Mitsubishi S4Q User manual

FOREWORD
This service manual is written to familiarize you with the maintenance of your S4Q, S4Q2 Diesel Engine. If the
engine is carefully maintained it will deliver a long productive life and efficient performance marked by power and
economy.
Before you attempt to inspect, disassemble, or repair the engine, read this manual carefully to learn more about the
engine and how to care for it properly. All descriptions, illustrations, specifications, and serial numbers in this manual
are effective as of the date printing of this manual.
The information contained in this manual applies to the engine model produced at the time of publication.
It should be noted that specifications and design may change due to improvements made thereafter.
Service Manual
Mitsubishi SQ-Series diesel engines
Version 08/2004
Copyright © 2004 MHI Equipment Europe B.V.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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How to use this manual
Following is a brief summary of the system used in compiling this service manual.
1.
2.
3.
4.
5.
The sections of the manual and their contents are listed in the index furnished at the beginning of the manual.
The contents of each section are listed in the index furnished at the beginning of the section.
The parts read in the texts or shown in the disassembled views are numbered in the disassembly sequence.
What to be inspected for during disassembly are indicated in
in the disassembled views.
The maintenance standards or specifications to be referred to for inspection and repair are indicated in easy-torefer passages of the texts and also in Section 11 in a tabulated form.
The following symbols are used in this manual to emphasize important and critical instructions:
NOTE
An operating procedure, condition, etc. that will help you work more efficiently.
CAUTION
Indicates operating procedure, practice, etc., resulting in personal injury or
damage to or destruction of engine.
WARNING
Indicates a specific potential hazard resulting in bodily injury.
6.
The following terms are used in the dimensional and other specifications:
Nominal Value
Assembly Standard
Standard Clearance
Repair Limit
Service Limit
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Indicates the standard dimension of a part.
Indicates the dimension of a part, the dimension to be attained at the time of reassembly
or the standard performance. The value is rounded to the nearest whole number needed
for inspection and is different from the design value.
Indicates the clearance to be obtained between mating parts at reassembly.
A part which has reached this limit must be repaired.
A part which has reached this limit must be replaced.
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TABLE OF CONTENTS
TABLE OF CONTENTS
GENERAL
1
2
OUTLINE........................................................................................................................................... 8
1.1 External View ........................................................................................................................... 8
1.2 Engine Serial Number Location ............................................................................................... 9
1.3 Engine Model and Application Codes ...................................................................................... 9
SPECIFICATIONS .......................................................................................................................... 10
GENERAL INSTRUCTIONS
3
4
5
6
DETERMINATION OF OVERHAUL TIMING .................................................................................. 12
TESTING THE COMPRESSION PRESSURE................................................................................ 13
TIPS ON DISASSEMBLY AND REASSEMBLY.............................................................................. 15
5.1 Disassembly........................................................................................................................... 15
5.2 Reassembly ........................................................................................................................... 15
PRECAUTIONS FOR DISASSEMBLY AND REASSEMBLY ......................................................... 16
6.1 Oil Seals................................................................................................................................. 16
6.2 O-rings ................................................................................................................................... 16
6.3 Bearings................................................................................................................................. 17
6.4 Lock Plates ............................................................................................................................ 17
6.5 Split Pins and Spring Pins...................................................................................................... 17
ENGINE MAIN PARTS
7
8
9
10
CYLINDER HEADS AND VALVE MECHANISM............................................................................. 20
7.1 Disassembly........................................................................................................................... 20
7.2 Inspection............................................................................................................................... 24
7.3 Reassembly ........................................................................................................................... 32
7.4 Valve Clearance Adjustment.................................................................................................. 36
FLYWHEEL ..................................................................................................................................... 38
8.1 Disassembly........................................................................................................................... 38
8.2 Inspection............................................................................................................................... 40
8.3 Reassembly ........................................................................................................................... 41
TIMING GEARS, CAMSHAFT AND OIL PAN................................................................................. 43
9.1 Disassembly........................................................................................................................... 43
9.2 Inspection............................................................................................................................... 48
9.3 Reassembly ........................................................................................................................... 53
PISTONS, CONNECTING RODS, CRANKSHAFT AND CRANKCASE......................................... 58
10.1 Disassembly........................................................................................................................... 58
10.2 Inspection............................................................................................................................... 64
10.3 Reassembly ........................................................................................................................... 76
INLET AND EXHAUST SYSTEM
11
12
DESCRIPTION................................................................................................................................ 86
DISASSEMBLY, INSPECTION AND REASSEMBLY ..................................................................... 87
COOLING SYSTEM
13
14
15
DESCRIPTION................................................................................................................................ 90
WATER PUMP, FAN....................................................................................................................... 91
14.1 Inspection............................................................................................................................... 91
THERMOSTAT................................................................................................................................ 92
15.1 Inspection............................................................................................................................... 92
FUEL SYSTEM
16
17
18
19
20
DESCRIPTION................................................................................................................................ 94
FUEL SYSTEM BLEEDING ............................................................................................................ 95
DISASSEMBLY ............................................................................................................................... 96
FUEL INJECTION TIMING CHECK ................................................................................................ 98
FUEL FILTER (PAPER-ELEMENT CARTRIDGE TYPE) ............................................................. 100
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TABLE OF CONTENTS
21
20.1 Disassembly and Inspection ................................................................................................ 100
FUEL INJECTION NOZZLES........................................................................................................ 101
21.1 Disassembly......................................................................................................................... 101
21.2 Testing ................................................................................................................................. 102
21.3 Reassembly ......................................................................................................................... 104
LUBRICATION SYSTEM
22
23
24
25
DESCRIPTION.............................................................................................................................. 106
OIL PUMP ..................................................................................................................................... 107
23.1 Disassembly......................................................................................................................... 107
23.2 Inspection............................................................................................................................. 107
23.3 Reassembly ......................................................................................................................... 108
OIL FILTER ................................................................................................................................... 109
24.1 Inspection............................................................................................................................. 109
PRESSURE RELIEF VALVE ........................................................................................................ 110
25.1 Inspection............................................................................................................................. 110
ELECTRICAL SYSTEM
26
27
28
29
30
GENERAL ..................................................................................................................................... 112
26.1 Wiring diagrams ................................................................................................................... 112
STARTER...................................................................................................................................... 114
27.1 Inspection before disassembly (inspection of assembly)..................................................... 114
27.2 Removal............................................................................................................................... 116
27.3 Disassembly......................................................................................................................... 117
27.4 Inspection............................................................................................................................. 118
27.5 Reassembly ......................................................................................................................... 121
27.6 Inspection and testing after reassembly .............................................................................. 122
ALTERNATOR .............................................................................................................................. 124
28.1 On-vehicle inspection........................................................................................................... 124
28.2 Removal............................................................................................................................... 126
28.3 Disassembly......................................................................................................................... 127
28.4 Inspection............................................................................................................................. 129
28.5 Assembly ............................................................................................................................. 132
28.6 Installation............................................................................................................................ 132
ETR type stop solenoid ................................................................................................................. 134
29.1 General ................................................................................................................................ 134
29.2 Solenoid specification .......................................................................................................... 135
29.3 Inspection............................................................................................................................. 136
29.4 Connecting rod adjustment .................................................................................................. 136
GLOW PLUGS .............................................................................................................................. 137
30.1 Removal............................................................................................................................... 137
30.2 Inspection............................................................................................................................. 137
30.3 Installation............................................................................................................................ 137
TESTING AND ADJUSTING
31
32
33
BENCH TEST................................................................................................................................ 140
31.1 Starting Up ........................................................................................................................... 140
31.2 Inspection after Starting Up ................................................................................................. 140
31.3 Bench Testing (Dynamometer) Conditions .......................................................................... 141
31.4 Inspection and Adjustment after Bench Testing .................................................................. 141
IDLING SPEED AND MAXIMUM SPEED SETTING INSPECTION AND ADJUSTMENT............ 142
PERFORMANCE TEST ................................................................................................................ 144
33.1 Engine Equipment Condition ............................................................................................... 144
33.2 Tests and Their Purposes.................................................................................................... 144
33.3 Other Inspections................................................................................................................. 144
33.4 Adjustment Engine Output ................................................................................................... 144
TROUBLESHOOTING
34
CAUSES OF ENGINE PROBLEMS AND REMEDIES ................................................................. 149
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Service Manual Mitsubishi SQ-Series diesel engines
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MAINTENANCE STANDARDS
35
36
37
38
MAINTENANCE STANDARDS TABLE......................................................................................... 160
TIGHTENING TORQUES ............................................................................................................. 166
36.1 Important Bolts and Nuts ..................................................................................................... 166
36.2 Standard Bolts ..................................................................................................................... 167
36.3 Standard Studs .................................................................................................................... 167
36.4 Standard Plugs .................................................................................................................... 167
THREAD SEALANTS.................................................................................................................... 168
MAINTENANCE SCHEDULE........................................................................................................ 169
SPECIAL TOOLS
39
SPECIAL TOOL LIST.................................................................................................................... 172
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Service Manual Mitsubishi SQ-Series diesel engines
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GENERAL
Service Manual Mitsubishi SQ-Series diesel engines
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OUTLINE
GENERAL
GENERAL
1
OUTLINE
1.1
External View
Hanger
Hanger
Thermostat
Exhaust manifold
Fan
Thermoswitch
Engine serial number
Alternator
Dipstick
Oil pressure switch
Crankshaft pulley
Oil filter
Flywheel housing
REAR
FRONT
RIGHT SIDE VIEW
Top oil filler
Fuel filter
Inlet cover
Air inlet elbow
Air vent screw
Fuel injector
Water pump
Stop solenoid
Fuel injection pump
Speed control lever
Fuel feed pump
Coolant drain plug
Starter
V-belt
Flywheel
Oil pan
Flywheel housing
Oil drain plug
REAR
FRONT
LEFT SIDE VIEW
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
GENERAL
OUTLINE
Note
Rotation of crankshaft is counterclockwise when seen
from flywheel end.
1.2
Engine Serial Number Location
The engine serial number is located on the side of the
crankcase.
1.3
Engine Model and Application
Codes
e.g. S 4 Q
S - Initial of “Sagamihara Machinery Works”
4 - Number-of-cylinders
Q - Series code
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SPECIFICATIONS
GENERAL
GENERAL
2
Engine model
SPECIFICATIONS
S4Q
Type
S4Q2
In-line, water-cooled, 4-stroke cycle
Firing order
1-3-4-2
Compression ratio
General
22
Combustion chamber type
Swirl chamber type
Weight (dry) kg [lb]
195 [430]
Number of cylinders
4
Bore x stroke mm [in.]
88 x 95 [3.46 x 3.74]
88 x 103 [3.46 x 4.06]
2.311 [141]
2.505 [153]
Displacement liter [cu in.]
Maximum permissible working angles for oil pickup
level in oil pan, longitudinal and lateral
Fuel system
10°
Injection pump, type
Bosch A
Injection nozzle, type
Bosch throttle
Fuel filter, type
Spin-on
Type
Lubrication
system
Electrical
system
Force feed
Oil filter, type
Spin-on cartridge of paper-element
Capacity liter [U.S. gal.]
Oil pan: 5.5 [1.5], approx.
Crankcase: 6.5 [1.7], approx.
Starter V-kW
12-2
Alternator V-A
12-50
Battery recommended
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12V-92Ah
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
GENERAL INSTRUCTIONS
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DETERMINATION OF OVERHAUL TIMING
GENERAL INSTRUCTIONS
GENERAL INSTRUCTIONS
3
DETERMINATION OF
OVERHAUL TIMING
In most cases the engine should be overhauled when
the engineís compression pressure is low. Other
factors that indicated the necessity of engine overhaul
are as follows:
1.
2.
3.
4.
5.
6.
7.
Decreased power.
Increased fuel consumption.
Increased engine oil consumption.
Increased blow-by gas volume through the
breather due to abrasion at the cylinder liner and
the piston ring.
Gas leakage due to poor seating of the inlet and
the exhaust valves.
Starting problems.
Increased noise from engine parts.
Any one or a combination of these symptoms may
indicate that engine overhaul is required. Of the items
listed above some are not directly related to the
necessity of engine overhaul. Items (2) and (6) are
more likely to be affected substantially by
•
•
•
•
•
Injection volume of the fuel injection pump
Fuel injection timing
Wear of injection-pump plunger
Fitting of the injection nozzle
Condition of electrical equipment: battery, starter,
or alternator
Item (4) above, however, requires special consideration
because decreased pressure due to wear at the
cylinder liner and the piston ring is one of the most
obvious signs that the engine requires overhauling.
The most effective way to make a decision is by testing
the compression pressure; other factors are to be
considered secondarily.
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TESTING THE COMPRESSION
PRESSURE
GENERAL INSTRUCTIONS
GENERAL INSTRUCTIONS
4
TESTING THE
COMPRESSION
PRESSURE
Compression
gage adapter
Start by:
a. Make sure the engine oil, air cleaner, starter
and battery are normal
b. Start the engine and allow it to warm up
thoroughly
1.
2.
Figure 1
Measuring compression pressure
3.
4.
Move the stop lever to the stop position.
Remove the glow plugs from all cylinder heads.
Connect compression gage (33391-02100) to the
cylinder on which the compression is to be
measured with compression gage adaptor (3069121100).
Crank the engine with the starter, then read the
compression gage indication while the engine is
running at the specified speed.
If the compression pressure is lower than the
repair limit, overhaul the engine.
CAUTION
a. Measure the compression pressure on all
cylinders.
b. Compression pressure varies with the
engine speed. Check the engine speed
when measuring the compression
pressure.
Unit: MPa (kgf/cm2) [psi]
Item
Compression pressure
Assembly
Standard
Repair
Limit
2.94
(30)
[427]
2.55
(26)
[370]
NOTE
Meaure the compression pressure with the engine
running at 150 to 200 rpm
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TESTING THE COMPRESSION
PRESSURE
GENERAL INSTRUCTIONS
CAUTION
a. Measure the compression pressure at
regular intervals to obtain correct data.
b. The compression pressure will be slightly
higher in a new or overhauled engine due
to new piston rings, valve seats, etc.
Pressure will drop gradually by the wear
of parts.
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TIPS ON DISASSEMBLY AND
REASSEMBLY
GENERAL INSTRUCTIONS
GENERAL INSTRUCTIONS
5
TIPS ON DISASSEMBLY
AND REASSEMBLY
This service manual covers recommended procedures
to be followed when servicing diesel engines. It also
contains information on special tools required and
basic safety precautions.
It is the responsibility of service personnel to be familiar
with these requirements, precautions and potential
hazards and to discuss these points with their foreman
or supervisor.
Study this manual carefully and observe the following
general precautions to prevent serious personal injury
and to avoid damage to the engine, equipment and
parts.
5.1
1.
2.
3.
4.
5.
6.
5.2
1.
2.
3.
4.
5.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Disassembly
Use the correct tools and instruments. Serious
injury or damage to the engine can result from
using the wrong tools and instruments.
Use an overhaul stand or a work bench if
necessary. Also, use assembly bins to keep the
engine parts in order of removal.
Lay down the disassembled or cleaned parts in the
order in which they were removed. This will save
you time at reassembly.
Pay attention to the marks on assemblies,
components and parts for positions or directions.
Put on your own marks, if necessary, to aid
reassembly.
Carefully check each part for faults during removal
or cleaning. Signs of abnormal wear will tell if parts
or assemblies are functioning improperly.
When lifting or carrying heavy parts, get someone
to help you if the part is too awkward for one
person to handle. Use jacks and chain blocks
when necessary.
Reassembly
Wash all parts, except for oil seals, O-rings, rubber
seals, etc., in cleaning solvent and dry them with
compressed air.
Always use tools that are in good condition and be
sure you understand how to use them before
performing any service work.
Use only good quality lubricating oils and greases.
Be sure to apply a coat of oil, grease or sealant to
parts as specified.
Use a torque wrench to tighten parts when
specified tightening torques are required.
Replace all gaskets and packing.
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PRECAUTIONS FOR DISASSEMBLY AND
REASSEMBLY
GENERAL INSTRUCTIONS
GENERAL INSTRUCTIONS
6
PRECAUTIONS FOR
DISASSEMBLY AND
REASSEMBLY
6.1
Oil Seals
When installing oil seals, carefully observe the
following points.
6.1.1 Driving oil seals into housings
Figure 2
1.
Check the seal lip for damage, and be sure to
position correctly in the housing.
2.
Apply a smear of grease to the surface of the oil
seal (to be fitted into the housing bore).
3.
Using an oil seal driver shown to guide the seal lip
and drive the outer diameter squarely. To avoid
damage to the oil seal and leaking, never hammer
on it directly.
Oil seal installer
6.1.2 Driving oil seals onto shafts
Figure 3
1.
Apply a smear of grease to the oil seal lip.
2.
Use an oil seal guide of the type shown when
driving the oil seal over the stepped portion,
splines, threads, or key way to prevent damage to
the oil seal lip.
Oil seal guide
6.2
O-rings
Use an O-ring guide to install an O-ring over stepped
parts, splines, threads, or key way to prevent damage
to the ring. Apply a smear of grease to the O-ring
before installation.
Figure 4
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O-ring guide
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PRECAUTIONS FOR DISASSEMBLY AND
REASSEMBLY
GENERAL INSTRUCTIONS
6.3
Figure 5
Figure 6
Bearings
1.
When installing a rolling bearing, be sure to push
the inner or outer race by which the bearing is
fitted. Be sure to use a bearing driver like the one
shown.
2.
Whenever possible, use a press to minimize shock
to the bearing and to assure proper installation.
Bearing driver
Installing a bearing with a press
6.4
Lock Plates
Bend lock plates against the flats of the nuts or bolt
heads as shown.
Good
Good
Bad
Bad
Good
Bad
Good
Figure 7
Bending lock plates
6.5
Split Pins and Spring Pins
Generally, split pins are to be replaced once disturbed.
Insert the pin fully and spread it properly. Drive each
spring pin into position to hold it in place after later
installation of parts has been completed.
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PRECAUTIONS FOR DISASSEMBLY AND
REASSEMBLY
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GENERAL INSTRUCTIONS
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGINE MAIN PARTS
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CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
ENGINE MAIN PARTS
7
CYLINDER HEADS AND
VALVE MECHANISM
7.1
Disassembly
16
21
22
High-speed option
1.
2.
3.
4.
5.
6.
7.
8.
Rocker cover
Adjusting screw
Bolt (short)
Bolt (long)
Valve cap
Snap ring
Rocker arm
Rocker shaft bracket
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9.
10.
11.
12.
13.
14.
15.
Rocker shaft spring
Rocker shaft
Valve pushrod
Cylinder head bolt
Cylinder head
Valve cotters
Upper valve retainer
ENGLISH
16.
17.
18.
19.
20.
21.
22.
Valve spring
Valve (inlet)
Valve (exhaust)
Valve stem seal
Cylinder head gasket
Inner valve spring
Lower valve spring
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.1.1 Removing rocker shaft assembly
1)
2)
Loosen the adjusting screw one turn.
Loosen the bolts, long and short, that hold the
rocker shaft bracket to the cylinder head. Be
sure to loosen the short bolt first. Remove the
rocker shaft assembly from the cylinder head.
CAUTION
If the long bolt is loosened first, the rocker shaft
bracket might suffer damage.
Figure 8
Removing rocker shaft assembly
7.1.2 Disassembling rocker shaft
assembly
Arrange the disassembled rockers in the order
removed, so you can install them in that order at
reassembly. This will ensure the same rockershaft
clearance as before.
Figure 9
Disassembling rocker shaft assembly
7.1.3 Removing cylinder head
Remove the cylinder head bolts. Lift the head off
the crankcase.
NOTE
If any parts of the cylinder head are faulty, check the
cylinder head bolts for torque with a torque wrench
before removing them.
Figure 10
Removing cylinder head
Valve
spring
pusher
7.1.4 Removing valves and valve springs
Use valve spring pusher (30691-04500) to
compress the valve spring squarely, then remove
the valve cotters.
NOTE
If the existing valves are to be reused, put a mark on
each valve for its location.
Figure 11
Removing valves and valve springs
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CYLINDER HEADS AND VALVE
MECHANISM
Figure 12
ENGINE MAIN PARTS
Removing valves and valve springs (high
speed option)
7.1.5 Removing valve stem seals
Remove the stem seals with a pliers, as shown in
the illustration.
7.1.6 Cleaning cylinder head
Clean the machined surface of the cylinder head
that makes contact with the gasket.
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Service Manual Mitsubishi SQ-Series diesel engines
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CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.1.7 Measuring piston protrusion
1)
2)
3)
Figure 15
Measuring piston protrusion
Determine the top dead center of the piston
with a dial indicator.
Install a dial indicator on the crankcase with its
point on the top of the piston. Set the indicator
to read 0 (zero).
Check the piston protrusion at three points on
the top of the piston, as shown in the
illustration, and average the three
measurements to determine the protrusion.
Subtract the projection from the compressed
thickness of the gasket to determine the
clearance between the piston top and the
cylinder head.
If the piston protrusion is not correct, check
the various parts for clearance.
Unit: mm [in.]
Item
Assembly Standard
Piston protrusion
0.13 to 0.60
[0.0051 to 0.0236]
Compressed thickness of
gasket
1.27 to 1.35
[0.0500 to 0.0531]
CAUTION
Incorrect piston protrusion affects engine
performance and causes valve interference with
piston.
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CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.2
Inspection
Replace
Check surface that makes
contact with walve cap for
wear. Check oil hole for
clogging. Check bushing
for wear.
Check threads for stripping.
Check surface that makes
contact with valve push rod
for wear.
Check for pitted or
fractured coils. Test
force and length.
Check for wear.
Check oil hole for
clogging.
Check ends
faces for wear.
Check for bend.
Replace
Check for wear.
