2004 ISUZU TF SERIES engine

ENGINE MECHANICAL 6A – 83































6. Remove the bearing cap.
7. Compare the width of the Plastigage attached to either the
crankshaft or the bearing against the scale printed on the
Plastigage container.
If the measured value exceeds the specified limit, perform
the following additional steps.
1. Use a micrometer to measure the crankpin outside
diameter.
2. Use an inside dial indicator to measure the bearing
inside diameter.
If the crank pin and bearing clearance exceeds the
specified limit, the crankshaft and/or the bearing must
be replaced.


Crankpin and Bearing Clearance mm (in)
Standard Limit
4JA1T (L),
4JA1TC 0.029-0.066
(0.0011-0.0026) 0.100 (0.0039)
4JH1TC 0.029-0.083
(0.0011-0.0033) 0.100 (0.0039)

CRANKSHAFT BEARING SELECTION
Crankshaft bearing selection is based on the measured
diameters of the crankshaft journals and the bearing inserts.
Match the crankshaft bearing housing grade marks and the
crankshaft journal grade marks in the table below to determine
the correct crankshaft bearing size.

Crankshaft Bearing Housing Grade Mark
Position
Crankshaft bearing housing grade marks 1, 2 or 3 are stamped
on the rear right hand side of the cylinder body.




Crankshaft Journal Grade Mark Position
The crankshaft journal grade marks (1 or -, 2 or --, 3 or ---) are
stamped on each crankshaft journal web.
The crankshaft journal and bearing clearance must be the
same for each position after installation of the crankshaft and
the crankshaft bearings.

NOTE:
The crankshaft journal mark No. 4 is stamped on
crankshaft No. 4 journal web front side or rear side.
015LX060
015RY00016

6A – 84 ENGINE MECHANICAL


015RY00017



RTW46ASH002501
REFERENCE


4JA1T(L), 4JA1TC mm (in)
Crankshaft
Bearing Housing Crankshaft Journal
Grade
MarkDiamaeterGrade
MarkDiamaeter Crankshaft
Bearing
Size Code
1 or
- 59.927-59.932
(2.3593-23.595)
2 or
- - 59.922-59.927
(2.3591-2.3539)Brown or 41 63.992-
64.000
(2.5194-
2.5197)
3 or
- - - 59.917-59.922
(2.3589-2.3591)Yellow or 5
1 or
- 59.927-59.932
(2.3593-2.3595)Black or 2
2 or
- - 59.922-59.927
(2.3591-2.3593)Blue or 3 2 63.983-
63.992
(2.5190-
2.5194)
3 or
- - - 59.917-59.922
(2.3589-2.3591)Brown or 4
1 or
- 59.927-59.932
(2.3593-2.3595)Green or 1
2 or
- - 59.922-59.927
(2.3591-2.3593)3 63.975-
63.983
(2.5187-
2.5190)
3 or
- - - 59.917-59.922
(2.3598-2.3591)Black or 2

4JH1TC mm (in)
Crankshaft
Bearing Housing Crankshaft Journal
Grade
MarkDiamaeterGrade
MarkDiamaeter Crankshaft
Bearing
Size Code
1 or
- 69.927-69.932
(2.7530-2.7532)
2 or
- - 69.922-69.927
(2.7528-2.7530)4 1 73.992-
74.000
(2.9131-
2.9134)
3 or
- - - 69.917-69.922
(2.7556-2.7528)5
1 or
- 69.927-69.932
(2.7530-2.7532)2
2 or
- - 69.922-69.927
(2.7528-2.7530)3 2 73.983-
73.992
(2.9127-
2.9131)
3 or
- - - 69.917-69.922
(2.7556-2.7528)4
1 or
- 69.927-69.932
(2.7530-2.7532)1
2 or
- - 69.922-69.927
(2.7528-2.7530)3 73.975-
73.983
(2.9124-
2.9127)
3 or
- - - 69.917-69.922
(2.7526-2.7528)2

ENGINE MECHANICAL 6A – 85
CRANKSHAFT PILOT BEARING
Check the crankshaft pilot bearing for excessive wear and
damage and replace it if necessary.















