Cetane Number of Diesel Fuel Oil1
An American National Standard
Designation: D 613 – 03b
Designation: 41/2000
Standard Test Method for
Cetane Number of Diesel Fuel Oil1
This standard is issued under the fixed designation D 613; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
Petroleum Products4
E 1 Specification for ASTM Thermometers5
E 456 Terminology Relating to Quality and Statistics6
E 542 Practice for Calibration of Laboratory Volumetric
E 832 Specification for Laboratory Filter Papers7
1. Scope*
1.1 This test method determines the rating of diesel fuel oil
in terms of an arbitrary scale of cetane numbers using a
standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected diesel engine.
1.2 The cetane number scale covers the range from zero (0)
to 100 but typical testing is in the range of 30 to 65 cetane
1.3 The values for operating conditions are stated in SI units
and are considered standard. The values in parentheses are the
historical inch-pounds units. In addition, the engine measurements continue to be in inch-pounds units because of the
extensive and expensive tooling that has been created for these
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For more specific
warning statements, see Annex A1.
3. Terminology
3.1 Definitions:
3.1.1 accepted reference value (ARV), n—a value that
serves as an agreed-upon reference for comparison, and which
is derived as: (1) a theoretical or established value, based on
scientific principles, or (2) an assigned or certified value, based
on experimental work of some national or international organization, or (3) a consensus or certified value, based on
collaborative experimental work under the auspices of a
E 456
scientific or engineering group. Discussion—In the context of this test method,
accepted reference value is understood to apply to the cetane
number of specific reference materials determined empirically
under reproducibility conditions by the National Exchange
Group or another recognized exchange testing organization.
3.1.2 cetane number, n—a measure of the ignition performance of a diesel fuel oil obtained by comparing it to reference
D 4175
fuels in a standardized engine test. Discussion—In the context of this test method,
ignition performance is understood to mean the ignition delay
of the fuel as determined in a standard test engine under
controlled conditions of fuel flow rate, injection timing and
compression ratio.
3.1.3 compression ratio, n—the ratio of the volume of the
combustion chamber including the precombustion chamber
with the piston at bottom dead center to the comparable volume
with the piston at top dead center.
3.1.4 ignition delay, n—that period of time, expressed in
degrees of crank angle rotation, between the start of fuel
injection and the start of combustion.
2. Referenced Documents
2.1 ASTM Standards:
D 975 Specification for Diesel Fuel Oils2
D 1193 Specification for Reagent Water3
D 2500 Test Method for Cloud Point of Petroleum Products2
D 4057 Practice for Manual Sampling of Petroleum and
Petroleum Products4
D 4175 Terminology Relating to Petroleum, Petroleum
Products, and Lubricants4
D 4177 Practice for Automatic Sampling of Petroleum and
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.01 on Combustion Characteristics.
Current edition approved June 10, 2003. Published August 2003. Originally
approved in 1941. Last previous edition approved in 2003 as D 613–03a.
Annual Book of ASTM Standards, Vol 05.01.
Annual Book of ASTM Standards, Vol 11.01.
Annual Book of ASTM Standards, Vol 05.02.
Annual Book of ASTM Standards, Vol 14.03.
Annual Book of ASTM Standards, Vol 14.02.
Annual Book of ASTM Standards, Vol 14.04.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 613 – 03b Discussion—In the context of this test method, the
Diesel National Exchange Group of Subcommittee D02.018 is
composed of petroleum industry, governmental, and independent laboratories. It conducts regular monthly exchange sample
analyses to generate precision data for this engine test standard
and determines the CNARV of reference materials used by all
3.2.8 reference pickups, n—transducer(s) mounted over the
flywheel of the engine, triggered by a flywheel indicator, used
to establish a top-dead-center (tdc) reference and a time base
for calibration of the ignition delay meter.
3.2.9 secondary reference fuels, n—volumetrically proportioned blends of two selected, numbered, and paired hydrocarbon mixtures designated T Fuel (high cetane) and U Fuel (low
cetane) that have been rated by the ASTM Diesel National
Exchange Group using primary reference fuels to determine a
cetane number accepted reference value for each individually
and for various combinations of the two.
3.1.5 injection timing (injection advance), n—that time in
the combustion cycle, measured in degrees of crank angle, at
which fuel injection into the combustion chamber is initiated.
3.1.6 repeatability conditions, n—conditions where independent test results are obtained with the same method on
identical test items in the same laboratory by the same operator
using the same equipment within short intervals of time.
E 456 Discussion—In the context of this method, a short
time interval between two ratings on a sample fuel is understood to be not less than the time to obtain at least one rating
on another sample fuel between them but not so long as to
permit any significant change in the sample fuel, test equipment, or environment.
3.1.7 reproducibility conditions, n—conditions where test
results are obtained with the same method on identical test
items in different laboratories with different operators using
different equipment.
E 456
3.2 Definitions of Terms Specific to This Standard:
3.2.1 cetane meter (ignition delay meter), n—the electronic
instrument which displays injection advance and ignition delay
derived from input pulses of multiple transducers (pickups).
3.2.2 Check Fuels, n—for quality control testing, a diesel
fuel oil of selected characteristics having a cetane number
accepted reference value determined by round-robin testing
under reproducibility conditions.
3.2.3 combustion pickup, n—pressure transducer exposed to
cylinder pressure to indicate the start of combustion.
3.2.4 handwheel reading, n—an arbitrary numerical value,
related to compression ratio, obtained from a micrometer scale
that indicates the position of the variable compression plug in
the precombustion chamber of the engine.
3.2.5 injector opening pressure, n—the fuel pressure that
overcomes the resistance of the spring which normally holds
the nozzle pintle closed, and thus forces the pintle to lift and
release an injection spray from the nozzle.
3.2.6 injector pickup, n—transducer to detect motion of the
injector pintle, thereby indicating the beginning of injection.
3.2.7 primary reference fuels, n— n-cetane, heptamethyl
nonane (HMN) and volumetrically proportioned mixtures of
these materials which now define the cetane number scale by
the relationship:
Cetane Number 5 % n2cetane 1 0.15 ~% HMN!
4. Summary of Test Method
4.1 The cetane number of a diesel fuel oil is determined by
comparing its combustion characteristics in a test engine with
those for blends of reference fuels of known cetane number
under standard operating conditions. This is accomplished
using the bracketing handwheel procedure which varies the
compression ratio (handwheel reading) for the sample and each
of two bracketing reference fuels to obtain a specific ignition
delay permitting interpolation of cetane number in terms of
handwheel reading.
5. Significance and Use
5.1 The cetane number provides a measure of the ignition
characteristics of diesel fuel oil in compression ignition engines.
5.2 This test method is used by engine manufacturers,
petroleum refiners and marketers, and in commerce as a
primary specification measurement related to matching of fuels
and engines.
5.3 Cetane number is determined at constant speed in a
precombustion chamber type compression ignition test engine.
The relationship of test engine performance to full scale,
variable speed, variable load engines is not completely understood.
5.4 This test method may be used for unconventional fuels
such as synthetics, vegetable oils, and the like. However, the
relationship to the performance of such materials in full scale
engines is not completely understood.
(1) Discussion—In the context of this test method, the
arbitrary cetane number scale was originally defined as the
volume percent of n-cetane in a blend with alphamethylnaphthalene (AMN) where n-cetane had an assigned
value of 100 and AMN an assigned value of zero (0). A change
from alpha-methylnaphthalene to heptamethylnonane as the
low cetane ingredient was made in 1962 to utilize a material of
better storage stability and availability. Heptamethylnonane
was determined to have a cetane number accepted reference
value (CNARV) of 15 based on engine testing by the ASTM
Diesel National Exchange Group, using blends of n-cetane and
AMN as primary reference fuels.
6. Interferences
6.1 (Warning—Avoid exposure of sample fuels and reference fuels to sunlight or fluorescent lamp UV emissions to
minimize induced chemical reactions that can affect cetane
number ratings.)9
Bylaws governing ASTM Subcommittee D02.01 on Combustion Characteristics are available from the subcommittee or from ASTM International.
Supporting data have been filed at ASTM International Headquarters and may
be obtained by requesting Research Report RR: D02–1502.
D 613 – 03b
A—Fuel Tanks
B—Air Heater Housing
C—Air Intake Silencer
D—Fuel Flow Rate Buret
E—Combustion Pickup
F—Safety Guard
G—Variable Compression Plug Handwheel
H—V.C.P. Locking Handwheel
I—Flywheel Pickups
J—Oil Filler Cap
K—Injection Pump Safety Shut-Off Solenoid
L—Injector Assembly
M—Fuel Injection Pump
N—Fuel Selector-Valve
O—Oil Filter
P—Crankcase Oil Heater Control
Q—Air Heater Switch
R—Engine Start-Stop Switch
S—Instrument Panel
T—Intake Air Temperature Controller
U—Dual Digital Cetane Meter
FIG. 1 Cetane Method Test Engine Assembly
fuel pump assembly, a cylinder with separate head assembly of
the precombustion type, thermal syphon recirculating jacket
coolant system, multiple fuel tank system with selector valving, injector assembly with specific injector nozzle, electrical
controls, and a suitable exhaust pipe. The engine is belt
connected to a special electric power-absorption motor which
acts as a motor driver to start the engine and as a means to
absorb power at constant speed when combustion is occurring
(engine firing). See Fig. 1.
7.1.1 See Annex A2 for detail and description of all critical,
non-critical and equivalent engine equipment.
7.2 Instrumentation10—This test method uses an electronic
instrument to measure injection and ignition delay timing as
well as conventional thermometry, gages and general purpose
7.2.1 A Cetane Meter, (Ignition Delay Meter) is critical and
shall be used for this test method.
7.2.2 See Annex A3 for detail and description of all critical,
non-critical and equivalent instrumentation.
6.1.1 Exposure of these fuels to UV wavelengths shorter
than 550 nm for a short period of time may significantly affect
cetane number ratings.
6.2 Certain gases and fumes present in the area where the
cetane test engine is located may have a measurable effect on
the cetane number test result.
6.3 This test method is not suitable for rating diesel fuel oils
with fluid properties that interfere with unimpeded gravity flow
of fuel to the fuel pump or delivery through the injector nozzle.
7. Apparatus
7.1 Engine Equipment10—This test method uses a single
cylinder engine which consists of a standard crankcase with
The sole source of supply of the engine equipment and instrumentation known
to the committee at this time is Waukesha Engine, Dresser Inc., 1000 West St. Paul
Avenue, Waukesha, WI 53188. Waukesha Engine also has CFR engine authorized
sales and service organizations in selected geographical areas. If you are aware of
alternative suppliers, please provide this information to ASTM International
Headquarters. Your comments will receive careful consideration at a meeting of the
responsible technical committee 1, which you may attend.
D 613 – 03b
with commercial glycol-based antifreeze added in sufficient
quantity to meet the boiling temperature requirement shall be
used when laboratory altitude dictates. A commercial multifunctional water treatment material should be used in the
coolant to minimize corrosion and mineral scale that can alter
heat transfer and rating results.
8.1.1 Water shall be understood to mean reagent water
conforming to Type IV of Specification D 1193.
8.2 Engine Crankcase Lubricating Oil—An SAE 30 viscosity grade oil meeting service classification SF/CD or SG/CE
shall be used. It shall contain a detergent additive and have a
kinematic viscosity of 9.3 to 12.5 cSt (mm2 per s) at 100°C
(212°F) and a viscosity index of not less than 85. Oils
containing viscosity index improvers shall not be used. Multigraded oils shall not be used. (Warning—Lubricating oil is
combustible, and its vapor is harmful. See Annex A1.)
8.3 Primary Reference Fuels—(Warning—Primary Reference Fuel—Combustible. Vapor Harmful. See Annex A1.)10,11
8.3.1 n-Cetane (n-hexadecane)—With a minimum purity of
99.0 % as determined by chromatographic analysis shall be
used as the designated 100 cetane number component.
8.3.2 Heptamethylnonane (2,2,4,4,6,8,8-heptamethylnonane)—With a minimum purity of 98 % as determined by
chromatographic analysis shall be used as the designated 15
cetane number component.
8.4 Secondary
Fuels 10 , 12 —(Warning—
Secondary Reference fuel—Combustible. Vapor Harmful. See
Annex A1.)
8.4.1 T Fuel—Diesel fuel with a CNARV typically in the
range of 73 to 75.
8.4.2 U Fuel—Diesel fuel with a CNARV typically in the
range of 20 to 22.
8.4.3 Storage and use of T Fuel and U Fuel should be at
temperatures above 0°C (32°F) to avoid potential solidification, particularly of T Fuel. Before a container that has been
stored at low temperature is placed in service, it should be
warmed to a temperature of at least 15°C (27°F) above its
Cloud Point. (See Test Method D 2500.) It should be held at
this temperature for a period of at least 30 min and then the
container should be thoroughly remixed.
8.5 Check Fuels13—Diesel fuel oils typical of Specification
D 975 grade No. 2-D distillate fuel oil. (Warning—Check
Fuel—Combustible. Vapor Harmful. See Annex A1.)
8.5.1 Low Cetane Check Fuel—With a CNARV typically in
the range of 38 to 42.
8.5.2 High Cetane Check Fuel—With a CNARV typically in
the range of 50 to 55.
7.3 Reference Fuel Dispensing Equipment—This test
method requires repeated blending of two secondary reference
fuel materials in volumetric proportions on an as-needed basis.
Measurement shall be performed accurately because rating
error is proportional to blending error.
7.3.1 Volumetric Blending of Reference Fuels—Volumetric
blending has historically been employed to prepare the required blends of reference fuels. For volumetric blending, a set
of two burets or accurate volumetric ware shall be used and the
desired batch quantity shall be collected in an appropriate
container and thoroughly mixed before being introduced to the
engine fuel system. Calibrated burets or volumetric ware having a capacity of 400 or 500 mL and a maximum volumetric tolerance
of 6 0.2 % shall be used. Calibration shall be verified in
accordance with Practice E 542. Calibrated burets shall be outfitted with a dispensing
valve and delivery tip to accurately control dispensed volume.
The delivery tip shall be of such size and design that shutoff tip
discharge does not exceed 0.5 mL. The rate of delivery from the dispensing system
shall not exceed 500 mL per 60 s. The set of burets for the reference and standardization fuels shall be installed in such a manner and be supplied
with fluids such that all components of each batch or blend are
dispensed at the same temperature. See Appendix X1, Volumetric Reference Fuel
Blending Apparatus and Procedures, for typical dispensing
system information.