Check for cranks, or
carbon or scale
deposits.
Replace
Check for uneven wear.
Check face for pitting or ridging (exhaust
valve). Check stem for scratches or scuff
marks.
Check for pitted or fractured
coils. Test force and length.
High speed option
Figure 16
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Inspection points
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.2.1 Cylinder head
Using a heavy accurate straight edge and a feeler
gage, check for warpage in three positions lengthwise,
two crosswise and two widthwise, as shown in the
illustration. If warpage exceeds the repair limit, reface
the head with a surface grinder.
Unit: mm [in.]
Item
Figure 17
Checking cylinder head for warpage
Warpage of
bottom face
Assembly
Standard
Repair Limit
0.05
[0.0020] or less
0.20
[0.0079]
7.2.2 Rocker arms and rocker shafts
1.
Measuring rocker arm bushing and rocker shaft
Measure the inside diameter of the rocker arm
(bushing bore) and the diameter of the rocker
shaft, as shown in the illustration, to check the
clearance between the rocker arm and shaft. If the
clearance is not correct, within the repair limit,
replace the rocker arm. If it exceeds the repair
limit, replace both rocker arm and bushing.
Figure 18
Unit: mm [in.]
Measuring rocker arm bushing and rocker
shaft
Item
Nominal
Value
Assembly
Standard
Repair
Limit
Inside diameter
of rocker arm
bushing
19
[0.75]
19.010 to
19.030
[0.7484 to
0.7492]
__
Diameter of
rocker shaft
19
[0.75]
18.980 to
19.000
[0.7472 to
0.7480]
__
__
0.010 to
0.050
[0.0004 to
0.0020]
0.070
[0.0028]
Clearance
between rocker
bushing and
shaft
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CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
2.
Measuring valve spring perpendicularity and free
length
Measure the free length and perpendicularity of
each valve spring. If the free length or
perpendicularity exceeds the service limit, replace
the spring.
Perpendicularity
Unit: mm [in.]
Free
length
Figure 19
Assembly
Standard
Service Limit
Free length
48.85 [1.92]
47.60 [1.87]
Perpendicularity
1.5° or less
__
Set force N (kgf)
[lbf]
177 to 196
(18 to 20)
[40 to 44]
147
(15)
[33]
Item
Measuring valve spring perpendicularity
and free length
Inner valve spring (high-speed option)
Unit: mm [in.]
Assembly
Standard
Service Limit
Free length
50.0 [1.9685]
49.0 [1.9291]
Perpendicularity
1.5° or less
__
Set force N (kgf)
[lbf]
56.9
(5.8)
[12.8]
48.1
(4.9)
[10.8]
Item
7.2.3 Valve pushrods
Using V-blocks and a dial indicator, check for runout, as
shown in the illustration. If runout exceeds the
assembly standard, replace the pushrod.
Unit: mm [in.]
Item
Pushrod runout
Figure 20
Measuring valve pushrod runout
Assembly Standard
0.3 [0.012] or less
NOTE
Assembly standards refer to dial gage readings.
26 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.2.4 Valves, valve guides and valve seats
Measuring
directions
1.
Measuring valve stem
Measure the diameter of the valve stem, as shown
in the illustration. If the service limit is exceeded,
replace the valve.
Unit: mm [in.]
Figure 21
Nominal
Value
Assembly
Standard
Service
Limit
Inlet
valves
8
[0.315]
7.940 to
7.955
[0.3126 to
0.3132]
7.900
[0.3110]
Exhaust
valves
8
[0.315]
7.920 to
7.940
[0.3118 to
0.3126]
7.850
[0.3091]
Item
Measuring points
Measuring valve stem
Valve
stem
diameter
2.
Checking clearance between valve stem and guide
The valve guide wears more rapidly at its both
ends than at any other parts. Measure the inside
diameter of the valve guide at its ends, as shown in
the illustration, to check the clearance. If the
clearance exceeds the service limit, replace the
guide or valve whichever is badly worn.
Inside micrometer caliper
Unit: mm [in.]
Item
Figure 22
Nominal
Value
Assembly
Standard
__
0.065 to
0.095
[0.0026 to
0.0037]
Measuring valve guide
Clearance
between
valve
stem and
guide
Inlet
valves
Exhaust
valves
Height to top of valve
guide
__
0.080 to
0.115
[0.0032 to
0.0045]
15.5
[0.61]
15.1 to 15.6
[0.5945 to
0.6142]
Repair
Limit
0.200
[0.0079]
__
NOTE
Before measuring the valve guides, clean the guides,
removing lacquer or other deposits by running wire
brush through them.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
27 / 174
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
3.
Replacing valve guide
1)
Valve guide remover
2)
To remove the valve guide for replacement,
use valve guide remover (32A91-00300).
To install a replacement valve guide, use valve
guide installer (32A91-00100) and a press.
CAUTION
Valve
guide
The height to top of valve guide is specified; be sure
to use the valve guide installer to insure the correct
height.
Figure 23
3)
Replacing valve guide
4)
Valve guide installer
15.5 mm
[0.61 in.]
Press
Insert a new valve into the guide just installed
to check how the valve slides in the guide.
After replacing the valve guides, check the
valve contact with the seats.
Valve guide
Figure 24
Installing valve guide
4.
Inspecting valve face
Coat the valve face lightly with red lead. Use the
Valve lapper to inspect the valve contacts with its
seat. If the contact is not uniform, or if the valve is
defective or if the service limit is exceeded, repair
or replace the valve and valve seat.
Valve lapper
Red lead
Figure 25
28 / 174
Inspecting valve face
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
NOTE
a
Check the valve contact after checking or
replacing the valve guides.
Do not rotate the valve when holding it
against the seat for checking the contact.
After refacing or replacing the valve or valve
seat, lap the valve in the seat. (See (8)
Lapping valves.)
b
c
Good
Figure 26
Bad
Valve contact pattern
Unit: mm [in.]
Item
Valve seat width
Width
1.18
[0.05]
1.04 to 1.32
[0.0409 to 0.0520]
1.6
[0.0630]
Valve
sinkage
0.8
[0.03]
0.7 to 0.9
[0.0276 to 0.0354]
1.3
[0.0512]
Valve margin
1.70
[0.07]
Valve
margin
1.20
[0.0472]
Valve contact with valve seat
5.
S
Replacing valve seat
1)
Weld
Bar
Valve seat
Stud
Figure 28
Repair
Limit
30°
Valve seat
Figure 27
Assembly
Standard
Angle
Valve seat angle
Valve
sinkage
Nominal
Value
Weld a stud to the valve seat. Insert a shaft
through the valve guide from the upper side of
the cylinder head to put its end on the stud, as
shown in the illustration. Then, drive the seat
off from the cylinder head.
NOTE
When welding the stud to the valve seat, avoid
contact of any spatter with the machined surface of
the cylinder head.
Replacing valve seat
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
29 / 174
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
2)
45°
Figure 29
8.8 ± 0.1
[0.346 ± 0.004]
2.8 ± 0.1
[0.11 ± 0.004]
2.8 ± 0.1
[0.11 ± 0.004]
8.8±0.1
[0.346 ± 0.004]
Unit: mm [in.]
41 +0.02
0
33 +0.02
0
[1.61 +0.0008
]
0
[1.30 +0.0008
]
0
Inlet valve
seat bore
Exhaust valve
seat bore
3)
4)
Before inserting a new valve seat, measure
the bores in the cylinder head for the valve
seats to make sure they are correct in
dimension.
Chill the valve seat in liquid nitrogen (about –
170°C [–274°F]) for more than 4 minutes with
the cylinder head kept at normal temperature,
or heat the cylinder head to 80 to 100°C [176
to 212°F] with the valve seat chilled in ether or
alcohol containing dry ice.
Use the caulking tool to install the valve seat.
45°
Valve seat bore dimensions
Tools needed
Caulking tool
Figure 30
Part number
Caulking tool (for inlet valve
seat)
30691-02700
Caulking tool (for exhaust
valve seat)
30691-02800
Installing valve seat
6.
Refacing valve face
If the valve face is badly worn, reface it with a
valve refacer.
NOTE
a
b
Figure 31
30 / 174
Set a valve refacer at an angle of 30°.
Grind the valve as little as possible. If the
margin seems to exceed the repair limit as a
result of grinding, replace the valve.
Refacing valve face
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.
Refacing valve seat
Use the Valve seat cutter or valve seat grinder to
reface the valve seat. After refacing, grind the seat
lightly using #400 grade sandpaper inserted
between the cutter and valve seat.
NOTE
a
b
Figure 32
Refacing valve seat
8.
Cut or grind the valve seat only as needed
for refacing.
Replace the valve seat if the seat width is
more than the repair limit as a result of wear
or cutting.
Lapping valve in valve seat
Be sure to lap the valve in the valve seat after the
seat has been replaced.
1)
Compound
NOTE
a
b
Figure 33
Lapping valve in valve seat
c
2)
3)
4)
5)
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Coat the valve face lightly with a lapping
compound.
ENGLISH
Do not permit the compound to come in
contact with the valve stem.
Use a compound of 120 to 150 mesh for
initial lapping and the compound finer than
200 mesh for finish lapping.
Mixing the compound with a small amount of
engine oil will facilitate coating.
Use the Valve lapper to lap the valve in the
seat. To lap, raise the valve off the seat, then
rotate the valve only a partial turn and strike it
against the seat.
Wash off the compound with diesel fuel.
Coat the valve face with engine oil, and again
lap the valve.
Check the valve face for contact.
31 / 174
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.2.5 Replacing combustion jets
Replace the combustion jets when they are cracked or
otherwise faulty.
Round bar
(6 mm [0.24 in.] diameter)
1)
2)
Combustion
jet
Figure 34
Combustion
jet
To remove the combustion jet, tap the jet off
the cylinder head with a 6 mm [0.24 in.]
diameter round bar inserted through the glow
plug hole, as shown in the illustration.
To install a replacement jet, position the jet so
that the orifice is toward the center of the
cylinder and drive it into position with a plastic
hammer.
Removing combustion jet
15°
Orifice
Center of
cylinder
Figure 35
Installing combustion jet
7.3
1.
Stem seal
installer
Reassembly
Installing valve stem seal
1)
2)
3)
Stem seal
Valve guide
Apply engine oil to the valve stem and put the
valve in the valve guide.
Put a new stem seal on the valve guide.
Using stem seal installer (32A91–00200),
install the stem seal to the valve guide,
making use of the valve stem as a guide.
Valve
Figure 36
32 / 174
Installing valve stem seal
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
Valve spring pusher
2.
Installing valve and valve spring
1)
Put the valve spring and retainer on the valve
guide. Using valve spring pusher (30691–
04500), compress the valve spring and install
the valve cotters to the valve.
CAUTION
Figure 37
Installing valve and valve spring
Compressing the valve spring excessively will cause
the retainer to make contact and damage the stem
seal.
Valve spring
pusher
Figure 38
Installing valve and valve spring (highspeed option)
2)
Figure 39
Tap the top of the valve with a soft faced
hammer several times to make sure the valve
spring and valve cotters are properly installed.
Testing valve cotter installation
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
33 / 174
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
3.
Installing cylinder head gasket
1)
2)
Make sure the machined surface of the
crankcase and the top of the pistons are
clean.
Put a new gasket on the crankcase with “UP”
mark side up. Make sure the locating dowels
enter their holes in the gasket.
CAUTION
Do not use any sealant.
Figure 40
Installing cylinder head gasket
4.
Installing cylinder head
Put the cylinder head on the crankcase. Make sure
the locating dowels enter their holes in the cylinder
head.
Locating
dowel
Locating
dowel
Figure 41
Installing cylinder head
5.
Tightening cylinder head bolt
Tighten the cylinder head bolts to the specified
torque in the sequence shown.
Front
Tightening torque
Figure 42
34 / 174
118 ± 5 N·m
(12.0 ± 0.5 kgf·m)
[87 ± 4 lbf·ft]
Cylinder head bolt tightening sequence
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
6.
Assembling rocker arms and rocker shaft
When installing the rocker arms to the rocker shaft,
position the arms with their assembly marks pointing forward. After installing the arms, make sure
they move smoothly.
7.
Installing valve pushrod
1)
2)
Assembly mark
Figure 43
Insert the pushrod into position through the
pushrod hole in the cylinder head.
Make sure the ball end of each pushrod rests
securely on the curved surface (R section) of
the tappet.
Assembling rocker arms and rocker shaft
8.
Installation of rocker shaft assembly
1)
2)
Install valve caps.
When installing rocker shaft brackets, tighten
the long bolts first, then tighten the short bolts
(reversal of removal sequence).
Long bolts
15 ± 2 N·m
(1.5 ± 0.2 kgf·m)
[11 ± 1 lbf·ft]
Short bolts
12 ± 1 N·m
(1.2 ± 0.1 kgf·m)
[9 ± 1 lbf·ft]
Tightening
torque
Figure 44
Installing rocker shaft assembly
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
35 / 174
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.4
1.
Valve Clearance Adjustment
Find the top dead center on the compression
stroke for No.1 piston as outlined below:
1)
2)
3)
Figure 45
Finding top dead center on compression
stroke for No. 1 piston — 1
Figure 46
Finding top dead center on compression
stroke for No. 1 piston — 2
2.
Adjusting screw
Insert a 0.25 mm [0.0098 in.] feeler gage into
between the rocker arm and valve cap.
Unit: mm [in.]
0.25 mm
[0.0098 in.]
Lock nut
Using the turning handle (30691–21800), turn
the nut on the crankshaft pulley in the
engineís forward rotating direction (clockwise
when viewed from the front of the engine).
Stop turning when the stamped “0” line on the
periphery of the crankshaft pulley aligns with
the pointer on the turning gear case.
Try to move up and down the inlet and
exhaust valve rocker arms of the No.1 cylinder
to make sure they are not being pushed up by
the pushrods. The No.1 piston is at the top
dead center on the compression stroke when
the rocker arms are not being pushed up by
the pushrods. If the rocker arms are being
pushed up, turn the crankshaft one turn.
Item
Valve
clearance (cold
setting)
Figure 47
36 / 174
Assembly Standard
Inlet
valves
0.13 to 0.60
[0.0051 to 0.0236]
Exhaust
valves
1.27 to 1.35
[0.0500 to 0.0531]
3.
Loosen the lock nut for the adjusting screw and
turn the adjusting screw in either direction until the
feeler gage is slightly gripped between the rocker
arm and valve cap.
4.
After adjusting, tighten the lock nut and recheck
the clearance.
Adjusting valve clearance
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
5.
Adjust the valve clearance on the remaining
cylinders by turning the crankshaft 180° at a time,
in the firing order.
Sequence (cylinder No.)
Turning angle
1–3–4–2
180°
CAUTION
After adjusting the valve clearance on all cylinders,
turn the crankshaft two or three turns and recheck the
clearance.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
37 / 174
FLYWHEEL
ENGINE MAIN PARTS
ENGINE MAIN PARTS
8
FLYWHEEL
8.1
Disassembly
3
2
1
4
Figure 48
Disassembly sequence
1.
2.
3.
4.
38 / 174
ENGLISH
Flywheel
Flywheel housing
Gasket
Oil seal
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGINE MAIN PARTS
FLYWHEEL
1.
Removing flywheel
1)
2)
Have someone hold the crankshaft pulley with
a wrench to prevent the flywheel from turning
during removal.
Remove one of the bolts that hold the
flywheel.
CAUTION
Figure 49
Removing flywheel
During removal, signal each other to avoid personal
injury.
3)
4)
Screw safety bar (M12 x 1.25 mm [0.47 x
0.049 in.]) in the bolt hole and remove the
remaining bolts.
Remove the flywheel from the crankshaft by
pulling it straight.
CAUTION
When removing the flywheel, wear heavy gloves to
protect your hands.
2.
Removing flywheel housing
The flywheel housing is doweled. To remove the
housing, pull it as straight as possible.
Figure 50
Removing flywheel housing
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
39 / 174
FLYWHEEL
ENGINE MAIN PARTS
8.2
Inspection
Check for cracks or
defective dowel holes.
Check friction surface for cracking
scoring, or other defects that affect
serviceability. Examine ring gear for
worn or defective teeth.
Replace
Replace
Figure 51
Inspection points
8.2.1 Flywheel and ring gear
1.
Flatness of flywheel
Put the flywheel on the surface plate. Set a dial
indicator at one side of the friction surface and
move it over to the opposite side of the surface, as
shown in the illustration. If the friction surface is not
flat over the repair limit, regrind it.
Unit: mm [in.]
Item
Figure 52
40 / 174
Checking flywheel
Flatness of flywheel
ENGLISH
Assembly
Standard
Repair
Limit
0.15 [0.0059]
of less
0.50
[0.0197]
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGINE MAIN PARTS
FLYWHEEL
2.
Replacing ring gear
(Removal)
1)
2)
Heat the ring gear evenly with an acetylene
torch.
Tap the ring gear all the way around with a bar
and a hammer to remove it from the flywheel.
(Installation)
Figure 53
Heat a replacement ring gear up to 150°C [302°F]
with a piston heater and install it to the flywheel
with the unchamfered side of the gear teeth foremost.
Removing ring gear
8.3
1.
Flywheel housing
Reassembly
Installing oil seal
Apply a small amount of grease to new oil seal and
drive the oil seal to flywheel housing by using
installer.
Be sure oil seal faces to the correct direction.
Flywheel side
NOTE
Replace, if oil seal sleave running surface of
crankshaft is badly worn.
2 to 3 mm
[0.08 to
0.12 in.]
Figure 54
Installing oil seal
2.
Gasket
Installing flywheel housing
1)
Flywheel
housing
2)
3)
Apply THREEBOND 1104 on the mounting
surfaces of both crankcase and flywheel
housing.
Install the gasket and flywheel housing on the
crankcase by aligning the holes on the
flywheel with the dowel pins on the crankcase.
Tighten the flywheel mounting bolts to the
specified torque.
Tightening torque
Figure 55
60 ± 6 N·m
(6.1 ± 0.6 kgf·m)
[44 ± 4 lbf·ft]
Installing flywheel housing
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
41 / 174
FLYWHEEL
ENGINE MAIN PARTS
3.
Installing flywheel
1)
2)
Install the flywheel in place by using the dowel
pins on the crankshaft for alignment.
Install the washers and bolts, and tighten the
bolts to the specified torque.
Tightening torque
Figure 56
83 ± 5 N·m
(8.5 ± 0.5 kgf·m)
[61 ± 4 lbf·ft]
Installing flywheel
4.
Measurement of flywheel runout
Measure the amount of runout of the installed
flywheel. If the measured value exceeds the
standard value, check the bolts for tightening
condition and the mounting face for foreign
particles.
Item
Flywheel
runout
Figure 57
42 / 174
Assembly
Standard
Repair Limit
0.15 [0.059] or less
0.50
[0.0197]
Measurement of flywheel runout
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
ENGINE MAIN PARTS
9
TIMING GEARS,
CAMSHAFT AND OIL
PAN
9.1
Disassembly
9
8
3
7
5
4
6
1
2
Figure 58
Disassembly sequence
1.
2.
3.
4.
5.
6.
7.
8.
9.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Crankshaft pulley
Cover
Timing gear case
Baffle plate
Idler gear
Oil pan
Oil pump
Camshaft
Front end plate
43 / 174
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
1.
Removing crankshaft pulley
1)
2)
Install two bolts (M12 x 1.25 mm [0.47 x 0.049
in.]) to the rear end of the crankshaft and put a
bar between the bolts to hold the crankshaft,
as shown in the illustration.
Remove the pulley from the crankshaft.
CAUTION
Bolts
(M12 x 1.25 mm)
[0.47 x 0.049 in.]
Figure 59
Make sure the bar will not come off when removing
the pulley.
Removing crankshaft pulley
2.
Removing timing gear case
Remove the timing gear case with the oil pump
drive gear and idler gear from the crankcase. Pull
the case straight off the locating dowels.
CAUTION
The front plate is bolted inside the gear case. Do not
attempt to remove the plate with the case by tapping.
Figure 60
Removing timing gear case
3.
Measuring timing gear backlash
Measure the backlash betw een the gears and
make a record of the measurements to be referred
to at the time of assembly. If the backlash exceeds
the service limit, replace the gears.
Unit: mm [in.]
Item
Figure 61
Measuring timing gear backlash
Backlash between
crankshaft gear and
idler gear
Backlash between
idler gear and
camshaft gear
Backlash between
injection pump drive
gear and idler gear
44 / 174
ENGLISH
Assembly
Standard
0.05 to 0.15
[0.0020 to 0.0059]
Service
Limit
0.25
[0.0098]
0.04 to 0.16
[0.0016 to 0.0063]
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGINE MAIN PARTS
TIMING GEARS, CAMSHAFT AND OIL
PAN
4.
Measuring idler gear end play
Measure the end play with feeler gages or a dial
gage. If the end play exceeds the repair limit,
replace the thrust plate.
Unit: mm [in.]
Item
Assembly
Standard
Service
Limit
End play of idler gear
0.05 to 0.20
[0.0020 to 0.0079]
0.35
[0.0138]
Thrust plate
Figure 62
Measuring idler gear end play
5.
Removing idler gear
Unscrew the bolt and washer and remove the idler
gear.
Figure 63
Removing idler gear
6.
Measuring camshaft end play
Use a dial gage to measure the end play of the
camshaft to which the camshaft gear is installed. If
the end play exceeds the service limit, replace the
thrust plate.
Unit: mm [in.]
Item
End play of camshaft
Figure 64
Assembly
Standard
Service
Limit
0.10 to 0.25
[0.0039 to 0.0098]
0.30
[0.0118]
Measuring camshaft end play
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
45 / 174
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
7.
Turning crankcase upside down
1)
Turn the crankcase upside down.
CAUTION
To prevent damage to the oil pan, do not place the
engine on the floor with the oil pan facing down.
