by following a definite and thorough procedure of
analysis and correction of all items affecting power and performance.
Economical, trouble-free operation can better be ensured if a complete tune-up is
performed once every years, preferably in the spring. Components that affect power
and performance to be checked are:
z Components affecting fuel injection ;
Nozzle, delivery valve, fuel filter, water separator, etc.
z Components affecting Intake & exhaust ;
Air filter, inter-cooler, turbo, silencer, etc.
z Components affecting lubrication & cooling ;
Air & oil filter, anti- freeze, etc.
4.6. Maintenance and Care
4.6.1. Periodical inspection and maintenance
In order to insure maximum, trouble-free engine performance at all times, regular
inspection, adjustment and maintenance are vital.
z Daily inspections in below figure should be checked every day.
z The maintenance should be executed thoroughly at regular internals.
(refer to appendix “General Engine Inspection Cycle”.)
4.6.2. Exchanging of lubrication oil
Engine oil and the oil filter are important factors affecting engine life. They affect
ease of starting, fuel economy, combustion chamber deposits and engine wear.
Refill and drain oil pan every 50 hours of operation or 6 months whichever occurs
first. At the end of the break-in period (50 hours), change the oil sump oil and replace
the oil filter.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4.6.3. Oil level
Check the oil level in the engine sump
daily with a dipstick.
z The
notches
in
dipstick
must
indicate the oil level between the
max. and the min. permissible.
z The oil level should be checked
with the engine horizontal and only
after it has been shut down for
about 5 minutes.
z Examining the viscosity and the contamination of the oil smeared at the dipstick
replace the engine oil if necessary.
CAUTION:
Do not add so much engine oil that the oil level rises above the max. marking
on the dipstick. Over lifting will result in damage to the engine.
4.6.4. Oil exchange procedure
While the oil is still hot, exchange oil as follows:
z Take out the oil dip dipstick.
z Remove the drain valve from oil
pan and the drain plug form oil filter
head, then drain out the engine oil
into a container.
z Reassemble the drain valve with
the oil pan and the drain plug with
oil filter head after draining out the
engine oil.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Refill with new engine oil at the oil
filler neck on the head cover and
the lubricating oil in accordance
with the oil capacity of the engine
through oil filler. Be careful about
the mixing of dust or contaminator
during the supplement of oil. Then
confirm
that
oil
level
gauge
indicates the vicinity of its maximum
level.
z For a few minutes, operate the engine at idling in order to circulate oil through
lubrication system.
z Thereafter shut down the engine. After waiting for about 10 minutes measure the
quantity of oil and refill the additional oil if necessary
4.6.5. Replacement of oil filter cartridge
At the same times of oil exchanges,
replace the oil filter cartridge.
z Drain engine oil by loosening the
drain plug on the filter head.
CAUTION:
Don't forget tightening the drain
plug after having drained engine oil.
z Loosen the oil filter by turning it
counter-clockwise
with
a
filter
wrench.
z With a rag wipe clean the fitting
face of the filter body and the oil filter body so that new oil filter cartridge can be
seated properly.
z Lightly oil the O-ring and turn the oil filter until sealing face is fitted against the Oring. Turn 1-1/4 turns further with the filter wrench.
NOTE:
It is strongly advisable to use DOOSAN genuine oil filter cartridge for
replacement.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4.7. Cooling System
The coolant must be changed at intervals of 1,200 hours operation or six months
whichever comes first. If the coolant is being fouled greatly, it will lead an engine
overheat or coolant blow off from the expansion tank.
4.7.1. Coolant draining
z Remove the pressure cap
z Open the drain valve at the radiator
lower part to drain the coolant as
the right figure.
z Loosen the coolant drain plug
Loosen the coolant drain plug of the
cylinder block.
CAUTION:
When removing the pressure filler cap while the engine is still hot, cover the
cap with a rag, then turn it slowly to release the internal steam pressure This
will prevent a person from scalding with hot steam spouted out from the filler
port.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
4.7.2. Cleaning of the cooling inside system circuit
(by authorized specialist personnel)
When the cooling system circuit are fouled with water scales or sludge particles, the
cooling efficiency will be lowered.
Investigations have shown that in many cases the poor condition of the coolant and
/or the cooling system accounts for damage to the water pump mechanical seal, The
poor condition of the cooling system is normally due to use of unsuitable or no antifreezing agents and corrosion inhibitor or defect, not early enough replaced covers
for filler neck and working valves.
If twice in a short time the water pump of an engine develops leases or the coolant is
heavily contaminated (dull, brown, mechanically contaminated, grey or black sings of
a leakage on the water pump casing) clean the cooling system prior to removing that
water pump as follows.
a) Drain coolant.
b) Remove thermostats, so that the whole cooling system is immediately flown
through when cleaned.
c) Fill the cooling system with a mixture of potable water and 1.5% by volume of
cleaner. (Henkel P3T5175)
d) Warm up engine under load. After a temperature of 60°C is reached, run engine
for a further 15 minutes.
e) Drain cleaning fluid.
f)
Repeat steps c) and d).
g) Flush cooling system.
h) Replace drain plug by drain plug with a bore of 8mm diameter.
i)
Fill cooling system with hot water.
j)
Run engine at idle for 30 minutes. At the same time continuously replenish the
water leaking from the bore in drain plug by adding fresh water.
Periodically clean the circuit interior with a cleaner.
- Cooling system cleaning interval: Every 1,200 hours.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
4.8. Adjustment of Valve Clearance
4.8.1. General information
The valve clearances are to be adjusted at the times of the following situations.
z After initial 50 hour's operation.
z When the engine is overhauled and the cylinder heads are disassembled.
z When severe noise comes from valve train.
z When the engine is not normally operated, even though there is no trouble in the
fuel system. The valve clearance of the cold engine are as follows.
- Intake valves
: 0.3 mm
- Exhaust valves : 0.3 mm
4.8.2. Method of adjusting the valve clearance
1) Loosen the lock-nuts ① using a
ring spanner.
2) Insert a thickness gauge of 0.3 mm
between valve stem ② and rocker
arm ③.
3) Turn the adjusting bolts ④ using a
screw driver until the gauge can be
pulled out with some restriction.
4) After
the
adjustment
fix
the
adjusting bolt not to rotate and
tighten the lock-nut at the same
time.
5) Measure the clearance one more
time and if necessary adjust again.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
4.9. Fuel System
4.9.1. Fuel filter
z After every 1,200 hour of operation,
drain the water and sediment from
the fuel-water separator.
z Shut off the engine. Use your hand
to open the drain valve ⑥.
z Turn the valve counter clockwise
approximately 2 ∼ 3 turns until
draining occurs. Drain the filter
sump of water until close fuel is
visible.
z Turn the valve clockwise to close the drain valve. Do not over tighten the valve,
overtightening can damage the threads.
4.9.2. Replacement of fuel filter
z Clean the area around the fuel filter
head ③.
z Remove the fuel filter ② by turning
it
counter-clockwise
with
filter
wrench.
(Discard the used filter.)
z Remove
the
fuel
filter
thread
adapter seal ring ④.
z Use a clean lint free cloth to clean
the gasket surface of the fuel filter
head ③.
z Install the new thread adapter seal ring ④ supplied with the new filter.
z Use clean oil to lubricate the filter seal ⑤, and fill the new filter with clean fuel.
z Install the filter on the filter head ③.
z Tighten the filter until the gasket contacts the filter head surface.
z Tighten the filter on additional one-half to three-fourths of a turn with the filter
wrench, on as specified by the filter manufacturer.
NOTE:
Mechanical over tightening of the filter can distort the thread or damage the
filter element seal.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
4.9.3. Fuel system checks
z Fill the tank with the recommended fuel. Keeping tanks full reduces water
condensation and helps keep fuel cool, which is important to engine performance.
z Make sure fuel supply valves (if used) are open.
z To insure prompt starting and even running, the fuel system must be primed with
the fuel feed pump manually before starting the engine the first time, or after a
fuel filter change.
z Refill at the end of each day's operation to prevent condensation from
contaminating the fuel. Condensation formed in a partially filled tank promotes the
growth of microbial organisms that can clog fuel filters and restrict fuel flow.
z If the engine is equipped with a fuel water separator, drain off any water that has
accumulated. Water in fuel can seriously affect engine performance and may
cause engine damage. DOOSAN recommends installation of a fuel water
separator on generator units.
4.9.4. Fuel Contamination and water trap
z In the generator environment, the most likely fuel contaminants are water and
microbial growth (black "slime"). Generally, this type of contamination is the result
of poor fuel handling practices.
z Black "slime" requires water in the fuel to form and grow, so the best prevention is
to keep water content to a minimum in storage tanks.
z If diesel fuel which contains moisture is used the injection system and the cylinder
liners / pistons will be damaged. This can be prevented to same extent by filling
the tank as soon as the engine is switched off while the fuel tank is still warm
(formation of condensation is prevented). Drain moisture from storage tanks
regularly. Installation of a water trap upstream of the fuel filter is also advisable.
NOTICE:
A galvanized steel tank should never be used for fuel storage, because the fuel
oil reacts chemically with the zinc coating to form powdery flakes which can
quickly clog the fuel filters and damage the fuel pump and injection nozzles.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
4.9.5. Priming pump strainer cleaning
z Clean the priming pump strainer
every 200 operation hours.
z The strainer is incorporated in the
priming pump inlet side joint bolt.
z Clean
the
strainer
with
the
compressed air and rinse it in the
fuel oil.
4.9.6. Bleeding the fuel system
After the cleaning of the fuel filter or
after the engine stop by the lack of fuel,
the bleeding of the fuel system must
be executed by all means.
Bleed
the
system
by
manually
operating the priming pump with fuel
filter outlet joint bolt and injection pump
bleeder screw loosened.
z Press the feed pump cap repetitively until the fuel without bubbles comes out
from the bleeding valves.
z After the whole air is pulled out, close the valve of the filter.
z Confirm the resistance of fuel delivery by the repetition pressing of the feed pump
cap, Pressure and turn the feed pump cap simultaneously to close it.