7.3.2 Gravimetric Blending of Reference Fuels—Use of
blending systems that allow preparation of the volumetricallydefined blends by gravimetric (mass) measurements based on
the density of the individual components is also permitted,
provided the system meets the requirement for maximum 0.2
% blending tolerance limits. Calculate the mass equivalents of the
volumetrically-defined blend components from the densities of
the individual components at 15.56°C (60°F).
7.4 Auxiliary Apparatus:
7.4.1 Injector Nozzle Tester—The injector nozzle assembly
shall be checked whenever the injector nozzle is removed and
reassembled to ensure the initial pressure at which fuel is
discharged from the nozzle is properly set. It is also important
to inspect the type of spray pattern. Commercial injector nozzle
testers which include a lever-operated pressure cylinder, fuel
reservoir and pressure gage are available from several sources
as common diesel engine maintenance equipment.
7.4.2 Special Maintenance Tools—A number of specialty
tools and measuring instruments should be utilized for easy,
convenient and effective maintenance of the engine and testing
equipment. Lists and descriptions of these tools and instruments are available from the manufacturers of the engine
equipment and those organizations offering engineering and
service support for this test method.
9. Sampling
9.1 Collect samples in accordance with Practice D 4057 or
D 4177.
The sole source of supply of primary reference fuels known to the committee
at this time is Humphrey Chemical Co., Devine Street, North Haven, CT 06473.
The sole source of supply of the secondary reference and check fuels known
to the committee at this time is Chevron Phillips Chemical Company LP., 1301
McKinney, Suite 2130, Houston, TX 77010–3030.
Blend Tables for batches of T Fuel and U Fuel can be obtained from the fuel
supplier or by requesting Research Report RR: D02–1302 from ASTM International.
8. Reagents and Reference Materials
8.1 Cylinder Jacket Coolant—Water shall be used in the
cylinder jacket for laboratory locations where the resultant
boiling temperature shall be 100 6 2°C (212 6 3°F). Water
D 613 – 03b
rate-micrometer is set to a typical operating position and the
variable timing device lever is at full advance (nearest to
operator). See Annex A4 for detailed instructions on setting
and checking the fuel pump timing.
10.2.5 Fuel Pump Inlet Pressure—A minimum fuel head
established by assembly of the fuel tanks (storage reservoirs)
and flow rate measuring buret so that the discharge from them
is 635 6 25 mm (25 6 1 in.) above the centerline of the fuel
injection pump inlet.
10.3 Assembly Settings and Operating Conditions:
10.3.1 Direction of Engine Rotation—Clockwise rotation of
the crankshaft when observed from the front of the engine.
10.3.2 Injection Timing—13.0° before-top-dead-center
(btdc), for the sample and reference fuels.
10.3.3 Injector Nozzle Opening Pressure—10.3 6 0.34
MPa (1500 6 50 psi).
10.3.4 Injection Flow Rate—13.0 6 0.2 mL/min (60 6 1 s
per 13.0 mL).
10.3.5 Injector Coolant Passage Temperature—38 6 3°C
(100 6 5°F).
10.3.6 Valve Clearances: Engine Stopped and Cold—Clearance between the
valve stem and valve rocker half-ball set to the following
approximate measurements upon assembly before the engine is
operated will typically provide the controlling engine running
and hot clearance:
9.1.1 Protection from Light—Collect and store sample fuels
in an opaque container such as a dark brown glass bottle, metal
can, or a minimally reactive plastic container to minimize
exposure to UV emissions from sources such as sunlight or
fluorescent lamps.
9.2 Fuel Temperature—Samples shall be brought to room
temperature typically 18 to 32°C (65 to 90°F) before engine
9.3 Filtration—Samples may be filtered through a Type I,
Class A filter paper at room temperature and pressure before
engine testing. See Specification E 832.
10. Basic Engine and Instrument Settings and Standard
Operating Conditions
10.1 Installation
Instrumentation—Installation of the engine and instrumentation requires placement of the engine on a suitable foundation
and hook-up of all utilities. Engineering and technical support
for this function is required, and the user shall be responsible
to comply with all local and national codes and installation
10.1.1 Proper operation of the test engine requires assembly
of a number of engine components and adjustment of a series
of engine variables to prescribed specifications. Some of these
settings are established by component specifications, others are
established at the time of engine assembly or after overhaul and
still others are engine running conditions that must be observed
or determined by operator adjustment, or both, during the
testing process.
10.2 Conditions Based on Component Specifications:
10.2.1 Engine Speed—900 6 9 rpm, when the engine is
operating with combustion with a maximum variation of 9 rpm
occurring during a rating. Engine speed when combustion is
occurring shall not be more than 3 rpm greater than that for
motoring without combustion.
10.2.2 Valve Timing— The engine uses a four-stroke cycle
with two crankshaft revolutions for each complete combustion
cycle. The two critical valve events are those that occur near
top-dead-center (tdc); intake valve opening and exhaust valve
closing. See Annex A4 for Camshaft Timing and Valve Lift
Measurement Procedure. Intake valve opening shall occur 10.0 6 2.5°
after-top-dead-center (atdc) with closing at 34° after-bottomdead-center (abdc) on one revolution of the crankshaft and
flywheel. Exhaust valve opening shall occur 40° beforebottom-dead-center (bbdc) on the second revolution of the
crankshaft or flywheel with closing at 15.0 6 2.5° after-topdead-center on the next revolution of the crankshaft or flywheel.
10.2.3 Valve Lift—Intake and exhaust cam lobe contours,
while different in shape, shall have a contour rise of 6.223 to
6.350 mm (0.245 to 0.250 in.) from the base circle to the top
of the lobe so that the resulting valve lift shall be 6.045 6 0.05
mm (0.238 6 0.002 in.). See Annex A4 for Camshaft Timing
and Valve Lift Measurement Procedure.
10.2.4 Fuel Pump Timing—Closure of the pump plunger
inlet port shall occur at a flywheel crank angle between 300 and
306°. on the engine compression stroke when the fuel flow-
Intake Valve
Exhaust Valve
0.075 mm (0.004 in.)
0.330 mm (0.014 in.)
These clearances should ensure that both valves have sufficient clearance to cause valve seating during engine warmup.
The adjustable-length valve push-rods shall be set so that the
valve rocker adjusting screws have adequate travel to permit
the final clearance setting. Engine Running and Hot—The clearance for both
intake and exhaust valves shall be set to 0.206 0.025 mm
(0.008 6 0.001 in.), measured under standard operating
conditions with the engine running at equilibrium conditions
on a typical diesel fuel oil.
10.3.7 Oil Pressure—172 to 207 kPa (25 to 30 psi). See
Annex A4 for the Adjusting Crankcase Lubricating Oil Pressure procedure.
10.3.8 Oil Temperature—57 6 8°C (135 6 15°F).
10.3.9 Cylinder Jacket Coolant Temperature—100 6 2°C
(212 6 3°F).
10.3.10 Intake Air Temperature—66 6 0.5°C (150 6 1°F).
10.3.11 Basic Ignition Delay—13.0° for the sample and
reference fuels.
10.3.12 Cylinder Jacket Coolant Level: Engine Stopped and Cold—Treated water/coolant
added to the cooling condenser—cylinder jacket to a level just
observable in the bottom of the condenser sight glass will
typically provide the controlling engine running and hot
operating level. Engine Running and Hot—Coolant level in the
condenser sight glass shall be within 61 cm (0.4 in.) of the
LEVEL HOT mark on the coolant condenser.
10.3.13 Engine Crankcase Lubricating Oil Level:
D 613 – 03b Engine Stopped and Cold—Oil added to the
crankcase so that the level is near the top of the sight glass will
typically provide the controlling engine running and hot
operating level. Engine Running and Hot—Oil level shall be
approximately mid-position in the crankcase oil sight glass.
10.3.14 Crankcase Internal Pressure—As mentioned by a
gage or manometer connected to an opening to the inside of the
crankcase through a snubber orifice to minimize pulsations, the
pressure shall be less than zero (a vacuum) and typically from
25 to 150 mm (1 to 6 in.) of water less than atmospheric
pressure. Vacuum shall not exceed 255 mm (10 in.) of water.
10.3.15 Exhaust Back Pressure—As measured by a gage or
manometer connected to an opening in the exhaust surge tank
or main exhaust stack through a snubber orifice to minimize
pulsations, the static pressure should be as low as possible, but
shall not create a vacuum nor exceed 254 mm (10 in.) of water
differential in excess of atmospheric pressure.
10.3.16 Exhaust and Crankcase Breather System
Resonance—The exhaust and crankcase breather piping systems shall have internal volumes and be of such length that gas
resonance does not result. See Appendix X2 for a suitable
procedure to determine if resonance exists.
10.3.17 Piston Over-Travel—Assembly of the cylinder to
the crankcase shall result in the piston protruding above the top
of the cylinder surface 0.381 6 0.025 mm (0.015 6 0.001 in.)
when the piston is at top-dead-center. Proper positioning is
accomplished through the use of plastic or paper gaskets,
available in several thicknesses and selected by trial and error
for assembly between the cylinder and crankcase deck.
10.3.18 Belt Tension—The belts connecting the flywheel to
the absorption motor shall be tightened, after an initial breakin, so that with the engine stopped, a 2.25 kg (5 lb) weight
suspended from one belt half way between the flywheel and
motor pulley shall depress the belt approximately 12.5 mm (0.5
10.3.19 Setting Injector Nozzle Assembly Pressure and
Spray Pattern Check—(Warning—Personnel shall avoid contact with the spray pattern from injector nozzles because of the
high pressure which can penetrate the skin. Spray pattern
performance checks shall be made in a hood or where adequate
ventilation insures that inhalation of the vapors is avoided.) Injector Opening or Release Pressure—The pressure adjusting screw is adjustable and shall be set to release
fuel at a pressure of 10.3 6 0.34 MPa (1500 6 50 psi). Check
this setting using an injector nozzle bench tester, each time the
nozzle is reassembled and after cleaning. Use of a commercial
injector nozzle bench tester is recommended. See Annex A4 for
procedural detail. Injector Spray Pattern—Check the spray pattern
for symmetry and characteristic by inspection of the impression of a single injection made on a piece of filter paper or
other slightly absorbent material placed at a distance of
approximately 7.6 cm (3 in.) from the nozzle. A typical spray
pattern is illustrated in Fig. 2.
10.3.20 Indexing Handwheel Reading—Handwheel readings are a simple and convenient indication of engine compression ratio which is a critical variable in the cetane method
FIG. 2 Typical Injector Spray Pattern
of test. The actual compression ratio is not important but an
indication of compression ratio which relates to cetane number
is a useful guide for selecting reference fuels to bracket the
sample of diesel fuel oil. The following procedure shall be used
to index the handwheel reading when the engine is new or
anytime the matched handwheel assembly/cylinder head combination is interchanged or mechanically reassembled. See
Appendix X3 for handwheel assembly reworking instructions. Handwheel Micrometer Drum and Scale
Setting—Refer to Table 1 to select the appropriate handwheel
reading to be used in aligning the drum and scale. Basic Setting of Variable Compression Plug—
Position the variable compression plug so that the flat surface
is just visible and exactly in line with the edge of the threads
of the combustion pickup hole, as verified with a straightedge. Setting Handwheel Reading—Tighten the small
locking handwheel snugly by hand to ensure that the variable
compression plug is held in place in the bore. Loosen the lock
nut of the large handwheel and remove the locking L-shaped
key. Turn the large handwheel so that the edge of the drum is
in alignment with the 1.000 graduation on the horizontal scale.
Reinstall the L-shaped key in the nearest keyway slot of the
large handwheel with the shorter leg in the handwheel. A slight
shifting of the handwheel to achieve slot line-up will not affect
the indexing. Tighten the lock nut hand-tight to hold the key in
place. Remove the locating screw from the drum and rotate the
drum so that the zero graduation mark is in line with the
selected reading from Table 1. Locate the screw hole in the
drum which lines up with the handwheel hub hole and reinstall
the locating screw. Wrench tighten the large handwheel lock
nut and recheck that the variable compression plug is properly
positioned and the handwheel reading is in accordance with the
value in Table 1.
10.3.21 Basic Compression Pressure—At a handwheel
reading of 1.000, the compression pressure for an engine
operated at standard barometric pressure of 760 mm Hg. (29.92
in. Hg) shall be 3275 6 138 kPa (475 6 20 psi) when read as
quickly as possible after shutdown of the engine which had
been at standard operating conditions. If the condition is not
within limits, recheck the basic handwheel setting and, if
TABLE 1 Handwheel Setting for Various Cylinder Bore Diameters
Cylinder Diameter, in.
Handwheel Reading
(Standard Bore)
(Rebored 0.010 in. Oversize)
(Rebored 0.020 in. Oversize)
(Rebored 0.030 in. Oversize)
D 613 – 03b
ables are at equilibrium and in compliance with basic engine
and instrument settings and standard operating conditions.
11.1.1 Engine warmup requires typically 1 h to ensure that
all critical variables are stable.
11.2 Checking Performance on Check Fuels—This engine
test does not have any satisfactory standardization fuel blend or
blends to qualify the engine. The Check Fuels are the most
helpful means available to permit judgement of good performance.
11.2.1 Test one or more of the Check Fuels.
11.2.2 Engine performance is judged satisfactory if the
cetane rating obtained on a Check Fuel is within the Check
Fuel tolerance limits calculated as follows:
necessary, perform mechanical maintenance. See Annex A4 for
the Checking Compression Pressure procedure. For engines operated at other than standard barometric pressure, the compression pressure will typically be in
proportion to the ratio of the local barometric pressure divided
by standard barometric pressure. As an example, an engine
located where the barometric pressure is 710 mm Hg would be
expected to have a compression pressure of approximately
30606 138 kPa (444 6 20 psi). (Warning—In addition to
other precautions, compression pressure testing using a compression pressure gage should be completed in as short a period
of time as possible to avoid the possibility of combustion
occurrence due to the presence of any small amount of oil in
the gage or combustion chamber.)
Compression Pressure ~LocalBaro.,mmHg!
5 3275 kPa 3 Local Baro./Standard Baro.
Tolerance Limits 5 CNARV 6 1.5 3 SARV
= the cetane number accepted reference value of
the Check Fuel,
= a selected tolerance limit factor (K) for normal
= the standard deviation of the Check Fuel data
used to determine CNARV. In the context of this test method, the statistical
tolerance limit factor (K), based on a sample size (n), permits
an estimation of the percentage of engines that would be able
to rate the Check Fuel within the calculated tolerance limits.
Based on a data set of 17 to 20 ratings used to determine the
Check Fuel CNARV, and a value of K = 1.5, it is estimated that
in the long run, in 19 cases out of 20, at least 70 % of the
engines would rate the Check Fuel within the calculated
tolerance limits.