Oil pan
Figure 65
Turning crankcase upside down
2)
3)
Figure 66
Unscrew the bolts that hold the oil pan to the
crankcase. Remove the oil pan.
Remove the gasket.
Removing oil pan and gasket
8.
Removing oil pump
Unscrew the set bolt and remove the oil pump from
the crankcase.
Oil pump
set bolt
Figure 67
46 / 174
Removing oil pump
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
9.
Removing camshaft
1)
2)
Position the camshaft gear so that its
lightening holes are on the top and bottom
sides. Unscrew the bolts that hold the thrust
plate with socket (34491–00300).
Pull the camshaft from the crankcase.
CAUTION
Socket
Figure 68
Do not cause damage to the lobes or bushing
journals when removing the camshaft.
Removing cramshaft
10. Removing front plate
Unscrew the bolts that hold the front plate to the
crankcase. Remove the plate (with the injection
pump) from the crankcase.
Figure 69
Removing front plate
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
47 / 174
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
9.2
Inspection
Replace
Check for wear or damage
Check teeth for wear, nicks burrs or
chips. Check keyway for damage.
Check bushing for wear.
Check for cranks or defective
dowel holes.
Check oil hole
for clogging.
Check for
wear.
Replace
Replace
Replace
Check V-belt groove
and oil seal running
surface for wear.
Figure 70
48 / 174
Inspection points
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
9.2.1 Crankshaft pulley
1.6 mm [0.063 in.]
Check the V-belt groove for wear. Wrap a new belt
around the pulley, pressing it in the groove as far as it
goes, and see if the top surface of the belt is above the
top of the pulley.
If the top surface of the belt (or the belts for the pulleys
having two or more grooves) is uniformly above the top
of the pulley all the way around, it is not necessary to
replace the pulley.
Figure 71
Wear limit of V-belt groove of pulley
If the top surface of the belt sinks into the groove more
than 1.6 mm [0.063 in.], replace the pulley.
9.2.2 Idler gear
1.
Checking clearance between idler gear and shaft
Measure the inside diameter of the idler gear and
the diameter of the shaft, as shown in the illustration, to check the clearance. If the clearance
exceeds the service limit, replace the gear or shaft
whichever is badly worn.
Unit: mm [in.]
Item
Figure 72
Measuring idler gear and shaft
Clearance between
idler gear and shaft
2.
2)
3)
Figure 73
Service
Limit
0.025 to 0.075
[0.0010 to 0.0030]
0.100
[0.0039]
Replacing idler gear bushing
1)
Idler gear
bushing
installer
Assembly
Standard
To replace the bushing, use idler gear bushing
installer (30691–51900).
When installing a replacement bushing, press
it into position until its end is flush with the end
of the gear boss.
After installing the bushing, finish its inside
diameter to 36 (1.42) H7 +0.025
( +0.0098
) 0.8 Ra.
0
0
Replacing idler gear bushing
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
49 / 174
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
3.
Idler gear shaft puller
Replacing idler gear shaft
To remove the shaft for replacement, use idler gear
shaft puller (MH061077).
NOTE
When installing a replacement shaft to the crankcase,
make sure the oil hole in the shaft points upward.
Figure 74
Replacing idler gear shaft
9.2.3 Camshaft
Measuring
points
1.
To fine the lobe lift, use the procedure that follows:
1) Measure lobe height (A).
2) Measure base circle (B).
3) Subtract base circle (B) from lobe height (A).
The difference is lobe lift (C).
If the lobe lift is less than the service limit,
replace the camshaft.
Measuring
directions
Figure 75
Checking lobe lift
Measuring cam lift
Unit: mm [in.]
C
Nominal
Value
Assembly
Standard
Service
Limit
Inlet
valve
A=
+0.1
46.916– 0.3
[1.84709]
[lobe height]
C=
6.684
[0.2631]
C=
6.184
[0.2435]
Exhaust
valve
A=
+0.1
45.944– 0.3
[1.80882]
[lobe height]
C=
7.344
[0.2891]
C=
6.844
[0.2694]
Item
A
Lobe
lift
B
50 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
2.
Measuring
points
Measure the diameter of the camshaft journal and
the inside diameter of the bore in the crankcase (or
bushing) for camshaft, as shown in the illustration,
to check the clearance. If the clearance exceeds
the service limit, replace the camshaft.
Measuring
directions
Figure 76
Checking clearance between camshaft journal and
bore in crankcase (or bushing)
Measuring camshaft journal
Unit: mm [in.]
Nominal
Value
Assembly
Standard
Service
Limit
No. 1
and
No.2
54
[2.13]
53.94 to
53.96
[2.1236 to
2.1244]
53.90
[2.1220]
No. 3
53
[2.09]
52.94 to
52.96
[2.0843 to
2.0850]
52.90
[2.0827]
__
0.07 to
0.11
[0.0028 to
0.0043]
0.15
[0.0059]
No. 1
(61GT
only)
54
[2.13]
54.030 to
54.050
[2.1272 to
2.1280]
__
No. 1
and
No. 2
54
[2.13]
54.030 to
54.050
[2.1272 to
2.1280]
__
No. 3
53
[2.09]
53.030 to
53.050
[2.0878 to
2.0886]
__
Item
Diameter
of
camshaft
journal
Figure 77
Measuring bore in crankcase (bushing) for
camshaft
Clearance between
camshaft journal
and bore in
crankcase (or
bushing) for
camshaft
Inside
diameter
of bushing
Inside
diameter
of bore for
camshaft
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
51 / 174
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
3.
Measuring camshaft deflection
If the deflection exceeds the repair limit, straighten
the camshaft with a press, or replace it with a new
one.
CAUTION
Set up a dial gage on the camshaft, then turn the
camshaft. Take one half (1/2) of the gage indication
as the deflection.
Figure 78
Unit: mm [in.]
Measuring camshaft deflection
Item
Camshaft deflection
4.
Assembly
Standard
Service
Limit
0.02 [0.0008] or
less
0.05
[0.0020]
Removing camshaft gear
To remove the camshaft gear, use a hydraulic
press.
Thrust plate
NOTE
Do not remove the camshaft, thrust plate or gear
unless it requires replacement.
Figure 79
Removing camshaft gear
5.
Installing camshaft gear and thrust plate
1)
2)
3)
Install the key and thrust plate to the
camshaft.
Heat the gear up to a temperature of 250°C
[482°F].
Drive the gear onto the camshaft.
NOTE
Thrust plate
Camshaft gear
Install the thrust plate before installing the gear to the
camshaft.
Figure 80
52 / 174
Installing camshaft gear and thrust plate
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
9.3
1.
Reassembly
Installing front end plate
1)
2)
Put the front end plate and gasket on the front
face of the crankcase. Make sure the locating
dowels enter their holes in the plate and
gasket.
Tighten two bolts to the specified torque.
Tightening torque
Figure 81
12 ± 1 N·m
(1.2 ± 0.1 kgf·m)
[9 ± 1 lbf·ft]
Installing front end plate
2.
Installing camshaft
1)
Apply engine oil to the journals and lobes of
the camshaft.
2)
Install the camshaft (with gear) in the
crankcase.
Apply engine oil
Figure 82
Applying engine oil to camshaft
NOTE
Do not cause damage to the journals and lobes.
3)
Socket
Figure 83
Installing camshaft
Tightening torque
4)
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Tighten the thrust plate bolts to the specified
torque with a torque wrench and socket
(34491–00300).
ENGLISH
12 ± 1 N·m
(1.2 ± 0.1 kgf·m)
[9 ± 1 lbf·ft]
Make sure the camshaft rotates smoothly.
Move the camshaft back and forth in the axial
direction to make sure it has correct end play.
53 / 174
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
3.
Installing oil pump
1)
2)
Gasket
Tightening torque
Oil pump
set bolt
Figure 84
34 ± 4 N·m
(3.5 ± 0.4 kgf·m)
[25 ± 3 lbf·ft]
Installing oil pump
4.
Installing oil pan
1)
2)
Apply THREE BOND
Figure 85
Install the oil pump in position in the
crankcase. Make sure the oil pump gear is
meshing with the oil pump drive gear of the
camshaft.
Install the oil pump set bolt with gasket and
tighten it to the specified torque.
3)
Apply THREE BOND 1207C or 1211, or
equivalent, to the seats formed of the
crankcase for the No.1 and No.5 main bearing
caps just enough to be forced out of the seats
when the oil pan gasket is installed.
Install the oil pan gasket to the bottom of the
crankcase by fitting it into the grooves in the
main bearing caps and into the seats to which
THREE BOND was applied in Step (a), as
shown in the illustration.
Tighten the oil pan bolts to the specified
torque.
Installing oil pan
Tightening torque
5.
7.8 ± 1 N·m
(0.8 ± 0.1 kgf·m)
[5.8 ± 1 lbf·ft]
Turn the crankcase upside down for the steps that
follow.
CAUTION
To prevent damage to the oil pan, do not place the
engine on the floor with the oil pan facing down.
Figure 86
54 / 174
Turning crankcase upside down
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
1)
2)
Apply engine oil to the idler gear shaft.
Install the idler gear with its marks in
alignment with the marks on the injection
pump drive gear, camshaft gear and
crankshaft gear, as shown in the illustration.
3)
Put the thrust plate on the idler gear and
tighten the bolt with washer to the specified
torque.
Move the idler gear back and forth in the axial
direction to make sure it has correct end play.
Injection
pump drive
gear
Camshaft
gear
Crankshaft
gear
Figure 87
Installing idler gear
33
3
2
22
6.
Idler gear
Marks on timing gears
Apply engine oil
4)
Thrust plate
Figure 88
Installing idler gear
7.
Checking timing gear backlash
After installing the timing gears, check them for
backlash, as shown in the illustration.
Unit: mm [in.]
Item
Backlash between crankshaft
gear and idler gear
Backlash between idler gear
and camshaft gear
Figure 89
Checking timing gear backlash
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Backlash between injection
pump drive gear and idler gear
ENGLISH
Assembly
Standard
0.05 to 0.15
[0.0020 to
0.0059]
Service
Limit
0.25
[0.0098]
0.04 to 0.16
[0.0016 to
0.0063]
55 / 174
TIMING GEARS, CAMSHAFT AND OIL
PAN
ENGINE MAIN PARTS
8.
Using an installer, install a new oil seal to the
timing gear case until it is flush with the end face of
the case, as shown in the illustration. The lip of the
seal must be toward the inside of the gear case.
Installer
Figure 90
Installing oil seal
Installing oil seal
9.
40 mm
[1.5748 in.]
Installing timing gear case
1)
2)
3)
4)
50 mm
[1.9685 in.]
Figure 91
Installing timing gear case
Install the oil pump drive gear and idler gear to
the timing gear case. Install the cover in
position.
Install the baffle plate to the crankshaft.
Install the timing gear case and gasket to the
front face of the crankcase. Make sure the
locating dowels enter their holes in the case
and gasket.
Install the eight long bolts (M8 x 1.25 mm
[0.315 x 0.049 in.], 1=50 mm [1.9685 in.]) and
one short bolt (M8 x 1.25 mm [0.315 x 0.049
in.], 1=40 mm [1.5748 in.]), and tighten to the
specified torque.
Tightening torque
12 ± 1 N·m
(1.2 ± 0.1 kgf·m)
[9 ± 1 lbf·ft]
10. Installing crankshaft pulley
1)
2)
3)
Washer
4)
Apply engine oil
Figure 92
Apply engine oil to the oil seal running surface
of the pulley.
Push the pulley on to the crankshaft in
alignment with the keys.
Install two lock bolts (M12 x 1.25 mm [0.47 x
0.049 in.]) to the rear end of the crankshaft
and insert a bar between the bolts to hold the
crankshaft.
Tighten the nut with washer to the specified
torque.
Installing crankshaft pulley
Tightening torque
56 / 174
ENGLISH
392 ± 10 N·m
(40 ± 1 kgf·m)
[289 ± 7 lbf·ft]
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGINE MAIN PARTS
TIMING GEARS, CAMSHAFT AND OIL
PAN
CAUTION
To ensure safety, make sure the bar and bolt used to
prevent the crankshaft from turning have sufficient
strength.
Figure 93
Crankshaft rotation stopper
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
57 / 174
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
ENGINE MAIN PARTS
10 PISTONS,
CONNECTING RODS,
CRANKSHAFT AND
CRANKCASE
10.1 Disassembly
12
13
14
16
11
10
9
7
8
2
15
1
6
5
4
3
Figure 94
58 / 174
Disassembly sequence
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Connecting rod cap
Connecting rod bearing (lower half)
Main bearing cap
Main bearing (lower half)
Crankshaft
Main bearing (upper half)
Connecting rod
Connecting rod bearing (upper half)
Snap ring
Piston pin
Piston
No.1 ring
No.2 ring
Oil ring
Tappet
Crankcase
NOTE
When replacing the crankcase, carefully remove the
parts (such as the relief valve, etc.) from the
crankcase to reuse them at the time of reassembly.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
59 / 174
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
1.
Laying crankcase on its side
Carefully lay the crankcase on its side.
Figure 95
Laying crankcase on its side
2.
Checking thrust clearance of connecting rod bigend
1)
2)
Check the clearance between the connecting
rod big-end and the crankpin with a feeler
gage, as shown in the illustration.
If the thrust clearance exceeds the service
limit, replace the connecting rod.
Unit: mm [in.]
Item
Figure 96
Checking thrust clearance of connecting
rod big-end
Thrust clearance of
connecting rod big-end
(End play)
3.
Matching
marks
Weight rank
mark
Figure 97
60 / 174
Assembly
Standard
Service
Limit
0.15 to 0.35
[0.0059 to 0.0138]
0.50
[0.0197]
Maximum permissible difference between average
weight of all connecting rod assemblies in one
engine
When replacing the connecting rods, select new
connecting rods having the same weight rank
marks so that the difference between average
weight of all connecting rod assemblies in one
engine does not exceeds the maximum
permissible limit.
Maximum permissible difference between
average weight of all connecting rod
assemblies in one engine
10 g
[0.35 oz]
Weight rank mark on connecting rod
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
4.
Removing connecting rod caps
1)
2)
3)
Put a mark on each cap so it can be installed
in the same position from which it was
removed.
Remove the caps and the lower halves of the
connecting rod bearings.
Put a mark on each connecting rod bearing
(lower half) so it can be installed in the same
position from which it was removed.
NOTE
Figure 98
Removing connecting rod caps
Be careful not to cause damage to the bearings.
Arrange the removed bearings in a proper order so
that they can be reinstalled in their original positions
during reassembly.
5.
Removing carbon from cylinders
Use a cloth or sandpaper to remove all carbon
deposits from the upper areas of the cylinder liner.
If any carbon deposits are present, this will make it
difficult to pull a piston upward.
Figure 99
Removing carbon from cylinders
6.
Removing piston and connecting rod
1)
2)
Turn the crankshaft to bring the piston to the
top dead center.
Push the piston and connecting rod away from
the crankshaft with the handle of a hammer
until the piston rings are above the cylinder.
Then remove the piston and connecting rod
from the crankcase.
Figure 100 Removing piston and connecting rod
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
61 / 174
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
Piston ring pliers
ENGINE MAIN PARTS
7.
Removing piston rings
Remove the piston rings with piston ring pliers
(31391–12900).
Figure 101 Removing piston rings
8.
Snap ring
pliers
Removing piston pins
Using ring pliers, remove the snap rings.
Remove the piston pin to separate the piston from
the connecting rod.
If it is difficult to pull out the pin, heat the piston
with a piston heater or in hot water to expand the
pin bore.
Figure 102 Removing piston pins
9.
Turning crankcase upside down
Turn the crankcase upside down with the oil pan
side up.
Figure 103 Turning crankcase upside down
10. Measuring end play of crankshaft
1)
2)
With a dial indicator at the end of the
crankshaft, check the end play, as shown in
the illustration.
If the end play exceeds the service limit,
replace the thrust bearing.
Unit: mm [in.]
Item
Figure 104 Measuring end play of crankshaft
62 / 174
End play of crankshaft
ENGLISH
Assembly
Standard
Service
Limit
0.10 to 0.20
[0.0039 to 0.0080]
0.30
[0.0118]
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
11. Removing main bearing caps
Remove the main bearing caps with lower halves
of the main bearings.
NOTE
Be careful not to cause damage to the main bearings.
Put a mark on each bearing cap so it can be installed
in the same position from which it was removed.
Figure 105 Removing main bearing caps
12. Removing crankshaft
Carefully remove the crankshaft.
NOTE
Be careful not to cause damage to the main journals
and crankpins. Put a mark on each bearing.
Figure 106 Removing crankshaft
13. Orderly arrangement of bearings
If bearings scatter during disassembly, they cannot
be reinstalled in their original positions. Be sure to
arrange the removed bearings in a proper order so
that they can be reinstalled in their original
positions.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
63 / 174
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
10.2 Inspection
Check for wear, score
marks, cracks or
carbon deposits.
Check for wear or damage.
Check for fatigue
Check for scale
deposits, corrosion or
other defects.
Check for wear.
Check for
stripped
threads
Check for wear or
clogged hole.
Check for cracks or
clogged oil hole.
Check for serrated
portions for wear or
cracks.
Check for wear.
Check for cracks, clogged oil
hole or other defects.
Check for nicks, chipping or
abnormal tooth contact.
Check for cracks.
Check for stripped
threads.
Typical failures for which main bearings are to be checked are scratches
due to dirt embedded into bearing material, loss of overlay due to lack of oil,
craters or pockets due to fatigue failure, failure due to poor seating, radius
ride, etc.
Figure 107 Inspection points
64 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
10.2.1 Pistons, piston rings and piston
pins
14 mm
[0.6 in.]
Direction transverse
to piston pin
1.
Measuring piston diameter
1)
Using a micrometer, measure the diameter of
each piston perpendicular to the piston pin (at
the position shown). If the diameter exceeds
the service limit, replace the piston. If any
pistons have to be replaced, select new
pistons so the weight difference in an engine
is within assembly standards.
Figure 108 Measuring piston diameter
Unit: mm [in.]
Front of engine
Nominal
Value
Assembly
Standard
Service
Limit
Standard
87.970
[3.4634]
87.955 to
87.985
[3.4628 to
3.4640]
87.770
[3.4555]
0.25
[0.0098]
oversize
88.220
[3.4732]
88.205 to
88.235
[3.4726 to
3.4738]
88.020
[3.4654]
0.50
[0.0197]
oversize
88.470
[3.4831]
88.455 to
88.485
[3.4825 to
3.4837
88.270
[3.4752]
5 g [0.2 oz]
or less
__
Item
Weight
identification
“Front” mark
Piston diameter
Size
identification
Figure 109 Identification on top of piston
Weight difference in one
engine
2)
2.
No. 1 ring
Checking piston and piston ring
1)
No. 2 ring
The weight of the piston is stamped on the top
of the piston.
Check the clearance between the groove and
the piston ring with a feeler gage, as shown in
the illustration. If the clearance exceeds the
service limit, replace the piston ring.
Unit: mm [in.]
Assembly
Standard
Service
Limit
No. 1
ring
0.060 to 0.100
[0.0024 to 0.0039]
0.200
[0.0079]
No. 2
ring
0.045 to 0.080
[0.0018 to 0.0032]
Oil
ring
0.025 to 0.065
[0.0010 to 0.0026]
Item
Figure 110 Checking between groove and piston ring
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Clearance
between
groove and
piston ring
ENGLISH
0.150
[0.0059]
65 / 174
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
2)
3.
Install a new piston rings and recheck the
clearance. If the clearance still exceeds the
service limit, replace the piston.
Checking clearance between ends of piston ring
Install the piston ring in a new cylinder or a gage
and measure the clearance between the ends of
the ring with a feeler gage. If the clearance
exceeds the service limit, replace all piston rings.
Inside diameters of gages
Standard gage:
88+0.035
mm [3.46+0.0014
in.]
0
0
Figure 111
0.25 mm (0.0098 in.) oversize gage:
Checking clearance between ends of
piston ring
88.25+0.035
mm [3.4744+0.0014
in.]
0
0
0.50 mm [0.0197 in.] oversize gage:
88.50+0.035
mm [3.4843+0.0014
in.]
0
0
NOTE
Use a piston to place the piston ring in the liner by
pushing it squarely.
Unit: mm [in.]
Item
Clearance
between
ends of
piston ring
4.
No. 1, No.
2 ring
Oil ring
Assembly
Standard
0.25 to 0.40
[0.00984 to 0.0157]
0.30 to 0.50
[0.0118 to 0.0197]
Service
Limit
0.150
[0.0059]
Checking clearance between piston pin and bore
Measure the inside diameter of the pin bore of the
piston and the diameter of the pin, as shown in the
illustration, to check the clearance. If the clearance
exceeds the service limit, replace the parts.
Measuring points
Measuring directions
Figure 112 Measuring piston pin and bore
66 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
Unit: mm [in.]
Item
Diameter of
piston pin
Clearance
between
piston pin
and bore
5.
Measuring
directions
Assembly
Standard
Service
Limit
28
[1.10]
27.994 to 28.0000
[1.1021 to 1.1024]
__
0.000 to 0.016
[0.0000 to 0.0006]
0.050
[0.0020]
Checking clearance between connecting rod
bushing and piston pin
Measure the inside diameter of the connecting rod
bushing bore and the diameter of the piston pin, as
shown in the illustration, to check the clearance. If
the clearance exceeds the service limit, replace
the parts.
Measuring
points
Unit: mm [in.]
Nominal
Value
Assembly
Standard
Inside
diameter of
bushing
28
[1.10]
28.020 to 28.045
[1.1031 to 1.1041]
Clearance
between
bushing and
piston pin
__
0.020 to 0.051
[0.0008 to 0.0020]
Item
Figure 113 Measuring connecting rod bushing
Nominal
Value
6.