4.9.7. Injection pump
z Check the fuel injection pump housing for cracks or breaks, and replace if
damaged.
z Check and see if the lead seal for idling control and speed control levers have not
been removed.
z No alterations must be made to the injection pump. If the lead seal is damaged
the warranty on the engine will become null and void.
z We strongly recommended that any faults developing in the injection pump should
be taken care of by authorized specialist personnel.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
4.10. Injection Nozzle Maintenance
(by authorized specialist personnel)
The injectors are designed to spray the
fuel delivered by the injection pump
directly into the spherical combustion
chamber in the piston crown.
The injector consists of the nozzle and
the nozzle holder.
A copper seal fitted to the injector
ensures gas-tight seating and good
heat dissipation.
The opening pressure of the nozzle is
adjusted by means of shims at the
compression spring.
z Install a nozzle to a nozzle tester.
z Check injection pressure, and adjust the nozzle using the adjusting shim if the
pressure does not meet the specified limit.
Engine Model
Injection nozzle pressure
DE12T
2
220 kg/cm
P126TI
1st : 160 kg/cm2
2nd : 220 kg/cm2
z Check nozzle spray patterns and replace if damaged.
CAUTION:
The injection lines are designed for high operating pressures and should thus
be handled with particular care.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z When mounting the pipes to the engine take care of good fitness.
z Do not bend pipes to permanent deformation (not for replacing the nozzles either).
z Do not mount any heavily bent pipes.
z Avoid bending the pipes at the ends by more than 2 to 3 degrees.
In case of faults in the injection system which might have resulted in excessive
operating pressures, not only the failed part but also the injection line has to be
replaced.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5. Maintenance of Major Components
5.1. Fuel Injection Pump
5.1.1. General information of fuel system
The fuel system consists of the fuel tank, injection pump, injection nozzle, fuel filter,
and fuel lines such as pipes and hoses necessary to connect those components.
1.
1a.
2.
3.
4.
5.
6.
Fuel filter
Fuel water drain plug
Air bleeding screw (for fuel filter)
Injection nozzle
Overflow tube
Fuel pipe (filter → injection pump)
Overflow valve
7.
8.
9.
10.
11.
12.
13.
Delivery pipe
Fuel pipe (manual pump → filter)
Fuel tank
Fuel return pipe
Suction pipe
Feed pump
Injection pump
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
5.1.2. Injection pump
The components relating to the injection pump should be serviced at regular
intervals as the plunger and delivery valve may be worn after a given length of time
for use and cause the deterioration of the engine.
Make sure that servicing should be performed at the professional maintenance shop
as authorized by Bosch or Zexel Company.
For adjustment of fuel injection volume, refer to the 'Specifications of fuel injection
pump' described on the following pages.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
1) DE12T
(1) Main data and specifications
Part No.
: 65.11101 -7222(106672-9920)
Model
: NP-PE6P120/720RS3000 (106061-7250)
Governor
: NP-EP/RSV200-1200PD36C311 (105407-4720)
Timer
: without timer
Plunger & barrel
: φ12, right hand helix 30 lead
Delivery valve
: 120 mm3/st (φ8 × 2.4 mm)
Fuel feed pump
: NP-FP/K-P (105207-1400)
Pre-stroke
: 4.7 mm
(2) Nozzle holder assembly
: 65.10101-7300 (105160-1400)
(3) Nozzle
: 65.10102-6046 (105029-1330)
(4) Injection pipe
: 65.10301-7004B
(5) Injection order
: 1-5-3-6-2-4
(6) Injection timing
: BTDC 12°
(7) Calibration data
Adjusting
point
Rack position
(mm)
Pump speed
(rpm)
Injection volume
(mm3/1,000st)
Variation
rate (%)
A
10.8
B
11
900
129±2
±2
875
(135)±3
-
C
Approx. 6.4
D
-
250
14.5±1.5
±15
100
193.5±10
-
Fixing
point
Specification
Engine
Application
Nozzle holder assembly
105780-8140
65.10101-7300
Nozzle
105780-0000
65.10102-6046
Nozzle holder
105780-2080
-
Content
Adjusting
conditions
Basic
point
Opening pressure
Injection pipe
175 kg/cm
2
φ 8 × φ 3 – 600 mm
Ref.
220 kg/cm2
φ 6 × φ 2.2 – 650 mm
2
Fuel delivery pressure
1.6 kg/cm
Fuel temperature
35 ∼ 45 °C
35 ∼ 45 °C
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
(8) Governor adjustment
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2) P126TI
(1) Main data and specifications
Part No.
: 65.11101 –7310 (106674-4130 ZEXEL)
Model
: NP-PE6P120/700RS3S (106067-6020)
Governor
: GAC electric (65.11501-7002A)
Plunger & barrel
: φ12, right hand double helix 30 lead
Delivery valve
: 90 mm3/st (φ7 × 2.35 mm)
Fuel feed pump
: NP-FP/KD-PS (105237-5470)
Pre-stroke
: 3.9±0.05 mm
(2) Nozzle holder assembly
: 65.10101-7054 (10501-8520)
(3) Nozzle
: 65.10102-6048 (105019-2450)
(4) Injection pipe
: 65.10301-6042, 65.10301-6043
(5) Injection order
: 1-5-3-6-2-4
(6) Injection timing
: BTDC 12°
Nozzle & Holder Ass’y
105780-8130
Opening pressure :
175 kg/cm2
-
φ3.0 x φ8.0 – 600 mm
ISO4113
Temperature :40 ±5°C
65.10101-7054
Nozzle (5 x φ0.37)
65.10102-6048
1st pressure : 160 kg/cm2
2
2nd pressure: 220 kg/cm
65.10301-6042
65.10301-6043
φ2.2 x φ6 – 600mm
(A) Test condition
for injection pump Injection pipe(ID ,OD ,L)
Test oil
Nozzle & holder Ass’y
(B) Engine standard
parts
Injection pipe(ID, OD ,L)
Rack diagram and setting valve at each point
Check
point
Rack
position
(mm)
B
Standby power
Pump
speed
(rpm)
Injection Q’ty on RIG
(mm3 / 1,000 st)
(A) Test condition
for inj. pump
900
(B) Engine
standard parts
Press.
(mmHg)
240±3
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
5.1.3. Governor system (P126TI)
Governor system for fuel injection pump consists of “Integral Actuator” and “ Speed
Control Unit”.
5.1.3.1. Integral actuator
<Side View>
<Top View>
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Fig. No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
*
35
36
Description
stop lever (emergency)
pump gasket
washer
allen screw
ball link
stop nut
operating lever
oil seal
counter nut
stop screw
connector screw
mounting bar
flat washer
lock washer
nut
flat washer
lock washer
nut
threaded bolt (part of bearing kit)
actuator spring
gasket, lower cover
lower cover
washer
allen screw
receptacle
sealing screw
gasket, upper cover
flat washer
screw, ball link
connecting rod
nut
stop plate
top cover
manual stop device complete
linkage complete
comprise pos. 5,6,28,29,30,31,32
fixing screw
stop nut
Q’ty
1
1
4
4
2
2
1
1
1
1
4
1
2
2
2
2
2
2
2
1
1
1
8
6
1
2
1
2
2
1
2
1
1
1
1
1
1
Remark
7 ~ 9 N.m
*
3.5 ~ 4.0 N.m *
4.5 ~ 6.0 N.m
17 ~ 21 N.m
7 ~ 9 N.m
2.0 ~ 3.0 N.m
3.5 ~ 4.5 N.m
*
*
*
*
12.5 ~ 13.0 N.m
12.5 ~ 13.0 N.m
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.1.3.2. Speed control unit for governor system
The ESD5550 Series speed control unit is an all electronic device designed to
control engine speed with fast and precise response to transient load changes. This
closed loop control, when connected to a proportional electric actuator and supplied
with a magnetic speed sensor signal, will control a wide variety of engines in an
isochronous or droop mode. It is designed for high reliability and built ruggedly to
withstand the engine environment.
Simplicity of installation and adjustment was foremost in the design. Non-interacting
performance controls allow near optimum response to be easily obtained.
The primary features of the ESD5550 Series speed control unit are the engine
STARTING FUEL and SPEED RAMPING adjustments. The use of these features
will minimize engine exhaust smoke experienced prior to attaining engine operating
speed.
Other features include adjustable droop and idle operation, inputs for accessories
used in multi-engine or special applications, protection against reverse battery
voltage, transient voltages, accidental short circuit of the actuator and fail safe
design in the event of loss of speed sensor signal or battery supply.
Engine model
GAC governor model
Speed control unit model
P126TI
ACE 175A
ESD5550
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.1.4. Specification
z Performance
Isochronous Operation/steady State Stability ............................ ± 0.25% or better
Speed Range/Governor .............................................. 1 K ~ 7.5 KHz continuous
Speed Drift with Temperature ....................................................... ± 1% Maximum
Idle Adjust CW ........................................................................... 60% of set speed
Idle Adjust CCW.....................................................................Less than 1,200 Hz.
Droop Range .......................................................................... 1 ~ 5 % regulation*
Droop Adj. Max. (K-L Jumpered) ...................... 400 Hz ± 75 Hz per 1.0 A change
Droop Adj. Min. (K-L Jumpered) .......................... 15 Hz ± 6 Hz. per 1.0 A change
Speed Trim Range .................................................................................. ± 200 HZ
Remote Variable Speed Range .......................... 500 ~ 7.5 Hz or any part thereof
Terminal Sensitivity
J.................................................... 100 Hz ± 15 Hz/Volt @ 5.0 K Impedance
L..................................................... 735 Hz ± 60 Hz/Volt @ 65 K Impedance
N ............................................... 148 Hz ± 10 Hz/Vo1t @ 1 Meg. Impedance
P ...................................................................10 VDC Supply @ 20 ma Max.