11.2.3 If the results are outside this tolerance range, the
engine is not acceptable for rating samples and a check of all
operating conditions is warranted followed by mechanical
maintenance which may require critical parts replacement. The
injector nozzle can be a very critical factor and this should be
the first item checked or replaced to achieve rating compliance.
Example: Compression Pressure710mmHg
5 3275 3 710/760 5 3060 kPa
10.3.22 Fuel Pump Lubricating Oil Level—With the engine
stopped, sufficient engine crankcase lubricating oil shall be
added to the pump sump so that the level is at the mark on the
dip stick. (Warning—As a result of engine operation, especially when the pump barrel/plunger assembly begins to wear,
the level in the sump will increase due to fuel dilution as
observed through a clear plastic side plate on the pump
housing. When the level rises appreciably, the sump should be
drained and a fresh charge of oil added.)
10.3.23 Fuel Pump Timing Gear Box Oil Level—With the
engine stopped, unplug the openings on the top and at the
mid-height of either side of the gear box. Add sufficient engine
crankcase lubricating oil through the top hole to cause the level
to rise to the height of the side opening. Replug both openings.
(Warning—The pump and timing gear box oil sumps are not
connected to each other and the lubrication for the two is
10.3.24 Instrumentation—Positioning of the reference pickups and injector pickup is important to ensure that timing of the
injection and ignition delay functions is uniform and correct. Setting Reference Pickups—These two pickups
are identical and interchangeable. They are installed in a
bracket positioned over the flywheel so that they clear the
flywheel indicator which triggers them. Position each pickup in the bracket so that it is
properly referenced to the flywheel indicator in accordance
with the instructions supplied with the specific pickup. Measurement of pickup to flywheel indicator
clearance, if required, shall be made using a non-magnetic
feeler gage.
10.3.25 Setting Injector Pickup Gap—Set the air gap to
typically 1 mm (0.040 in.) with the engine stopped. Individual pickups may require more or less air
gap to obtain steady meter operation when the engine is
ultimately running but too little gap can cause the ignition
delay angle display to drive off scale.
12. Procedure
12.1 Bracketing by Handwheel Procedure—See Appendix
X2 for the details of engine operation and the adjustment of
each of the individual operating variables.
12.1.1 Check that all engine operating conditions are in
compliance and equilibrated with the engine running on a
typical diesel fuel oil. (Warning—In addition to other precautions, always position the ignition delay meter (Mark II and
earlier models) to CALIBRATE before proceeding with fuel
switching so that violent meter needle full-scale pegging does
not occur. Calibration adjustment should be checked before
each rating but never changed during a rating.)
12.1.2 Introduce the sample to an empty fuel tank, rinse the
fuel buret, purge any air from the fuel line to the pump and
position the fuel-selector valve to operate the engine on this
fuel. (Warning—Sample and Fuel—Combustible. Vapor
Harmful. See Annex A1.)
12.1.3 Fuel Flow Rate—Check the fuel flow rate and adjust
the flow-rate-micrometer of the fuel pump to obtain 13 mL per
min consumption. The final flow rate measurement shall be
11. Calibration and Engine Qualification
11.1 Engine Compliance—It is assumed that the engine has
been commissioned and that all settings and operating vari7
D 613 – 03b
made over a full 60 6 1 s period. Note the flow-ratemicrometer reading for reference.
12.1.4 Fuel Injection Timing—After establishing the fuel
flow rate, adjust the injection-timing-micrometer of the fuel
pump assembly to obtain a 13.0 6 0.2° injection advance
reading. Note the injection-timing-micrometer reading for
12.1.5 Ignition Delay—Adjust the handwheel to change the
compression ratio and obtain a 13.0 6 0.2° ignition delay
reading. Make the final handwheel adjustment in the clockwise
direction (viewed from front of engine) to eliminate backlash
in the handwheel mechanism and a potential error.
12.1.6 Equilibration—It is important to achieve stable injection advance and ignition delay readings. Stable readings should typically occur within 5 to
10 min. The time used for the sample and each of the
reference fuels should be consistent and shall not be less than
3 min.
12.1.7 Handwheel Reading—Observe and record the handwheel reading as the representative indication of the combustion characteristic for this fuel sample.
12.1.8 Reference Fuel No. 1—Select a secondary reference
fuel (T Fuel and U Fuel) blend close to the estimated cetane
number of the sample.
NOTE 2—Typically, the fuel-flow-rate should be the same for both
reference fuels because they are sufficiently similar in composition. If the handwheel reading for the sample is bracketed by those of the reference fuel blends, continue the test;
otherwise try an additional reference fuel blend(s) until this
requirement is satisfied.
12.1.10 Repeat Readings—After operation on a satisfactory
second reference fuel blend, perform the necessary steps to
rerun Reference Fuel No. 1, then the sample and finally
Reference Fuel No. 2. For each fuel, be certain to check all
parameters carefully and allow operation to reach equilibrium
before recording the handwheel readings. The fuel switching
shall be as illustrated in Fig. 3 Sample and Reference Fuel
Reading Sequence A. If a sample is tested immediately following one
for which the Reference Fuel No. 2 will be applicable, that
reference fuel handwheel reading can be utilized for the new
sample. The fuel switching shall thus be as illustrated in Fig. 3,
Sample and Reference Fuel Reading Sequence B.
13. Calculation of Cetane Number
13.1 Calculate the average handwheel readings for the
sample and each of the reference fuel blends.
13.2 Calculate the cetane number by interpolation of these
average handwheel readings proportioned to the cetane numbers of the bracketing reference fuel blends in accordance with
Eq 4. See Fig. 4.
13.2.1 For the Handwheel Bracketing Procedure:
NOTE 1—The handwheel reading vs cetane number relationship based
on this procedure is engine and overhaul dependent but it can be
established for each engine as testing experience is gained after each
overhaul. A plot or table of handwheel readings provides a simple guide
to selection of the reference fuel.
HRF 2 HWLRF Prepare a fresh 400 or 500 mL batch of the selected
reference blend. Introduce Reference Fuel No. 1 to one of the
unused fuel tanks taking care to flush the fuel lines in the same
manner as noted for the sample. Perform the same adjustment and measurement
steps used for the sample and record the resulting handwheel
12.1.9 Reference Fuel No. 2—Select another secondary
reference fuel blend which can be expected to result in a
handwheel reading that causes the two reference fuel handwheel readings to bracket that for the sample. The difference
between the two reference fuel blends shall not exceed 5.5
cetane numbers. Typically, blends differing by 5 volume
percent T Fuel will span about 2.7 cetane numbers and those
differing by 10 volume percent T Fuel will span about 5.3
cetane numbers. Prepare a fresh 400 or 500 mL batch of the selected
reference fuel blend. Introduce Reference Fuel No. 2 to the third fuel
tank taking care to flush the fuel lines in the same manner as
noted for the sample. Perform the same adjustment and measurement
steps used for the sample and first reference fuel and record the
resulting handwheel reading.
FIG. 3 Sample and Reference Fuel Reading Sequence
D 613 – 03b
TABLE 2 Cetane Number Repeatability and Reproducibility
Average Cetane Number
Repeatability Limits,
Cetane Number
Reproducibility Limits
Cetane Number
Values for cetane numbers intermediate to those listed above, may be
obtained by linear interpolation.
15.1.2 Reproducibility—The difference between two single
and independent results obtained on identical test samples
under reproducibility conditions would, in the long run, in the
normal and correct operation of the test method, exceed the
values in Table 2 only in 1 case in 20.
15.1.3 Repeatability precision limits are based on the
ASTM National Exchange Group (NEG) monthly sample
testing program data from mid-1978 through 1987. During this
period each exchange sample was rated twice on the same day
by the same operator on one engine in each of the Member
15.1.4 Reproducibility precision limits are based on the
combined NEG monthly sample testing program data from
mid-1978 through mid-1992, the Institute of Petroleum
monthly sample data for 1988 through mid-1992 and the
Institut Francais du Petrole monthly sample data for 1989
through early 1992.
15.1.5 The combination of the large number of sample sets
and the fact that each sample is tested by 12 to 25 laboratories
provides a comprehensive picture of the precision achievable
using this test method. Analyzed graphically, the respective
sample standard deviations were plotted vs cetane number. The
variation in precision with respect to cetane number level for
these data is best expressed by a linear regression of the values.
The average standard deviation for each cetane number level
has been multiplied by 2.772 to obtain the respective limit
15.2 Bias—The procedure in this test method for cetane
number of diesel fuel oil has no bias because the value of
cetane number can be defined only in terms of the test method.
FIG. 4 Example of Cetane Number Calculations
= cetane number of sample,
= cetane Number of low reference fuel,
= cetane number of high reference fuel,
= handwheel reading of sample,
HWLRF = handwheel reading of low reference fuel, and
HWHRF = handwheel reading of high reference fuel.
13.2.2 Do not interpolate using reference fuel blend volume
percent of T Fuel values and convert that equivalent percent to
cetane number.
13.3 Round the calculated cetane number to the nearest
tenth. Any cetane number ending in exactly 5 in the second
decimal place shall be rounded to the nearest even tenth
number; for example, round 35.55 and 35.65 to 35.6 cetane
14. Report
14.1 Report the calculated result as cetane number.
14.2 If the sample was filtered before testing, include this
information in the report.
15. Precision and Bias
15.1 Handwheel Bracketing Procedure Precision—The precision of this test method and procedure based on statistical
examination of interlaboratory test results is as follows:
15.1.1 Repeatability—The difference between two test results, obtained on identical test samples under repeatability
conditions would, in the long run, in the normal and correct
operation of the test method, exceed the values in Table 2 only
in 1 case in 20.
16. Keywords
16.1 cetane number; diesel performance; ignition delay
Supporting data (a listing of the data and the analyses used to establish the
precision statements) have been filed at ASTM International Headquarters and may
be obtained by requesting Research Report RR: D02–1303.
D 613 – 03b
(Mandatory Information)
A1.1 Introduction
A1.1.1 In the performance of the standard test method there
are hazards to personnel. These are indicated in the text. For
more detailed information regarding the hazards, refer to the
appropriate Material Safety Data Sheet (MSDS) for each of the
applicable substances to establish risks, proper handling, and
safety precautions.
A1.2.2.7 Secondary reference fuels, T Fuel and U Fuel
A1.2.2.8 Check Fuel.
A1.2.2.9 Kerosine.
A1.2.2.10 Warmup fuel.
A1.2.2.11 Engine crankcase lubricating oil.
A1.3 Warning
A1.3.1 Flammable. Vapors harmful if inhaled. Vapors may
cause flash fire.
A1.3.2 Applicable Substances:
A1.3.2.1 Petroleum based solvent.
A1.2 Warning
A1.2.1 Combustible. Vapor harmful.
A1.2.2 Applicable Substances:
A1.2.2.1 Diesel fuel oil.
A1.2.2.2 Reference material.
A1.2.2.3 Reference fuel.
A1.2.2.4 n-cetane.
A1.2.2.5 Heptamethylnonane.
A1.2.2.6 Alpha-methylnaphthalene.
A1.4 Warning
A1.4.1 Poison. May be harmful or fatal if inhaled or
A1.4.2 Applicable Substances:
A1.4.2.1 Ethylene glycol based antifreeze
TABLE A2.1 General Engine Characteristics and Information
A2.1 Engine Equipment
A2.1.1 The single cylinder cetane test engine is manufactured as a complete unit by Waukesha Engine Division, Dresser
Industries, Inc. and consists of both critical and non-critical
equipment. The Waukesha Engine Division designation is
Model CFR F-5 Cetane Method Diesel Fuel Rating Unit.
Waukesha Engine Division Part Numbers or References are
included in parenthesis after the items where applicable.
A2.1.1.1 See Table A2.1.
Cylinder Type
Cylinder Head Type
Compression Ratio
Cylinder Bore (Diameter), in.
A2.2 Critical Equipment—Critical engine components
and primary assemblies which shall be used for this test
method are listed. The bearings, gears, seals, covers, special
fittings or hardware and gaskets manufactured by Waukesha
Engine Division and applicable to each critical assembly shall
also be considered critical.
Stroke, in.
Displacement, cu in
Valve Mechanism
Intake and Exhaust Valves
Piston Rings:
Compression Type
A2.2.1 Crankcase Assembly—Model CFR-48 (109520D)
specified to include the following major items (See Fig. A2.1):
A2.2.1.1 Crankshaft Assembly (A109511H).
A2.2.1.2 Piston Assembly (0023204B).
A2.2.1.3 Rings, Piston, Compression, Straight (106222A), 4
Oil Control
Camshaft Over lap, degree
Fuel System
Spray Nozzle
Weight of Engine
Weight of Complete Test Unit
Model CFR-48 (Preferred), High or Low Speed
Models (Optional)
Single bore cast iron with integral coolant
Cast Iron with turbulence precombustion
chamber, variable compression plug
passage, integral coolant passages, and
in-head valve assembly
Adjustable 8:1 to 36:1 by external handwheel
3.250 (Standard), Reboring to 0.010, 0.020,
0.030 over is acceptable
In-head with enclosure
Stellite faced, plain type without shroud
Cast iron, flat top
4, Ferrous, straight sided (Top may be chrome
1, Cast iron, one piece, slotted (Type 85)
Injection pump with variable timing device and
Holder with by-pass pressure release valve
Closed, differential-needle, hydraulicallyoperated, pintle type
Approximately 400 kg (880 lb)
Approximately 1250 kg (2750 lb)
NOTE A2.1—Ring, Piston, Compression, Straight, Chrome (106222B),
Use of a chrome ring in the top groove is optional with 3 compression
rings (106222A) in the other 3 compression ring grooves.
A2.2.1.8 Counterweight for Balancing Shaft, (109565) 2
A2.2.1.9 Flywheel (109501H) (applicable for 50 or 60 Hz
A2.2.1.10 Oil Pump Assembly (110150A).
Ring, Piston, Oil (23505).
Connecting Rod Assembly (BA111666).
Camshaft (109583B).
Balancing Shaft, 2 required (109510A).
D 613 – 03b
FIG. A2.1 CFR-48 Crankcase—Sectional Views
Gasket, Cylinder Base—0.021 in. thick (105181)
Gasket, Cylinder Base—0.015 in. thick (105181A)
Gasket, Cylinder Base—0.010 in. thick (105181B)
Gasket, Cylinder Base—0.003 in. thick (105181C)
A2.2.3 Cylinder Head Assembly—(AF105082B) of cast
iron with internal coolant passages, a flat-top combustion
chamber surface, a horizontal and cylindrical precombustion
chamber to accept a matched and pinned, variable compression
ratio handwheel housing on one end and including a passage
for insertion of an injector assembly at the other end. An angled
passage, 0.5 in. square in cross-section, connects the precombustion chamber to the main combustion chamber. The assembly is specified to include the following major items (See Fig.