Weight mark side
Service
Limit
0.080
[0.0032]
Replacing connecting rod bushing
1)
2)
Oil
holes
3)
Use a connecting rod bushing puller to
replace the connecting rod bushings.
When installing a new bushing, align the oil
holes in the bushing and connecting rod.
Position the ends of the bushing at the
location shown in the illustration.
After installing the bushing, insert the piston
pin into position and make sure it rotates
smoothly.
End of bushing
Figure 114 Installing connecting rod bushing
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
67 / 174
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
10.2.2 Connecting rods
Unit: mm (in.)
C 0.05 (0.0020)
---- < ----------------------------------100 (3.94)
1.
Measure “C” and “ ”. If the measurement at C is
larger than 0.05 mm [0.0020 in.] per 100 mm [3.94
in.] of , straighten the rod with a press.
Unit: mm (in.)
Piston pin
C 0.05 (0.0020)
---- < ----------------------------------100 (3.94)
Item
Twist
Bend
Connecting rod
bend and twist
Nominal Value
Assembly
Standard
0.05/100
[0.0020/3.94] or
less
0.15/100
[0.059/3.94]
Figure 115 Inspecting connecting rod
2.
A connecting rod aligner is generally used for
checking the connecting rod for twist and bend.
NOTE
To check the connecting rod for bend, install the cap
to the rod and tighten the cap nuts to the specified
torque.
Figure 116 Checking connecting rod with a
connecting rod aligner
3.
D
C
A
When the measurement is taken with the piston
installed to the connecting rod, place the piston
upside down on a surface plate, insert a round bar
having the same diameter as the crank pin, and
measure the height of the round bar using a dial
gage.
B
Figure 117 Checking connecting rod with a dial
indicator
68 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
Measuring
directions
Measuring
points
54 ± 5 N·m
(5.5 ± 0.5 kgf·m)
[40 ± 4 lbf·ft]
10.2.3 Crankshaft
1.
Checking oil clearance of connecting rod bearing
1)
Install the upper and lower halves of the
bearing and the cap to the connecting rod,
and tighten the cap nuts to the specified
torque. Measure the inside diameter of the
bearing, as shown in the illustration.
Tightening torque
54 ± 5 N·m
(5.5 ± 0.5 kgf·m)
[40 ± 4 lbf·ft]
Figure 118 Measuring connecting rod bearing
2)
Measuring
directions
Measuring
points
Measure the diameter of the crankpin of the
crankshaft, as shown in the illustration, and
subtract the diameter of the crankpin from the
inside diameter of the bearing (Step (1)). The
difference is the oil clearance of the
connecting rod bearing.
Unit: mm [in.]
Item
Figure 119 Measuring crankpin
Diameter of
crankpin
(standard)
Oil clearance
3)
4)
Nominal
Value
Assembly
Standard
Repair
Limit
58
[2.28]
57.955 to 57.970
[2.2817 to
2.2823]
__
__
0.03 to 0.09
[0.0012 to
0.0035]
0.20
[0.0079]
If the oil clearance exceeds the repair limit,
replace the bearing and recheck the oil
clearance.
If the oil clearance still exceeds the repair
limit, use 0.25 mm [0.0098 in.], 0.50 mm
[0.0197 in.] or 0.75 mm [0.0295 in.] undersize
bearings. When using undersize bearings,
refinish the crankpins to any of the undersizes
listed below.
Unit: mm [in.]
Finishing dimension
Undersize
of crankpin
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
0.25
[0.0098]
– 0.030
– 0.0012
57.75
[2.2736
]
– 0.045
– 0.0018
0.50
[0.0197]
– 0.030
– 0.0012
57.50
[2.2638
]
– 0.045
– 0.0018
0.75
[0.0295]
– 0.030
– 0.0012
57.25
[2.2539
]
– 0.045
– 0.0018
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PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
NOTE
a
b
Grind all crankpins to the same undersize.
Finish the fillet radius to 3 mm [0.12 in.]
R
3 mm
[0.12 in.]
Figure 120 Fillet radius
Measuring diagram
2.
Checking oil clearance of main bearing
1)
Install the upper and lower halves of the
bearing and the cap to the crankcase, and
tighten the cap nuts to the specified torque.
Measure the inside diameter of the bearing,
as shown in the illustration.
Tightening torque
83 ± 5 N·m
(8.5 ± 0.5 kgf·m)
[61 ± 4 lbf·ft]
Figure 121 Measuring main bearing
2)
Measuring
directions
Measuring
points
Measure the diameter of the journal of the
crankshaft, as shown in the illustration, and
subtract the diameter of the journal from the
inside diameter of the bearing (Step (1)). The
difference is the oil clearance of the main
bearing.
Unit: mm [in.]
Item
Figure 122 Measuring journal
Diameter of
journal
(standard)
Oil clearance
3)
4)
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ENGLISH
Nominal
Value
Assembly
Standard
Repair
Limit
65
[2.56]
64.965 to 64.985
[2.5577 to
2.5585]
__
__
0.035 to 0.100
[0.0014 to
0.0039]
0.200
[0.0079]
If the oil clearance exceeds the repair limit,
replace the bearing and recheck the oil
clearance.
If the oil clearance still exceeds the repair
limit, use 0.25 mm [0.0098 in.], 0.50 mm
[0.0197 in.] or 0.75 mm [0.0295 in.] undersize
bearings. When using undersize bearings,
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
refinish the journals to any of the undersizes
listed below.
Unit: mm [in.]
Finishing dimension
Undersize
of journal
R 3 mm
[0.12 in.]
R 3 mm
[0.12 in.]
0.25
[0.0098]
– 0.015
– 0.0006
64.75
[2.5492
]
– 0.035
– 0.0014
0.50
[0.0197]
– 0.015
– 0.0006
64.50
[2.5394
]
– 0.035
– 0.0014
0.75
[0.0295]
– 0.015
– 0.0006
64.25
[2.5295
]
– 0.035
– 0.0014
NOTE
a
b
Grind all crankpins to the same undersize.
Finish the fillet radius to 3 mm [0.12 in.]
Figure 123 Fillet radius
3.
Flywheel housing
Checking oil seal running surface
Check the oil seal sleeve running surface of the
crankshaft rear-end. If the sleeve is badly worn by
the oil seal, replace the oil seal sleeve.
Oil seal
Oil seal
running
surface
Oil seal
sleeve
Figure 124 Checking oil seal running surface
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
1)
Removing oil seal sleeve
Hold a flat cold chisel at right angles to the
sleeve and cut the sleeve at three places to
loosen it, as shown in the illustration. If it is
impossible to remove the sleeve in this
method, hold the chisel in the axial direction
and lightly tap the sleeve to loosen it.
CAUTION
Be extra careful not to cause damage to the
crankshaft when removing the sleeve.
Figure 125 Removing oil seal sleeve
2)
Installing oil seal sleeve
Apply oil to the inside of an oil seal sleeve
and, using crankshaft sleeve installer set
(30691–13010), install the sleeve in position,
as shown in the illustration.
Sleeve installer
Guide
(30691-13100)
CAUTION
Be extra careful not to cause damage to the sleeve
when installing it.
Installer
(30691-13200)
Figure 126 Installing oil seal sleeve
When the oil seal sleeve is worn after the
engine has been operated, replace both oil
seal and oil seal sleeve.
Flywheel housing
Oil seal
Oil seal
running
surface
Oil seal
sleeve
Figure 127 Checking oil seal running surface
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ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
4.
Checking crankshaft deflection
Support the crankshaft on its front and rear
journals in V-blocks. With the dial indicator set at
0.00 mm [0.0000 in.] at the center journal, turn the
camshaft full one revolution and read the indicator,
as shown in the illustration. If deflection is out of
the assembly standard but does not exceed the
repair limit, repair the crankshaft by grinding. If
deflection exceeds the repair limit, repair the
crankshaft by cold working. Replace the crankshaft
if runout exceeds the repair limit excessively.
Unit: mm [in.]
Figure 128 Checking crankshaft deflection
Item
Crankshaft
deflection
5.
Assembly
Standard
Repair Limit
0.02 [0.0008] or
less
0.05
[0.0020]
Removing crankshaft gear
Remove the crankshaft gear with a gear puller, as
shown in the illustration.
NOTE
Do not remove the gear unless it requires
replacement.
Figure 129 Removing crankshaft gear
6.
Installing crankshaft gear
1)
Fit key into keyway
2)
3)
Heat the gear in an oven to a temperature of
100°C to 150°C [212°F to 302°F].
Install the key to the crankshaft.
Install the gear by fitting the key into the
keyway in the gear.
Figure 130 Installing crankshaft gear
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
10.2.4 Crankcase
Measuring
directions
1.
Checking crankcase bore
1)
Measuring
points
Measure the entire bore with a cylinder bore
gage having a dial indicator. Take
measurements at A, B and C positions in the
bore on axes 90° apart, as shown in the
illustration, to check the diameter, out-ofround and taper. If the bores exceeds the
service limit for diameter, out-of-round and
taper, increase them for oversize pistons.
Unit: mm [in.]
Figure 131 Checking crankcase bore
Piston available
Size
Size
Code
Assembly Standard
Standard
STD
88 +0.035
[3.46+0.0014
]
0
0
0.25
[0.0098]
oversize
25
88.25 0
0.50
[0.0197]
oversize
50
88.50 0
Out-of-round and
taper of bores
14 mm
[0.55 in.]
Bore Diameter
Perpendicular
to piston pin
+0.035
+0.035
+0.0014
[3.47440
+0.0014
[3.48420
0.015 [0.0006] or less
Service
Limit
]
+0.2
[+0.008]
]
__
2)
Boring of cylinders
a
There are two piston oversizes (0.25 mm
[0.0098 in.] and 0.50 mm [0.0197 in.] over
standard size) as listed above. Determine the
piston size to be used based on the largest
bore diameter of the cylinders.
b
Measure the outside diameter of the piston to
be used.
c
Based on the measurement of the piston
outside diameter, calculate the finishing
dimension to be achieved by boring.
A : Measured piston outside diameter selected
oversized piston) mm
B : Clearance between piston and cylinder
(standard value) 0.03 mm [0.0012 in.]
C : Honing allowance 0.04 mm [0.0016 in.] or
less
Finishing dimension = A + B - C
Figure 132 Measuring piston diameter
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ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
d
Bore the cylinders to the calculated
dimension.
CAUTION
Before the cylinders in the order of the cylinder
numbers to prevent distortion due to the heat
generated by the boring operation.
e
2.
Hone the cylinders to the final dimension
(piston outside diameter + cylinder clearance).
Checking crankcase top face
Check the top face for warpage, using an accurate
straight edge and a feeler gage, in three positions
lengthwise, two crosswise and two widthwise, as
shown in the illustration. If warpage exceeds the
repair limit, grind the crankcase.
Unit: mm [in.]
Item
Warpage of
crankcase top
face
Figure 133 Checking crankcase top face
Assembly
Standard
Repair Limit
0.05 [0.0020] or
less
0.20
[0.0079]
NOTE
The maximum limit of stock to be removed from the
crankcase and cylinder head for grinding is 0.2 mm
[0.0079 in.] in all.
10.2.5 Tappets
1.
Checking for wear
Check the cam contact face of each tappet for
wear. Replace badly worn tappets if any.
Good
Bad
Bad
Figure 134 Cam contact face of tappet
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
2.
Checking clearance between tappet and bore
Measure the diameter of the tappet and the inside
diameter of the bore in the crankcase for the
tappet, as shown in the illustration, to check the
clearance. If the clearance exceeds the service
limit, replace the tappets.
Unit: mm [in.]
Nominal
Value
Assembly
Standard
Repair
Limit
Inside
diameter of
bore for
tappet
14
[0.55]
14.000 to 14.018
[0.5512 to
0.5519]
14.100
[0.5551]
Clearance
between
tappet and
bore
__
0.016 to 0.052
[0.0006 to
0.0021]
0.080
[0.0032]
Item
Figure 135 Checking clearance between tappet and
bore
NOTE
If the bores are worn beyond the service limit, replace
the crankcase.
10.3 Reassembly
Apply engine oil
1.
Installing tappet
1)
2)
Apply engine oil to the tappets and install them
in the bores in the crankcase.
Make sure the tappets rotate smoothly.
Figure 136 Installing tappet
No. 5 bearing
(with flange)
Apply engine oil
2.
Installing main bearings
1)
Tab and
notch
NOTE
a
b
Figure 137 Installing main bearings
76 / 174
Install the lower halves of the main bearings in
the main bearing caps. Install the upper
halves of the main bearings in the crankcase.
ENGLISH
Make sure the upper and lower halves of the
main bearings are installed so the bearing
tabs fit into the notch in the crankcase and
main bearing caps.
Only the upper halves of the main bearings
to be installed in the crankcases has an oil
groove.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
2)
3)
3.
Install the upper and lower halves of the main
bearing having flanges in the crankcase and
main bearing cap for No.5 journal of the
crankshaft.
Lightly coat the inside surface of the shells
with engine oil.
Installing crankshaft
1)
2)
3)
Wash the crankshaft with cleaning solvent and
blow dry with compressed air. Make sure all oil
holes in the crankshaft are clean. Check the
oil holes for condition.
Hold the crankshaft in a horizontal position by
using a hoist, and carefully put it in the
crankcase.
Lightly coat the journals with engine oil.
Figure 138 Installing crankshaft
“Front” mark
4.
Installing main bearing caps
Install the main bearing caps in position so the
“front” mark (arrow) on the cap is toward the front
of the engine and the number on the cap is the
same as the number on the crankcase on the left
side of each main bearing cap.
Front of
engine
NOTE
Flush
Cap number
Figure 139 Installing main bearing caps
The end faces of No.1 and No.5 bearing caps must
be flush with the end faces of the crankcase.
5.
Tightening main bearing cap bolts
Tighten the main bearing cap bolts evenly to the
specified torque.
Tightening torque
83 ± 5 N·m
(8.5 ± 0.5 kgf·m)
[61 ± 4 lbf·ft]
Figure 140 Tightening main bearing cap bolts
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
77 / 174
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
6.
Checking crankshaft for rotation
Make sure the crankshaft rotates smoothly.
Figure 141 Checking crankshaft for rotation
7.
Measuring crankshaft end play
1)
Check the crankshaft end play with a dial
indicator, as shown in the illustration.
Unit: mm [in.]
Item
End play of
crankshaft
2)
Figure 142 Measuring crankshaft end play
3)
8.
A
Repair Limit
0.10 to 0.20
[0.0039 to 0.0080]
0.30
[0.0020]
If the end play is less than the assembly
standard, retighten the main bearing cap
bolts.
If it exceeds the service limit, replace the
flanged bearings.
Reassembling piston and connecting rod
1)
Weight identification
2)
Matching
mark
Assembly
Standard
Put the connecting rod in position in the piston
with the matching mark of the rod on the same
side as the weight identification on the top of
the piston.
Apply engine oil to the piston pin and install it
in position.
View A
Figure 143 Reassembling piston (1)
78 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
3)
Pliers
Install the snap rings in the grooves in the
piston with a pliers. Make sure the snap rings
fit in the grooves properly.
NOTE
The snap ring ends must be toward the bottom of the
piston.
Figure 144 Reassembling piston (2)
Mark pointing
upwards
9.
Installing piston rings
Using piston ring pliers (31391–12900), install the
compression (No.1 and No.2) rings and oil ring on
the piston with the mark “R” toward the top of the
piston.
No. 1
ring
No. 2
ring
Oil ring
Figure 145 Piston and piston rings
Spring joint
NOTE
The oil ring must be installed on the piston with the
ring end gap 180° from the coil spring joint.
Ring end gap
Figure 146 Oil ring end gap and spring joint
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
79 / 174
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
10. Laying crankcase on its side
Lay the crankcase on its side.
Figure 147 Laying crankcase on its side
11. Apply engine oil to bores
Clean the bores with a clean rag and apply engine
oil to the bores.
Apply engine oil
Figure 148 Apply engine oil to bores
12. Installing connecting rod bearing
1)
Tab and notch
2)
Install the connecting rod cap bolts in the bigend of the connecting rod so the flats of their
heads fit on the connecting rod properly.
Install the tipper half of the connecting rod
bearing in the big-end of the connecting rod.
Make sure the tab on the back of the bearing
is in the notch of the connecting rod.
Apply engine oil
Figure 149 Installing connecting rod bearing
80 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
Camshaft side
Thrust direction
13. Installing piston assembly
End gap of
No.1 ring
1)
2)
Apply engine oil to the piston rings.
Make sure the piston ring end gaps are
arranged on the piston, as shown in the
illustration.
3)
Turn the crankshaft to bring the No.1 (or No.
4) crankpin to the top center.
Put piston installer (30691–58100) on the top
of the crankcase in alignment with the bore
center. Hold the installer in position by one
hand.
Put the piston assembly in the crankcase
through the installer. Make sure the “front”
mark on the top of the piston is toward the
front of the engine.
Piston pin
End gap of
oil ring
End gap of
No. 2 ring
Combustion
chamber side
Anti-thrust
direction
Figure 150 Installing piston assembly (1)
4)
5)
“Front” mark
Piston installer
Figure 151 Installing piston assembly (2)
“Front” mark
NOTE
Make sure the big-end of the connecting rod fits on
the crankpin properly.
6)
Lightly tap the top of the piston with the handle
of a hammer to put the big-end of the
connecting rod on the crankpin.
Front of engine
Figure 152 Installing piston assembly (3)
CAUTION
Be careful not to cause damage to the crankpin when
putting the connecting rod on the crankpin.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
14. Installing connecting rod cap
1)
2)
3)
Apply engine oil
Install the lower half of the connecting rod
bearing in the connecting rod cap. Make sure
the tab on the back of the bearing is in the
notch of the connecting rod cap. Apply engine
oil to the inside of the bearing.
Install the connecting rod cap (with the
bearing) to the connecting rod (over the
crankpin) with the matching mark of the cap
on the same side as the mark of the rod.
Tighten the connecting rod cap nuts finger
tight.
Figure 153 Installing connecting rod cap (1)
NOTE
Steps (a) through (c) are for the installation of the
piston assemblies in the No.1 and No.4 cylinders.
Turn the crankshaft 180° and install the piston
assemblies in the No.2 and No.3 cylinders.
Matching marks
4)
Tighten the connecting rod cap nuts evenly to
the specified torque with a torque wrench.
Figure 154 Installing connecting rod cap (2)
Tightening torque
5)
54 ± 5 N·m
(5.5 ± 0.5 kgf·m)
[40 ± 4 lbf·ft]
Check the thrust clearance of the connecting
rod big-end. If the thrust clearance is less than
the assembly standard, retighten the cap nuts.
15. Raising crankcase
Raise up the crankcase with the oil pan side up.
Figure 155 Raising crankcase
82 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
ENGINE MAIN PARTS
16. Checking crankshaft rotation
Make sure the crankshaft rotates smoothly.
Figure 156 Checking crankshaft rotation
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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PISTONS, CONNECTING RODS,
CRANKSHAFT AND CRANKCASE
84 / 174
ENGINE MAIN PARTS
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
INLET AND EXHAUST SYSTEM
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
85 / 174
DESCRIPTION
INLET AND EXHAUST SYSTEM
INLET AND EXHAUST SYSTEM
11 DESCRIPTION
Exhaust manifold
86 / 174
Inlet manifold
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
DISASSEMBLY, INSPECTION AND
REASSEMBLY
INLET AND EXHAUST SYSTEM
INLET AND EXHAUST SYSTEM
12 DISASSEMBLY,
INSPECTION AND
REASSEMBLY
5
6
4
Check for cracks
Replace
Put gasket with
rounded side toward
exhaust manifold
when installing it
2
1
3
1.
2.
3.
4.
5.
6.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Check for cracks
Air inlet elbow
Gasket
Inlet manifold
Gasket
Exhaust manifold
Gasket
87 / 174
DISASSEMBLY, INSPECTION AND
REASSEMBLY
88 / 174
INLET AND EXHAUST SYSTEM
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
COOLING SYSTEM
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
89 / 174
DESCRIPTION
COOLING SYSTEM
COOLING SYSTEM
13 DESCRIPTION
Radiator
Thermostat
Bypass pipe
Fan
Water pump
90 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
COOLING SYSTEM
WATER PUMP, FAN
COOLING SYSTEM
14 WATER PUMP, FAN
14.1 Inspection
Visually check the water pump and replace it as an
assembly if any defect is found.
Replace
Check blades for cracks or
distortion
5
1
8
2
7
6
Check for coolant leakage,
rough rotation or cracks
3
Check for wear,
fraying or separated
piles
4
Figure 157 Disassembly sequence
1.
2.
3.
4.
5.
6.
7.
8.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Fan
Spacer
Pulley
V-belt
Water Pump assembly
Gasket
Plate
Gasket
91 / 174
THERMOSTAT
COOLING SYSTEM
COOLING SYSTEM
Valve lift, mm [in.]
15 THERMOSTAT
8
[0.3]
0
15.1 Inspection
76.5 ± 1.5
[170 ± 2.7]
90
[194]
Temperature, °C [°F]
Put each thermostat in a glass jar filled with water, and
test it for thermostatic action by heating the jar to raise
the water temperature. In the test, measure the
temperature at which the valve starts opening and that
at which the valve lift is more than 8 mm [0.3 in.]. If
these measurement are out of the assembly standard,
replace the thermostat.
Unit: mm [in.]
Figure 158 Testing thermostat
Item
Assembly Standard
Temperature at which valve
starts opening
76.5 ± 1.5°C
[170 ± 2.7°F]
Temperature at which valve lift
exceeds 8 mm [0.3 in.]
90°C [194°F]
CAUTION
a
b
92 / 174
ENGLISH
Stir up the water with a stick to keep the
temperature uniform.