Speed switch adjustment range............................................... 1,000 ~ 10,000 Hz
z Environmental
Ambient Operating Temperature Range ......- 40 °F to 180 °F (- 40 °C to + 85 °C)
Relative Humidity..................................................................................up to 95 %
All Surface Finishes ..................................Fungus Proof and Corrosion Resistant
z Input power
Supply...................................................................12 or 24 VDC Battery Systems
(Transient and Reverse Voltage Protected)**
Polarity.............................................................. Negative Ground (Case Isolated)
Power Consumption ................................50 ma continuous plus actuator current
Actuator Current Range @ 77°F (25 °C)
(Inductive Load) ...............................Min.2.5 Amps/ Max. 10 Amps continuous ***
Speed Sensor Signal ............................................................ 0.5 ~ 120 Volts RMS
Speed switch relay contacts (N.O. and N.C.) ..........................................10 Amps
z Reliability
Vibration...................................................................................1G @ 20 ~ 100 Hz
Testing ..........................................................................100% Functionally Tested
z Physical
Dimensions ......................................................................................... See Outline
Weight.....................................................................................1.8 lbs (820 grams)
Mounting .............................................................. Any Position, Vertical Preferred
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
NOTE:
* Droop is based on a speed sensor frequency of 4,000 Hz and an actuator
current change of 1 amp from no load to full load. Applications with higher
speed
sensor
signals
will
experience
less
percentage
of
droop.
Applications with more actuator current change will experience higher
percentages of droop. See droop description for specific details on
operation of droop ranges.
** Protected against reverse voltage by a series diode. A 15 Amp. fuse must be
Installed in the positive battery lead,
*** Protected against short circuit to actuator (shuts off current to actuator),
unit automatically turns back on when shorts is removed.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.1.5. Diagram
NOTE:
z If wire leads are longer than 3 meters (10 ft), a shielded cable should be
used. Ground shield at one end only.
z The speed control unit is rugged enough to be placed in a control cabinet
or engine mounted enclosure with other dedicated control equipment. If
water, mist, or condensation may come in contact with the controller, it
should be mounted vertically. This will allow the fluid to drain away from
the speed control unit.
z Extremely heat should be avoided.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
CAUTION:
An overspeed shutdown device, independent of the governor system, should
be provided to prevent loss of engine control which may cause personal injury
or equipment damage. Do not rely exclusively on the governor system electric
actuator to prevent overspeed. A secondary shutoff device, such as a fuel
solenoid must be used.
5.1.5. Wiring
z Basic electrical connections are illustrated above. Actuator and battery
connections to Terminals A, B, E, and F should be #16 AWG (1.3 mm2) or larger.
Long cables require an increased wire size to minimize voltage drops.
z The battery positive (+) input, Terminal F, should be fused for 15 amps as
illustrated.
z Magnetic speed sensor connections to Terminals C and D MUST BE TWISTED
AND/OR SHIELDED for their entire length. The speed sensor cable shield should
only be connected to terminal D. The shield should be insulated to insure no other
part of the shield comes in contact with engine ground, otherwise stray speed
signals may be introduced to the speed control unit. With the engine stopped,
adjust the gap between the magnetic speed sensor and the ring gear teeth. The
gap should not be any smaller than 0.020 in, (0.45 mm). Usually, backing out the
speed sensor 3/4 turn after touching the ring gear tooth will achieve a satisfactory
air gap. The magnetic speed sensor voltage should be at least 1 VAC RMS during
cranking.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.1.6. System Trouble shooting
z System inoperative
If the engine governing system does not function, the fault may be determined by
performing the voltage tests described in Steps 1, 2, 3, and 4. (+) and (-) refer to
meter polarity. Should normal values be indicated as a result of following the
trouble shooting steps, the fault may be with the actuator or the wiring to the
actuator See the actuator publication for testing details.
Step
Terminals
Normal reading
1
F(+) & E(-)
Battery supply
voltage
(12 or 24 VDC)
2
C&D
1.0 VAC RMS
min.,
while cranking
3
P(+) & G(-)
10 VDC,
Internal Supply
4
F(+) & A(-)
1.0 ∼ 2.0 VDC
while cranking
Probable cause of abnormal reading
1. DC battery power not connected.
Check for blown fuse
2. Low battery voltage.
3. Wiring error.
1. Gap between speed sensor and gear
teeth too great. Check gap.
2. Improper or defective wiring to the
speed sensor. Resistance between
terminals C and D should be 30 to
1,200 ohms.
3. Defective speed sensor.
1. Short on terminal P (This will cause a
defective unit.)
2. Defective Speed Control.
1. SPEED adjustment set too low
2. Short/open in actuator wiring.
3. Defective speed control.
4. Defective actuator.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Unsatisfactory performance
If the governing system functions poorly, perform the following tests.
Symptom
Engine
overspeeds
Test
Probable fault
1. Do not crank. Apply DC power 1. Actuator goes to full fuel. Then,
to the governor system
disconnect speed sensor at
Terminals C & D.
If actuator still at full fuel speed
control unit defective. If actuator
at minimum fuel position erroneous speed signal. Check
speed sensor data.
2. Manually hold the engine at 1. If the voltage reading is 1.0 to 2.0
the desired running speed.
VDC.
Measure the DC Svoltage
a) SPEED adjustment set above
between Terminals A(-) & F(+)
desired speed.
on the speed control unit.
b) Defective speed control unit.
2 If the voltage reading is above 2.0
VDC, a) Actuator or linkage
binding.
3. If the voltage reading is below 1.0
VDC, a) Defective speed control
unit.
4. Gain set too low.
Actuator does 1. Measure the voltage at the 1. If the voltage is less than 7V for a
not
energize
battery while cranking.
12V system, or14V for a 24V
fully.
system, replace the battery if it is
weak or undersized.
2. Momentarily connect Terminals 1. Actuator or battery wiring in error.
A and F The actuator should
move to the full fuel position.
2. Actuator or linkage binding.
3. Defective actuator.
4. Fuse opens. Check for short in
actuator or actuator wiring
harness.
Engine remains 1. Measure the actuator output. 1. If voltage measurement is within
below desired
Terminals A & B, while running
approximately 2 volts of the
governed
under governor control.
battery supply voltage, then fuel
speed.
control restricted from reaching
full fuel position. Possibly due to
interference from the mechanical
governor, carburetor spring or
linkage alignment.
2. Speed setting too low.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.1.7. Fuel feed pump
1) General descriptions and construction
The P-type injection pump is mounted with K-ADS or KP type feed pump. These
pumps have the same basic construction and operation, and the general
descriptions of the KP type pump are given below:
The figures show its construction (right figure) and operation (below figure). The
piston in the fuel feed pump is driven by the push rod and tappet via the camshaft of
injection pump and performs reciprocating operation to control the suction and
delivery of fuel. When the cam reaches the Bottom Dead Center as shown in the
figure, the fuel is drawn in through the check valve on the inlet side.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
The fuel pressurized as the cam rotates on flows through the check valve on the
outlet side as shown in (B). If the feeding pressure increases abnormally, the spring
is compressed, resulting in interrupting further delivery of fuel as shown in (C).
This feed pump is mounted with a priming pump designed to permit manual feeding
of fuel from the fuel tank with the injection pump mounted in the engine. During the
manual feeding operation, air must be bled from the fuel lines.
When using the priming pump, fix it securely to prevent the possible entry of
moisture or other foreign substances in the inside of feed pump.
In addition, a strainer is fitted into joint bolt on the inlet side of the fuel feed pump to
filtrate any foreign substances possibly mixed in fuel.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
2) disassembly
z Clamp the feed pump with a vise and disassemble the plugs (30, 32), strainer
(31) and gaskets (35, 36).
z Take off the priming pump (25), plug (16), both gaskets (18), spring (15), and
check valve (14).
z Take off the prig (7), gasket (8), spring (6), and piston (5) on the piston side.
z Pull out the snap ring (20) holding the tappet (10).
z Disassemble the snap ring, then take off the tappet (10) and push rod (1).
3) Inspection
z If the check valve is damaged or scored on its seat face, replace it with a new
one.
z Inspect the piston and tappet for damage.
z Replace the push rod if excessively worn, and replace together with the pump
housing if required. The inspection for wear should be performed in the same
procedure as for suction pressure test described below.
4) Reassembly
Reassembly operation is performed in reverse order of disassembly. All the
gaskets must be replaced with new ones at reassembly.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5) Testing
(1) Suction capacity test
Connect one end of a hose to the
inlet side of the feed pump and
immerse the other end of it into the
fuel tank as illustrated.
Hold the feed pump in position
about 1 m above the level of fuel in
the fuel tank.
Operate the tappet at the rate of
100 rpm and check to see if fuel is
drawn in and delivered for 40
seconds or so.
(2) Delivery test
Make a test with the feed pump
mounted on a pump tester as
illustrated. Operate the pump at
the rate of 1,000 rpm and check to
see if the pump delivery is more
than 405 cc/15 seconds.
(3) Sealing test
Plug up the delivery port on the
feed pump and apply compressed
air of 2 kg/cm2 into the inlet side.
Submerge the feed pump in a
container of diesel fuel and check
for air leak.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.1.8. Injection nozzle
1) General descriptions
Pressurized fuel delivered from the fuel injection pump is sprayed into the
combustion chamber past the injection nozzle at proper spray pressure and spray
angle, then burnt completely to achieve effective engine performance.
2) 1-spring type
(1) Disassembly
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
(2) Reassembly
z After removing carbon deposit,
submerge the nozzle in diesel
oil and clean it.
z Replace all the gaskets with
new ones.
z Assemble the parts and tighten
them to specified torque.
(3) Adjustment
z Remove
the
cap
nut
and
assemble a nozzle to a nozzle
tester.
z With
the
adjusting
screw
loosened, operate the nozzle 2
~ 3 times to bleed it.
z Operate the nozzle tester lever
at the specified rate.
z Adjust the injection pressure to
the standard pressure using the
adjusting screw.
z After adjusting the injection pressure, tighten the cap nut to specified torque.
z Re-check the injection pressure and see if the spray pattern is normal.
(4) Testing
With the nozzle assembled to a
nozzle tester and pressure of 20 ~
21 MPa (200 ~ 210 bar) applied,
check the nozzle for fuel leakage.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3) 2-spring type
(1) Disassembly
1.
2.
3.
4.
6.
7.
10.
11.
12.
Nozzle holder body
Push rod
Primary spring
Adjusting screw
Gasket
Cap nut
Adjusting shim
Secondary spring
Spring seat
13.
14.
15.
16.
17.
30.
31.
A.