A2.2 and Fig. A2.3):
A2.2.3.1 Integral but replaceable, hardened, Valve Seat
Inserts (105987A),
A2.2.3.2 Integral but replaceable Valve Guides (23109A),
A2.2.3.3 Intake and Exhaust Valve (106625),
A2.2.1.11 Oil Suction Screen Assembly (0109552).
A2.2.1.12 Oil Pressure Control Valve Assembly
A2.2.1.13 Crankcase Breather Assembly (Group 070.00).
A2.2.1.14 Accessory Bracket, Fuel Pump (109515A).
A2.2.1.15 Stud Assembly, Crankcase to Cylinder (B839.4
required: B5764.2 required).
A2.2.1.16 Stud Nuts, Cylinder (105361, 6 required).
A2.2.2 Cylinder Assembly—(0105081) of cast iron with
internal coolant passages and a basic bore diameter of 3.250
in., specified to include the following (See Fig. A2.2):
A2.2.2.1 Stud Assembly, Cylinder to Head (B-8200, 5
A2.2.2.2 Stud Nuts, Cylinder Head (105361, 7 required).
A2.2.2.3 Crankcase to Cylinder Spacer Gasket Set—
Selection of one or more gaskets must be made at the time of
cylinder assembly to achieve the specified piston over travel.
Available gaskets are:
D 613 – 03b
FIG. A2.2 Exploded View of Cetane Cylinder and Head Assembly
FIG. A2.3 Cylinder Head and Handwheel Assembly—Sectional View
A2.2.3.4 Valve Spring, Rotator Assembly (G-806-3) including spring (109659), spacer (110200), felt (B4680), rotator
(110165B) and tapers (109658),
A2.2.3.5 Valve Rocker Arm Subassembly (Group
A2.2.4 Handwheel—Variable
Assembly—(A105097) including an expandable plug that is
screwed in or out of the handwheel housing, an adjusting
handwheel, a micrometer scale and barrel vernier to indicate
plug position, and a locking wheel to cause a dished, splitwasher to flatten and expand the variable compression plug to
seal the precombustion chamber. See Fig. A2.3.
A2.2.5 Cylinder Coolant System Assembly, specified to
include the following major items.
A2.2.5.1 Condenser Body Assembly (A109264A) including
condenser coil subassembly, baffle tube and sight glass subassembly.
A2.2.5.2 Condenser Water Pipe Assembly (0109131B).
D 613 – 03b
A2.4 Equivalent Equipment
A2.2.5.3 Water Inlet Pipe (105083).
A2.2.6 Inlet Air System Assembly (Group G-841-9) specified to include the following major items:
A2.2.6.1 Air Silencer Elbow (105188), with gaskets, nuts
and washers.
A2.2.6.2 Air Heater Silencer Assembly (AA110468).
A2.2.6.3 Air Inlet Heater Assembly (A106583E).
A2.2.7 Fuel System—Components required to permit constant pressure introduction of sample or reference fuel blends
to an injection pump, the injection pump with adjustment for
flow rate, an integral variable timing device, a pump gallery air
trap device, a high pressure fuel delivery tubing and an injector
nozzle assembly with mechanism to permit sensing of the time
of injection. Critical Equipment is specified to include the
following major items:
A2.2.7.1 Fuel Injection Pump Assembly (C106941C)
Bosch specification APE 1B-50P-5625C Injection Pump
equipped with a 5 mm Barrel and Plunger Assembly (110754).
A2.2.7.2 Fuel Selector-Valve Assembly (A111388)
Including pump inlet fitting (105303A).
A2.2.7.3 Fuel Line Air Trap Assembly (Group G-808-9)
Including pump outlet fitting (105302).
A2.2.7.4 Variable Timing Device Assembly (Group G-80810)
For integral mounting to the pump housing and including the
Timing Device (110778) and associated Disk Coupling
A2.2.7.5 Shaft Coupling Assembly (Group G-808-11)
For connection of the variable timing device shaft to the
engine camshaft.
A2.2.7.6 Fuel Injection Tube or Line (A106318E)
For connection of the fuel pump to the injector assembly.
This tube shall be 28 in. long of 1⁄4 in. OD, 1⁄16 in. ID steel
A2.2.7.7 Fuel Injector Assembly (A75067E)
Including an O.M.T., S.p.A. specification SP8-S-1003/W
Injector Nozzle (110700), a nozzle opening pressure adjustment, an extended pintle feeler pin for indication of time of
injection and a fuel by-pass valve to release injection pump
fuel pressure from the nozzle.
A2.2.8 Power Absorption Motor
Reluctance-type, synchronous, single-speed, electric motor
for belt drive connection to the engine and capable of both
starting the engine and absorbing the power developed when
combustion is in process. Waukesha Engine Division is the sole
supplier of this item in order to insure meeting the following
speed and load absorbing specifications. Part numbers are
dependent on the three-phase electrical service voltage and
frequency available at the site of unit installation.
A2.2.8.1 Speed
1200 rpm 6 1 % for 60 Hz, three-phase power; 1500 rpm 6
1 % for 50 Hz, three-phase power.
A2.4.1 Crankcase Assembly—Commonly known as the
standard or low-speed crankcase which was the original model
developed in 1933. Parts for this crankcase are no longer
A2.4.2 Crankcase Assembly—Commonly known as the
high-speed crankcase, this model was the standard version
manufactured from about 1939 through 1954. Parts for this
crankcase are no longer manufactured.
A2.4.3 Cylinder Assembly—(0105081) which has, through
operational wear, exceeded the basic bore diameter tolerance
and has been successfully rebored to 0.010, 0.020, or 0.030 in.
A2.4.4 Piston Assembly for rebored cylinder assemblies as
A2.4.4.1 For 0.010 in. oversize cylinders (23204B1).
A2.4.4.2 For 0.020 in. oversize cylinders (23204B2).
A2.4.4.3 For 0.030 in. oversize cylinders (23204B3).
A2.4.5 Ring, Piston, Compression, Straight for rebored
cylinder assemblies as follows:
A2.4.5.1 For 0.010 in. oversize pistons (106222A1) or
chrome (106222B1).
A2.4.5.2 For 0.020 in. oversize pistons (106222A2) or
chrome (106222B2).
A2.4.5.3 For 0.030 in. oversize pistons (106222A3) or
chrome (106222B3).
A2.4.6 Ring, Piston, Oil for rebored cylinder assemblies as
A2.4.6.1 For 0.010 in. oversize pistons (23505-1).
A2.4.6.2 For 0.020 in. oversize pistons (23505-2).
A2.4.6.3 For 0.030 in. oversize pistons (23505-3).
A2.4.7 Injector Nozzle, American Bosch ADN-30S-3/1
(110700) which was the predecessor to the current SP8-S1003/W but which is no longer manufactured.
A2.5 Non-Critical Equipment and Specifications—A number of components and devices are required to integrate the
critical equipment items into a complete working system or
unit. Many of these are common hardware, tubing, fasteners
and electrical items potentially available from multiple
sources. In some cases, however, selection of specific sizes or
specification criteria are important to achieve the proper
conditions for the cetane testing equipment unit. Important
criteria for a component are included when applicable.
A2.5.1 Foundation and Bedplate:
A2.5.1.1 Foundation
Typically, in the form of a reinforced concrete block, site
poured, the foundation should be approximately 700 mm wide,
1320 mm long and a minimum of 280 mm high (28 in. wide,
52 in. long and a minimum of 11 in. high). Height of the
foundation should be minimized so that the fuel sample
reservoirs are at an elevation for safe pouring of fuel oil by
operators of average height without the use of a raised platform
or step in front of the engine. If the unit is placed on an
industrial building floor of reinforced concrete approximately
200 mm or 8 in. thick, no special support for the foundation is
A2.3 Engine Dimensions
A2.3.1 See Table A2.2.
D 613 – 03b
TABLE A2.2 Engine Dimensions, Manufacturing Tolerances and Replacement Limits
Basic Dimension
Manufacutring Tolerances
Replacement Limits
Oil Passages in Crankcase
Pass 1⁄4 in. rod
Crankshaft Bearings:
Front Main:
Journal Diameter
Journal to Bearing Clearance
0.0035 to 0.0049
0.006 max
Rear Main:
Journal Diameter
Journal to Bearing Clearance
0.0035 to 0.0049
0.006 max
Main Bearing to Case Clearance (Both)
0.0005 to 0.002
Crankshaft End-play
0.006 to 0.008
0.010 max
Connecting Rod Bearing (Big-End):
Crankshaft Journal Diameter
Journal to Bearing Clearance
0.0011 to 0.0036
0.005 max
0.008 to 0.014
0.016 max
Connecting Rod Bearing (Piston Pin End):
1⁄16 min
Rod End to Piston Boss Clearance
Piston Pin to Bushing Clearance
0.0005 to 0.0010
0.015 max
Connecting Rod Alignment:
Piston wall perpendicular to axis of journal within 0.003
Piston pin twist in length of big-end bearing within 0.002
Centerline of rod perpendicular to axis of bearings within 0.003
Camshaft Bearings:
Camshaft Journal Diameter:
1.7795 to 1.7805
1.2485 to 1.2495
Front Journal to Bearing Clearance
0.0015 to 0.003
0.004 max
Rear Journal to Bearing Clearance
0.002 to 0.0035
0.004 max
Bearing to Case Clearance (Both)
0.0005 to 0.002
0.002 to 0.005
0.007 max
Balancing Shaft Bearings:
Balancing Shaft Journal Diameter
1.748 to 1.749
Shaft to Bearing Clearance (Both)
0.0015 to 0.003
0.004 max
Bearing to Case Clearance (Both)
0.0005 to 0.002
0.002 to 0.006
0.010 max
Idler Gear:
Stub Shaft Diameter
0.9980 to 0.9985
Stub Shaft to Bearing Clearance
0.0015 to 0.003
0.004 max
0.002 to 0.004
0.008 max
Gear Tooth Backlash
0.002 to 0.004
0.006 max
Tappet Guide Clearance
0.0005 to 0.002
0.003 max
Valve Timing (Based on 0.008 6 0.001 valve clearance):
Inlet Valve Opens
10° atdc 6 2.5°
Inlet Valve Closes
34° abdc
Exhaust Valve Opens
40° bbdc
Exhaust Valve Closes
15° atdc 6 2.5°
Side Face Runout
0.005 max
0.007 max
Rim Surface Eccentricity
0.003 max
0.005 max
Piston Diameters:
Top Land
3.235 to 3.237
Second/Fifth Lands
3.242 to 3.244
oversize piston diameter dimensions increase
Skirt Diameter
3.2465 to 3.2475
0.010, 0.020 and 0.030 in respectively
Piston to Cylinder Clearance
Top Land
0.013 to 0.015
Second/Fifth Lands
0.006 to 0.008
0.0025 to 0.0035
Ring to Land Side Clearances:
0.001 to 0.003
All Others
0.001 to 0.0025
Ring Gap Clearances:
Compression Rings
0.007 to 0.017
Oil Ring
0.010 to 0.018
Piston Pin Diameter
1.2495 to 1.2498
Pin to Piston Clearance
0.0002 to 0.0004
Piston Pin Retainers (Truarc):
Free Diameter after Compression
1.340 min
Piston Pin Hole Alignment
0.001 max.
Piston Over-Travel:
Piston top above top of cylinder
0.014 to 0.016
Standard Cylinder:
Internal Diameter
3.250 to 3.2515
0.006 over original bore
NOTE A2.2—Reboring of cylinders to + 0.010, + 0.020, or + 0.030 inch oversize is permitted with a tolerance of 0.0000 to + 0.0015 inch.
D 613 – 03b
Basic Dimension
Bore Out of Round
Bore Surface Quality
Hardness, Bore Surface
Wall Thickness
Cylinder Head:
Hardness, Combustion Chamber Surface
Combustion Pick-up Hole Depth
(Top face to bottom of variable compression plug hole)
Variable Compression Plug Hole Diameter
Nozzle Hole Diameter
Nozzle Seat Counter Bore (O.D.)
Nozzle Sealing Ring Groove:
Hole Diameter for Guide
Valve Port
Concentricity to Valve Axis
Rocker Arms:
Bearing Clearance, plain
Bearing Shaft Diameter
Ball Seats
Valves, Intake and Exhaust:
Stem Diameter
Face Angle, degrees
Concentricity, Stem to Face (Run-out)
Valve Guides, Intake and Exhaust:
Internal Diameter
Valve Guide to Valve Stem Clearance:
Valve Seat Inserts, Intake and Exhaust:
Concentricity, Seat to Guide
Seat Width
Face Angle, degrees
NOTE—For interference angle approach, use face angle of 46 to 47° on seats.
Valve Head Recess from Cylinder Head Surface
0.020 min.
Valve Springs:
Free Length (rotator type)
Handwheel Assembly:
Variable Compression Plug:
External Diameter
Internal Diameter (At Head)
Split Locking Washer Diameter (Ground)
Housing Nut to Sleeve Clearance
Fuel Injection Pump:
Plunger Diameter
5 mm
Plunger Lift at Port Closure
Fuel Injector Nozzle:
Pintle Lift
Fuel Injection Tube or Line (High Pressure):
Manufacutring Tolerances
Replacement Limits
0.0005 max.
10 to 20 microinches
200 to 235 Brinell
0.312 to 0.375
Scored and/or pitted
180 to 220 Brinell
2.2812 to 2.3125
1.6245 to 1.6250
0.554 to 0.557
0.4062 to 0.4375
1.630 max.
1.333 to 1.343
0.187 to 0.192
0.6250 to 0.6255
0.001 to 0.002
0.6230 to 0.6235
Smooth and fit ball
0.3725 to 0.3720
0.3705 min.
0.0015 max.
0.3750 to 0.3765
0.003 to 0.004
0.3785 max.
0.005 max.
0.0010 max.
0.050 to 0.060
0.070 max.
0.020 to 0.025
0.060 max.
2.125 min.
2.125 min.
1.6230 to 1.6235
1.4585 to 1.4590
1.457 to 1.458
0.010 max.
0.010 max.
0.075 to 0.091
0.004 to 0.006
A2.5.1.2 Bedplate (27671H), of cast iron, 24 in. wide, 48 in.
long and 4 in. high such that the engine and power absorption
motor can be solidly mounted and aligned as well as providing
a platform for assembly of accessory electrical equipment,
controls, instrumentation and utility connections.