Install the thermostat with its air vent hole
up.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
FUEL SYSTEM
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
93 / 174
DESCRIPTION
FUEL SYSTEM
FUEL SYSTEM
16 DESCRIPTION
Fuel filter
Air vent plug
Fuel injection nozzle
Return pipe
Air vent plug
Fuel feed pump
Fuel injection pump
94 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
FUEL SYSTEM
FUEL SYSTEM BLEEDING
FUEL SYSTEM
17 FUEL SYSTEM
BLEEDING
1.
Fuel filter
1)
2)
3)
Bleeding button
2.
Loosen air vent plug on the fuel filter (by
turning it 1.5 turns).
Unlock bleeding pump plunger by turning it to
the left, and operate the pump.
Tighten the air vent plug when the fuel flows
free of bubbles.
Fuel injection pump
1)
2)
3)
Loosen air vent plug on the injection pump (by
turning it 1.5 turns).
Unlock bleeding pump plunger by turning it to
the left, and operate the pump.
Tighten the air vent plug when the fuel flows
free of bubbles.
Air vent plug
NOTE
Air vent plug
a
b
If the vent plug is tightened before the
bleeding pump plunger is locked, fuel
pressure acts on the feed pump, making it
difficult to restore the plunger.
Clean up fuel spillage.
Bleeding button
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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DISASSEMBLY
FUEL SYSTEM
FUEL SYSTEM
Return pipe
18 DISASSEMBLY
Fuel injection
pipe
1.
Disconnecting fuel pipes
Remove the pipe clamp from the injection pipes.
Disconnect the injection pipes at the injection
pump and at the injection nozzles. Disconnect the
leak-off pipes from the nozzles by loosening the
lock nuts.
Clamp
Lock nut
CAUTION
Figure 159 Disconnecting fuel pipes
Put protection caps on the pump and nozzles to keep
dirt and foreign material out of the fuel system.
2.
Removing fuel injection nozzles
Using a box wrench, remove the fuel injection
nozzles with gaskets from the engine.
NOTE
Remove the nozzle gaskets from the cylinder head, if
any, with a wire or a screwdriver and discard them.
Figure 160 Removing fuel injection nozzles
3.
Removing fuel injection pump
1)
Check the alignment of the mark on the fuel
injection pump with the mark on the flange
plate.
Figure 161 Removing fuel injection pump (1)
96 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
FUEL SYSTEM
DISASSEMBLY
2)
3)
4)
Remove the front end cover from the engine.
Put marks on the fuel injection pump drive
gear and idler gear.
Unscrew the bolts that hold the fuel injection
pump flange to the front end plate and remove
the pump and flange from the end plate.
NOTE
Idler gear
a
Fuel injection
pump drive gear
b
Figure 162 Removing fuel injection pump (2)
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Do not attempt to turn the engine after
removing the injection pump from the
engine.
To remove the fuel injection pump drive
gear, loosen its nut with the pump on the
engine.
97 / 174
FUEL INJECTION TIMING CHECK
FUEL SYSTEM
FUEL SYSTEM
19 FUEL INJECTION
TIMING CHECK
The injection timing varies according to the output, rpm
and specifications of the engine. Be sure to verify the
timing by referring to the specifications.
1.
Bringing the No.1 cylinder piston to the top dead
center on compression stroke
1)
Figure 163 Finding top dead center on compression
stroke
2)
3)
2.
Delivery
valve
Delivery valve
holder
Seat
surface
Spring
Relief valve
Delivery valve
Checking injection timing
1)
2)
3)
Figure 164 Checking injection timing (1) (Removing
delivery valve)
Put socket (30691–21800) on the crankshaft
pulley nut and turn the crankshaft in the
normal direction (clockwise as seen from the
front end).
Stop turning the crankshaft when the timing
mark “0” on the crankshaft pulley is aligned
with the pointer.
Push down on the inlet and exhaust valve
rocker arms for the No.1 cylinder to make sure
they are not being pushed up by the pushrods
(the inlet and exhaust valves have some
clearance).
4)
5)
Remove delivery valve holder from the No.1
plunger of the injection pump. Remove
delivery valve and spring from the holder,
restore the holder to the pump.
Connect a spare injection pipe to the No.1
plunger, with its free end held downward so
that you can observe the fuel flow from that
end.
Turn the crankshaft to bring the No.1 piston to
60° position before top dead center on
compression stroke.
While operating the priming pump to allow the
fuel to flow from the injection pipe, slowly turn
the crankshaft in the normal direction. Stop
turning the crankshaft when the fuel flow
stops.
Make sure the timing mark on the crankshaft
pulley is aligned with the pointer.
Figure 165 Checking injection timing (2)
98 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
FUEL SYSTEM
FUEL INJECTION TIMING CHECK
3.
Adjusting injection timing
1)
If the injection timing is retarded, move the
injection pump toward the crankcase. If the
timing is advanced, move the pump away
from the crankcase.
2)
One graduation of the scale on the injection
pump coupling changes the timing by 6° in
terms of crank angle.
To advance injection
timing
To retard
injection
timing
Figure 166 Adjusting injection timing (1)
Figure 167 Adjusting injection timing (2)
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
99 / 174
FUEL FILTER (PAPER-ELEMENT
CARTRIDGE TYPE)
FUEL SYSTEM
FUEL SYSTEM
20 FUEL FILTER (PAPERELEMENT CARTRIDGE
TYPE)
20.1 Disassembly and Inspection
Air vent plug
1
Cracks,
damages
threads
Apply engine oil to
packing at installation
2
Clogged, cracked.
Replace every 500 service
hours.
Figure 168 Disassembly sequence
1.
2.
100 / 174
ENGLISH
Element assembly
Bracket
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
FUEL SYSTEM
FUEL INJECTION NOZZLES
FUEL SYSTEM
21 FUEL INJECTION
NOZZLES
21.1 Disassembly
Check for wear
7
Check for defect
6
5
4
3
Check for wear
2
1
Check for carbon on tip
or in orifice
Figure 169 Disassembly sequence
1.
2.
3.
4.
5.
6.
7.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Retaining nut
Nozzle tip assembly
Piece
Pin
Spring
Washer
Nozzle body
101 / 174
FUEL INJECTION NOZZLES
FUEL SYSTEM
21.2 Testing
1.
Injection pressure (valve opening pressure)
1)
2)
3)
Figure 170 Testing fuel injection nozzle
Install the injection nozzle on the tester. Slowly
operate the tester handle full strokes to bleed
(remove) air from the pipe and nozzle.
Make a slow increase in pressure by
operating the tester handle at a speed of more
than one stroke per second while observing
the pressure gage.
The pressure gage reading will slowly
increase and, when the nozzle starts
discharging fuel, it will go down fast. Take the
gage reading right then as the injection
pressure.
Unit: MPa (kgf/cm2) [psi]
Item
Assembly Standard
14.22+0.78
0
Injection pressure
+8
(145 0 )
+113
[2063 0 ]
CAUTION
When testing the injection nozzle, keep its tip pointed
away from the operator. Fuel from the orifices in the
tip of the nozzle is under high pressure and can
cause injury to the operator.
4)
If the injection pressure is not correct, make
an adjustment of the nozzle by adding or
removing the shims inside the nozzle holder.
Figure 171 Removing nozzle tip
102 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
FUEL SYSTEM
FUEL INJECTION NOZZLES
2.
Spray pattern
1)
Good nozzles
(reusable)
Bad nozzles (recondition or
replace if necessary)
2)
Figure 172 Possible spray pattern
Operate the tester handle at a speed of one
stroke per second and look at the spray
pattern (shape of discharge) when fluid begins
to flow through the fuel injection nozzle. The
discharge must be 0°. Any change is an
indication of a bad nozzle.
If the nozzle is bad, loosen the retaining nut
and remove the tip from the nozzle. Wash the
tip — needle valve and body — in clean diesel
fuel. After washing, put the needle valve in the
body in clean diesel fuel.
CAUTION
Be careful not to cause damage to the tip when
removing it from the nozzle body.
3)
Needle
valve
Body
After cleaning the nozzle tip, install it to the
nozzle body and tighten the retaining nut to
the specified torque.
Tightening torque
Figure 173 Washing nozzle tip
4)
37 ± 2.5 N·m
(3.77 ± 0.25 kgf·m)
[27 ± 1.8 lbf·ft]
If the discharge pattern (nozzle) is still bad
after the nozzle tip has been washed, replace
the tip.
NOTE
a
b
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Do not touch the sliding surface of the
needle valve.
When installing a new nozzle tip, remove
resin film from the tip and slide the needle
valve in the body in clean diesel fuel to wash
off inhibitor completely.
103 / 174
FUEL INJECTION NOZZLES
FUEL SYSTEM
21.3 Reassembly
7
6
5
Retaining nut
Tightening torque:
37 ± 2.5 N·m
(3.77 ± 0.25 kgf·m)
[27 ± 1.8 lbf·ft]
4
Tightening torque for fuel
injection nozzle:
59 ± 10 N·m
(6.0 ± 1 kgf·m)
[44 ± 7 lbf·ft]
3
2
1
Figure 174 Ressembly sequence
7654321
104 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
LUBRICATION SYSTEM
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
105 / 174
DESCRIPTION
LUBRICATION SYSTEM
LUBRICATION SYSTEM
22 DESCRIPTION
Valve mechanism
Valve push rod
Tappet
Valve
Pressure relief
valve
Piston
Camshaft
Main gallery
Timing gear
Crankshaft
Oil pump
Oil filter (with built-in
bypass valve)
Oil strainer
Drain plug
106 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
LUBRICATION SYSTEM
OIL PUMP
LUBRICATION SYSTEM
23 OIL PUMP
23.1 Disassembly
Abnormal gear, friction
Figure 175 Disassembly sequence
1.
2.
3.
Oil strainer
Cover
Oil pump
23.2 Inspection
1.
Checking clearance between outer rotor and inner
rotor
Check the clearance with a feeler gage, as shown
in the illustration. If the clearance exceeds the
service limit, replace the pump assembly.
Unit: mm [in.]
Figure 176 Checking clearance between outer rotor
and inner rotor
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Item
Assembly
Standard
Service
Limit
Clearance between outer
rotor and inner rotor
0.13 to 0.15
[0.0051 to 0.0059]
0.20
[0.0079]
ENGLISH
107 / 174
OIL PUMP
LUBRICATION SYSTEM
2.
Checking clearance between rotors and cover
Check the clearance with a feeler gage and
straight edge, as shown in the illustration. If the
clearance exceeds the service limit, replace the
pump assembly.
Unit: mm [in.]
Item
Assembly
Standard
Service
Limit
Clearance between rotors
and cover
0.04 to 0.09
[0.0016 to 0.0035]
0.15
[0.0059]
Figure 177 Checking clearance between rotors and
cover
3.
Checking clearance between outer rotor and case
Check the clearance with a feeler gage, as shown
in the illustration. If the clearance exceeds the
service limit, replace the pump assembly.
Unit: mm [in.]
Item
Assembly
Standard
Service
Limit
Clearance between outer
rotor and case
0.200 to 0.275
[0.0079 to 0.0108]
0.500
[0.0197]
Figure 178 Checking clearance between outer rotor
and case
23.3 Reassembly
Put the outer rotor in the case. Make sure the mark on
the case is in alignment with the mark on the cover and
tighten the bolts that hold the cover.
Figure 179 Marks on cover and case
108 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
LUBRICATION SYSTEM
OIL FILTER
LUBRICATION SYSTEM
24 OIL FILTER
24.1 Inspection
Apply engine oil to
O-ring at installation
Replace every 250 service hours
1.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Oil filter
109 / 174
PRESSURE RELIEF VALVE
LUBRICATION SYSTEM
LUBRICATION SYSTEM
Shims
Tightening torque:
49 ± 5 N·m
(5.0 ± 0.5 kgf·m)
[36 ± 4 lbf·ft]
Pressure relief valve
25 PRESSURE RELIEF
VALVE
25.1 Inspection
1.
Check the valve and valve seat for condition. Also,
check the spring for damage.
2.
Check the valve opening pressure (the oil
pressure when the engine is running at the rated
rpm). If the pressure is not correct, make an
adjustment by adding or removing shim. The
pressure tap (RP 1/8 thread (PS 1/8)) is located
near the oil filter.
Figure 180 Pressure relief valve
Unit: kPa (kgf/cm2) [psi]
Item
Valve opening pressure
110 / 174
ENGLISH
Assembly Standard
343 ± 49
(3.5 ± 0.5)
[50 ± 7]
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
111 / 174
1.
2.
4
3
2
1
ENGLISH
Starter relay
32A66-19100
L
S
5
C
3
4
6
5
R1
B
Starter
BR
ACC
S
5
SW
B
0.85
B
0.85
R2
0.85
0.85
5
M
0.85
0.85
60
Diode
MM434-062
Diode
MM434-062
Themo switch
MC880-900
Battery switch
05125-00102
0.85
60
Charge pilot lamp
MM201-122
Press. switch
MM130-066
Pilot lamp
MM201-123
Pilot lamp
MM201-124
+
2
Battery
5
–
60
8
7
6
5
Control timer
16A12-02000
0.85
0.85
3
1
P
L
R
0.85
2
B
Alternator
0.85
S R L P E
Safety relay
MM130-767
12V–50A
Solenoid (ETS)
12V–2.0kW
Alternator
2 mm2 or more
5 mm2 or more
60 mm2 or more
5
60
0.85 mm2 or more
B R1 ACC R2 C BR
2
0.85
St
ACC
OFF
R1
Position
Connection of
starter switch
Terminal
12V–92AH
Starter
S4Q,S4Q2
Battery
Model
< ETS type stop solenoid >
0.85
Figure indicates a nominal size of automotive low-tension line (JIS C 3406).
This schematic shows the electrical system of the standard engine equipped with a key shut down solenoid and glow plugs.
Starter switch
30890-05200
Pilot lamp
MM201-124
5
0.85
Glow relay
MM431-28201
5
Glow timer
MM431-762
0.85
112 / 174
0.85
Glow plug
GENERAL
ELECTRICAL SYSTEM
ELECTRICAL SYSTEM
26 GENERAL
26.1 Wiring diagrams
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
1.
2.
0.85
ENGLISH
4
3
2
1
S
Starter relay
32A66-19100
L
SW
B
0.85
B
5
R2
C
0.85
3
4
6
5
R1
B
Starter
BR
ACC
S
5
0.85
5
M
0.85
0.85
60
0.85
Battery switch
05125-00102
60
5
Diode
MM434-062
Diode
MM434-062
Themo switch
MC880-900
Press. switch
MM130-066
Charge pilot lamp
MM201-122
Pilot lamp
MM201-123
Pilot lamp
MM201-124
+
Battery
3
0.85
3
0.85
0.85
–
4
2
60
3
1
0.85
8
1
4
B
5
0.85
Pull in (white)
A
Controller
31A66-06100
B
1
7 6 5 3
Control timer
16A12-02001
0.85
N.C. (B type) relay
31A90-05100
0.85
0.85
0.85
P
L
R
0.85
Alternator
0.85
S R L P E
Safety relay
MM130-767
3
12V–2.0kW
12V–50A
Alternator
Solenoid (ETR)
60 mm2 or more
5 mm2 or more
3 mm2 or more
0.85 mm2 or more
B R1 ACC R2 C BR
Common (black)
Hold (red)
60
5
3
0.85
St
ACC
OFF
R1
Position
Connection of
starter switch
Terminal
12V–92AH
Starter
S4Q,S4Q2
Battery
Model
3
0.85
Figure indicates a nominal size of automotive low-tension line (JIS C 3406).
This schematic shows the electrical system of the standard engine equipped with a key shut down solenoid and glow plugs.
Starter switch
30890-05200
Pilot lamp
MM201-122
(Red)
5
0.85
0.85
Glow relay
MM431-28201
5
Glow timer
30L66-00700
0.85
Glow plug
ELECTRICAL SYSTEM
GENERAL
< ETR type stop solenoid >
113 / 174
STARTER
ELECTRICAL SYSTEM
ELECTRICAL SYSTEM
27 STARTER
Lightly press
the tip
S
27.1 Inspection before disassembly
(inspection of assembly)
If an abnormality is found, disassemble and repair.
+
-
Starter
Battery
12V
1.
24V (option)
0.1 to 2.5 mm
[0.0039 to
0.0984 in.]
Pinion gap
1)
Connect the positive (+) cable of the battery to
terminal S of the starter and the negative (-)
cable to the starter body to extend the pinion.
Figure 181 Inspection of pinion gap
CAUTION
Do not supply electricity for more than 10 continuous
seconds.
2)
3)
2.
Switch
No-load test
1)
Ammeter
A
2)
Starter
Revolution
indicator
V
-
+
Battery
Lightly press the tip of the extended pinion
shaft with a finger, and measure the distance
of the shaft movement.
If the measured value is not within a range of
0.1 to 2.5 mm [0.0039 to 0.0984 in.], increase
or decrease the number of packings at the
magnetic switch section for adjustment. An
increase of packings results in a decrease of
the pinion gap.
As shown in the diagram, connect an
ammeter, voltmeter, revolution indicator and
battery.
Turning on the switch should extend the pinion
and operate the starter at the specified speed
or faster.
If the current or rotating speed does not
conform to the standard value, disassemble
the starter for inspection and repair.
12V
24V (option)
Standard
value
Item
Figure 182 No-load test
Starter model
M008T70371
Nominal output
No-load
characteristics
V-kW
Terminal voltage
V
11
Current
A
130 or lower
Rotation speed rpm
114 / 174
ENGLISH
12-2.0
3600 or higher
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
STARTER
Option
Standard
value
Item
Starter model
MT008T80772
Nominal output
No-load
characteristics
V-kW
24-3.2
Terminal voltage
V
23
Current
A
80 or lower
Rotation speed rpm
3000 or higher
CAUTION
a
b
c
3.
S
M
+
—
Battery
12V
24V (option)
Use thick wires, and tighten the connections
at the terminals.
It should be noted that the rotation sound is
louder than the sound produced by a starter
without a reduction gear mechanism.
When measuring the rotation speed at the
tip of the pinion, be careful of the pinion
extension at the start of operation.
Inspection of magnetic switch
Conduct the following inspection. If the magnetic
switch is faulty, replace.
1)
Disconnect the wire from terminal M.
2)
Suction test
Connect the battery to terminals S and M of
the magnetic switch. The pinion should extend
when the switch is turned on.
CAUTION
Do not supply electricity for more than 10 continuous
seconds.
Disconnect
connector
Figure 183 Suction test
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
115 / 174
STARTER
ELECTRICAL SYSTEM
3)
Disconnect connector
S
M
Holding test
With the battery connected to terminals S and
the body of the magnetic switch, pull out the
pinion fully with fingers. The pinion should not
return to the original position when it is
released.
CAUTION
+
—
Battery
12V
24V (option)
Do not supply electricity for more than 10 continuous
seconds.
Figure 184 Holding test
4)
Disconnect connector
M
+
Return test
With the battery connected to terminals M and
the body of the magnetic switch, pull out the
pinion fully with fingers. The pinion should
return immediately to the original position
when it is released.
CAUTION
—
Battery
12V
24V (option)
Do not supply electricity for more than 10 continuous
seconds.
Figure 185 Return test
27.2 Removal
Wires
1.
Disconnect the cables from the battery terminals.
Be sure to disconnect the negative (-) cable first.
2.
Disconnect the wires from the starter.
3.
Remove the two starter mounting nuts, and
dismount the starter.
Nut
Figure 186 Removal of starter
116 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
STARTER
27.3 Disassembly
Disassembly sequence
1. Pinion set
2. Magnetic switch
3. Rear bracket
4. Brush holder
5. Yoke
6. Armature
7. Ball bearing
8. Ball
9. Packing set
10. Gear
11. Lever
12. Washer set
13. Gear shaft
14. Internal gear
15. Overrunning clutch
16. Front bracket
17. Bearing
18. Oil Seal
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
117 / 174
STARTER
ELECTRICAL SYSTEM
27.3.1 Removing Pinion
S1
B
S2
M
S
Battery
Starter
Supply electric current to the switch to set the pinion in
the protruded condition. Remove the M-terminal
connecttor, and connect the battery and starter, as
shown in the diagram. Close swithes S1 and S2 to set
the pinion in the protruded condition. Then, open switch
S2 to stop the pinion rotation. Set a pipe-shape tool on
the pinion stopper, and lightly tap the tool with a
hammer to remove the pinion.
In some cases, the stopper does not dislodge from the
position and the pinion retracts into the original
position. When this happens, repeat the procedure.
27.3.2 Ball
The ball serving as the bearing in the armature thrust
direction may be stuck to grease on the tip of the shaft
when the armature is removed. Do not loose this
bearing ball.
27.4 Inspection
27.4.1 Armature
118 / 174
1.
Testing for short circuits
Place the armature on a growler, and slowly
revolve it with a hacksaw blade held above the
armature core. The hacksaw blade vibrates
against the core when it is above a slot containing
a shorted winding. Replace the armature if
shorted.
2.
Testing for grounded circuits
If there is any continuity between the commutator
and shaft (or core), the armature is grounded and
should be replaced.
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
STARTER
3.
Inspecting commutator
1) Support the armature in V-blocks and
measure the runout of the commutator with a
dial indicator. If the runout is near the service
limit, recondition the commutator, making sure
the commutator diameter does not exceed the
service limit which is 31.4 mm [1.236 in.].
If the commutator surface is rough, smoothen
it with a sandpaper of #300 to #500.
Unit: mm [in.]
Item
Service Limit
Runout of commutator
2)
0.1 [0.004]
Measure the diameter of commutator. If it is
smaller than the service limit, replace the
armature.
Unit: mm [in.]
Item
Diameter of
commutator
3)
Normal Size
Service Limit
32
[1.26]
31.4
[1.236]
Measure the depth of each mold between
segments with a depth gauge. If the depth is
less than the repair limit, recondition the mold.