Lift pin
Pin
Spacer
Pin
Retaining nut
Gasket
Eye bolt
Nozzle
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
(2) Inspection and adjustment
a. Adjusting the primary opening
pressure Install the plate of
plate
assembly
(157944-
9520) onto a vise.
NOTE:
Use the plate assembly (1579449520) in fixing a nozzle holder
having a flange. A nozzle holder
without flange should be directly
installed onto a vise.
b. With the nut, install the two
pins on the plate.
c. Install the nozzle holder body
(1) onto the plate with the cap
nut side facing downward.
d. Assemble adjusting shim (10),
secondary spring (11), and
spring seat (12) on the nozzle
holder body in the order as
described.
NOTE:
The secondary spring is the same
one as the primary spring.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
e. Assemble the pin (14), lift
piece (13), and spacer (15)
with the nozzle holder body.
f.
Install the pin (16) and nozzle
(A) onto the spacer.
g. After
installing
the
gasket
(157892-1500) on the nozzle,
use the cap nut (1578924000 : SW22mm) to fix the
nozzle onto the nozzle holder.
NOTE:
While tightening the cap nut, keep
checking to see if the lock pin
comes all the way into the nozzle.
NOTE:
Tighten the retaining nut until it
resists
hand
tightening,
then
further tighten it using a torque
wrench.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
h. Be sure to follow the specified
torque rating when tightening
the adjusting retaining nut.
Torque
i.
With
the
6.0 ∼ 8.0 kg.m
cap
nut
facing
upward, install the nozzle
holder on the plate.
j.
Assemble the push rod (2),
primary
spring
(3),
and
adjusting screw (4) on the
nozzle holder in the order
described.
k. Install the gasket and cap nut
onto the adjusting screw.
l.
Assemble
the
nozzle
and
nozzle holder assembly to the
nozzle tester (105785-1010).
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
m. Adjust the primary opening
pressure
to
the
specified
pressure using the adjusting
screw (4).
n. With a monkey wrench, fix the
nozzle holder securely and
tighten
the
cap
nut
(SW
19mm) to specified torque.
Torque
3.0 ∼ 4.0 kg.m
‹ Inspecting the needle valve for full lift
a. Install gasket (026508-1140)
and
plug
(157892-1600
:
SW12mm) onto the adjusting
retaining nut (157892-1400).
b. Install the nozzle holder on
the plate with the cap nut
facing upward.
c. Install the holder into the cap
nut.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
d. Install a nut (157892-1000 :
SW 17 mm) on the holder.
e. Assemble the pin (1578924200 or 157892-4300) to the
dial gauge (157954-3800).
Part No.
L (mm)
157892-4200
160
157892-4300
110
NOTE:
"L" means the length of the pin
except the threaded portion.
f.
Install the dial gauge on the
holder assembly so that the
pin is brought into contact
with the upper end of the
push rod, then fix the pin with
the nut.
NOTE:
Fix the dial gauge so that a stroke of
2 mm or so can be measured.
NOTE:
Overtightening the nut may cause a
sticking of the dial gauge seat.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
g. Assemble
the
nozzle
and
nozzle holder assembly to the
nozzle tester and zero the dial
gauge.
h. Operate the nozzle tester,
bleed the retaining nut, and
check for fuel leakage.
i.
Operate the nozzle tester and
increase the tester pressure
up to 350 ~ 450kgf/cm2 in
order that the needle valve
can be fully lifted. Then,
record the full lift value "L".
NOTE:
This testing is to be made in order
to check the nozzle seat portion for
unusual wear or whether the nozzle
assembly is a standard item.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
‹ Inspection of pre-lift
a. If the nozzle tester handle is
released with the needle
valve engaged in a full lift
condition, the tester pressure
drops, being accompanied by
decrease in the needle valve
lift value (indicated value on
the dial gauge).
b. Take the indicated value on
the dial gauge at the point of
time when the secondary
spring completes its operation
and the needle valve puts an
end to descent (the position
of needle valve lift value " l "
as shown in the above and
right figures) and check that
the value is within the
specified limit.
Measuring point for pre-lift
Take the indicated value on the dial
gauge at a point of primary opening
pressure + approx. 1 0 kgf/cm2.
NOTE:
Locate the point of primary opening
pressure + approx. 10 kgf/cm2 while
dropping the pressure.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
c. If the measured pre-lift value
deviates from the specified
limit, replace the pin (14, 16),
lift piece (13), spacer (15),
and nozzle assembly (A) with
a new "nozzle service kit".
‹ Inspection of secondary opening pressure
a. After confirming the pre-lift,
operate the nozzle tester and
increase the internal pressure
up to 350 ~ 450 kgf/cm2 to
fully lift the needle valve.
b. Release the nozzle tester
handle to decrease the tester
pressure, then take a note of
the movements of the dial
gauge.
c. Take the indicated value on
the pressure gauge at the
point of time when the needle
of the dial gauge indicates the
specified
needle
valve
lift
value. (In general, pre-lift " l "
+ 0.05mm. Refer to following
figure.)
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
‹ Adjusting secondary opening pressure
a. In
the
event
that
measured
value
from
specified
the
the
deviates
limit,
readjust the primary opening
pressure if the amount of
deviation is small. (to the
standard range of the primary
opening pressure)
-
If the secondary opening pressure is lower than the standard value:
Adjust the primary opening pressure up to the top limit of the standard
vague, and then measure the secondary opening pressure.
-
If the secondary opening pressure is higher than the standard value: In
a reverse manner, readjust the primary opening pressure down to the
bottom limit of the standard value.
b. If
the
secondary
opening
pressure still deviates from
the specified limit in spite of
the readjusting the primary
opening pressure, take off the
nozzle fixing portion from the
nozzle holder and remove the
adjusting shim (10).
c. If the secondary opening pressure is higher than the standard value, fit a
thinner adjusting shim than the existing one.
d. After replacing the existing adjusting shim, measure the secondary opening
pressure and continue the adjustment until a value satisfying the standard
value.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Adjusting shim for secondary opening pressure
(Out diameter = φ 9.5 , Inner diameter = φ 4.5)
Part No.
150538-4900
150538-5000
150538-5100
150538-5200
Thickness (mm)
0.40
0.50
0.52
0.54
Part No.
150538-5300
150538-5400
150538-5500
150538-5600
Thickness (mm)
0.56
0.58
0.60
0.70
‹ Retaining nut
a. Take out the dial gauge, nut,
holder and gasket from the
cap nut.
b. Remove
the
adjusting
retaining nut and gasket, and
install the original retaining
nut. (SW 19 mm)
Torque
6.0 ∼ 8.0 kg.m
‹ Inspection at completion
a. Assemble the nozzle holder
to a nozzle tester and check
the primary opening pressure,
spray patterns, oil tightness of
seat portion, and oil leakage
from each part.
b. When replacing the nozzle,
replace it with a new "nozzle
service kit" integrated with a
nozzle, lift piece, and spacer
as a complete set.
NOTE:
If only a nozzle is replaced, the
amount of pre-lift will deviate from
the specified value.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.1.9. Diagnostics and troubleshooting
Complaints
Possible causes
Corrections
1. Engine won't start
1) Fuel not being pumped (1) Fuel pipes clogged or air into pipe
out from feed pump
fine
(2) Feed pump valve defective
(3) Feed pump piston or Push rod
sticking
2) Fuel not being injected
(1) Fuel filter element restricted
from injection pump
(2) Air in fuel filter or injection pump
(3) Plunger and/or delivery valve
sticking or defective
3) Fuel injection timing
(1) Injection pump not properly
Incorrect
installed on pump bracket
(2) Injection pump tappet incorrectly
adjusted
(3) Cams on cam shaft worn
excessively
4) Injection nozzles
(1) Needle valves sticking
inoperative
(2) Fuel leaking past clearance
between nozzle and needle valve
(3) Injection pressure incorrect
(1) Pipe from feed pump to injection
2. Engine starts but stalls
pump clogged or filter clogged
immediately
(2) Air in fuel
(3) Feed pump delivery insufficient
(4) Fuel delivery insufficient due to
clogging of fuel tank air breather
(1) Plunger worn excessively
3. Engine lacks power
(2) Injection timing incorrect
(3) Delivery valves defective
(4) Nozzle leaks excessively
(5) Nozzle not working normally
(1) Injection timing too fast
4. Engine knocking
(2) Nozzle injection pressure too high
(3) Nozzles not working normally
5. Engine knocks seriously (1) Injection timing incorrect
producing excessive
(2) Nozzle injection pressure too low
exhaust smoke
(3) Nozzle spring broken
(4) Nozzles not working normally
(5) Plungers worn excessively
(6) Delivery valves seat defective
(7) Supply of fuel excessively
Correct
Replace
Disassemble, correct
Clean
Bleed
Disassemble, correct
Check, correct
Check, correct
Replace
Correct or replace
Correct or replace
Adjust
Clean
Bleed
Disassemble, correct
Replace breather
Replace
Adjust
Replace
Correct or replace
Disassemble, correct
Adjust
Adjust
Disassemble, correct
Adjust
Adjust
Replace
Replace
Adjust
Replace
Check feed pump
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Complaints
6. Engine output unstable
7. Engine does not reach
maximum speed
8. Engine idling Unstable
Possible causes
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(1)
(2)
(1)
(2)
(3)
Corrections
Supply of fuel insufficient
Air in fuel
Water in fuel
Operation of plungers unsmooth
Movement of control rack sluggish
Nozzles defective
Injection starting pressure of
each barrel incorrect
Automatic timer defective
Nozzles not working normally
Governor defective
Movement of control rod sluggish
Operation of plungers unsmooth
Control pinions not engaged with
control rod correctly
Check feed pump
Bleed
Replace fuel
Disassemble, correct
Disassemble, correct
Disassemble, correct
Adjust
Disassemble, correct
Disassemble, correct
Disassemble, correct
Disassemble, correct
Disassemble, correct
Disassemble, correct
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.2. Cooling System
5.2.1. General information
This engine is water-cooling type. Heat from the combustion chamber and engine
oil heat are cooled down by coolant and radiated to the outside, resulting in the
normal operation of the engine.