A2.5.2 Heater for Crankcase (B3109A), dual element, 300
watt maximum, surface mounting, flat, circular electrical
A2.5.3 Exhaust Discharge System Assembly (023242A and
A109887E)—Piping, with or without water cooling, suitable to
discharge exhaust fumes from the combustion chamber to
atmosphere and having adequate volume and length to comply
with the specified operating conditions for exhaust back
pressure without resonance.
A2.5.4 Filter Assembly for Crankcase Oil (AA111345).
A2.5.5 Fuel Oil Sample and Reference Fuel Reservoir
Assembly (Groups 216 and 400)—Minimum of three (3) fuel
0.006 max.
tanks each of 300 mL minimum capacity with a sight glass
assembly to indicate fuel level and including discharge tubing
of stainless steel or other material impervious to diesel fuel oil.
Discharge tubing diameter shall be as small as practical to
minimize system holdup but shall not be smaller than that of
either 10 mm OD or 5⁄16 in. OD standard tubing.
A2.5.6 Belting, Engine Flywheel to Power Absorption
Motor—Set of two “C” section, typically of 2160 mm or 85 in.
length (027970 for 60 Hz power; OB5500 for 50 Hz power).
A2.5.7 Electrical Switchgear, including input connections
and circuit protection for three phase power to operate the
power absorption motor and single phase power to operate
start-stop circuitry, controls, heaters, safety devices and instrumentation. Circuit design shall ensure that failure of either the
single or three phase power source will disconnect the other
D 613 – 03b
A3.1 Instrumentation
A3.1.1 The single cylinder cetane test engine is manufactured by Waukesha Engine Division, Dresser Industries and
includes both critical and non-critical instrumentation. Waukesha Engine Division Part Numbers are included in parenthesis
after the items where appropriate.
A3.3.4 Cetane Meter Transducers—pickups required to
provide input pulses to the Cetane Meter to indicate critical
engine cycle events.
A3.3.4.1 Reference Pickups (111464) 2 required to establish
a crank angle degree time base for calibration of the Mark I and
Mark II Ignition Delay Meters.
A3.2 Critical Instrumentation—Critical instrumentation
components or specifications for instrumentation which shall
be used for this test method are listed.
A3.2.1 Cetane Meter Specification—The instrumentation
shall be capable of sensing diesel engine combustion cycle
events. The parameters which shall be indicated are as follows:
A3.2.1.1 Injection Advance, in terms of the crank angle
degrees before top-dead-center at which fuel injection is
A3.2.1.2 Ignition Delay, in terms of the crank angle degrees
from the time of fuel injection to the first indication of
A3.2.1.3 The crank angle degree values shall be stable
average measurements of the results of multiple combustion
cycles presented in either analog or digital form. The range
shall be 0 to 18°. The readability shall be at least 0.1°.
A3.2.2 Cetane Meter, Waukesha Dual Digital Cetane Meter
A3.2.3 Cetane Meter Transducers—Pickups required to
provide input pulses to the dual digital cetane meter to indicate
critical engine cycle events.
A3.2.3.1 Reference Pickups (111464A)
Two are required to establish a crank angle degree time base
for calibration of the dual digital cetane meter.
A3.2.3.2 Injection Pickup (111465A)
To sense the beginning of fuel injection.
A3.2.3.3 Combustion Pickup (111463A)
To sense the beginning of combustion as evidenced by a
significant increase in the rate-of-change of pressure in the
combustion chamber.
A3.4 Non-Critical Instrumentation
A3.4.1 Temperature Measurement:
A3.4.1.1 Intake Air Thermometer Assembly (0106317A),
using Thermometer (106317A) having a range from 15 to 70°C
graduated in 1°C divisions (60 to 160°F graduated in 1°F
divisions) and conforming to the requirements for Thermometer 83C (83F) in Specification E 1.
A3.4.1.2 Intake Air Temperature Controller, with associated
thermal sensor, for on/off (AA111412B) or proportional temperature control to within the specified limits as measured by
the Intake Air Thermometer.
A3.4.1.3 Cylinder Jacket Coolant Thermometer Assembly
(0105180), using Thermometer (105180) having a range
from −15 to 105°C graduated in 1°C divisions (0 to 220°F
graduated in 2°F divisions) and conforming to the requirements for Thermometer 82C (82F) in Specification E 1.
A3.4.1.4 Injector Coolant Passage Thermometer Assembly
(0105180), using Thermometer (105180) having a range
from −15 to 105°C graduated in 1°C divisions (0 to 220°F
graduated in 2°F divisions) and conforming to the requirements for Thermometer 82°C (82°F) in Specification E 1.
A3.4.1.5 Engine Crankcase Lubricating Oil Temperature
Indicator (105321D), having a range of 15 to 85°C readable to
3°C (60 to 180°F readable to 5°F).
A3.4.2 Pressure Measurement:
A3.4.2.1 Crankcase Internal Pressure Gage (pressure/
vacuum gage) (109929), with a range that includes −500 to 500
mm (−20 to 20 in.) of water. A water manometer may be
A3.4.2.2 Exhaust Back Pressure Gage—with a range that
includes 0 to 500 mm (0 to 20 in.) of water. A water manometer
is a satisfactory alternative.
A3.4.3 Flow Rate Measurement:
A3.4.3.1 Fuel Buret (106334), 16 mm I.D. glass buret, 176
mm long with 1 mL graduations.
A3.4.3.2 Fuel Flow Rate Micrometer Assembly (0109427),
readable to 0.025 mm (0.001 in.).
A3.4.4 Time Measurement:
A3.4.4.1 Fuel Flow Rate Timer
Any commercial stop watch or electrical timer having a
range in excess of 60 s and graduated in tenths of 1 s.
A3.4.4.2 Fuel Injection Timing Micrometer Assembly
Readable to 0.025 mm (0.001 in.).
A3.3 Equivalent Instrumentation
A3.3.1 Ignition Delay Meter, Model Mark I, which is no
longer manufactured or serviced but which, as the predecessor
to the Mark II, meets the requirements of the specifications
with the exception that it is only readable to 0.25°.
A3.3.2 Ignition Delay Meter, Model Mark II (A111462),
which is no longer manufactured but meets the requirements of
the specifications with the exception that it is only readable to
A3.3.3 Expanded Scale Meter Kit with Ignition Delay
Meter, Mark II—The Expanded Scale Meter Kit (made in
limited quantity and no longer manufactured or serviced)
upgrades the Mark II instrument so that crank angle events can
be read to 0.1°.
D 613 – 03b
A4.1.2.1 Measurement is best made when the cylinder
assembly is removed from the crankcase although it is possible
with the cylinder, head and valve mechanism in place.
A4.1.2.2 Assemble a dial indicator on the deck of the
crankcase so that it can be positioned to indicate the lift of the
intake valve tappet.
A4.1.2.3 The dial indicator must have a minimum travel of
0.250 in. and read to 0.001 in.
A4.1.2.4 Position the flywheel to top dead center (tdc) on
the compression stroke and zero the dial indicator to zero.
A4.1.2.5 Rotate the flywheel in the normal direction until
the valve tappet rises causing movement of the dial indicator.
A4.1.2.6 Continue flywheel rotation until the dial indicator
reading is 0.054 in.
A4.1.2.7 Read the flywheel crank angle and compare it to
the specification which is 30°.
A4.1.2.8 If the observed crank angle is within 30 6 2°, the
timing is satisfactory. Otherwise, the camshaft needs retiming
either by shifting the cam gear with respect to the crankshaft or
by locating the cam gear on its shaft by using one of the other
three keyways. Changing the point of mesh of the cam gear
with respect to the crankshaft gear by one full gear tooth makes
a 9.5° change on the flywheel for a given mark. Four keyways
in the cam gear permit shifts of timing in 1°, 11 min increments
for a given mark. Cam gears are supplied with an X mark at the
tooth to be aligned with the corresponding X mark on the
crankshaft gear. If another keyway is used, the gear X mark is
A4.1 Camshaft Timing & Valve Lift Measurement: The
camshaft for the Model CFR-48 crankcase used for the cetane
method has intake and exhaust cam lobes both ground to
produce a valve lift of 0.238 in. Each lobe is designed to
include a quieting ramp at the beginning and end of the contour
change from the base circle diameter. These quieting ramps are
flat spots in the contour which occur at 0.008 to 0.010 in. rise
from the base circle of the lobe and which extend for typically
4 to 6° of crank angle rotation. Actual valve lift does not take
place until valve clearance is overcome and this is essentially
coincident with the flat spot of the quieting ramp. The
maximum height of the lobe from the base circle is typically
0.248 in.
A4.1.1 Measurement Principle: It is difficult to define the
actual point at which a valve should open or close because the
event takes place on the quieting ramp where the rate-ofchange of the cam profile is minimal. The following procedure
uses a point higher up on the contour of the lobes where
maximum lift velocity occurs. Thus, all timing events are
referenced to the flywheel crank angle degree readings which
occur at a rise of 0.054 in. off the cam lobe base circle. Timing
of the camshaft can be judged by measurement of the intake
valve opening event which along with the exhaust valve
closing event are the so-called “top end1” events that are most
critical. Fig. A4.1 illustrates both the intake and exhaust lobe
profiles and their relationship in the 720° of rotation of the
flywheel during one combustion cycle.
A4.1.2 Timing Check Procedure:
FIG. A4.1 Camshaft Timing Diagram
D 613 – 03b
A4.2.2 Disconnect the fuel injection tube from the fuel
pump outlet and remove delivery valve holder C, spring D and
delivery valve E from the pump as shown in Fig. A4.2.
(Warning—Wear gloves to protect lapped or polished surfaces
that could be etched by body acid if handled with bare fingers.)
(Warning—Immerse all disassembled parts in a container of
diesel fuel oil such as secondary reference fuel. Any mated
parts, such as delivery valve and seat or barrel and plunger
assembly, must be kept together. When making replacements
always use a complete mated assembly. Wash each part in a
clean diesel fuel oil and wipe it with a clean, lint-free cloth.
Check replacement parts by number and visual inspection.
Lubricate moving parts with SAE 30 engine crankcase lubricating oil before assembly.)
A4.2.3 Reinstall delivery valve holder C without the spring
and delivery valve.
A4.2.4 Provide and install suitable items to use a rubber
bulb to blow air into the delivery valve holder C when
A4.2.5 Disconnect the tube that is between buret D, Fig. 1
and the glass fuel line air trap on the injection pump. Connect
a piece of plastic tubing to the fuel line air trap connection and
submerge the other end of this tube in a small container of
diesel fuel oil such that bubbling in the container may be
observed when appropriate.
A4.2.6 Set the fuel selector-valve between, rather than on,
the numbered mark for a specific fuel tank. Set the flywheel to
a position at any point on the intake stroke. Remove the
irrelevant and the proper tooth for the unmarked keyway must
be determined. Greater detail is available from the engine
NOTE A4.1—The other valve opening and closing events may also be
checked but the single measurement based on the intake valve opening
event is sufficient to make the judgement as to proper camshaft timing.
A4.1.3 Valve Lift Check Procedure:
A4.1.3.1 With the dial indicator still positioned over the
intake valve tappet, continue rotation of the flywheel until a
maximum reading is obtained on the dial indicator.
A4.1.3.2 Read the dial indicator and compare it to the
specification which is 0.246 to 0.250 in. If the rise is less than
0.246 from the base circle of the cam, wear of the lobe has
occurred and camshaft replacement is indicated.
A4.1.3.3 Valve lift for the exhaust cam lobe should also be
checked by repeating the procedure with the dial indicator
positioned over that valve tappet. The lift specification is the
same as for the intake valve.
A4.2 Fuel Pump Timing—Pump timing involves coupling
the drive shaft of the variable timing device of the pump
assembly to the engine camshaft so that the time of fuel
injection occurs at the proper point in the combustion cycle.
With the pump shaft rotated to cause the pump plunger to just
close the fuel inlet ports, the engine flywheel shall be positioned between 300 and 306° on the compression stroke.
A4.2.1 Fuel pump timing is required whenever the pump is
disassembled or when critical pump parts are replaced. Fig.
A4.2 illustrates the important parts related to the timing
FIG. A4.2 Fuel Injection Pump—Sectional View
D 613 – 03b
heavy spring pulls the solenoid shaft, the connecting linkage
and the fuel control rack to a zero delivery position. When the
engine is running, the solenoid overcomes the force of the
spring and allows the rack to move into contact with the fuel
flow rate micrometer. At no time should the linkage setting
permit the linkage to force movement of the solenoid core
piece which typically causes loud humming or buzzing and
ultimately leads to overheating of the winding. A slot in the
solenoid connecting linkage permits an adequate range of
freedom of micrometer adjustment to provide the proper fuel
flow rate for typical fuels. The connecting linkage includes an
adjustable shaft which should be set so that the slotted control
yoke permits play relative to the solenoid core piece when the
solenoid is energized and the fuel flow-rate micrometer is at a
typical operating position. To adjust, loosen the locknut and
change the length of the connecting screw appropriately and
then relock the nut.
machine bolt which connects the fuel rack to the safety shutoff
solenoid and check that the rack is forced forward against the
fuel flow-rate micrometer which should be in a typical operating position. Rotate the fuel injection timing micrometer so
that the advance lever is at full advance (nearest to operator).
A4.2.7 While slowly rotating the flywheel in the clockwise
direction (as seen from the front of the engine), use the rubber
bulb to blow air steadily into the delivery valve holder C, Fig.
A4.3, and observe air bubbles at the end of the tube submerged
in the container of diesel fuel oil. When the bubbles stop, the
port has just been closed by the plunger on its upward stroke.
Determine this point by several trials noting the flywheel crank
angle for each to establish an average point.
A4.2.8 For reference purposes, use this average flywheel
position and observe the scribed line on the edge of the variable
timing device drive hub and scribe a matching line on the
housing if one is not already present. This reference mark may
change if new components are installed in the injection pump.
A4.2.9 For proper timing, the closure of the plunger should
occur at a flywheel crank angle of between 300 and 306° on the
compression stroke. If not, remove the two cap screws which
fasten the pump to camshaft vernier coupling disks together.
Hold the pump disk at the port closing mark, rotate the
flywheel to a 300° to 306° position and reinstall the two
coupling cap screws using the best matching holes.
A4.2.10 Reinstall the delivery valve, spring, fuel injection
tube and the tube between the fuel line air trap and the buret.
Also reconnect the fuel rack safety shutoff solenoid linkage.
A4.5 Fuel Injector Nozzle Assembly Opening Pressure
Setting—Fuel injection occurs when the pressure in the nozzle
assembly passages forces the nozzle pintle to lift against the
force of an adjustable spring in the nozzle assembly. The
setting should be checked each time the nozzle is disassembled
and cleaned.
A4.5.1 To adjust the injection opening pressure, assemble
the injector nozzle assembly in a suitable injector nozzle tester
in a ventilated hood.