Segment
Unit: mm [in.]
Item
Mold depth
Good
Bad
Depth of
commutator mold
Assembly
Standard
Service Limit
0.4 to 0.6
[0.016 to 0.024]
0.2 [0.008] or
less
27.4.2 Field Coil
1.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Testing for open circuits
If there is no continuity between the lead wire and
positive (+) brush, the field coil is open and the
yoke assembly should be replaced.
119 / 174
STARTER
ELECTRICAL SYSTEM
2.
Testing for grounded circuits
If there is no continuity between the yoke and
positive (+) brush, the insulation and re-pair or
replace the yoke assembly.
27.4.3 Brushed and holders
Brush
1.
Wear of brushes
Measure the brush length and, if it is less than the
service limit, replace the brushes. If the brushed
are unevenly worn or rough, recondition them with
a sandpaper of #300 to #500.
Unit: mm (in.)
Item
Length of brush
2.
Assembly
Standard
Service Limit
18 [0.71]
11 [0.43]
Brush spring force
Test the spring force using a new brush. In the test,
read the road at the instant the spring moves off
the brush. If the force is less than the service limit,
replace the spring.
Unit: N (kgf) [lbf]
Item
Force of brush
spring
3.
120 / 174
ENGLISH
Assembly
Standard
Service Limit
29 to 39
(3.0 to 4.0)
[6.6 to 8.8]
19.6
(2.0)
[4.4]
Testing brush holders insulation
If there is any continuity between the positive (+)
brush holder and negative (–) holder plate, replace
the brush holder assembly.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
STARTER
27.4.4 Overrunning Clutch
Make sure that the pinion shaft turns freely when
turned in the direction of driving (clockwise) and it is
locked when turned in the opposite direction. If not,
replace the overrunning clutch.
27.5 Reassembly
To reassemble, follow the disassembly sequence in
reverse. Be sure to observe the following during
reassembly.
2
Apply grease to sliding
surface of lever
Apply grease
11
14
15
13
3
4
Apply grease
1
7
18
17
16
5
6
9
10
8
12
Apply grease
Apply grease
Reassembly sequence
18 → 17 → 16 → 12 → 13 → 14 → 15 → 1 → 10 → 11
→9→8→5→6→7→4→3→2
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
121 / 174
STARTER
ELECTRICAL SYSTEM
27.6 Inspection and testing after
reassembly
-
+
27.6.1 Pinion clearance adjustment
1.
S-terminal
Battery
2.
M-terminal
3.
If the reassembled starter is wired as shown, the
pinion will shift and turn slowly. Remove the
connector from the M terminal to stop the pinion.
Under this condition, lightly push in the pinion
toward the armature, and measure the movement
(clearance) of the pinion.
To adjust the clearance, increase or decrease the
number of packings fitted to the magnetic switch.
Increasing the number of packings decreases the
pinion clearance.
Unit: mm [in.]
Item
Assembly Standard
Pinion clearance
0.5 to 2.0 [0.020 to 0.079]
NOTE
Pinion clearance
Do not test the starter continuously for more than 20
seconds to prevent the switch coil from overheating.
27.6.2 No-Load Test
A
After adjusting the pinion clearance, hook up the starter
as shown, and test it for no-load characteristics.
Ammeter
Switch
Battery
S
V
Voltmeter
B
M
Switch
Starter
CAUTION
Use wires as thick as possible and tighten each
terminal securely.
Starter
No-Load
characteristic
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ENGLISH
Voltage,
V
Current,
A
Speed,
rpm
11
130 or less
4000 or
less
23
(Option)
80 or less
3000 or
more
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
STARTER
27.6.3 Magnetic switch
B terminal
1)
Testing coil for open circuits
If there is no continuity between S and M
terminals and between S terminal and body
(ground) , replace the switch.
2)
Checking contactors for fusion
If there is continuity between B and M
terminals, replace the switch.
3)
Checking contactors for poor contact action
Check for voltage drop. If voltage drop is
excessive, the contactors are defective.
S terminal
M terminal
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
123 / 174
ALTERNATOR
ELECTRICAL SYSTEM
ELECTRICAL SYSTEM
28 ALTERNATOR
If a problem occurs in the charge system, check the
following abnormal conditions to locate the cause of the
problem. Only when inspection cannot be conducted
on the alternator installed on the engine, dismount the
alternator for inspection and repair.
Overcharging
Voltage regulator adjustment value is
high.
Faulty battery.
Voltage relay adjustment value is low.
Faulty alternator output.
Overdischarging
Power consumption is extremely high.
Special load is used.
Faulty wiring.
28.1 On-vehicle inspection
28.1.1 Cautions in handling
Handle the alternator carefully. Incorrect handling can
result in alternator damage and malfunctions.
1.
2.
3.
4.
5.
6.
7.
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ENGLISH
Do not connect the battery cables in reverse. Note
that the negative cable is a grounding wire.
Do not use a high-voltage tester such as a megger.
When charging the battery, disconnect the cables
from the battery terminals.
Do not disconnect the lead wire from terminal B of
the alternator while the engine is operating.
Do not ground terminal B of the alternator since it
is constantly applied with battery voltage.
Do not short or ground terminal L. (unit with
integrated IC regulator)
When using a steam cleaner, do not allow steam to
directly contact the alternator.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
ALTERNATOR
28.1.2 Inspection of adjustment voltage
(unit with integrated IC regulator)
1.
Ammeter
+
A
2.
-
Switch
3.
L
+
-
Battery
R
+
12V
V Voltmeter
24V (option)
4.
5.
Figure 187 Inspection of adjustment voltage
Disconnect the cable from the positive (+) terminal
of the battery, and connect an ammeter between
the terminal and cable.
Connect a voltmeter between terminal L and
ground.
Make sure that the voltmeter indicates “0” when
the starter switch is turned off.
Make sure that the voltmeter indicates a voltage
level sufficiently lower than the battery voltage
when the starter switch is turned on (without
starting the engine).
Short-circuit the terminal of the ammeter, and start
the engine.
Read the indication (adjustment voltage) on the
voltmeter with the ammeter indicating 5 A or lower,
the engine operating at 1800 to 2500 rpm, and the
lamp switches turned off.
Unit: V
Item
Adjustment
voltage at 20°C
Standard
Value
V-kW
14.7 ± 0.5
12-50
Option
28.5 ± 0.5
Option
24-25
24.35
28.1.3 Inspection of output (unit with
integrated IC regulator)
1.
2.
Ammeter
A
+ Voltmeter
B
V
Charge
lamp
L
R
Switch
3.
4.
5.
6.
Disconnect the grounding cable from the battery.
Disconnect the wire from terminal B of the
alternator, and connect an ammeter. Connect a
voltmeter between terminal B and ground.
Connect the grounding cable to the battery.
Start the engine.
Immediately after the engine starts, turn on all load
devices such as lamps.
Increase the engine speed. When the voltmeter
indicates 27.0 V, read the maximum current at the
specified alternator rotation speed.
If the measured value conforms to the standard
value, the alternator is normal.
Figure 188 Wiring diagram for output test (unit with
integrated IC regulator)
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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ALTERNATOR
ELECTRICAL SYSTEM
Output characteristics:
Standard Value
Item
Model
Rotation
speed
13.5V/33A
2500 rpm
13.5V/47A
5000 rpm
A7TA8077
(option)
27.0V/18A
2500 rpm
27.0V/22A
5000 rpm
A3TN5776
(option)
27.0V/29A
2500 rpm
27.0V/33A
5000 rpm
A7T02077C
Option
characteristic
(when warm)
Terminal
voltage/
current
28.2 Removal
Brace bolt
1.
Disconect the battery cables.
2.
Disconnect the lead wire from terminal B located
on the back side of the alternator.
3.
Disconnect the alternator connector.
4.
Unscrew the alternator brace bolt and support bolt,
and push the alternator toward the engine, then
remove the fan belt.
5.
Dismount the alternator.
Support bolt
Figure 189 Removal of alternator
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ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
ALTERNATOR
28.3 Disassembly
Not provided in 24V-35A
(A3TN5776)
Disassembly sequence
1. Nut and washer
2. Pulley and spacer
3. Front bracket assembly
4. Rotor assembly
5. Stator
6. Rear bracket
7. Regulator assembly
8. Rectifier assembly
9. Nut set
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ENGLISH
127 / 174
ALTERNATOR
ELECTRICAL SYSTEM
28.3.1 Key points in disassembly
1.
Separation of front bracket from stator core.
1)
Insert the tip of a slotted screwdriver into the
gap between the stator core and front bracket,
and pry open.
CAUTION
Do not insert the screwdriver too far into the
assembly to prevent damage to the stator core.
Figure 190 Disassembly of alternator
2.
Removal of pulley
1)
2)
Wrap the rotor with a cloth for protection, and
hold it with a vice. Unscrew the pulley nut,
then remove the pulley and spacer.
Remove the rotor from the front bracket.
Figure 191 Removal of pulley
Soldered sections
3.
Removal of stator core and rectifier
1)
Rectifier
Disconnect the lead wires from the stator core
to the rectifier at the soldered sections. Then,
remove the stator core.
CAUTION
Soldered section
Melt the soldered sections as quickly as possible. If
heat is applied for an extended period of time, the
diodes can be damaged.
Figure 192 Removal of stator core
128 / 174
2)
ENGLISH
Unscrew the rectifier mounting screws, and
dismount the rectifier.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
ALTERNATOR
28.4 Inspection
Open circuit, short circuit, wear
Cracks, damage
Shape distortion, damage
Cracks, damage
Open circuit, short
circuit
Not provided in 24V-35A
(A3TN5776)
Worn brush
Open circuit, short circuit
Figure 193 Inspection locations on alternator
28.4.1 Key points in inspection
Trio diodes
1.
(–) heat sink
(+) heat sink
Inspecting diodes
For inspection of individual diodes, check the
resistance between each diode lead and heat sink.
Take resistance measurements by connecting the
positive (+) wire of a tester to the diode and also by
connecting the negative (-) wire to the diode. If the
resistance shows “infinite” in both measurements,
there is an open circuit. If the resistance is close to
0 in both measurements, there is a short circuit.
If there is an open or short circuit, the diode is
faulty and the rectifier must be replaced.
Diode lead
Figure 194 Inspecting diodes
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ENGLISH
129 / 174
ALTERNATOR
ELECTRICAL SYSTEM
2.
Inspecting field coil
1)
Check the continuity between the slip rings.
If there is no electric conduction, there is an
open circuit: replace the field coil.
2)
Check the continuity between the slip ring and
shaft (or core).
If there is electric conduction, the field coil is
grounded: replace the field coil.
Figure 195 Field coil continuity
Figure 196 Field coil grounding test
3.
Inspecting stator core
1)
Check the continuity between the stator core
and each lead wire.
If there is no electric conduction, there is an
open circuit: replace the stator core.
Figure 197 Stator core continuity test
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
ALTERNATOR
2)
Check to make sure that there is no continuity
between the lead wires and core.
If there is continuity, the circuit is grounded:
replace the stator.
Figure 198 Stator core grounding test
4.
Inspecting brushes
1)
If the brushes are worn close to the wear limit
line (service limit), replace the brushes.
Unit: mm [in.]
Assembly
Standard
7 mm [0.276 in.]
5 mm [0.197 in.]
(option)
Wear limit line
Service Limit
7 [0.276]
Brush length
Figure 199 Inspecting brush
2)
Soldered sections
18.5 [0.728]
5 [0.197]
Option
(A7TA80AA)
(A3TN5776)
Disconnect the brush lead wires at the
soldered sections to remove the brushes and
springs.
Figure 200 Replacement of brushes
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ENGLISH
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ALTERNATOR
ELECTRICAL SYSTEM
3)
To install new brushes, press them into the
brush holders as shown in the diagram, then
solder the lead wires.
Figure 201 Replacement of brushes
28.5 Assembly
To reassemble, follow the disassembly sequence in
reverse.
Be sure to observe the following during assembly.
Wire
28.5.1 Key points in reassembly
1.
Rear bracket
2.
Brush
When press-fitting the rear bearing into the rear
bracket, heat the rear bracket to 50 to 60°C [122 to
140°F].
The brushes must be raised before the rotor is
installed to the rear bracket. To do so, put a wire
through the small hole located on the rear bracket,
then remove the wire after completing the
reassembly.
Wire
Figure 202 Reassembly of alternator
28.6 Installation
1.
Install the fan belt on the alternator, and mount the
alternator on the engine.
Temporarily tighten all the bolts.
2.
Insert a bar between the alternator and crankcase.
Using the bar as leverage, move the alternator and
adjust the belt tension.
While keeping the alternator at that position,
tighten the bolt that secures the alternator to the
adjusting plate.
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Figure 203 Installation of alternator
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ELECTRICAL SYSTEM
ALTERNATOR
3.
98 N (10 kgf) [22 lbf]
Adjusting
plate
Alternator
pulley
Water pump
pulley
Check the belt tension. If the belt tension does not
conform to the standard value, loosen the belt and
repeat the above step (2).
Unit: mm [in.]
Item
About
13 mm
[0.5118 in.]
Bolt
Crankshaft
pulley
Belt tension (crankshaft
pulley - alternator pulley)
4.
Standard Value
Approx. 13 [0.5118] (when
pressed with force of 98 N
(10 kgf) [22 lbf])
When the belt tension is properly adjusted, tighten
all the bolts that secure the alternator in place.
Figure 204 Inspection of belt tension
Service Manual Mitsubishi SQ-Series diesel engines
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ENGLISH
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ETR type stop solenoid
ELECTRICAL SYSTEM
ELECTRICAL SYSTEM
29 ETR type stop solenoid
Idle
Connector P/N 30A87-01600
(Counter-Connector P/N 30A87-00600)
Full
Run
Stop
Spring clip
Figure 205
29.1 General
The energize-to-run (ETR) solenoid controlled engine
shutdown system operates as follows:
When the starter switch is turned to the "ON" position,
the hold coil and the pull coil are energized
simultaneously, pulling the stop lever to the "RUN"
position. However, the pull coils is energized only for
about 1 second (maximum 3 seconds) by a special
controller.
The hold coil of the solenoid remains energized in both
the "ON" and "START" position of the starter switch,
keeping the stop lever in the "RUN" position. When the
current to the hold coil is interrupted, the hold coil is no
longer energized causing that the stop lever
immediately will be pushed to the no-injection position
by the internal return spring force of the solenoid. The
engine then stops.
This system is a safety device designed to stop the
engine whenever the wiring is open or when the starter
switch is turned "OFF".
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
ETR type stop solenoid
NOTE
If the electrical system includes a control timer to stop
the engine, the starter switch should be turned in the
"OFF" position for at least 10 seconds before making
another start attempt in order to reset the control
timer automatically.
Hold coil
Red
Pull coil
White
152±1
Lock nut
10º Min.
Spherical
movement
Adjustment location
Common ground
Black
Return spring
Colour code blue
Note: Plunger shown in energized position
Figure 206
29.2 Solenoid specification
current
connection
resistance (+/-10%) at 20 ºC
wire color
rated 12V
rated 24V
rated 12V
rated 24V
hold coil
red
55 A
29 A
11.15 Ω
41.35 Ω
pull coil
white
1.1 A
0.6 A
0.217 Ω
0.817 Ω
common ground
black
Notice that the housing is ungrounded.
Replace the complete solenoid if not within the above
mentioned specification.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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ETR type stop solenoid
ELECTRICAL SYSTEM
CAUTION
To avoid damage to the stop solenoid, do not
energize the pull coil for more than 10 seconds. Allow
the solenoid to cool down before energizing again.
29.3 Inspection
1.
Check the spring: the coil ends should be squared
and ground.
2.
Check the connecting rod spherical movement
freely.
3.
Check the rubber boot for any cracks or leaks.
Replace the complete solenoid assy if any failure at 1,
2 or 3.
4.
The plunger and hub should be free of any wear,
dirt or grease: clean if necessary. Install a tie rap to
install the rubber boot.
5.
Check the spring clip to secure well.
29.4 Connecting rod adjustment
1.
Check the connecting rod length and adjust to 152
+/- 1 mm if necessary (see Figure 206 on
page 135).
2.
Install the connecting rod from inside out to the
stop lever and lock it by the spring clip (see
Figure 205 on page 134).
3.
Start and stop the engine to check proper
operation of the shutdown system.
WARNING
Wrong adjustment will cause that the engine can not
run or can not be stopped. It is also possible that the
engine can not reach its maximum output.
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ELECTRICAL SYSTEM
GLOW PLUGS
ELECTRICAL SYSTEM
30 GLOW PLUGS
30.1 Removal
Nut
Connection
plate
Glow plug
1.
2.
Unscrew the connection plate retaining nut, and
remove the connection plate.
Remove the glow plug from the cylinder head.
CAUTION
After removing the glow plug, cover the glow plug
mounting hole with tape to prevent dust from entering
the cylinder head.
Figure 207 Removal of glow plug
30.2 Inspection
As shown in the diagram, check the conductivity
between the terminal and body. If there is no
conductivity or if the resistance is high, replace the
glow plug.
Unit: Ω
Item
Assembly Standard
Resistance
1.0
Figure 208 Inspection of glow plug
30.3 Installation
1.
Install the glow plug in the cylinder head by
tightening to the specified torque.
Tightening torque
2.
Install the connection plate to the glow plug, and
tighten the retaining nut to the specified torque.
Tightening torque
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
18 ± 2 N·m
(1.8 ± 0.2 kgf·m)
[13 ± 1 lbf·ft]
1.3 ± 0.2 N·m
(0.13 ± 0.02 kgf·m)
[0.96 ± 0.14 lbf·ft]
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GLOW PLUGS
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ELECTRICAL SYSTEM
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TESTING AND ADJUSTING
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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BENCH TEST
TESTING AND ADJUSTING
TESTING AND ADJUSTING
31 BENCH TEST
An overhauled engine should be tested for
performance on a dynamometer. This test is also for
breaking in the major running parts of the engine, follow
the procedures described below:
31.1 Starting Up
1.
Inspect the levels in the radiator, oil pan and fuel
tank. Prime the fuel and cooling systems to bleed
air out.
2.
Crank the engine with the starter for 15 seconds to
permit lubricating oil to circulate through the
engine. For this cranking, do not supply fuel to the
engine.
3.
Move the speed control lever slightly in the
direction of increasing the injection, and turn the
starter switch to START to start the engine. Do not
move the control lever to the “full fuel injection”
positon.
4.
After the engine starts, let it to idle under no load
by operating the speed control lever.
31.2 Inspection after Starting Up
After starting up the engine, check the following points.
If you find anything wrong, immediately stop the
engine, then investigate for the cause.
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1.
Lubricating oil pressure should be 0.2 to 0.4 MPa
(2 to 4 kgf/cm2) [29 to 58 psi] at rated speed or
over 0.1 MPa (1 kgf/cm2) [15 psi] at idling speed.
2.
Coolant temperature should be 75°C to 85°C
[167°F to 185°F].
3.
Lube oil temperature should be 70°C to 90°C
[158°F to 194°F].
4.
Check for leakage of oil, coolant, fuel.
5.
Knocking should die away as the coolant
temperature increases. No other defective noise
should be heard.
6.
Check for exhaust color and abnormal odors.
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TESTING AND ADJUSTING
BENCH TEST
31.3 Bench Testing (Dynamometer)
Conditions
Here is a summary table of bench testing conditions.
Step
Speed (rpm)
Load (PS)
Time (min.)
1
1000
No-load
30
2
1500
25%
30
25%
10
50%
10
75%
30
100%
20
3
Ratted (varies
according to
specifications)
4
5
6
31.4 Inspection and Adjustment
after Bench Testing
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
1)
Adjusting valve clearance
2)
Adjusting injection timing
3)
Re-tightening external bolts and nuts
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IDLING SPEED AND MAXIMUM SPEED
SETTING INSPECTION AND ADJUSTMENT
TESTING AND ADJUSTING
TESTING AND ADJUSTING
32 IDLING SPEED AND
MAXIMUM SPEED
SETTING INSPECTION
AND ADJUSTMENT
CAUTION
a
b
c
d
The idling speed (no-load) and maximum
speed are set for each engine at factory
bench testing, then the set bolts are sealed.
These settings are to be inspected and
adjusted at Mitsubishi service shops only.
After adjusting the governor be sure to seal
the stopper.
The stoppers are specified to be sealed.
Whether the seals are intact or not has
importance bearing on the validity of claims
under the warranty.
When inspecting and adjusting these
settings, be ready to operate the engine stop
lever manually against the engine
overrunning.
NOTE
Prior to inspection and adjustment, warm up the
engine until coolant and oil temperature rise to 70°C
[158°F] or higher.
1.
Starting the engine
1)
Governer set
bolt
Idle subspring
adjusting
screw
2)
3)
Speed control lever
Pull the speed control lever toward the HIGHS
SPEED side, and operate the starter switch.
The engine ignites when the rotation speed
reaches approximately 150 rpm. When the
engine speed starts to increase, operate the
speed control lever and maintain the engine
speed between 800 and 1000 rpm.
After the engine speed stabilizes, return the
speed control lever to the low idling position.
Low idling
set bolt
Figure 209 Starting the engine
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TESTING AND ADJUSTING
IDLING SPEED AND MAXIMUM SPEED
SETTING INSPECTION AND ADJUSTMENT
2.
Low idling set bolt
Low idling setting (no-load minimum rotation speed
setting)
1)
Set the speed control lever at the position of
no-load minimum rotation speed, then secure
the lever in that position using the low idling
set bolt.
CAUTION
If there is a speed range which causes dangerous
torsional vibration, avoid setting the engine speed in
that range.
Figure 210 Low idling setting
3.