Looking into the cooling system, the water pumped up by the water pump circulates
around the oil cooler through the water pipe to absorb the oil heat, and then flows
through the water jacket of the cylinder block and water passage of the cylinder
head to absorb the heat of the combustion chamber.
The water absorbing the oil heat and combustion chamber heat goes on to the
thermostat through the water pipe, and circulates to the water pump if water
temperature is lower than the valve opening temperature on the thermostat, while
circulating to the radiator at water temperature higher than the valve opening
temperature. At the radiator, the heat absorbed in the coolant is radiated to cool
down and the coolant recirculates to the water pump.
z Specification
Item
1. Water pump
type
Delivery
Pumping speed
Pumping back pressure
2. Thermostat
Operating temperature
3. Cooling fan and belt
Fan diameter – Number of blades
Fan belt tension
Specification
Centrifugal type
About 350 liter/min
2,100 rpm
760 mmHg
83 ∼ 95°C
755 - 7
15mm/ deflection by thumb
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.2.2. Water pump
z Loosen the bolt (16) to disassemble the housing cover (15).
z Heat the impeller (6) slightly, then remove it using a puller jig.
z Remove the mechanical seal.
z Unscrew the socket bolt (12) and remove the shaft and bearing assembly from
the housing.
z With a press, remove the spline shaft and bearing.
z Reverse the disassembly sequence for reassembly operation.
z Replace the oil seal (7) with a new one at reassembly.
z To reassemble the impeller, maintain a constant gap (0.3 ∼ 0.6 mm) between
the impeller and pump housing using a feeler gauge.
<Construction of water pump>
1.
4.
5.
6.
7.
Water pump housing
Shaft
Mechanical seal
Impeller
Oil seal
8.
9.
10.
11.
12.
Ball bearing
Space
Ball bearing
Bearing cover
Socket bolt
13.
14.
15.
16.
Spline shaft
Gasket
Housing cover
Bolt
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.2.3. Thermostat
z General descriptions and main data
The
thermostat
maintains
a
constant temperature of coolant
(90 ~ 95 °C) and improves thermal
efficiency
of
the
engine
by
preventing heat loss.
Namely, when the temperature of
coolant is low, the thermostat valve
is closed to make the coolant
bypass to directly enter the water
pump;
when
the
coolant
temperature rises to open wide
the thermostat valve, the bypass
circuit is closed and the water
passage to the radiator is opened
so that the coolant is forced to
flow into the radiator.
Item
Type
Open at
Open wide at
Valve lift
Specifications
Wax-pallet type
83 °C
95 °C
8 mm or more
z Inspecting
(1) Check
the
wax
pallet
and
spring for damage.
(2) Put
the
thermostat
in
a
container of water, then heat the
water
slowly
and
check
temperature with a thermometer.
If the valve lift is 0.1 mm
(starting to open) at temperature
of 83 °C and 8 mm or more
(opening wide) at temperature
of 95 °C, the thermostat is
normal.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Replacing thermostat and precautions for handling
(1) Precautions for handling
The wax pallet type thermostat does not react as quickly as bellows type one
to a variation of temperature of coolant. Such relatively slow reaction is mainly
due to the large heat capacity of the wax pellet type thermostat. Therefore, to
avoid a sharp rise of coolant temperature, it is essential to idle the engine
sufficiently before running it. In cold weather, do not run the engine at
overload or overspeed it immediately after starting off.
(2) When draining out or replenishing coolant, do it slowly so that air is bled
sufficiently from the entire cooling system.
(3) Replacing thermostat
If the thermostat is detected defective, retrace with a new one.
5.2.4. Diagnostics and troubleshooting
Complaints
Possible causes
1. Engine overheating z Lack of coolant
z Radiator cap pressure valve
spring weakened
z Fan belt loosened or broken
z Fan belt fouled with oil
z Thermostat inoperative
z Water pump defective
z Restrictions in water passages
due to deposit of scales
z Injection timing incorrect
z Restriction in radiator core
z Gases leaking into water
jacket due to broken cylinder
head gasket
2. Engine overcooling z Thermostat inoperative
z Ambient temperature too low
3. Lack of coolant
z Radiator leaky
z Radiator hoses loosely
connected or damaged
z Radiator cap valve spring
weakened
z Water pump leaky
z Heater hoses loosely
connected or broken
z Cylinder head gasket leaky
z Cylinder head or cylinder
block cracked
4. Cooling system
z Water pump bearing defective
noisy
z Fan loosely fitted or bent
z Fan out of balance
z Fan belt defective
Corrections
z Replenish coolant
z Replace cap
Adjust or replace fan belt
Replace fan belt
Replace thermostat
Repair or replace
Clean radiator and water
passages
z Adjust injection timing correctly
z Clean exterior of radiator
z Replace cylinder head gasket
z
z
z
z
z
Replace thermostat
Install radiator curtain
Correct or replace
Retighten clamps or replace
hoses
z Replace cap
z
z
z
z
z Repair or replace
z Tighten or replace hoses
z Replace cylinder head gasket
z Replace cylinder head block
z Replace bearing
z Retighten or replace fan
z Replace fan
z Replace fan belt
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.3. Lubricating System
5.3.1. General descriptions and main data
z General descriptions
All the engine oil pumped up from the oil pan by the gear type oil pump is
filtrated through the oil cooler and oil filter, and this filtrated oil is forced through
the main oil gallery in the cylinder block from where it is distributed to lubricate
the various sliding parts, and fuel injection pump in order to ensure normal
engine performance.
z Specifications
Item
Specifications
Lubricating system
Item
Forced pressure Oil filter type
circulation
Oil pump type
Gear type
Bypass for filter element
Relief valve opening pressure 10±1.5 kg/cm2
Valve opening pressure
Bypass for oil cooler
Bypass for entire oil filter
Opening pressure
5+1 kg/cm2
Valve opening pressure
Adjusting valve for spray nozzle
Opening pressure
1.5 ~ 1.8 kg/cm2
Specifications
Full flow
1.8 ~ 2.3 kg/cm2
4.0 ~ 4.8 kg/cm2
z Diagram of lubricating system
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.3.2. Oil pump
z Disassembly
(1) Disassembly of oil pump drive gear
a. Unscrew
the
screw
and
disassemble the oil relief
valve.
b. Unfold the washer for the oil
pump drive gear fixing nut
and remove the nut.
c. Disassemble the drive gear.
(2) Remove the oil pump cover
fixing nuts and disassemble the
oil pump cover.
The oil pump cover is fixed with
the two dowel pins.
(3) Disassemble the drive gear
and driven gear.
z Inspection and correction
(1) With steel rule and feeler gauge,
measure the axial end play of
the oil pump gear. Replace if
the measured value is beyond
the limit.
End play
0.025 ~ 0.089 mm
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
(2) With a feeler gauge, measure
the
amount
of
backlash
between the oil pump drive
gear and driven gear. Replace
if the measured value is beyond
the limit.
Backlash
0.50 ~ 0.64 mm
(3) Measuring clearance between drive shaft and bushing
a. Measure the outside diameters of the drive shaft and driven shaft, and
replace if the measured values are less than the limit.
Standard
φ16.95 ∼ φ16.968 mm
b. Measure the inside diameter of the pump body bushing to determine the
clearance between the bushing and shaft, and compare the measured
value with the standard value to determine whether to replace or not.
Clearance
0.032 ~ 0.077 mm
z Reassembly
(1) For reassembly, reverse the disassembly sequence.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.3.3. Oil filter
The oil filter mounted in this engine is of cartridge type, so it is necessary to replace
it with a new one at the specified intervals.
5.3.4. Diagnostics and troubleshooting
Complaints
1. Oil consumption
excessive
2. Oil pressure too low
3. Oil deteriorates
quickly
Possible causes
Corrections
z
z
z
Poor oil
Oil seal or packing leaky
Pistons or piston rings worn
z
z
z
z
z
Cylinder liner worn
Piston rings sticking
z
z
z
z
z
z
z
Use suggested oil
Replace
Clean strainer
z
z
z
z
z
z
z
Valve guide oil seals or valve
guides, or valve stem worn
Poor oil
Relief valve sticking
Restrictions in oil pump
strainer
Oil pump gear worn
Oil pump feed pipe cracked
Oil pump defective
Oil pressure gauge defective
Various bearings worn
Restriction in oil filter
Gases leaking
Use suggested oil
Replace
Replace pistons and/or
piston rings
Replace cylinder liner
Replace pistons and/or
piston rings
Replace
z
z
z
z
z
z
z
z
Wrong oil used
Replace
Replace
Correct or replace
Correct or replace
Replace
Replace filter element
Replace piston rings and
cylinder liner
Use suggested oil
z
z
z
z
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.4. Turbocharger
5.4.1. Main data and specifications
1) Main data and specifications
Specification
Turbocharger Model
At maximum output
DE12T
P126TI
TV45
TV51
Air pressure
at compressor outlet
Approx. 1.257 kg/cm
Air suction volume
Approx. 19.0 m3/min
Approx. 26.0 m3/min
Speed of turbine revolution
Approx. 95,000 rpm
Approx. 91,000 rpm
110,000 rpm
105,414 rpm
750 °C
750 °C
External oil supply
External oil supply
14 kg
14 kg
Maximum allowable speed
Max. allowable temperature of exhaust gas
at turbine inlet
Lubricating system
Weight
2
Approx. 1.9 kg/cm2
2) Operating principle
The turbocharger is a system designed to make use of the engine exhaust gas
energy to charge high-density air into the cylinders, thereby to increase the engine
output.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
3) Construction
1
2
5
7
8
9
10
11
12
13
14
Turbine housing
Plug
Crank
V-band
Wheel
Piston ring
Wheel shroud
Center housing
Retainer ring
Bearing
Retainer ring
15
16
17
18
19
20
21
22
23
24
Retainer ring
Bearing
Thrust collar
Screw
Thrust bearing
Thrust space
Piston ring
Seal ring
Seal ring
Rear plate
25
26
27
28
29
30
31
32
38
45
Bolt
O-ring
Compressor wheel
Nut
Bolt
Clamp
Compressor housing
Elbow
Retainer
Bolt
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
5.4.2. General descriptions
The engine output is determined by the fuel delivery volume and engine efficiency.