A4.5.2 Loosen the locknut B, Fig. A4.4 on the pressure
adjusting screw A and turn the adjusting screw as required to
obtain the specified 10.3 6 0.34 MPa (1500 6 50 psi) injection
pressure. This is a trial and error procedure whereby the
pressure is checked by use of the injector tester after each
screw adjustment accompanied by relocking of the locknut B.
Inspection for possible nozzle pintle drip as well as spray
pattern should be observed when making this setting.
A4.5.3 After setting injection opening pressure, check that
the injector pickup gap is typically 1 mm (0.040 in.) before
reinstalling the injector assembly in the engine.
A4.3 Fuel Pump Plunger Lift—The port of the pump
plunger should close when the plunger has moved up 0.076 in.
from the base circle of the pump can. This setting is made at the
factory and there is no provision for field adjustment.
A4.4 Fuel Pump Safety Shutoff Solenoid Linkage Setting—
This safety solenoid is utilized to stop fuel delivery to the
engine and thus prevent uncontrolled engine overspeed in the
event of electrical power failure. In the power off condition, a
A4.6 Checking Compression Pressure—Determination of
the compression pressure requires use of a compression pressure gage assembly such as that illustrated in Fig. A4.5,
FIG. A4.3 Fuel Pump Timing Test Fittings
FIG. A4.4 Injector Assembly Showing Pickup Mounted
D 613 – 03b
A4.6.5 Remove the combustion pickup from the cylinder
head and install the compression pressure gage assembly.
(Warning—Personnel shall avoid contact with the combustion
pickup because it is extremely hot and can cause serious
A4.6.6 Set the handwheel to 1.000, regardless of the bore
diameter of the cylinder in use.
A4.6.7 Restart the engine and operate in a motoring mode
without any fuel being injected into the cylinder.
A4.6.8 Observe the compression pressure gage reading,
release the pressure once or twice using the deflator valve and
record the equilibrium pressure which results. (Warning—In
addition to other precautions, read the compression pressure
gage in whatever position it faces without twisting the gage and
hose which can distort the readings.)
A4.6.9 Satisfactory basic handwheel indexing is indicated if
the compression pressure is 3275 6 138 kPa (475 6 20 psi).
NOTE A4.2—Compression pressure values for engines operating at
barometric pressures below 27 in. Hg have not been established.
A4.6.10 Shut the engine down, remove the compression
pressure gage assembly, reinstall the combustion pickup with a
new gasket and tighten the pickup to the specified torque
setting (30 lbf-ft).
FIG. A4.5 Compression Pressure Gage Assembly
(Waukesha Part Number A110376), readable to 2.5 psi and
equipped with a suitable check valve and deflator or pressure
release valve.
A4.6.1 Compression pressure is measured after the engine
has been thoroughly warmed up on a typical diesel fuel oil
under standard operating conditions for that fuel. The following steps should be performed as quickly as possible to ensure
that the pressure readings represent hot engine conditions.
A4.6.2 Collect and have ready a calibrated compression
pressure gage assembly and the tools required to remove the
combustion pickup and install the gage assembly in the
combustion chamber pickup hole.
A4.6.3 Shut the engine down by opening the injector
assembly fuel by-pass valve and then turning off the engine
power switch. The by-pass valve must remain open for the
remainder of the compression pressure check procedure.
A4.6.4 The fuel selector valve must be positioned so that
fuel will continue to be delivered to the fuel pump to maintain
proper pump barrel and plunger lubrication.
A4.7 Adjusting Crankcase Lubricating Oil Pressure: The
oil pressure of the lubricating oil in the engine crankcase
gallery is dependent on the setting of the pressure control valve
located at the lower left side of the engine crankcase when
viewed from in front of the engine. (See Fig. A4.6.)
A4.7.1 The oil pressure should be adjusted with the engine
hot and running.
A4.7.2 Remove the acorn nut and gasket from the oil
pressure control valve assembly.
A4.7.3 Loosen the gasketed locknut so that the adjusting
screw is free.
A4.7.4 While observing the engine oil pressure gauge, set
the adjusting screw to obtain the specified 0.17 to 0.20 MPa (25
to 30 psi) pressure.
A4.7.5 Tighten the gasketed locknut while observing that
the pressure remains within limits.
A4.7.6 Reinstall the gasket and acorn nut.
D 613 – 03b
FIG. A4.6 Oil Pressure Control Valve Assembly
(Nonmandatory Information)
X1.1 Background—Primary reference fuels which are used
infrequently are usually packaged in relatively small containers
and storage and dispensing is handled in the manner used for
general chemicals. Secondary reference fuels are supplied in
bulk containers of 5 or 55 U.S. gallon capacity (0.019 or 0.208
m3) and for laboratory safety reasons these bulk quantities are
typically stored in a special fuel storage room or outside of the
engine laboratory.
X1.2 Delivery from Storage—Delivery of reference fuel
material from the bulk storage container to a dispensing
apparatus in the engine laboratory may be handled in any of
several ways. The equipment and procedures required for
delivery of the reference fuel material are the responsibility of
the user of this standard.
X1.3 Dispensing Equipment—A common means of accurately measuring reference fuel blend volumes applies a
matched pair of calibrated glass burets, one for each of the two
secondary reference fuels. Fuel is dispensed either through an
integral glass stopcock or a separate valve.
X1.3.1 Burets of glass with an automatic zero top fitting
provide accurate, efficient and convenient measurement. A
typical buret is illustrated in Fig. X1.1. Specifications for a
typical buret are given in Table X1.1.
X1.3.2 Separate Dispensing Valves—It is common practice
to utilize burets that do not have a dispensing stopcock. Bottom
delivery from the buret is from a straight tubing bib which is
connected by plastic tubing to a three-way valve similar to that
shown in Fig. X1.2. The most important feature of such a valve
assembly is the dispensing fitting which is formed so that only
a very minimum of drip can occur if the collection container is
FIG. X1.1 Typical Reference Fuel Dispensing Buret
inadvertently touched against the orifice tip. These valves can
also be the means for controlling discharge flow rate to
specification by use of the 6 mm (3⁄16 in. O.D.) tubing for the
formed tip.
X1.4 System Installation and Operation—User experience
with reference fuel systems has pointed out a number of
D 613 – 03b
TABLE X1.1 Typical Buret Specifications
Buret Capacity
Automatic Zero
Major Marks
Minor Marks
Internal Diameter of Graduated Tube:
Scale Length, 5 to 100 %:
Top of Overflow Bulb to 5 %
Mark Length (nominal)
Overall Length (including tip):
Scale Error (Maximum)
X1.4.5.1 Avoid the use of gravity flow delivery of reference
fuel to burets.
X1.4.6 Thoroughly clean reference fuel burets on a regular
basis to minimize hangup or clinging on the inner surface of
the buret that can lead to blending errors.
X1.4.7 Burets should not be filled until a blend is required
in order to minimize any tendency for deterioration of the fuel
by exposure to light.
X1.4.8 Use stainless steel tubing, or other opaque tubing
that does not react with reference fuel, to connect between the
bulk reference fuel container and the dispensing buret.
X1.5 Procedure for Use of Buret System:
X1.5.1 To fill the buret, set the valve or stopcock to“ fill”
position, so that fuel rises in the buret until it overflows at the
automatic zero. Stop filling by setting the valve to “off”
position. Check that any bubbles are purged at the zero tip and
refill the tip, if necessary.
X1.5.2 To dispense fuel, set the valve to “dispense” position, so that fuel is delivered to the collection container. Stop
dispensing by setting the valve to “off” position while carefully
noting the level of the fuel in the calibrated section of the buret
and locating the bottom of the liquid meniscus at the desired
volume percent mark.
X1.5.3 Before drawing a measured volume, make certain
that the tip of the dispensing tube is full. When the measured
volume has been collected, be certain not to drain any fuel
from the tip of the dispensing tube as this will cause an error.
important aspects that support the following recommendations:
X1.4.1 Use amber glass burets for dispensing reference
fuels or provide opaque shielding around all but the calibration
mark area of clear glass burets.
X1.4.2 Mount burets vertically at an elevation that permits
horizontal sighting of all calibration marks.
X1.4.3 Install a separate buret for each of the reference
X1.4.4 Mount burets in a manner that ensures freedom from
X1.4.5 Store bulk reference fuel containers and provide
appropriate tubing for delivery of the fuels to the dispensing
burets in accordance with the instructions of the manufacturer
and in compliance with all local codes and regulations.
D 613 – 03b
FIG. X1.2 Typical Fill/Dispense Valve
tions for each specific diesel fuel oil or reference fuel.
Changing handwheel setting changes the ignition delay period.
Low cetane number fuels have inherently longer ignition delay
characteristics than high cetane number fuels. The cetane
method test procedure requires that all fuels operate at a
specified ignition delay period and therefore changes in handwheel setting are necessary.
X2.2.2 Handwheel Adjustment Procedure:
X2.2.2.1 Loosen the small locking wheel of the handwheel
assembly by counterclockwise rotation as viewed from the
front of the engine. This releases the mechanism and permits
the larger handwheel to be turned so that the variable compression plug can be properly moved in or out of the precombustion
X2.2.2.2 Set the larger handwheel to establish the required
ignition delay period as indicated on the ignition delay meter.
Clockwise rotation of the handwheel (viewed from in front of
the engine) increases C.R. and decreases the ignition delay
crank angle degree reading.
X2.2.2.3 Always make the final adjustment of the handwheel in the clockwise direction to minimize scale reading
errors by eliminating the unavoidable play in the handwheel
X2.2.2.4 Lock the mechanism by turning the small locking
wheel clockwise until tight. (Warning—Hand tightening of
the locking wheel should be adequate if the handwheel
mechanism is in proper working order. The need to use
additional leverage to achieve a locked condition indicates a
need for handwheel assembly maintenance.)
X2.1 Compression Ratio vs Handwheel Reading—The
compression ratio of the cetane engine is variable and depends
upon the position of the variable compression plug in the
precombustion chamber of the cylinder head. The variable
compression plug is positioned by the screw action of the
handwheel and the relative location of the plug is indicated by
an indexed vernier scale. This handwheel reading scale extends
from 0.500 to 3.000 and is inversely related to compression
ratio. Low handwheel readings correspond to high compression ratio conditions while high handwheel readings reflect low
compression ratio conditions.
X2.1.1 If the handwheel has been carefully indexed, the
compression ratio of the cetane engine for any position of the
variable compression plug can be calculated using the following equation:
C.R. 5
VS 1 ~V CC 1 VTP 1 VPU! 1 V PC
~VCC 1 VTP 1 V PU! 1 VPC
C.R. = compression ratio,
= volume swept by piston in cylinder,
VCC = volume in main combustion chamber above piston
at tdc including the valve recesses and piston
top-land clearance,
VTP = volume of turbulence passage between combustion
and pre-combustion chambers,
VPU = volume of threaded pickup hole with a pickup
installed, and
VPC = volume of pre-combustion chamber.
X2.1.2 Volumes VCC, VTP, and VPU are independent of
cylinder bore diameter and are based on the physical dimensions of the cylinder head. The sum of these volumes is 0.659
cu. in. (10.8 cc) as determined by both calculation and
measurement. The equation for compression ratio, when calculated using cu. in. units is thus:
C.R. 5
VS 1 V PC 1 0.659
VPC 1 0.659
X2.3 Fuel System Operation: As illustrated in Fig. X2.1 the
fuel system incorporates three fuel tanks each with a drain
valve ahead of a selector valve. The selector valve is positioned
to deliver fuel from a specific fuel tank by rotation of the valve
to the mark for that tank. The selected fuel is delivered to the
fuel pump inlet and fills the fuel sump or gallery. The pump
gallery also connects to the flow-rate buret through an air trap
which is fitted with a drain valve. The fuel level in the buret
will be the same as that in the fuel tank. When the selector
valve is positioned so that the pointer is indexed between the
fuel tank marks, fuel delivery from the tank is blocked. In this
X2.2 Adjusting Compression Ratio Using the Handwheel:
X2.2.1 Cetane method testing requires adjustment of compression ratio (C.R.) to attain the proper ignition delay condi23
D 613 – 03b
close and open the valve a few times to remove any entrained
air from the passages before finally closing the drain valve.
X2.3.2.5 In a series of quick steps, drain the buret leg,
position the selector-valve to introduce the new fuel and when
fuel begins to appear in the buret, position the selector-valve to
between marks so the engine operates from the buret alone.
This step purges the fuel system with the exception of the line
from the pump to the injector. When the engine runs out of
fuel, repeat the purging sequence. Engine operation on the
purge sequences will afford sufficient time to completely
displace the fuel in the line from the injection pump to the
NOTE X2.1—Diesel fuel oils which are highly viscous or cause discoloring of the flow-rate-buret, may require more drastic flushing action for
adequate purging.
X2.3.3 Measuring Fuel Flow Rate:
X2.3.3.1 Fill the flow-rate-buret and turn the selector-valve
to between the marks.
X2.3.3.2 Using an electric stop clock (or stop watch),
measure the fuel consumption by starting the clock as the
meniscus passes a millilitre graduation on the buret and
stopping the clock as the meniscus passes the mark selected for
the amount of fuel to be consumed (typically 13 mL below the
starting mark). Turn the fuel-selector-valve back to the mark to
again draw fuel from the appropriate tank.
X2.3.3.3 If the time registered by the clock is not correct (60
6 1 s for 13 mL), readjust the fuel flow-rate-micrometer to
change the pump rack position and thereby the amount of fuel
being injected to the engine (see Fig. X2.2). Turn the flow rate
micrometer clockwise (as viewed from in front of the engine)
to increase fuel flow (shorten the clock time per unit volume).
Typically, 0.005 micrometer divisions will cause a change of 1
s for 13 mL of fuel consumption.
X2.3.3.4 Repeat the flow rate measurement procedure until
the specified fuel flow rate is achieved.
FIG. X2.1 Fuel System Schematic
mode, the engine will continue to operate on the fuel which is
in the gallery and the line from the flow rate buret. Fuel flow
rate measurement can thus be performed by first filling the flow
rate buret from the tank with the selector valve positioned on
the tank mark and then positioning the valve between tank
marks so that fuel from the buret leg alone supplies the fuel
X2.3.1 The fuel flow-rate-buret is mounted so that the vent
hole at the top of the buret is slightly above the level of the top
of the fuel tanks thus preventing fuel overflow from the buret
when the tank is full. The calibration marks on the buret are in
1 mL increments so that fuel flow rate is easily measured by
noting the time required for engine consumption to lower the
buret fuel level by a specific number of mL.