Governor set
bolt
Governor setting (maximum rotation speed setting)
1)
2)
Keep the speed control lever at the position of
the specified maximum rotation speed.
With the speed control lever held in that
position, adjust and set the governor set bolt
(maximum rotation speed set bolt) to the
specified rotation speed.
Figure 211 Governor setting
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
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PERFORMANCE TEST
TESTING AND ADJUSTING
TESTING AND ADJUSTING
33 PERFORMANCE TEST
There are various performance test procedures, and
here the procedures for “Earth moving machinery
Engines, Part 1: Test code of net power (JIS D 0006-1)”
and “Earth moving machinery Engines, Part 2:
standard format of specifications and tests methods of
diesel engines (JIS D 0006-2)” are described. Other
test items may be required on application. Engine
performance is judged with integrated test results.
33.1 Engine Equipment Condition
Engine must be equipped with such standard
auxiliaries as cooling fan, air cleaner and alternator.
33.2 Tests and Their Purposes
1.
Operation load test
Conduct this test to evaluate engine output,
torque, fuel consumption and governor performance under various load conditions.
2.
Continuous load test
Operate the engine continuously for 10 hours at
90% load (continuous load application) of nominal
net shaft output while engine speed is maintained
at revolutions corresponding to the nominal shaft
output. In this test, evaluate fuel consumption and
operating condition and confirm continuous engine
operation.
3.
No-load minimum revolution test
Conduct this test to confirm that the engine can
operate stably at the specified no-load minimum
revolutions.
33.3 Other Inspections
During performance testing, inspect for leakage of
gases, coolant, lubricating oil, or fuel, and for noise or
hunting. Make adjustment, as needed.
33.4 Adjustment Engine Output
Diesel engine output is affected by atmospheric
pressure, temperature, and humidity. Therefore, the
engine output should be set for standard atmospheric
conditions.
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
TESTING AND ADJUSTING
PERFORMANCE TEST
1.
Standard atmospheric conditions
Temperature
298 K (25°C) [77°F]
Atmospheric pressure
100 kPa [750 mmHg]
Atmospheric vapor pressure
99 kPa [743 mmHg]
2.
Calculation of corrected output value
Multiply the measured shaft output or torque by the
calculated diesel engine correction factor (see
below) to obtained a corrected value.
Corrected output = Correction factor (αc) x Measured shaft
output
1)
Atmospheric conditions for test
Temperature (T): 283 K (10ºC) [50ºF] ≤ T ≤
313 K (40ºC) [104ºF]
Dry atmospheric pressure (Pd): 80 kPa (600
mmHg) ≤ Pd ≤ 110 kPa (825 mmHg)
3.
Calculation of correction factor (αc)
αc = (fa)fm
fa: Atmospheric factor
fm: Engine factor
1)
Calculation of atmospheric factor (fa)
a
Natural aspiration engine and engine with
mechanically driven air charger
99
Pd
T
298
fa = ( ------- ) · ( ---------- )0.7
b
Turbocharged engine without air cooler (after
cooler) or with air-to-air cooler
99
Pd
T
298
fa = ( ------- )0.7 · ( ---------- )1.2
c
Turbocharged engine with air-to-liquid cooler
99
Pd
T
298
fa = ( ------- )0.7 · ( ---------- )0.7
2)
Calculation of engine factor (fm)
fm = 0.036 qc – 1.14
a
q
r
qc (Corrected fuel supply volume) = --( z ) × ( Fuel flow rate g/s )
q = ------------------------------------------------------------------------------------------------------------------( Stroke volume ) × ( Engine revolution rpm )
z = 120000 (4-cycle engine)
r: Ratio of pressure at turbocharger or air
cooler to atmospheric pressure (r = 1 for
natural aspiration engine)
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ENGLISH
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PERFORMANCE TEST
TESTING AND ADJUSTING
b
Applicable range of engine factor (fm)
37.2 ≤ qc ≤ 65 mg/( -cycle)
• qc ≤ 37.2 mg/( -cycle) : fm = 0.2 (Constant)
• 65 mg/( -cycle) ≤ qc : fm = 1.2 (Constant)
3)
Range of correction equation use
The range of correction factor (αc) use is as
follows: 0.9 ≤ αc ≤ 1.1.
If this range is exceeded, indicate the
corrected value and record the test conditions
on the test record sheet.
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TROUBLESHOOTING
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Version 08/2004
ENGLISH
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TROUBLESHOOTING
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
TROUBLESHOOTING
34 CAUSES OF ENGINE
PROBLEMS AND
REMEDIES
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Version 08/2004
ENGLISH
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CAUSES OF ENGINE PROBLEMS AND
REMEDIES
TROUBLESHOOTING
(• Refer to the separate troubleshooting chart.)
Problems/Symptoms
No exhaust smoke
Small amount of exhaust smoke
Large amount of exhaust smoke
Cranking speed low
Engine can be cranked manually
Engine can not be cranked
manually
Glow plugs do not produce red heat
Glow plugs do produce red heat to fast
Small amount of exhaust smoke
Large amount of white exhaust smoke
Large amount of black exhaust smoke
At idling
White
Black
Engine produces loud knocking sound
Engine produces abnormal noice
Engine produces irregular combustion sound
At idling
In operation
Engine
hunts
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Greater variance of fuel
injection quantity
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Injection pump oil seals
defective
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Insufficient fuel injection
volume
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Excessive fuel injection
volume
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Injection nozzle defective
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Excessive fuel return from
injection nozzles
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Injection timing is too
advanced
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Injection timing is too retarded
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Engine speed is too low
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Failure to stop
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Improper fuel
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Fuel viscosity is too high
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Improper oil quality
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Oil viscosity is too high
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Oil viscosity is too low
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Oil pressure does not rise
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Excessive pumping up of oil
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Clogged oil filter
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Oil pressure switch or lamp
defective
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Possible causes
Fuel system
Exhaust
smoke
abnormal
No fuel to injection pump
Engine
does not
turn
Engine turns
Lubricating system
Not enough
power
Hard starting
Oil leaks
150 / 174
ENGLISH
In
operation
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
TROUBLESHOOTING
(• Refer to the separate troubleshooting chart.)
Engine vibrates excessively
Engine stalls
Poor response for deceleration
Engine does not pick up speeds
Engine operates at high speeds and does not stop
Engine rotates in reverse direction
Fuel consumption is high
Oil consumption is high
Fuel mixes with oil
Water mixes with oil
Excessive blowby
Indicator does not light when engine is not
operating
Indicator lights when engine operates at low
speed
Indicator lights when engine operates at
high speed
Overheating
Low
Indicator does not light when engine is not
operating
Indicator lights when engine operates at
high speed
Abnormality in Abnormal Alternator
lubrication
coolant
system
temperature defective
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•
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Remedies
If disassembled, replace parts.
•
•
•
Replace nozzle tip(s).
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Use oil of proper viscosity.
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Use oil of proper viscosity.
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Tighten bolts and nuts. Replace
packing(s) if necessary.
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•
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Replace filter element and oil.
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Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
•
Use fuel designed for cold areas.
Use high quality oil.
Replace filter element and oil.
151 / 174
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
TROUBLESHOOTING
(• Refer to the separate troubleshooting chart.)
Problems/Symptoms
Exhaust
smoke
abnormal
No exhaust smoke
Small amount of exhaust smoke
Large amount of exhaust smoke
Cranking speed low
Engine can be cranked manually
Engine can not be cranked
manually
Glow plugs do not produce red heat
Glow plugs do produce red heat to fast
Small amount of exhaust smoke
Large amount of white exhaust smoke
Large amount of black exhaust smoke
At idling
White
Black
Engine produces loud knocking sound
Engine produces abnormal noice
Engine produces irregular combustion sound
At idling
In operation
Engine
hunts
Insufficient intake air
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Insufficient compression
pressure
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⊗
⊗
⊗
⊗
⊗
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⊗
Ambient temperature is too
high, or ambient pressure is
too low (high altitude)
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Engine
does
not turn
Engine turns
Possible causes
Air intake system
Not enough
power
Hard starting
In
operation
Cooling system
Engine is too cold
Excessive cooling by radiator
Insufficient coolant
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Excessive cooling by radiator
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Water leakage from cylinder
head gasket
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Cracks in crankcase water
jacket
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Starter magnetic switch
defective
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Starter defective
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Starter switch defective
Electrical system
Starter free wheel defective
Flywheel ring gear and pinion
defective
Battery voltage is too low
Open circuit in glow plug or
pilot lamp
Short circuit in glow plug
Alternator malfunction
Relay defective
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Wiring defective
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152 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
TROUBLESHOOTING
(• Refer to the separate troubleshooting chart.)
Engine vibrates excessively
Engine stalls
Poor response for deceleration
Engine does not pick up speeds
Engine operates at high speeds and does not stop
Engine rotates in reverse direction
Fuel consumption is high
Oil consumption is high
Fuel mixes with oil
Water mixes with oil
Excessive blowby
Indicator does not light when engine is not
operating
Indicator lights when engine operates at low
speed
Indicator lights when engine operates at
high speed
Overheating
Low
Indicator does not light when engine is not
operating
Indicator lights when engine operates at
high speed
Abnormality in Abnormal Alternator
lubrication
coolant
system
temperature defective
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(Adjust full-load setting of
governor.)
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Heat oil pan at starting. After
starting warm up engine
thoroughly.
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•
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If bolts must be tightened,
replace gasket.
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Disassemble and replace
crankcase.
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Disassemble and repair.
Replace part(s) if necessary.
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Repair or replace.
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Repair or replace starter if
necessary.
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Repair or replace ring gear.
Replace pinion gear.
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Charge or replace battery. Heat
it if necessary.
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Replace copper packing(s).
Replace glow plug(s), if
necessary.
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Replace alternator if necessary.
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Adjust or replace.
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Connect wires properly.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Remedies
Repair or replace.
Replace part(s).
153 / 174
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
TROUBLESHOOTING
(• Refer to the separate troubleshooting chart.)
Problems/Symptoms
Exhaust
smoke
abnormal
No exhaust smoke
Small amount of exhaust smoke
Large amount of exhaust smoke
Cranking speed low
Engine can be cranked manually
Engine can not be cranked
manually
Glow plugs do not produce red heat
Glow plugs do produce red heat to fast
Small amount of exhaust smoke
Large amount of white exhaust smoke
Large amount of black exhaust smoke
At idling
White
Black
Engine produces loud knocking sound
Engine produces abnormal noice
Engine produces irregular combustion sound
At idling
In operation
Engine
hunts
Seizing of moving parts
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Worn cylinder(s), piston(s) or
piston ring(s)
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Worn piston ring(s)
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Loose connecting rod cap
bolts
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Interference between valve(s)
and piston(s)
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Damaged valve spring(s)
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⊗
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Engine
does
not turn
Engine turns
Possible causes
Mechanical problems
Not enough
power
Hard starting
Excessive oil clearance
Excessive valve clearance
Foreign item in cylinder(s)
Excessive gear backlash
154 / 174
ENGLISH
In
operation
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
TROUBLESHOOTING
(• Refer to the separate troubleshooting chart.)
Engine vibrates excessively
Engine stalls
Poor response for deceleration
Engine does not pick up speeds
Engine operates at high speeds and does not stop
Engine rotates in reverse direction
Fuel consumption is high
Oil consumption is high
Fuel mixes with oil
Water mixes with oil
Excessive blowby
Indicator does not light when engine is not
operating
Indicator lights when engine operates at low
speed
Indicator lights when engine operates at
high speed
Overheating
Low
Indicator does not light when engine is not
operating
Indicator lights when engine operates at
high speed
Abnormality in Abnormal Alternator
lubrication
coolant
system
temperature defective
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⊗
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⊗
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⊗
⊗
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Repair or replace.
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Check and replace bearings with
undersize ones if necessary.
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__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
Reinstall timing gears or adjust
valve sinkage.
⊗
⊗
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
Replace part(s).
⊗
⊗
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
Adjust valve clearance to 0.25
mm [0.0098 in.].
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
Repair.
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
__
Repair gear(s) or idler gear
bushing.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
Remedies
•
Repair or replace.
Tighten.
155 / 174
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
Causes
Fuel is not supplied to
injection pumps properly
Irregular injection pump
operation
Insufficient fuel injection
volume (by injection pump)
Excessive fuel injection
volume
Fuel injection nozzle(s)
defective
Fuel injection timing is too
advanced
Fuel injection timing is too
retarded
156 / 174
TROUBLESHOOTING
Details of Causes
Remedies
Fuel tank supply valve is closed
Open the valve.
No fuel in tank
Add fuel.
Fuel lines restricted
Repair or clean fuel pipes with compressed air.
Air in fuel system
Tighten mounting sections or replace fuel pipes.
Fuel leakage
Retighten connections.
Fuel filter is clogged
Clean or replace filter element.
Inadequate air bleeding
Conduct air bleeding.
Sticking of plunger(s)
Disassemble and replace parts.
Worn plunger(s)
Disassemble and replace parts.
Worn bearing(s)
Disassemble and replace parts.
Damaged plunger spring(s)
Disassemble and replace parts.
Loose plunger pinion(s)
Reinstall by matching marks.
Delivery valve(s) defective
Replace parts.
Damaged delivery valve spring(s)
Replace parts.
Catching of governor stop lever link
Repair link properly and set lever to neutral position.
Control rack does not move
Supply lubricant, or disassemble and repair.
Seizing of plunger(s)
Disassemble and replace parts.
Worn plunger(s)
Disassemble and replace parts.
Worn bearing(s)
Disassemble and replace parts.
Loose plunger pinion(s)
Reinstall by matching marks.
Full-load setting of governor does not move
Readjust governor setting on bench.
Stop lever sticking in “increase” position
Repair link properly and set lever to neutral position.
Full-load setting of governor improper
Adjust governor setting on bench.
Loose plunger pinion(s)
Reinstall by matching marks.
Seizing of nozzle tip needle
Repair or replace.
Nozzle tip seat(s) defective
Repair or replace.
Damaged nozzle spring(s)
Replace parts.
Fuel injection pressure is too low
Change adjusting shim and set standard injection
start pressure using nozzle tester.
Carbon deposits on packing at nozzle tip(s)
Remove carbon deposits.
Faulty mounting angle of injection pump
Tilt injection pump toward outside of engine and
adjust timing.
Timing gears incorrectly installed
Correct timing gear engagement.
Faulty mounting angle of injection pump
Tilt injection pump toward outside of engine and
adjust timing.
Timing gears incorrectly installed
Correct timing gear engagement.
Worn fuel injection pump bearing
Replace parts.
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
TROUBLESHOOTING
Causes
Improper fuel
Low oil pressure
Pumping up of oil
Insufficient intake air
Insufficient compression
pressure
Insufficient coolant
Insufficient cooling by
radiator
Details of Causes
Remedies
Poor fuel quality
Drain fuel, and add high-quality fuel.
Water is mixed with fuel
Drain fuel, and add high-quality fuel.
Insufficient amount of oil in oil pan
Add oil to specified level.
Air in oil strainer
Correct damaged pipe and loose flange by replacing
parts and tightening.
Oil pump defective
Disassemble and repair.
Oil lines restricted
Disassemble and clean.
Relief valve defective
Disassemble and inspect for damaged spring, foreign
particles on valve, and other abnormalities.
Clogged oil filter
Replace filter element and oil.
Leak in oil lines
Disassemble and repair.
Too much oil in oil pan
Drain oil to specified level.
Worn cylinder(s), piston(s) or piston ring(s)
Disassemble and repair. Replace parts.
Seizing of piston ring(s)
Disassemble and repair. Replace parts.
Worn valve guide(s)
Disassemble and repair. Replace parts.
Engine operated too long under no load
Disassemble and repair if engine continues to
produce smoke for a while or if large amount of oil is
discharged from exhaust pipe.
Clogged air cleaner
Clean or replace filter element.
Clogged intake manifold
Inspect and clean.
Valve seat(s) defective
Disassemble and correct.
Seizing of valve stem(s)
Disassemble and correct.
Valve is pressed down by rocker
Adjust valve clearance to 0.25 mm [0.0098 in.].
Worn cylinder(s), piston(s) or piston ring(s)
Disassemble and repair. Replace parts.
Seizing of piston ring(s)
Disassemble and repair. Replace parts.
Gas leakage from cylinder heah gasket
Tighten. Replace gasket if necessary.
Damaged valve spring(s)
Disassemble and replace parts.
Insufficient starter speed (at startup)
Disassemble and replace parts.
Overheating
Add coolant to specified level.
Water leakage from unit seal of water pump
Disassemble and replace parts.
Cracks in crankcase water jacket
Disassemble and replace parts.
Water leakage from other part(s)
Disassemble and replace parts.
Inadequate air bleeding of cooling system
Loosen air vent plug, drainage plug or hose clamp,
and bleed air.
Rust or water scale accumulation inside radiator
Clean.
Dust accumulation on radiator
Clean.
Fan belt slipping
Adjust belt tension.
Thermostat defective (stuck closed)
Replace parts.
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
157 / 174
CAUSES OF ENGINE PROBLEMS AND
REMEDIES
Causes
Excessive cooling by
radiator
Seizing of moving parts
158 / 174
TROUBLESHOOTING
Details of Causes
Remedies
Ambient temperature is low
Radiator is not covered
Cover radiator.
Thermostat defective (stuck open)
Replace parts.
Seizing of cylinder(s), piston(s) or piston ring(s)
Disassemble and repair. Replace parts.
Seizing of main or connecting rod bearing(s)
Disassemble and repair. Replace parts.
Seizing of idler gear bushing
Disassemble and repair. Replace parts.
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
MAINTENANCE STANDARDS
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
159 / 174
MAINTENANCE STANDARDS TABLE
MAINTENANCE STANDARDS
MAINTENANCE STANDARDS
35 MAINTENANCE
STANDARDS TABLE
Unit: mm [in.]
Group
Inspection Point
Maximum speed, (no-load), rpm
Minimum speed, (no-load), rpm
Compression pressure, MPa
(kgf/cm2) [psi]
General
Engine oil pressure, MPa (kgf/
cm2) [psi]
Nominal
Value
Assembly
Standard
(Standard
Clearance)
2.55 (26) [370]
0.2 to 0.4 (2 to 4) [28 to 57] at
rated rpm
0.15 (1.5)
[21.3]
0.1 (1) [14] or more at low idle
speed
0.05 (0.5) [7]
Fan (water pump) and alternator
drive belt tension
13 [0.5], approx.
Flatness of
surface gasket
0.05 [0.0020] or
less
160 / 174
Bore for main bearing
Main bearing
Engine Main Parts
Cylinder
When belt is pushed inward
with 98 N (22 lbf) [10 kgf]
pressure exerted midway
between crankshaft and
alternator pulleys.
0.20
[0.0079]
Regrind if warpage is minor.
+0.035
+0.0014
[3.460
]
0.01 [0.0004] or
less
Cylindricity
0.015 [0.0006] or
less
69
[2.72]
Standard injection timing is
indicated here. The timing for
each model of engine varies
according to its specification.
Be sure to verify the timing by
referring to the specifications
of each model.
880
Circularity
Inside diameter
Oil temperature
70 to 90°C
[158 to 194°F]
Bolt inlet and exhaust valves.
BTDC 20°
88
[3.46]
Oil and water temp.
20 to 30°C [68 to 86°F]
BTDC 30°
ATDC 50°
BTDC 74°
ATDC 30°
±3° (crank angle)
0.25 [0.0098]
Fuel injection timing
Remark
Adjust governor setting.
2.94 (30) [427] at 150 to 200
rpm
Valve clearance (cold)
Inside diameter
Service
Limit
(Clearance)
Vary according to
specifications
Inlet valves open
Inlet valves close
Exhaust valves open
Exhaust valves closed
Valve timing
Crankcase
Repair Limit
(Clearance)
Increase bore to 0.25 [0.0098]
or 0.50 [0.0197] oversize and
use oversize piston.
+0.019
690
+0.0008
[2.720
]
Out-of-round
0.02 [0.0008] or
less
Concentricity
0.05 [0.0020] or
less
ENGLISH
With main bearing cap
installed (bolts tightened).