To burn the supplied fuel completely to change into effective power for the engine, the
volume of air enough to burn the fuel completely should be supplied into the cylinders.
Therefore, the engine output is determined substantially by the cylinder capacity, and
a greater volume of compressed air is charged into cylinders of given capacity, the
greater engine output can be obtained as a greater volume of air charged into the
cylinders burns so much more fuel.
As explained, the compressing of air to supply into the cylinders is called
"Supercharging" and the making use of the energy of exhaust gas discharged from the
combustion chamber to charge the compressed air into the cylinders is called
"Turbocharging".
5.4.3. Functions
1) Turbine
Exhaust gas discharged from the combustion chamber distributes its own energy to
the turbine blades while passing the inside of the turbine housing, with the result
that the turbine shaft can get rotating force. This is the operating principle of 'turbine',
which is mounted with seal rings and heat protector to prevent exhaust gas from
affecting the bearings adversely.
2) Compressor
The compressor, which is connected to the turbine over the one and same shaft to
form a rotating body, takes in and compresses ambient air with rotating force
transmitted from the turbine shaft. Then, the compressed air is delivered to the
intake stake. This is the operating principle of the compressor.
3) Bearings
(1) Thrust bearing
The turbine wheel creates thrust force. Therefore, exercise care so that the shaft
is not deviated from its the original position due to this thrust.
(2) Journal bearing
This journal bearing of floating type forms a dual oil film on both the inside and
outside of the bearing so that the bearing can rotate independently. As the dual oil
film plays a role as a damper, the sliding speed of the bearing surface becomes
lower than the rotating speed of the shaft, resulting in assurance of stability in its
movement.
4) Sealing-Compressor shaft
The compressor is of a dual construction type composed of seal plate and seal ring
to prevent the leak of compressed air or lubricating oil.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
5.4.4. Precautions for operation
1) Precautions for operation of engine
The following precautions should be observed when starting, operating, or stopping
the engine:
Operations
When starting
the engine
Immediately
after starting
During operation
When stopping
the engine
Precautions
Reasons
1) Check oil level
2) Crank the engine with starter 2) Abrupt starting of the engine
to check the increase in oil
causes the engine to rotate with
pressure(until the needle of
oil not being distributed not only
pressure gauge starts to
to each part but also to the
move or pressure indicator
turbocharger,
resulting
in
lamp is actuated) before
abnormal wear or seizure on the
starting the engine.
bearing due to insufficient supply
of oil.
3) When having replaced oil, oil 3) In the case of the engine
stopped for extended time or in
filter element, or lubricating
a cold place, oil fluidity within the
parts, or when having
pipes can be deteriorated
stopped the engine for
extended period of time, or in
a cold place, loosen the oil
pipe connections and operate
the starter motor until oil is
discharged. After completing
the operation, be sure to
retighten
the
oil
pipe
connections portion before
starting the engine.
1) Run the engine at idle for 5 1) Applying load abruptly If load is
minutes after starting off.
abruptly applied with the engine
and
turbocharger
rotating
unsmoothly, such parts that a
sufficient amount of oil has not
reached can be seized up.
2) Check each part for leakage 2) Leakage of oil, gas, and air
of oil, gas, and air, and take
(especially, oil leak) causes drop
proper measure.
in oil pressure and loss of oil
results in seizure of the bearing.
Check the followings:
1) Oil pressure At idle: 0.8 1) Excessively low oil pressure
kg/cm2 or more At full load:
causes unusual wear or seizure
3.0 4.8 kg/cm2
of the bearing. Too high pressure
causes oil leakage.
2) If unusual sound or vibration 2) The engine Is operated
is heard or felt, reduce
continuously with unusual sound
engine revolutions slowly and
or vibration not corrected, it can
locate the cause.
be damaged beyond repair.
1) Run the engine at idle for 5 1) If the engine is put to a stop
minutes before stopping.
after being operated at high
load, heat from the red-hot
turbine blades is transmitted to
the bearing portion and burns oil
to cause seizure of the bearing
metal and rotating shaft.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
5.4.5. Walk-around check and servicing
As the condition of turbocharger depends greatly on how well the engine is serviced, it
is very important to maintain the engine in accordance with the specified maintenance
procedure.
1) Intake system
Pay particular attention to the air cleaner when servicing the intake system.
In the case of wet-type air cleaner, if the level of oil surface is lower than specified,
cleaning effect is poor; if too high, the cleaner draws in oil to foul the case.
Especially, if the rotor is fouled, the sophisticatedly-tuned balance is broken to
create vibration and to cause seizure and unusual wear to the bearing.
Therefore, it is very important to use a good quality air cleaner all the time.
In the case of dry-type air cleaner, it is essential to clean it to reduce intake
resistance as much as possible.
2) Exhaust system
Pay particular attention to prevent gas leaks and seizure when servicing the exhaust
system because leakage of exhaust gas from discharge pipes, turbocharger fixing
portions, etc. lowers charging effect.
As such components as turbine chamber that becomes red-hot during operation use
heat resisting steel nuts, do not interchange these nuts with ordinary steel nuts. In
addition, apply anti-seizure coating to fixing nuts on the portions as designated.
3) Fuel system
If the full load stopper regulating the maximum injection volume and the maximum
speed stopper regulating the maximum speed in the fuel injection pump are
adjusted without using a pump tester, the turbocharger rotates at excessively rapid
speed and may suffer damage.
Besides of it, if spray pattern from the fuel injection nozzles is bad or the injection
timing is incorrect, temperature of exhaust gas rises up to affect the turbocharger
adversely. To avoid such trouble, be sure to make a nozzle test.
4) Lubricating system
Pay particular attention to oil quality and oil filter change intervals when servicing
the lubricating system. Deteriorated engine oil affects adversely not only the engine
but torso the turbocharger. Suggested engine oils for the turbocharger-mounted
engine are as follows:
z SAE 15W30
z API grade CD or CE
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
5.4.6. Maintenance
(by authorized specialist personnel)
The turbochargers do not call for any specific maintenance.
The only points to be observed are the oil pipes which should be checked at every oil
change for leakage and restrictions.
The air cleaners should be carefully serviced.
Furthermore, a regular check should be kept on charge air exhaust gas pipes. Any
leakages should be attended to at once because they are liable to cause overheating
of the engine.
When operating in highly dust or oil-laden atmospheres, cleaning of the air impeller
may be necessary from time to time. To this end, remove compressor casing (Caution ,
Do not skew it!) and clean in a non-acid solvent, if necessary using a plastic scraper.
If the air compressor should be badly fouled, it is recommended that the wheel be
allowed to soak in a vessel with solvent and to clean it then with a stiff brush. In doing
so, take care to see that only the compressor wheel is immersed and that the
turbocharger is supported on the bearing casing and not on the wheel.
5.4.7. Periodical checking and servicing
Make it a rule to check the turbocharger assembly for condition and contamination
periodically.
1) Guide for checking the rotor for rotating condition
The inspection of the rotor assembly for rotating condition should be performed by
the degree of unusual sound. If a sound detecting bar is used, install its tip on the
turbocharger housing and increase the engine revolutions slowly. If a high-pitch
sound is heard continuously, it means that the rotor assembly is not normal. In this
case, as the metal bearing and rotor are likely to be in abnormal conditions, the
turbocharger should be replaced or repaired.
2) Guide for checking rotor end play
Disassemble the turbocharger from the engine, then check the rotor axial play and
radial play.
When disassembling the turbocharger, be sure to plug the oil inlet and outlet ports
with taps, etc.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
(1) Rotor axial play
z Measuring rotor axial clearance
Axial clearance
0.2 mm
(2) Rotor radial play
z Measuring radial clearance
Radial clearance
0.65 mm
(3) If the measured axial and radial plays are beyond the limit of wear, replace or
repair the turbocharger.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
3) Guide for disassembling/cleaning and checking the turbocharger
First, disassemble the turbocharger from the engine and clean/check it with the oil
inlet and outlet plugged with tape and so on.
4) Precautions for reassembling the tarbocharger onto the engine
For reassembly of the turbocharger or handling it after reassembly operation, be
sure to observe the following precautions:
Especially, exercise extreme care to prevent foreign matters from entering the
inside of the turbocharger.
(1) Lubricating system
z Before reassembling the turbocharger onto the engine, inject new oil in the
oil inlet port and lubricate the journal and thrust bearings by rotating them
with hand .
z Clean not only the pipes installed between the engine and oil inlet port but
also the oil outlet pipe and check them for damage or foreign matters.
z Assemble each joint on oil pipes securely to prevent oil leaks.
(2) Intake system
z Check the inside of the intake system for foreign matters.
z Assemble each joint on the intake duct and air cleaner securely to prevent
air leaks.
(3) Exhaust system
z Check the inside of the exhaust system for foreign matters.
z Be sure to use heat resisting steel bolts and nuts. Do not interchange them
with ordinary steel bolts and nuts when performing reassembly operation.
Apply anti-seizure coating to the bolts and nuts.
z Assemble each joint on the exhaust pipes securely to prevent gas leaks
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
5.4.8. Diagnostics and troubleshooting
Complaints
1. Excessive black smoke
2. Excessive white smoke
3. Low engine output
4. Unusual sound or
vibration
Possible causes
Corrections
1) Air cleaner element clogged
2) Restrictions in air duct
3) Leakage at intake manifold
4) Turbocharger seized up and not rotating
5) Turbine blades and compressor blades
coming in contact with each other or
damaged
6) Exhaust piping deformed or clogged
1) Oil leak into turbine and compressor
2) Worn or damaged seal ring due to excessive
wear of bearing
1) Gas leak at each part of exhaust system
2) Air cleaner element restricted
3) Turbocharger fouled or damaged
4) Leakage at discharge port on compressor
side
1) Rotor assembly coming in contact
2) Unbalanced rotation of rotor
3) Seized up
4) Each joint loosened
Replace or clean
Check and correct
Check and correct
Disassemble/repair
or replace
Disassemble/repair
or replace
Check and correct
Disassemble/repair
or replace
Disassemble/repair
or replace
Check and correct
Replace or clean
Disassemble/repair
or replace
Check and correct
Disassemble/repair
or replace
Disassemble/repair
or replace
Disassemble/repair
or replace
Check and correct
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.5. Air Intake System
5.5.1. Maintenance
(only when engine is switched off)
Empty the dust bowl (7) regularly. The bowl should never be filled more than halfway
with dust.