X2.3.2 Changing to a New Fuel—Introduction of a diesel
fuel oil involves filling a fuel tank, purging the flow-rate-buret
and air trap leg and displacement of the fuel in the fuel line
from the pump to the injector assembly. (Warning—Diesel
Fuel Oil—Combustible. Vapor harmful. See Annex A1.) The
typical sequence for this process is as follows:
X2.3.2.1 Check that there is sufficient fuel in the buret leg to
operate the engine while filling a tank with a new fuel.
(Warning—Do not allow the fuel pump to run dry, except
during the momentary periods required to switch from one fuel
to another, because the fuel pump is partly dependent on fuel
for lubrication.)
X2.3.2.2 Position the selector-valve so that it is between
marks but adjacent to the mark for the fuel tank into which the
new fuel is to be introduced.
X2.3.2.3 Check that the selected fuel tank is empty by
opening the tank drain valve.
X2.3.2.4 Introduce the fuel to the fuel tank while leaving the
associated drain valve open for an instant; then alternately
FIG. X2.2 Fuel Pump Flow Rate and Injection Timing Micrometers
D 613 – 03b
X2.5.1 Check that the injector by-pass valve (see Fig. X2.3)
is open and the handwheel is set to about 1.000.
X2.5.2 Position the off-run-start switch to start and hold it in
the start position for a few seconds to allow oil pressure to rise
sufficiently to actuate the engine run circuitry so that the engine
continues to operate when the start switch is released to the run
X2.5.3 Turn on the intake air heater.
X2.5.4 Allow the engine to motor (operate under non-firing
conditions) for an additional few seconds to purge the fuel lines
and injector.
X2.5.5 Initiate engine combustion by closing the injector
by-pass valve and if necessary, by increasing the C.R. through
clockwise rotation (as viewed from in front of the engine) of
the unlocked handwheel. After firing commences, back off the
handwheel toward the higher reading direction (counterclockwise) until the engine operates smoothly. (Warning—Sharp
knocking sounds may occur and blowby smoke may appear
from the mechanism as the handwheel is rotated in the
counterclockwise direction which increases the handwheel
reading. These are normal.)
X2.5.6 Energize the cetane or ignition delay meter instrumentation in accordance with manufacturer instructions.
X2.5.7 Set the fuel flow rate to approximately the specified
X2.5.8 Set the injection timing to approximately the specified value.
X2.5.9 Check that the ignition delay period is nominally at
the specified value.
X2.3.3.5 When the fuel level in the fuel tank lowers, the
level in the flow-rate-buret may not be adequate to permit good
flow rate measurement. In this case, use a suction bulb applied
to the top vent hole of the buret and with the selector-valve
positioned on the tank mark, pull fuel up from the pump gallery
to the desired level. Before removing the suction bulb, quickly
move the selector-valve to a position between the tank marks.
Flow rate measurement must then be started almost immediately because the engine will be drawing fuel from the buret
and the level in the buret will be falling.
X2.3.3.6 Determination of the proper flow rate is a trial and
error procedure. Initial checks may be made using a 10 s time
interval which should result in consumption of approximately
2 mL of fuel. The final flow rate measurement shall be made
over a full 60 6 1 s period.
X2.3.4 Adjusting Fuel Injection Timing—While operating
the engine at the proper fuel flow rate and with the fuelselector-valve positioned on the mark for the fuel being
evaluated, observe the indicated injection timing (injection
advance) value. Adjust the fuel injection timing micrometer to
achieve the specified injection advance degrees (see Fig. X2.2).
Turn the injection timing micrometer clockwise (as viewed
from in front of the engine) to decrease the indicated number
of degrees of advance.
X2.4 Preparations Before Starting Engine:
X2.4.1 Check the jacket coolant level in the condenser sight
X2.4.2 Check the engine crankcase lubricating oil level in
the crankcase oil sight glass.
X2.4.2.1 Check the crankcase breather assembly to insure
that it is clean and operable.
X2.4.2.2 Turn on the crankcase oil heater or oil heat
temperature controller.
X2.4.3 Check the fuel pump lubricating oil level using
either the dip stick or by sighting through the plastic sump
cover located on the side of the pump.
X2.4.4 Fill one of the fuel tanks with a diesel fuel oil
suitable for engine warmup taking care to purge the tank line of
any trapped air.
X2.4.4.1 Set the fuel-selector valve to the mark for the
specific fuel tank so that fuel will flow to the fuel pump gallery
and flow rate buret leg.
X2.4.4.2 Purge the fuel pump gallery of any entrained air by
opening and closing the drain valve from the glass air trap three
X2.4.5 Open the cooling water valve or check that cooling
water will be available for both the condenser and the injector
coolant chamber when the engine is started.
X2.4.6 Using the hand crank, manually rotate the engine
crankshaft three or four complete revolutions to ensure that all
parts move freely. Complete the cranking so that the flywheel
is positioned at top-dead-center on the compression stroke to
minimize the load on the absorption motor when the engine is
X2.5 Starting the Engine—It is assumed that the engine has
been commissioned and is in operable condition and that
electrical circuits and cooling water are available on demand.
FIG. X2.3 Fuel Injector Assembly
D 613 – 03b
standard operating conditions with the ignition delay period
carefully set to 13.0°.
X2.7.2 Prepare a series of at least four more reference fuel
blends of higher cetane number so that there is a difference of
about 4 cetane numbers between each successive pair of
X2.7.3 Operate the engine on each successive blend without
changing the handwheel reading established for the 35 cetane
number blend but adjusting the fuel flow rate to 13 mL/min and
the injection timing to 13°. Record the resulting ignition delay
values for each of the reference fuel blends.
X2.7.4 Plot the data on a graph similar to that in Fig. X2.4
so that the sensitivity characteristic can be observed. If the
points do not fit an easily defined smooth curve, the injector
nozzle is probably suspect and may require further cleaning
maintenance or replacement. If a nozzle is faulty, it is often
easily noted by the erratic operation and data scatter of the
results obtained during the early stages of this procedure.
X2.5.10 Continue engine warmup for approximately 1 h
taking care to periodically observe and if necessary, readjust all
critical operating conditions.
X2.6 Stopping the Engine:
X2.6.1 Turn off the cetane or ignition delay meter and the
intake air heat switches.
X2.6.2 Open the injector by-pass valve to prevent further
injection of fuel to the combustion chamber.
X2.6.3 Stop the engine by positioning the stop-run-start
switch to the off position.
X2.6.4 Using the hand crank, manually rotate the engine to
set it on top-dead-center on the compression stroke so that the
intake and exhaust valves are closed. This will minimize
possible valve warping or corrosion in the combustion chamber
between operating periods.
X2.6.5 Drain all fuel tanks and fuel lines.
X2.6.6 Turn off the cooling water.
NOTE X2.2—Cooling water flow may be continued for a period of 20 to
30 min after engine shut down, especially to the injector coolant passage,
to minimize the build-up of a hard coke deposit on the tip of the injector
nozzle due to potential pintle drip.
X2.8 Checking Exhaust and Crankcase Breather Systems
for Resonance:
X2.8.1 Resonance in the piping systems can occur when the
configuration creates a critical length/volume relationship. A
resonant condition affects the primary pressure within the
system and can affect critical operating conditions.
X2.8.2 Exhaust system resonance may be checked by providing either a 3⁄4 inch or larger gate or ball valve at the surge
tank or close to the engine exhaust port. Opening the valve
should drastically change the exhaust discharge configuration
while the engine is operating at standard conditions to determine if there is an effect.
X2.7 Checking Ignition Delay vs. Cetane Number
Sensitivity—The sensitivity characteristic illustrated in Fig.
X2.4 can provide a measure of confidence that the injector
assembly and particularly the injector nozzle are performing in
a satisfactory manner. It is a test that requires approximately 1
h to perform but it is useful to judge nozzle acceptance when
engine instability has been experienced after cleaning and
X2.7.1 Using a secondary reference fuel blend of approximately 35 cetane number, adjust all engine variables to
FIG. X2.4 Ignition Delay vs Cetane Number Characteristic
D 613 – 03b
X2.8.2.1 Operate the engine at standard operating conditions on a typical diesel fuel oil and allow sufficient time for the
ignition delay period to stabilize.
X2.8.2.2 Open the valve or effect the change in exhaust
piping with the engine running.
X2.8.2.3 If the ignition delay is not affected, resonance does
not occur and the piping system is satisfactory.
X2.8.2.4 If ignition delay is affected when the valve is
opened, resonance may be a factor and typically a change in
the length of the exhaust discharge pipe will correct the
X2.8.3 Crankcase breather system resonance typically
causes the crankcase pressure to be positive. Resonance in the
discharge piping is not a problem as long as the operating
engine creates a crankcase vacuum.
X3.1 Importance of Maintenance: The need for proper
maintenance of the cetane engine unit cannot be overemphasized if reliable cetane number ratings of diesel fuel oils are to
be obtained. The care used in the inspection, adjustment, and
especially the overhaul of the combustion chamber components is a major factor in achieving these aims.
ING notice on the unit panel indicating repairs are in process
and that no attempt is to be made to start the engine. Shut off
coolant water to the unit.)
X3.2.5 Auxiliary Equipment Maintenance—Volumetric
glassware such as the engine fuel flow rate buret and the
reference fuel blending burets should be chemically cleaned on
a regular basis to insure accurate volumetric measurement.
X3.2.5.1 Quarterly cleaning of volumetric ware is recommended.
X3.2 Types of Maintenance:
X3.2.1 Daily Checks—Those checks associated with the
preparations before starting the engine as detailed in Appendix
X3.2.2 Top Overhaul—The generally accepted term used to
describe valve reconditioning, the cleaning of the combustion
chamber, piston, piston rings, variable expansion plug or
handwheel assembly and the cleaning of the coolant jacket
passages and the coolant condenser. Some other parts may also
be given attention during a top overhaul, depending on need.
X3.2.2.1 Typically, a top overhaul is necessary every 100 to
300 h and the need is usually indicated by unstable or
non-repeatable performance of the engine. The interval between top overhauls varies and depends primarily upon the
severity of the conditions under which the unit is operated.
X3.2.3 Injector Assembly Inspection—The disassembly and
cleaning of the nozzle, checking nozzle opening pressure and
spray pattern.
X3.2.3.1 It is recommended that injector inspection and
checking be performed at every top overhaul. However,
depending on the severity of testing, the process may need to
be performed more frequently and some testing facilities make
it a practice to install a cleaned and checked injector prior to
each unit startup.
X3.2.4 Crankcase/Unit Inspection—Encompasses crankcase cleaning, mechanical component wear checks, alarm
function checks, power absorption motor inspection, belt
tension adjustment, instrumentation checks, etc.
X3.2.4.1 The recommended interval between crankcase/unit
inspections is every 2000 h of operation or biannually, whichever comes first. Model CFR-48 crankcases, which can be
completely restored by the manufacturer, have been found to
perform acceptably for periods of 40 000 h or more before such
restoration is required. (Warning—Deactivate the engine unit
before performing any maintenance. Shut off electrical power
at the main disconnect, lock out, if possible. Place a WARN-
X3.3 Top Overhaul Procedures:
X3.3.1 Disassemble the complete combustion chamber and
associated assemblies from the engine crankcase. Components
to be removed include:
X3.3.1.1 Combustion and injector pickups.
X3.3.1.2 Thermometers and any temperature sensors.
X3.3.1.3 Intake air elbow, silencer and heater assemblies.
X3.3.1.4 Fuel injector tubing and injector assembly.
X3.3.1.5 Circulating cooling water piping at the coolant
condenser, the condenser/water pipe assembly and the water
inlet pipe to the cylinder.
X3.3.1.6 Exhaust pipe assembly.
X3.3.1.7 Handwheel assembly from the cylinder head using
detailed instructions available from the manufacturer.
X3.3.1.8 Valve cover, rocker arm bracket assembly, rocker
half-balls and push rods.
NOTE X3.1—Marking of push rods as intake and exhaust ensures they
will be reassembled in the same positions.
X3.3.1.9 Cylinder head.
X3.3.1.10 Valve rotators, valve springs, and valves.
X3.3.1.11 Cylinder.
X3.3.1.12 Piston pin retainers, piston pin, and piston.
X3.3.2 Component Cleaning—All combustion deposits,
gasket material, rust, etc. should be removed from components.
X3.3.2.1 Commercial chemical cleaning solutions may be
used in accordance with the manufacturers instructions as long
as they do not etch or affect the surface finish of the machined
surfaces. Except for electromechanical pickups, use of ultrasonic bath equipment has been demonstrated to be effective
and heating of some cleaning solutions can also be beneficial.
(Warning—Chemical Cleaning Solutions—Poison. May be
Harmful or Fatal if Inhaled or Swallowed. See Annex A1.)
D 613 – 03b
X3.3.4.2 Cylinders rebored to 0.010, 0.020, and 0.030 in.
larger than the original 3.250 in. diameter are permitted and the
same wear limits apply based on the unworn skirt diameter of
the rebore.
X3.3.5 Piston and Rings:
X3.3.5.1 Replace the piston if there is evidence of scoring
or a wear pattern.
X3.3.5.2 Replacement of all rings at the time of every
overhaul is typical. If a chrome plated top compression ring is
used, it may be reused for several overhaul periods.
X3.3.5.3 The ring gaps should be checked by feeler gauge
with the ring inserted in the skirt end of the cylinder. The piston
should be used to square the ring in the bore about 1 in. beyond
the chamfer. Rings should be rejected if the gap is not within
0.007 to 0.030 in. for compression rings and 0.010 to 0.030 in.
for oil rings.
X3.3.5.4 After assembly of the rings on the piston, the ring
to land clearances, as measured using a feeler gage, should not
exceed 0.004 in. for top compression ring or 0.0035 in. for all
other rings.
X3.3.5.5 Piston pin replacement should be made when
scoring or wear marks are observed.
X3.3.6 Handwheel Assembly—The handwheel assembly is
an integral part of the cylinder head assembly and includes a
variable compression plug that is a close fit in the precombustion chamber bore. It is screwed in and out of the head by the
handwheel to effect changes in compression ratio. To prevent
leakage of combustion gases, this plug, which has no seals or
rings, is expanded by action of the locking wheel which is
connected to a drawbolt that exerts pressure on a dished and
split washer inserted in the plug causing it to expand and clamp
the plug in the bore. The variable compression plug mechanism
should be kept free-working, and easily adjusted. The locking
wheel should be easily released and locked by hand without the
use of an auxiliary wrench.
X3.3.6.1 Detailed instructions, available from the manufacturer, include specific inspection criteria, proper parts selection,
as well as the proper order of reassembly and lubrication
X3.3.7 Rocker-Arm Assembly:
X3.3.7.1 Inspect each rocker for excessive bearing wear or
wobble on the rocker shaft.