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Tappet bore
Oil clearance (clearance
between crankshaft
journal and main
bearing)
Bore in crankcase for camshaft
(0.035 to 0.100)
([0.0014 to 0.0039])
Inside diameter
14
[0.55]
14.000 to 14.018
[0.5512 to 0.5519]
14.100
[0.5551]
(0.016 to 0.052)
([0.0006 to 0.0021])
(0.080)
([0.0032])
Clearance between
tappet and bore
Inside
diameter of
bores for
camshaft
54
[2.13]
54.030 to 54.050
[2.1272 to 2.1280]
No. 1 and
No. 2
54
[2.13]
54.030 to 54.050
[2.1272 to 2.1280]
No. 3
53
[2.09]
53.030 to 53.050
[2.0878 to 2.0886]
Out-of-round
0.02 [0.0008] or
less
Concentricity
0.05 [0.0020] or
less
Cylinder head
Compressed thickness
of gasket
Valve stem
diameter
Clearance
between
stem and
guide
Exhaust
valve
0.05 [0.0020] or
less
1.3
[0.05]
8
[0.315]
Regrind if warpage is minor
7.900
[0.3110]
7.920 to 7.940
[0.3118 to 0.3126]
7.850
[0.3091]
Exhaust
valve
(0.080 to 0.115)
([0.0032 to 0.0045])
Angle
0.20
[0.0079]
7.940 to 7.955
[0.3126 to 0.3132]
(0.065 to 0.095)
([0.0026 to 0.0037])
15.5
[0.61]
(0.15)
([0.0059])
1.27 to 1.35
[0.0500 to 0.0531]
Inlet valve
Height to top of valve
guide
61GT only
(0.07 to 0.11)
([0.0028 to 0.0043])
Warpage of bottom face
(0.200)
([0.0079])
15.1 to 15.6
[0.5945 to 0.6142]
30°
Valve sinkage
0.8
[0.03]
0.7 to 0.9
[0.0276 to 0.0354]
1.3
[0.0512]
Width
1.18
[0.05]
1.04 to 1.32
[0.0409 to 0.0520]
1.6
[0.0630]
Valve margin
Up to 1.20
[0.0472] by
refacing
1.70
[0.0669]
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
Remark
(0.200)
([0.0079])
22.979 to 23.000
[0.9047 to 0.9055]
Inlet valve
Valves and valve guide
Service
Limit
(Clearance)
23
[0.91]
Clearance between
camshaft and journal
Valve seat
Repair Limit
(Clearance)
Width of thrust journals
Inside diameter of
bushing (No. 1)
Engine Main Parts
Assembly
Standard
(Standard
Clearance)
ENGLISH
at
w
id
th
Inspection Point
Main bearing
Group
Nominal
Value
MAINTENANCE STANDARDS TABLE
Se
MAINTENANCE STANDARDS
Valve
Valve
margin
Valve seat sinkage
angle
161 / 174
MAINTENANCE STANDARDS TABLE
Group
Inspection Point
Nominal
Value
Valve spring
Inner valve spring (highspeed option)
Rocker arm
Valve
pushrod
Engine Main Parts
Service
Limit
(Clearance)
1.5° or less
Set length/set force N
(kgf) [lbf]
43 [1.69]/
177 to 196
(18 to 20)
[40 to 44]
147
(15)
[33]
50.0
[1.9685]
49.0
[1.9291]
Free length
Perpendicularity
(distortion)
Inside diameter of rocker
arm (bushing)
19
[0.75]
Clearance between
rocker arm and shaft
38.5 [1.52]/
48.1 (4.9)
[10.8]
19.010 to 19.030
[0.7484 to 0.7492]
18.980 to 19.000
[0.7472 to 0.7480]
(0.010 to 0.050)
([0.0004 to 0.0020])
Runout
(0.070)
([0.0028])
0.3 [0.012] or less
0.02 [0.0008] or
less
Diameter of journal
65
[2.56]
64.965 to 64.985
[2.5577 to 2.5585]
Diameter of crankpin
58
[2.28]
57.955 to 57.970
[2.2817 to 2.2823]
Distance from center of
journal to center of
crankpin
47.5
[1.870]
47.46 to 47.54
[1.8685 to 1.8716]
Parallelism between
journal and crankpin
Dial indicator reading
0.05
[0.0020]
Runout: 0.01
[0.0004] or less
Out-of-round of journal
and crankpin
0.01 [0.0004] or
less
Taper of journal and
crankpin
End play
Squareness of ends with
respect to center line
38.5 [1.52]/
56.9 (5.8) [12.8]
Diameter of rocker shaft
Fillet radius of journal
and crankpin
Squareness of ends with
respect to center line
1.5° or less
Set length/set force N
(kgf) [lbf]
Remark
47.60
[1.87]
Perpendicularity
(distortion)
Deflection
Crankshaft
Repair Limit
(Clearance)
48.85
[1.92]
Free length
162 / 174
Assembly
Standard
(Standard
Clearance)
MAINTENANCE STANDARDS
3
[0.12]
0.03
[0.0012]
±0.2 [±0.008]
(0.10 to 0.20)
([0.0039 to 0.0080])
ENGLISH
(0.30)
([0.0118])
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
MAINTENANCE STANDARDS
Assembly
Standard
(Standard
Clearance)
Standard
87.970
[3.4634]
87.955 to 87.985
[3.4628 to 3.4640]
87.770
[3.4555]
0.25 [0.0098]
oversize
88.220
[3.4732]
88.205 to 88.235
[3.4726 to 3.4738]
88.020
[3.4654]
0.50 [0.0197]
oversize
88.470
[3.4831]
88.455 to 88.485
[3.4825 to 3.4837]
88.270
[3.4752]
Outside diameter (at
skirt)
Weight difference in one
engine
5 g [0.2 oz] or less
Clearance between
groove and ring
0.13 to 0.60
[0.0051 to 0.0236]
Clearance between
end of piston ring
Piston ring
Protrusion
No. 1 ring
(0.060 to 0.100)
([0.0024 to 0.0039])
No. 2 ring
(0.045 to 0.080)
([0.0018 to 0.0032])
Oil ring
(0.025 to 0.065)
([0.0010 to 0.0026])
No. 1, No. 2
ring
(0.25 to 0.40)
([0.0098 to 0.0157])
28
[1.10]
Remark
Check bearing clearance.
(0.200)
([0.0079])
(0.150)
([0.0059])
Replace piston rings if
service limit is not
exceeded. Replace piston if
service limit is exceeded.
27.994 to 28.000
[1.1021 to 1.1024]
Replace pin if service limit is
nog exceeded. Replace
piston if service limit is
exceeded.
Clearance between pin
and bore
0.000 to 0.016
[0.0000 to 0.0006]
0.050
[0.0020]
Clearance between pin
and bushing
(0.020 to 0.051)
([0.0008 to 0.0020])
(0.080)
([0.0032])
Replace pin or bushing.
Ream if necessary.
(0.50)
([0.020])
Replace connecting rod.
28
[1.10]
28.020 to 28.045
[1.1031 to 1.1041]
0.05/100 [0.0020/
3.94] or less
0.15/100
[0.0059/3.94]
Clearance between
crankpin and
connecting rod bearing
(oil clearance)
(0.03 to 0.09)
([0.0012 to 0.0035])
(0.20)
([0.0079])
Thrust clearance of
connecting rod big-end
(End play)
(0.15 to 0.35)
([0.0059 to 0.0138])
Weight difference in one
engine
10 g [0.35 oz] or
less
Flatness
0.15 [0.0059] or
less
Face runout
0.15 [0.0059] or
less
Bend and twist
Connecting rod
Service
Limit
(Clearance)
(0.30 to 0.50)
([0.0118 to 0.0197])
O-ring
Inside diameter of
bushing
Flywheel
Repair Limit
(Clearance)
(1.50)
([0.0591])
Diameter
Piston pin
Engine Main Parts
Nominal
Value
Inspection Point
Piston
Group
MAINTENANCE STANDARDS TABLE
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
0.50
[0.0197]
163 / 174
MAINTENANCE STANDARDS TABLE
Group
Inspection Point
Nominal
Value
Engine Main Parts
Idler gear
Backlash
Straighten by cold working
or replace.
6.844
[0.2694]
No. 1, 2
54
[2.13]
53.94 to 53.96
[2.1236 to 2.1244]
53.90
[2.1220]
No. 3
53
[2.09]
52.94 to 52.96
[2.0843 to 2.0850]
52.90
[2.0827]
5
[0.20]
(0.10 to 0.25)
([0.0039 to 0.0098])
(0.30)
([0.0118])
Replace thrust plate.
Clearance between
shaft and bushing
(0.025 to 0.075)
([0.0010 to 0.0030])
(0.100)
([0.0039])
Replace bushing.
End play
(0.05 to 0.20)
([0.0020 to 0.0079])
(0.35)
([0.0138])
Replace thrust plate.
(0.25)
([0.0098])
Replace gears.
Lobe lift C
7.344
[0.2891]
Injection pump drive
gear and idler gear
(0.04 to 0.16)
([0.0016 to 0.0063])
Clearance between
outer rotor and inner
rotor
(0.13 to 0.15)
([0.0051 to 0.0059])
(0.20)
([0.0079])
Clearance between
rotors and cover
(0.04 to 0.09)
([0.0016 to 0.0035])
(0.15)
([0.0059])
Clearance between
outer rotor and case
(0.200 to 0.275)
([0.0079 to 0.0108])
(0.500)
([0.0197])
Relief valve opening
pressure, kPa (kgf/cm2)
[psi]
A
B
(0.05 to 0.15)
([0.0020 to 0.0059])
Idler gear and camshaft
gear
Shaft diameter
C
(-0.039 to -0.076)
([-0.0015 to 0.0030])
13
[0.51]
Clearance between
shaft and case
Thermostat
0.05
[0.0020]
Remark
A=
+0.1
45.944– 0.3
[1.80882]
Exhaust valve
End play
Oil pump
Lubrication system
0.02 [0.0008] or
less
Service
Limit
(Clearance)
6.184
[0.2435]
Crankshaft gear and
idler gear
Cooling system
Repair Limit
(Clearance)
6.684
[0.2631]
Inlet valve
Fit (interference) of
shaft in crankcase bore
164 / 174
Assembly
Standard
(Standard
Clearance)
A=
+0.1
46.916– 0.3
[1.84709]
Diameter of
journals
Camshaft
Deflection
MAINTENANCE STANDARDS
12.985 to 13.000
[0.5112 to 0.5118]
(0.032 to 0.074)
([0.0013 to 0.0029])
343
(3.5)
[50]
343 ± 49
(3.5 ± 0.5)
[50 ± 7]
Temp. at which valve
starts opening
76.5 ± 1.5°C
[170 ± 2.7°F]
Temp. at which valve
lifts more than 8 [0.3]
90°C [194°F]
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
MAINTENANCE STANDARDS
Group
Inspection Point
Injection nozzle
Fuel system
Valve opening pressure,
MPa (kgf/cm2) [psi]
Spray cone angle
Commutator
Oil tightness of needle
valve seat
Diameter
Assembly
Standard
(Standard
Clearance)
14.22
(145)
[2063]
14.22 to 15.00
(145 to 153)
[2063 to 2177]
Repair Limit
(Clearance)
Service
Limit
(Clearance)
0°
Apply pressure of 3.92 ± 0.25
MPa (40 ± 2.5 kgf/cm2) [569 ± 36
psi] with N2 gas and submerge in
an oil tank (at room temperature)
for more than 5 minutes. Check to
make sure there is no leakage.
Wash or replace nozzle tip.
32
[1.26]
31.4
[1.24]
Commutator mica depth
0.4 to 0.6
[0.016 to 0.024]
18
[0.71]
0.10
[0.0039]
0.2
[0.008]
11
[0.43]
29 to 39
(3.0 to 4.0)
[6.5 to 8.8]
Spring tension,
N (kgf) [lbf]
Remark
Check nozzle with a hand
tester (at fuel oil
temperature 20°C [68°F]).
Replace the nozzle tip if the
spray pattern is still bad
after washing in clean fuel
oil.
0.05
[0.0020]
Brush
Starter
Nominal
Value
Runout
Length
Electrical system
MAINTENANCE STANDARDS TABLE
19.6
(2.0)
[4.4]
0.5 to 2.0
[0.020 to 0.079]
Pinion clearance
For 12V
No-load characteristics
Magnetic switch operating voltage
Voltage, V
Current, A
Speed, rpm
11
130 or less
4000 or more
8 volts or less, with pinion held at 2 mm [0.08 in.] position
from cranking position
For 24V (Option)
No-load characteristics
Magnetic switch operating voltage
Voltage, V
Current, A
Speed, rpm
23
80 or less
3000 or more
16 volts or less, with pinion held at 2 mm [0.08 in.] position
from cranking position
Alternator
7
[0.276]
Brush length
18.5
[0.728]
Resistance between slip
ring
3.4 Ω
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
5 [0.197]
Option
(A7TA80AA)
(A3TN5776)
At 20°C [68°F]
165 / 174
TIGHTENING TORQUES
MAINTENANCE STANDARDS
MAINTENANCE STANDARDS
36 TIGHTENING TORQUES
36.1 Important Bolts and Nuts
Parts to be fastened
Thread Dia. x
Pitch, mm (Mthread)
Width across
flats, mm [in.]
Torque
N·m
kgf·m
lbf·ft
Cylinder head
M12 x 1.75
19 [0.75]
118 ± 5
12.0 ± 0.5
87 ± 4
Rock cover
M8 x 1.25
12 [0.47]
12 ± 1
1.2 ± 0.1
9±1
Rocker shaft bracket (long bolt)
M8 x 1.25
12 [0.47]
15 ± 2
1.5 ± 0.2
11 ± 1
Main bearing cap
M12 x 1.75
12 [0.47]
83 ± 5
8.5 ± 0.5
61 ± 4
Connecting rod cap
M10 x 1
14 [0.55]
54 ± 5
5.5 ± 0.5
40 ± 4
Flywheel
M12 x 1.25
17 [0.67]
83 ± 5
8.5 ± 0.5
61 ± 4
Camshaft thrust plate
M8 x 1.25
12 [0.47]
12 ± 1
1.2 ± 0.1
9±1
Front end plate
M8 x 1.25
12 [0.47]
12 ± 1
1.2 ± 0.1
9±1
Timing gear case and cover
M8 x 1.25
12 [0.47]
12 ± 1
1.2 ± 0.1
9±1
Crankshaft pulley
M24 x 1.5
34 [1.34]
392 ± 10
40 ± 1
289 ± 7
Flywheel housing
M10 x 1.25
14 [0.55]
60 ± 6
6.1 ± 0.6
44 ± 4
Oil pan
M8 x 1.25
12 [0.47]
7.8 ± 1
0.8 ± 0.1
5.8 ± 1
Oil pan drain plug
M14 x 1.5
22 [0.87]
39 ± 4
4.0 ± 0.4
29 ± 3
Oil filter shaft
M20 x 1.5
__
49 ± 5
5.0 ± 0.5
36 ± 4
Oil filter
M20 x 1.5
__
12 ± 1
1.2 ± 0.1
9±1
Fuel injection nozzle
M20 x 1.5
21 [0.83]
59 ± 6
6.0 ± 0.6
43 ± 4
Fuel injection nozzle retaining nut
M16 x 0.75
21 [0.83]
37 ± 2.5
3.77 ± 0.25
27 ± 1.8
Fuel leak-off pipe
M12 x 1.5
17 [0.67]
23 ± 2
2.3 ± 0.2
17 ± 1
Fuel injection pump gear
M12 x 1.75
19 [0.75]
64 ± 5
6.5± 0.5
47 ± 4
B terminal of starter
M8 x 1.25
12 [0.47]
11 ± 1
1.1 ± 0.1
8±1
Glow plug (body)
Glow plug (terminal)
M10 x 1.25
M4 x 0.7
12 [0.47]
8 [0.31]
18 ± 2
1.3 ± 0.2
1.8 ± 0.2
0.13 ± 0.02
13 ± 1
0.94 ± 0.14
Exhaust manifold
M8 x 1.25
12 [0.47]
30 ± 2
3.1 ± 0.3
22 ± 2
Pressure relief valve
M22 x 1.5
27 [1.06]
49 ± 5
5.0 ± 0.5
36 ± 4
Coolant drain plug
1/4-18NPTF
14 [0.55]
39 ± 4
4.0 ± 0.4
29 ± 3
Fuel injection pipe
M12 x 1.5
19 [0.75]
29 ± 3
3.0 ± 0.3
22 ± 2
Fuel return pipe
M10 x 1.25
14 [0.55]
20 ± 2
2.0 ± 0.2
14 ± 1
Oil pump set bolt
M12 x 1.75
17 [0.67]
34 ± 4
3.5 ± 0.4
25 ± 3
Overheat warning unit (thermoswitch)
M16 x 1.5
19 [0.75]
23 ± 2
2.3 ± 0.2
17 ± 1
Drain plug
M16 x 1.5
24 [0.94]
44 ± 5
4.5 ± 0.5
33 ± 4
166 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
MAINTENANCE STANDARDS
TIGHTENING TORQUES
36.2 Standard Bolts
Torque
Thread Dia. x Pitch mm (M-thread)
4T
7T
N·m
kgf·m
lbf·ft
N·m
kgf·m
lbf·ft
M6 x 1.0
4±1
0.4 ± 0.1
3±1
9±1
0.9 ± 0.1
7±1
M8 x 1.25
12 ± 1
1.2 ± 0.1
9±1
18 ± 3
1.85 ± 0.35
13 ± 3
M10 x 1.25
22 ± 3
2.2 ± 0.3
16 ± 2
35 ± 6
3.6 ± 0.6
26 ± 4
M12 x 1.25
35 ± 6
3.6 ± 0.6
26 ± 4
64 ± 10
6.5 ± 1
47 ± 7
36.3 Standard Studs
Torque (tap end)
Thread Dia. x Pitch mm (M-thread)
For driving in aluminium materials
For driving in ferrous materials
N·m
kgf·m
lbf·ft
N·m
kgf·m
lbf·ft
M8 x 1.25
7.4 ± 0.8
0.75 ± 0.1
5.4 ± 0.6
13 ± 1
1.3 ± 0.1
9 ±1
M10 x 1.5
14 ± 1
1.4 ± 0.1
10 ± 1
24 ± 2
2.4 ± 0.2
17 ± 1
36.4 Standard Plugs
Torque
Thread Dia. x Pitch
For aluminium materials
For ferrous materials
N·m
kgf·m
lbf·ft
N·m
kgf·m
lbf·ft
NPTF 1/16
6 ± 1.5
0.65 ± 0.15
4.7 ± 1
10 ± 2
1.0 ± 0.2
7±1
PT 1/8
10 ± 2
1.0 ± 0.2
7±1
18 ± 3
1.85 ± 0.35
13 ± 3
PT 1/8, NPTF 1/4
25 ± 5
2.5 ± 0.5
18 ± 4
39 ± 5
4.0 ± 0.5
29 ± 4
__
__
__
64 ± 10
6.5 ± 1
47 ± 7
PT 3/8
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
167 / 174
THREAD SEALANTS
MAINTENANCE STANDARDS
MAINTENANCE STANDARDS
37 THREAD SEALANTS
Application Point
Mating Parts
Sealant
How to Use
Cylinder head coolant hole plug
Cylinder head
Three Bond 1386D
Apply to hole and install plug.
Crankcase coolant hole plug
Crankcase
Three Bond 1386D
Apply to hole and install plug.
Crankcase oil gallery plug
Crankcase
Three Bond 1386D
Apply to hole and install plug.
Crankcase oil return pipe
Crankcase
Three Bond 1344
Apply to pipe and tighten.
Crankcase No.1 and No.5 bearing
cap grooves
Oil pan gasket and U-seal
Three Bond 1207C or 1211
See page 54.
Starter mounting stud
Rear plate
Three Bond 1344
Apply to stud and tighten.
Injection pump mounting stud
Flange plate
Three Bond 1344
Apply to stud and tighten.
168 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
MAINTENANCE STANDARDS
MAINTENANCE SCHEDULE
MAINTENANCE STANDARDS
38 MAINTENANCE
SCHEDULE
1.
Use the service meter to determine servicing
intervals.
2.
The servicing intervals in the schedule are for an
average operating conditions. Service the engine
earlier than the scheduled intervals if necessary.
(The intervals depends on application, operating
conditions and fuel oil and lube oil used in the
engine. Adjust the intervals to meet the actual
operating conditions.)
3.
Perform service on items at multiples of the
original requirement. For example, at Every 250
service hours, also service those items listed
under Every 50 service hours and Every 10 service
hours.
⊗
Check, clean, wash or adjust.
•
Change.
S
Rely on Mitsubishi dealer if necessary.
*
Items to be serviced after initial 50 hours of
operation of a new, reconditioned or long-stored
engine.
Interval
Group
Item
Lubrication system
General
Walk-around
inspection
Every 10
service
hours
Check
Every 250
service
hours
Boils and nuts
(cylinder head
bolts)
*
*
•
Change
*
•
Drain moisture
S
S
⊗
⊗
Fuel filter
Change
•
Injection
nozzles
Check
⊗
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
S
⊗
Change oil
Fuel tank
Remarks
⊗
Oil pan
Oil filter
(cartridge)
Every 1000
service
hours
⊗
Retighten
Check oil level
Every 500
service
hours
⊗
Valve clearance Check
Check oil level
Fuel system
Every 50
service
hours
ENGLISH
S
169 / 174
MAINTENANCE SCHEDULE
MAINTENANCE STANDARDS
Interval
Electrical system
Air inlet system
Cooling system
Group
170 / 174
Item
Radiator
Check coolant
level
Every 10
service
hours
Every 50
service
hours
Clean
Fan belt
Check tension
Check indicator
Air cleaner
(paper-element
type)
Every 500
service
hours
Every 1000
service
hours
Remarks
⊗
Change coolant
Radiator fins
Every 250
service
hours
Every 2 years
⊗
⊗
⊗
S
⊗
Clean element
Change
element
•
Battery
Check
electrolyte level
and specific
gravity
Alternator
Check
⊗
S
Starter
Check
⊗
S
Check specific
gravity from
time to time
⊗
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
SPECIAL TOOLS
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
171 / 174
SPECIAL TOOL LIST
SPECIAL TOOLS
SPECIAL TOOLS
39 SPECIAL TOOL LIST
Tool name
Part No.
Shape
Use
Valve spring pusher
30691-04500
Valve spring removal/installation
Valve guide remover
32A91-00300
Valve guide removal
Valve guide installer
32A91-00100
Valve guide installation
Valve seat insert
caulking tool
Intake 30691-02700
Exhaust 30691-02800
Valve seat installation
Idler gear bushing
installer
30691-51900
Idler gear bushing removal/
installation
Idler gear shaft puller
MH061077
Idler gear shaft removal
Piston ring pliers
31391-12900
Piston ring removal/installation
172 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
SPECIAL TOOLS
Tool name
SPECIAL TOOL LIST
Part No.
Shape
Use
Crankcase oil seal
sleeve installer set
30691-13010
Crankshaft rear oil seal sleeve
installation
Piston guide (installer)
30691-58100
Piston installation
Adaptor
30691-21100
Compression pressure testing
Compression gage
33391-02100
Compression pressure testing
Turning handle
30691-21800
Engine turning
Socket
34491-00300
Camshaft thrust plate and rocker
shaft bracket installation
Stem seal installer
32A91-00200
Stem seal installation
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
173 / 174
BLANK PAGE
174 / 174
ENGLISH
Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004