On slipping off the two clamps (3), the dust bowl can be removed. Take off the cover
(6) of the dust bowl and empty.
Be careful to assemble cover and bowl correctly.
There is a recess in the cover rim and a lug on the collector which should register.
Where the filter is installed horizontally, watch for “top” mark on cleaner bowl.
5.5.2. Changing filter element
CAUTION:
Do not allow dirt to get into the
clean air end.
On removing the hexagon nut, take out
the dirty cartridge and renew or clean.
M1041A
Wipe the cleaner housing with a damp
cloth, in particular the sealing surface for
the element.
CAUTION:
Unless the maximum number of cleanings (up to 5 x) have been done, the filter
cartridge should be renewed every two years or 4,000 hours operation.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.5.3. Cleaning filter elements
z By compressed air
(wear goggles)
For the purpose, the air gun should
be fitted with a nozzle extension
which is bent 90° at the discharge
end and which is long enough to
reach down inside to the bottom of
the element.
Moving the air gun up and down,
blow out the element from the inside
(maximum 500kPa - 5 bar) until no
more dust comes out of the filter
pleats.
z
By washing
Before washing, the element should
be
precleaned
by
means
of
compressed air, as described above.
Then allow the element to soak in
lukewarm washing solvent for 10
minutes, and then move it to and for
in the solvent for about 5 minutes.
Rinse thoroughly in clean water,
shake out and allow drying at room
temperature. The cartridge must be
dry before it is reinstalled. Never use
steam sprayers, petrol (gasoline),
alkalis or hot liquids etc. to clean the
filter elements.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Knocking out dirt by hand
In emergencies, when no compressed air or cleaning agent is available, it is
possible to clean the filter cartridge provisionally by hitting the end disk of the
cartridge with the ball of one's thumb.
Under no circumstances should the element be hit with a hard object or knocked
against a hard surface to loosen dirt deposits.
z Checking the filter cartridge
Before reinstalling the cartridge, it
must be checked for damage e.g. to
the paper pleats and rubber gaskets,
or for bulges and dents etc. in the
metal jacket.
Cracks and holes in the paper
pleating
inspecting
can
the
be
established
cartridge
with
by
a
flashlight.
Damaged cartridges should not be
reused under any circumstances. In
cases of doubt, discard the cartridge
and install a new one.
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
5.6. V-belts
The tension of the V-belts should be checked after every 2,000 hours of operation.
(1) Change the V-belts if necessary
If in the case of a multiple belt drive, wear or differing tensions are found, always
replace the complete set of belts.
(2) Checking condition
Check V-belts for cracks, oil, overheating and wear.
(3) Testing by hand
The tension is correct if the V-belts can
be pressed in by about the thickness of
the V-belt. (no more midway between
the belt pulleys)
A more precise check of the V-belt
tension is possible only by using a Vbelt tension tester.
(4) Measuring tension
① Lower indicator arm (1) into the scale.
z Apply tester to belt at a point
midway between two pulleys so
that edge of contact surface (2)
is flush with the V- belt.
z Slowly depress pad (3) until the
spring
can
be
heard
to
disengage. This will cause the
indicator to move upwards.
If pressure is maintained after the
spring has disengaged a false
reading will be obtained!
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
② Reading of tension
z Read of the tensioning force of
the belt at the point where the
top surface of the indicator arm
(1) intersects with the scale.
z Before taking readings make
ensure that the indicator arm
remains in its position.
Tensioning forces on the tester
Type
new installation
Drive belt width
After 10 min.
Installation
running time
M
A ★
B
C
9.5 mm
11.8 mm
15.5 mm
20.2 mm
50 kg
55 kg
75 kg
75 kg
45 kg
50 kg
70 kg
70 kg
When servicing after
long running time
40 kg
45 kg
60 kg
60 kg
★ : Adopted in DE12T and P126TI
(5) Tensioning and changing V-belt
z Remove fixing bolts. (1)
z Remove lock nut. (2)
z Adjust nut (3) until V-belts have
correct tensions.
z Retighten lock nut and fixing bolts.
To change the V-belts loosen mounting
bolts (1) and lock nut (2) and push
tension pulley inwards by turning
adjusting nut (3).
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
6. Special Tool List
No.
Part No.
Figure
Tool Name
1
DPN-5337
Nozzle tube insert ass’y
2
EF.123-082
Nozzle tube extractor
3
EF.123-015
Injection pump setting ass’y
4
EF.123-127
Oil seal insert ass’y (FR)
5
EF.123-053
Oil seal insert ass’y (RR)
6
EF.123-052
Oil seal puller ass’y (FR)
7
EF.123-048
Oil seal puller ass’y (RR)
8
EU.2-0531
Cylinder pressure tester adapter
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
No.
Part No.
Figure
Tool Name
Cylinder liner puller ass’y
9
EU.123-087
10
EF.123-066
Valve stem seal punch
11
EU.2-0131
Valve clearance adjust ass’y
12
EF.123.-065
Valve spring press
13
EU.2-0647
Crankshaft gear punch
14
60.99901-0027
Feeler gauge
15
T7610001E
Snap ring plier
16
T7621010E
Piston ring plier
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Appendix
z Tightening torque for major parts
Screw
Strength
(Diameter x pitch) (grade)
Major Parts
Tightening Torque
Remarks
6 kg.m + 180°+150°
Cylinder head bolt
M14 x 1.5
12.9T
Connecting rod bearing cap bolt
M14 x 1.5
12.9T
28.0 kg.m
Crankshaft main bearing cap bolt
M16 x 1.5
12.9T
30.0 kg.m
Balance weight fixing bolt
M14 x 1.5
10.9T
9.0 kg.m
Flywheel fixing bolt
M14 x 1.5
10.9T
18.0 kg.m
Crankshaft gear fixing bolt
M12 x 1.5
10.9T
13.4 kg.m
Angle
z Tightening torque for injection pump system
Parts
Injection pump delivery valve holder
Nozzle holder fixing cap nut
Nozzle fixing cap nut
High pressure injection pipe fixing cap nut
Tightening Torque
2.0 ~ 3.0 kg.m
7.0 kg.m
6.0 ~ 8.0 kg.m
Max. 3.0 ~ 5.0 kg.m
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
z Standard bolt tightening torque table
Refer to the following table for bolts other then described above
Degree of strength
Diameter
x
pitch
(mm)
3.6
4.6
4.8
5.6
5.8
6.6
6.8
6.9
8.8
10.9
12.9
(4A)
(4D)
(4S)
(5D)
(5S)
(6D)
(6S)
(6G)
(8G)
(10K
)
(12K
)
54
64
90
108
0.48
0.85
1.3
2.1
2.3
4.2
4.9
7.2
7.7
11.5
12.5
18.5
19.5
24.2
27.5
35
39.5
46
52
58
67
0.5
0.9
1.4
2.2
2.4
4.4
5
7.5
8
12
13
18
20
25
28
36
41
49
56
63
74
0.75
1.25
1.95
3.1
3.35
6.2
7
10.5
11.2
17
18.5
26
28
36
41
51
58
67
75
82
93
0.9
0.5
2.35
3.8
4.1
7.4
8.4
12.5
13.4
20
22
31
33
43
49
60
68
75
85
92
103
Limit value for elasticity (kg/mm2)
20
24
32
30
0.15
0.28
0.43
0.7
0.73
1.35
1.5
2.4
2.55
3.7
4.1
5.6
6.2
7.8
9.1
11.5
12.8
15.5
17
20.5
23
0.16
0.30
0.46
0.75
0.8
1.4
1.6
2.5
2.7
3.9
4.3
6
6.5
8.3
9.5
12
13.5
16
18.5
21.5
25
0.25
0.45
0.7
1.1
1.2
2.2
2.5
3.7
4
6
6.6
9
9.7
12.5
14.5
18
20.5
24.5
28
33
37
0.22
0.4
0.63
1
1.1
1.9
2.1
3.3
3.5
5.2
5.7
8
8.6
11
12.5
16
18
21
24
27
31
40
36
48
Tightening torque (kg.m)
M5
M6
M7
M8
M8x1
M10
M10x1
M12
M12x1.5
M14
M14x1.5
M16
M16x1.5
M18
M18x1.5
M20
M20x1.5
M22
M22x1.5
M24
M24x1.5
0.31
0.55
0.83
1.4
1.5
2.7
3.1
4.7
5
7.5
8.3
11.5
12.5
16
18.5
22
25
30
34
40
45
0.28
0.47
0.78
1.25
1.34
2.35
2.8
4.2
4.6
7
7.5
10.5
11.3
14.5
16.7
19
22.5
26
29
34
38
0.43
0.77
1.2
1.9
2.1
3.7
4.3
6.3
6.8
10
11.1
17.9
17
21
24.5
31.5
35
42
47
55
61
Others :
1. The above torque rating have been determined to 70% or so of the limit value for
bolt elasticity.
2. Tension is calculated by multiplying tensile strength by cross section of thread.
3. Special screws should be tightened to 85% or so of the standard value.
For example, a screw coated with MoS2 should be tightened to 60% or so of the
standard value.