X3.3.7.2 Inspect the rocker adjusting screws for galled ball
ends and also for damaged Phillips screwdriver slots.
X3.3.7.3 Inspect the rocker ball sockets for wear or galling.
X3.3.7.4 Replace any worn or out of specification parts.
X3.3.2.2 Scraping, brass wire brushes (manually or power
driven), and fine steel wool have been found to be effective
cleaning aids.
X3.3.2.3 Complete any cleaning sequence by rinsing of all
parts with a solvent, such as kerosine. (Warning—Kerosine—
Combustible. Vapor Harmful. See Annex A1.)
X3.3.3 Cylinder Head:
X3.3.3.1 Combustion Chamber Surface
Discard head if badly pitted or corroded.
X3.3.3.2 Precombustion Chamber
Discard head and handwheel housing if internal diameter of
chamber exceeds 1.630 in.
X3.3.3.3 Valve Guides
Replace a guide when the internal diameter exceeds 0.3785
in. Replacement requires special tools.
X3.3.3.4 Valves
Discard if stem is badly scuffed or diameter is less than
0.3705 in. Reface to 45° using a valve refacing (grinding)
machine so that face runout is within less than 0.0015 in.
Discard valve if grinding has created a sharp edge at the outer
diameter of the head indicating stellite coating has been
X3.3.3.5 Valve Seats
Reface seats using a valve seat grinding machine or a valve
seat cutter kit. Use a 45° seat angle and subsequently lap the
valve to the seat. Alternatively, an interference angle approach
may be utilized by refacing the seat at both 46° and 15° so that
the intersecting line becomes the contact surface with a 45°
faced valve. When an interference angle approach is utilized,
lapping may be performed but extreme care must be taken to
exert very light pressure to prevent creating a groove in the
valve face.
X3.3.3.6 Valve to Valve Seat Matchup
Check the valve to seat contact. Lapped valve seat width
must not exceed 0.070 in. as viewed on the valve. The top edge
of the contact line or area shall be at least 0.030 in. from the top
edge of the faced portion of the valve. The valve head shall be
recessed at least 0.020 in. below the surface of the cylinder
head, however, the recess shall not exceed 0.060 in.
X3.3.3.7 Face of Nozzle Hole in Head—Check that surface
against which the nozzle seats is flat and not excessively
X3.3.3.8 Valve Rotators— Inspect the races which should
rotate freely so that, when the engine is operating, the valve
will rotate at approximately 1 to 2 rpm.
X3.3.3.9 Reassemble valves, felt lubrication washers,
springs, spacers and rotators. Install valve springs with closely
wound coils next to the cylinder head.
X3.3.4 Cylinder:
X3.3.4.1 Check the cylinder bore diameter at the top,
middle, and bottom areas of ring travel in two planes which are
90° apart. Replace the cylinder if the internal diameter at the
area of maximum wear is more than 0.006 in. larger than the
unworn skirt internal diameter. Replace the cylinder if the bore
is out of round in excess of 0.0025 in.
NOTE X3.2—When installing the rocker arm shaft, the pipe plug end
should face the intake side and the center feed hole should point
downward to receive oil. The exhaust rocker bushing must have a hole to
permit pressurized oil to reach the distribution channel on the top rocker
X3.3.8 Condenser and Cooling System:
X3.3.8.1 Inspect the inner surfaces of the condenser and the
baffle tube for rust or scale deposits, wipe out the cavity, and
rinse with hot water prior to reassembly.
X3.3.8.2 Inspect the cooling coil, clean surface deposits,
and observe that the coils are slightly separated from each other
to maximize the cooling surface exposed to coolant steam.
D 613 – 03b
X3.3.9.14 Introduce coolant water through the condenser
cover fill hole until coolant just appears in the condenser sight
X3.3.9.15 Install a cleaned and inspected injector assembly
using a new solid copper gasket. Install the associated fuel
X3.3.9.16 Install the injector pickup and set the pickup gap
to 0.040 in. using a non-magnetic feeler gage.
X3.3.9.17 Turn on the main cooling water and establish
flow through the injector cooling passage. Observe the face of
the injector nozzle through the pickup hole to be certain the
injector assembly is tightened evenly and coolant is not leaking
past the nozzle into the precombustion chamber.
X3.3.9.18 Index the handwheel assembly.
X3.3.10 Crankcase Breather:
X3.3.10.1 Disconnect the breather pipe and remove the
breather assembly from the engine crankcase.
X3.3.10.2 Unscrew the cap from the body, remove the
plastic cup, and clean the emulsion deposits from all of the
X3.3.10.3 Inspect the cup and if the surface of the open
edge is rounded rather than square, replace the cup.
X3.3.10.4 Rinse the components using a petroleum based
solvent or kerosine and reassemble them on the engine.
(Warning—Petroleum Based Solvent—Flammable. Vapors
Harmful if Inhaled. Vapors may Cause Flash Fire. See Appendix X1.) (Warning—Kerosine—Combustible Vapor Harmful.
See Annex A1.)
X3.3.11 Crankcase Oil Change:
X3.3.11.1 Drain the used oil and add new SAE 30 Grade
engine crankcase lubricating oil.
X3.3.11.2 It is recommended that the crankcase lubricating
oil be changed at intervals of approximately 50 h of engine
operation and at the time of each top overhaul.
X3.3.11.3 It is recommended that the oil filter cartridge be
changed at the time of every other oil change.
X3.3.12 Fuel Injection Pump:
X3.3.12.1 Drain the used oil and add new SAE 30 Grade
engine crankcase lubricating oil.
X3.3.12.2 The fuel pump assembly seldom needs maintenance or basic adjustment other than attention to regular and
proper lubrication. If any disassembly is attempted in the field,
it should be performed by a qualified fuel injection equipment
X3.3.12.3 If diesel fuel oils having high sulfur content are
being tested on a fairly regular basis, inspection of the fuel
pump delivery valve holder and delivery valve is recommended at approximately 500 h periods of operation. Typically
this inspection could be part of a top overhaul. If pitting or
corrosion of these components is observed, the parts should be
X3.3.13 Engine Starting Preparations—See Appendix X2.
X3.3.8.3 Chemical cleaning of coolant system surfaces
should take place whenever significant deposits are observed or
at least at every third top overhaul. One approach is to
introduce a commercial cooling system cleaner in the cooling
system after reassembly of the engine. By running the engine
for intermittent periods, the solution can be heated to 80 to
90°C (180 to 200°F). The solution should be kept at this
temperature for approximately 30 min and drained. The system
should then be flushed with clean hot water before recharging
with rust inhibited coolant water. (Warning—Chemical cleaning solutions are poisonous and may be harmful or fatal if
inhaled or swallowed. See Annex A1.)
X3.3.9 Reassembly Procedures:
X3.3.9.1 Install the piston, piston pin and pin retainers on
the connecting rod. Lubricate the rings with SAE 30 engine
crankcase oil.
X3.3.9.2 Place a selection of cylinder base gaskets on the
crankcase surface. Cylinder base gaskets of several thicknesses
are available and the number and thicknesses must be selected
by trial and error to obtain the proper piston overtravel of 0.014
to 0.016 in.
X3.3.9.3 Rigidly support the piston above the crankcase
surface. Install the cylinder over the piston so that it is seated
on the cylinder base gaskets. Care should be taken not to break
any of the rings as they enter the chamfered bore. (Use of a ring
compressor tool over the piston rings is advisable despite the
cylinder chamfer). Manually rotate the crankshaft through
several revolutions so that the cylinder is centered. Tighten and
torque the cylinder stud nuts to 75 lbf-ft.
X3.3.9.4 Manually rotate the crankshaft so that the piston is
at top-dead-center as indicated by the flywheel pointer.
X3.3.9.5 Place a true piece of metal flat stock on the piston
so that it projects over the top cylinder surface. Using a feeler
gage, measure the piston overtravel or separation of the flat
stock above the cylinder surface. Make the same measurement
in two directions, parallel to and at 90° to the crankshaft center
line. The overtravel should be 0.014 to 0.016 in. or the cylinder
must be removed and the number and thickness of the cylinder
base gaskets changed to bring the overtravel within specification.
X3.3.9.6 Place the cylinder head gasket on the cylinder
NOTE X3.3—Current cylinder head gaskets have a special non-stick/
sealer coating and do not require additional sealer/lubricant.
X3.3.9.7 Install the cylinder head.
X3.3.9.8 Install the marked push rods, and manually rotate
the crankshaft so that both rods are at their lowest point of
travel (flywheel at top-dead-center, compression stroke).
X3.3.9.9 Install the rocker-arm assembly with the half-balls
properly inserted.
X3.3.9.10 Install, tighten and torque the head nuts to 75
X3.3.9.11 Set the valve clearances to 0.004 in. for the intake
valve and 0.014 in. for the exhaust valve.
X3.3.9.12 Install the handwheel assembly.
X3.3.9.13 Reassemble the condenser, the intake air elbow
and silencer, the exhaust pipe, the cooling water lines to the
condenser and injector cooling passage.
X3.4 Injector Assembly Inspection:
X3.4.1 Disassembly.
X3.4.1.1 With the engine shut down, close the coolant water
valves (supply and return) to the injector cooling passage, and
drain the coolant from the injector cooling passage.
X3.4.1.2 Disconnect the fuel lines at the injector assembly.
D 613 – 03b
X3.5.1.6 Disassemble the valve lifters from the top of the
crankcase, clean, inspect and, if necessary, replace worn
assembly components.
X3.5.1.7 Approximate the rear main bearing clearance by
dial indicator measurement of the movement of the crankcase
edge of the flywheel outer surface. Measure with the flywheel
at rest and then with the flywheel lifted using an appropriate
lever, if the difference in the measurements exceeds 0.006 in.,
crankcase rebuilding is recommended.
X3.5.1.8 Disassemble the oil pressure control valve assembly, solvent clean, inspect for worn components and replace as
required. (Warning—In addition to other precautions, avoid
over tightening the four relief valve body fastening bolts to
prevent valve body distortion and restriction of the plunger
X3.5.1.9 Inspect the outer crankcase surfaces for indications
of oil seal leakage which may require extensive maintenance or
crankcase rebuilding.
X3.5.2 Power Absorption Motor—Inspect the power absorption motor annually as follows:
X3.5.2.1 Turn off all the electrical power circuits to the
engine and unit.
X3.5.2.2 Check the condition and tension of the drive belts.
Replace belts as required and adjust the motor position to
achieve proper belt tension.
X3.5.2.3 Inspect the motor bearing housings for evidence of
wear or loss of lubricant. Flush lubricate the bearings if the unit
is equipped with field lubrication fittings.
X3.5.2.4 Remove dust and dirt from the motor end bell
openings using low pressure compressed air.
X3.5.3 Safety Cutoff Checks:
X3.5.3.1 High Coolant Temperature Switch—After shutting
off the cooling water to the condenser coil, the engine should
stop within one minute. Check and adjust the thermal switch
set point as required.
X3.5.3.2 Low Oil Pressure Switch—When starting the engine, release of the momentary start switch before the oil
pressure reaches approximately 20 psi (138 kPa), should result
in unit shut down.
X3.5.3.3 Electrical Interlock—Disconnecting either the
single phase or the three phase power at the appropriate supply
switch should cause unit shut down.
X3.5.3.4 Fuel Pump Safety Solenoid—Disconnecting the
single phase power should cause release of the fuel pump
safety solenoid, closing of the fuel pump rack with the result
that combustion ceases.
X3.4.1.3 Remove the injector pickup and associated
X3.4.1.4 Remove the injector assembly.
X3.4.2 Nozzle Cleaning:
(Warning—Injector nozzles are precision devices which
have finely finished fits and meticulously polished surfaces.
Scrupulous cleanliness must be observed to prevent dirt or
moisture from causing damage. As parts are removed, they
should be placed in a clean container and submerged in diesel
fuel oil or kerosine. Do not touch the critical lapped surfaces
with bare fingers because body acids can cause undesirable
X3.4.2.1 Clamp the injector assembly in a vise so that the
nozzle cap nut can be loosened and removed. Separate the
nozzle from the cap nut.
X3.4.2.2 Clean the carbon from the nozzle, pintle and cap
nut by immersion in a suitable cleaner for as long as necessary.
Placing the parts container of cleaner solution in an ultrasonic
bath hastens the cleaning process.
X3.4.2.3 Reassemble the nozzle components on the injector
assembly and tighten the nozzle cap nut to a torque of 50 lbf-ft.
X3.4.2.4 Check the injector nozzle opening pressure and
spray pattern.
X3.4.2.5 Reinstall the injector assembly with injector
pickup on the engine and check for cooling water leakage past
the nozzle into the precombustion chamber.
X3.4.2.6 Before installing the combustion pickup, motor the
engine for a short time to blow out any water which may have
entered the combustion chamber during the maintenance process. Restricting the pickup hole by pressing a cloth (not paper)
wiper against the opening will aid in removing any entrained
X3.5 Crankcase/Unit Inspection:
X3.5.1 Crankcase—Inspect the crankcase annually as follows.
X3.5.1.1 Turn off the electrical power circuits to the engine
and unit.
X3.5.1.2 Drain the crankcase lubricating oil and clean the
crankcase sump using a petroleum based solvent.
X3.5.1.3 Disassemble the oil suction screen assembly and
clean the components.
X3.5.1.4 Disassemble the crankcase breather body from the
crankcase side door and clean the internal passage and baffles.
X3.5.1.5 Disassemble the connecting rod from the crankshaft. Inspect the big end bearing shells and replace if wear is
indicated. Reassemble the connecting rod and torque the
bearing cap bolts to 104 lbf-ft.
TABLE X3.1 Recommended Torque Values
Cylinder head stud nuts
Cylinder stud nuts
Crankshaft balancing weight bolts
Balancing shaft weight bolts
Balancing shaft weight bolt locknuts
Connecting rod big end bolts
Combustion pickup
Injector Cap Nut
Torque, lbf-ft
Torque, N-m
D 613 – 03b
X3.6 Engine Torque Tightening Recommendations—
Recommended torque values are given in Table X3.1.
Subcommittee D02.01 has identified the location of selected changes to this standard since the last issue
(D 613–03a) that may impact the use of this standard (approved June 10, 2003).
(1) Revised 7.3 to allow for gravimetric blending of reference
(2) Revised X1.4 for clarity and emphasis.
Subcommittee D02.01 has identified the location of selected changes to this standard since the last issue (D 613–03) that may
impact the use of this standard (approved May 10, 2003).
(1) Added warning statement to 8.2.
(2) Clarified warning statements in Annex A1.
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