Printed in Sep. 2008 PS-MMG0715-E1B
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Operation and Maintenance Manual
z Maintenance specification table
Group
Part
Check
Inside diameter of
cylinder liner for wear
Engine
body
Projected portion of
Cylinder
liner
block &
The upper surface of
liner
cylinder block of
distortion
Hydraulic test for 1
minute (kg/cm2)
Stand value
for assembly
Limit
for use
φ123~φ123.023 φ123.223 Replace liner
0.03~0.08
-
0.05
-
4
-
0~0.3
0.55
0~0.3
114.95 ~115
0.55
113.9
4
-
φ122.854~φ122.886
-
0.114~0.169
-
Top ring
3.5
-
2nd ring
3.060~3.080
-
Oil ring
4.040~4.060
-
0~0.12
-
Valve seat
Intake
Cylinder depression
head &
Exhaust
valve
Height
Hydraulic test for 1
minute (kg/cm2)
Piston diameter
(18mm from the lower
Correction
Correct with a
surface grinder
Remark
Measure unworn
portion beneath the
rim of upper side
Per distortion length
for 200mm
In case of new
valve
and seat
Replace cyl. head
Replace if leaky
Water temp. 70°C
side)
Clearance between
piston and liner
Piston
Major
moving
parts
Piston
ring
Width of
piston ring
grooves
Piston projection from
cylinder block upper
surface
Permissible weight
difference of each
piston
Piston ring Top ring
gap
2nd ring
Oil ring
±15g
96g
0.30~0.45
0.35~0.50
0.30~0.50
1.5
1.5
1.5
Top ring
2nd ring
Oil ring
0.07~0.102
0.05~0.085
0.15
0.15
-
-
Piston ring
groove
clearance
Direction of ring gap
Replace piston if
groove width is
beyond specified
value
Measure unworn
portion beneath the
rim of upper side
Standard gauge
inside
diameter : φ123
Replace ring or
piston
Limit for use if for
standard clearance
Install ring
by 120°C
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Group
Part
Check
Axial run-out of journal
and pin
Outside diameter of
journal
Outside diameter of pin
Crank
shaft
Out of round of journal
and pin
Permissible radial run
out of journal and pin
Permissible taper of
journal and pin
Clearance between
crankshaft and bearing
0.03
0.01
0.03
0.072~0.142
0.25
60
Tightening torque of
journal bearing cap
bolt(kg.m)
30
Permissible weight
difference of each conrod
Tightening torque of
con-rod bearing cap
bolt (kg.m)
Outside diameter of
cam shaft
Clearance between
cam shaft and bush
Axial play of camshaft
Clearance between idle
gear shaft and inserting
hole
End play of idle gear
shaft
Between crank gear &
idle gear
Between idle gear &
camshaft gear
Correct with a
grinder
Replace
φ94.966
crankshaft
Replace
φ81.966
crankshaft
0.01
Balance of crankshaft
Correction
0.1
0.025
0.05
Connect
ing rod
Connecting rod bearing
crush height
Limit
for use
0.008
Run-out of crankshaft
Clearance between
con-rod bearing &
crank pin
End play of con-rod
crush
Clearance between
small end bush &
piston pin
Timing
gear
φ95.966~
φ95.988
φ82.966~
φ82.988
0.15~0.325
Oil seal for wear
Cam
shaft
0.05
End play of crankshaft
Journal bearing crush
Major
moving
parts
Stand value
for assembly
Replace bearing
Replace thrust
bearing
Adjust by a press
0.1 or less
if bent
Check dynamic
60 or less
balance
Remark
In horizontal and
vertical directions
φ96 g6
φ83 g6
Measure in the
position of crown
0.5
-
Apply oil to bolt
No.4 bearing
(holding no. 1 & 7)
Measure at 400
rpm
No oreign ,matters
on bearing cap
installing surface
Measure by tightening
metal cap & then
loosening one stud
bolt
0.15~0.25
-
-
-
Replace oil seal
if oil leaking
0.049 ~ 0.119
0.20
Replace bearing
0.22 ~ 0.319
0.5
Replace con.-rod
0.050~0.080
0.12
0.086~0.116
-
±18 g
-
28
-
φ59.860~
φ59.880
φ59.52
0.050~0.128
0.20
0.13~0.27
0.30
0.025~0.091
0.15
0.043~0.167
0.3
0.10~0.20
-
0.10~0.20
-
Replace with new
one, use shim
After completing of
bearing loosen one
stud bolt & measure
Apply oil to bolt
φ60
Replace thrust
plate
Replace thrust
collar
Replace gear
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Group
Part
Check
Outside diameter
of intake valve stem
Outside diameter
of exhaust valve stem
Clearance
Intake
between valve
stem and valve
Exhaust
guide
Valve
Valve
system
Stand value
for assembly
φ10.950~
φ10.970
φ10.935~
φ10.955
Limit
for use
0.030~0.065
0.15
Replace
valve & guide
0.045~0.080
0.18
Replace
φ10.87
φ10.84
Thickness
of valve
Intake
1.5
1 or more
Exhaust
1.5
0.9 or more
Perm. radial
run-out between
valve stem &
valve head
Intake
0.04 ~ 0.07
0.2
Exhaust
0.04 ~ 0.07
0.25
0.01 ~ 0.39
-
22
-
22
-
75.5
72
61.8~68.3
61.8
1.0
2.0
65
61.75
36.1~39.9
36.1
1.0
2.0
75.5
72
61.8~68.3
61.8
1.0
2.0
0.3
-
0.3
-
Correction
Replace
valve & guide
Remark
Replace valve
uide together
when replacing
valve
Replace
Replace
Clearance between valve
guide & cyl. head
installing hole
Clearance
Intake
between valve
guide & valve
Exhaust
spring seat
Free length
Spring tension
(set length:
Intake
37mm) kg
spring
Straightness
(against free
length)
Free length
Spring tension
(set length:
Inner 34mm) kg
Straightness
Exha
(against free
ust
length)
sprin
Free length
g
Spring tension
(set length:
Outer 37mm) kg
Straightness
(against free
length)
Valve
Intake
clearance
Exhaust
(at cold)
Contacting face of valve
stem & rocker arm
Clearance between
rocker arm shaft &
rocker arm bush
-
-
0.020~0.093
0.2
φ23.978~φ23.9
59
Permissible taper of push rod
0.3
Rocker arm shaft for wear
Apply oil to valve
guide & press in
Replace
valve spring
Replace
valve spring
Adjust
Correct or replace
if severely pitted
on tip of arm and
stem
Replace bush
or shaft
φ23.75
Replace
-
Replace
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Group
Part
Valve
Tappet
system
Check
Clearance between
tappet & cyl. block
Outside diameter
of tappet
Contacting face of
tappet & cam
Oil
pressure
Oil pressure
2
(normal speed) kg/cm
Oil pressure (idling)
kg/cm2
Max. permissible
oil temperature °C
Oil
Permissible
temp.
oil temperature
in short time °C
Axial play of oil pump
gear
Clearance between
gear shaft & oil pump
over hole
Clearance between
drive gear bushing &
cover hole
Outside diameter of
gear shaft
Oil
Outside diameter of
pump
Lubrica
drive gear bushing
ting
Between
system
crank gear &
oil pump drive
gear
Backlash Between oil
pump drive
gear &
intermediate
gear
Oil pressure control
valve (kg/cm2 )
By-pass valve for filter
2
element (kg/cm )
By-pass valve for full
Valve
oil filter (kg/cm2 )
opening
pressure By-pass valve2 for oil
cooler (kg/cm )
Relief valve for oil
2
pump (kg/cm )
Control valve for spray
nozzle (kg/cm2 )
Oil
Oil filter element for
filter
damage
Stand value
for assembly
Limit
for use
0.035~0.077
0.15
Replace tappet
φ19.944~
φ19.965
-
Replace tappet
-
-
4.5 or less
3.5
0.8~1.4
0.6
-
105
-
120
0.055~0.105
-
Correction
Remark
Replace if
excessively worn
of deformed
Correct oil leakage
and clearance
between each part
Use suggested oil
Temperature above
this not allowable
Replace gear
or cover
0.032~0.068
-
0.040~0.082
-
Replace bushing
or cover
-
Replace gear
φ17e7
-
Replace bushing
φ28e7
φ16.950~
φ16.968
φ27.939~
φ27.960
0.15~0.25
0.8
Adjust backlash
0.15~0.25
0.8
4.3 ~ 4.7
-
1.8 ~ 2.3
-
4.0 ~ 4.8
-
5~6
-
8.5 ~ 11.5
-
1.5 ~ 1.8
-
-
-
Replace valve
Clean or replace
Printed in Sep. 2008 PS-MMG0715-E1B
DE12T/P126TI
Operation and Maintenance Manual
Group
Part
Radiator
Cooling
system
Water
pump
Cooling
water
temp
Thermostat
Check
-
-
Correct or replace
Test for leakage
(air pressure) (kg/cm2 )
1.0
-
Submerge in water
and replace if air
bubbles found
0.5
-
0.2
-
Approx. 270
-
0.3~0.6
-
90~95
95
103
103
83
-
95 or lower
-
-
-
Correct or replace
-
-
Clean or replace
220
-
Adjust by shim
1.6
-
Replace valve
4.3
-
Replace cyl. head
& nozzle
0.2 ~ 0.4
-
-
-
24 ~ 28
24 or
more
±10% or less
against
average
-
Pressure valve for
opening pressure
(kg/cm2 )
Negative pressure valve
for opening pressure
(kg/cm2 )
Delivery volume l/min
- Engine speed 1,800rpm
- Water temp. 24°C
2
- Back pressure : 1 kg/cm
Clearance between
pump impeller & pump
body
Operating temperature
(permissible temp.) °C
Permissible temperature
in a short time °C
Thermostat
opening temp. °C
Remark
Replace if
contacted impeller
& pump body
Temperature above
this not allowable
Replace if defective
(under atmospheric pressure)
Running-in the engine
pressure
Correction
Radiator & water pump
for corrosion, damage &
improper connecting
Full operating temp. °C
Fuel pipe, injection pipe
& nozzle holder for
Piping &
damage, cracks,
the
looseness, bad packing
other
Fuel filter element for
damage
Fuel
Injection pressure of injection
system nozzle (kg/cm2)
Operating pressure of overflow
2
valve (kg/cm )
Height of projected nozzle on the
cyl. head (mm)
Clearance between injection pump
coupling and coupling (mm)
Inspecti
on at
completi
Cylinder
on
Stand value
Limit
for assembly for use
Cylinder compression
2
pressure of cylinder (kg/cm )
Compression pressure
difference of each cylinder
Stroke : min. 8mm
Refer to
supplement
“running-in”
Overhaul the
engine
Correct
1st :160 , 2nd : 220
Retighten head bolt
after running in
at 200rpm or more
(20°C)
Printed in Sep. 2008 PS-MMG0715-E1B
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