Crankshaft Pilot Bearing Replacement
Crankshaft Pilot Bearing Removal
Use the pilot bearing remover to remove the crankshaft pilot
bearing.
Pilot Bearing Remover: 5-8840-2000-0
Sliding Hammer: 5-8840-0019-0
















Crankshaft Pilot Bearing Installation
1. Place the crankshaft pilot bearing right angle across the
crankshaft bearing installation hole.
2. Tap around the edges of the crankshaft pilot bearing outer
races with a brass hammer to drive the bearing into the
crankshaft bearing installation hole.
Pilot Bearing Installer: 5-8522-0024-0

NOTE:
Strike only the crankshaft pilot bearing outer race with
the hammer. Do not strike the bearing inner race.
Bearing damage and reduced bearing service life will
result.







































FLYWHEEL AND RING GEAR
Flywheel
1. Inspect the flywheel friction surface for excessive wear and
heat cracks.
2. Measure the flywheel friction surface depth.
If the measured value is within the specified limit, the
flywheel may be reground.
If the measured value exceeds the specified limit, the
flywheel must be replaced.


Flywheel Friction Surface Depth (1) mm (in)
Standard Limit
4JA1T (L),
4JA1TC 20 (0.7874) 21 (0.8267)
4JH1TC 18 (0.7087) 19 (0.7480)

Ring Gear
Inspect the ring gear.
If the ring gear teeth are broken or excessively worn, the ring
gear must be replaced.
015RY00010
015RY00019015RY00018

6A – 86 ENGINE MECHANICAL





Ring Gear Replacement
Ring Gear Removal
Strike around the edges of the ring gear with a hammer and
chisel to remove it.




Ring Gear Installation
1. Heat the ring gear evenly with a gas burner to invite
thermal expansion.
Do not allow the temperature of the gas burner to exceed
200
C (390
F).
2. Install the ring gear when it is sufficiently heated.
The ring gear must be installed with the chamfer facing the
clutch.






PISTON
Piston Grade Selection and Cylinder Bore
Measurement
Refer to the Section "Cylinder Body", Item "Cylinder Liner Bore
Measurement" for details on piston grade selection and
cylinder liner bore measurement.





Piston Ring Gap
1. Insert the piston ring horizontally (in the position it would
assume if it were installed to the piston) into the cylinder
liner.




2. Push the piston ring into the cylinder bore until it reaches
the measuring point 1 or 2 where the cylinder liner bore is
the smallest.
Do not allow the piston ring to slant to one side or the
other. It must be perfectly horizontal.
Measuring Point 1 10 mm (0.4 in)
or
Measuring Point 2 120 mm (4.7 in)



020LX008
020LX009
015LX023
015RY00020

ENGINE MECHANICAL 6A – 87

3. Use a feeler gauge to measure the piston ring gap.
If the measured value exceeds the specified limit, the
piston ring must be replaced.


Piston Ring Gap mm (in)
4JA1T (L), 4JA1TC
Standard Limit
1st Compression Ring
2nd Compression Ring0.3-0.3
(0.0118-0.0197)
Oil Ring 0.250-0.450
(0.0098-0.0177) 1.5
(0.059)


4JH1TC
Standard Limit
1st Compression Ring
2nd Compression Ring0.3-0.5
(0.0118-0.0197)
Oil Ring 0.250-0.450
(0.0098-0.0177) 1.5
(0.059)


Piston Ring and Piston Ring Groove Clearance
Use a feeler gauge to measure the clearance between the
piston ring and the piston ring groove at several points around
the piston.
If the clearance between the piston ring and the piston ring
groove exceeds the specified limit, the piston ring must be
replaced.


Piston Ring and Piston Ring Groove Clearance mm (in)
4JA1T (L), 4JA1TC
Standard Limit
1st Compression Ring0.09-0.125
(0.0035-0.0049)
2nd Compression Ring0.05-0.085
(0.0020-0.0033)
Oil Ring 0.03-0.070
(0.0012-0.0028) 0.15
(0.0059)


4JH1TC
Standard Limit
1st Compression Ring0.09-0.130
(0.0035-0.0051)
2nd Compression Ring0.05-0.090
(0.0020-0.0035)
Oil Ring 0.03-0.070
(0.0012-0.0028) 0.15
(0.0059)

015RY00021
015LX025

6A – 88 ENGINE MECHANICAL


4. Visually inspect the piston rings.
If a piston ring groove is damaged or distorted, the piston
must be replaced.



Piston Pin Diameter
Use a micrometer to measure the piston pin diameter at
several points.
If the measured value is less than the specified limit, the piston
pin must be replaced.


Piston Pin Diameter mm (in)
Standard Limit
30.995-31.000
(1.2202-1.2204) 30.97
(1.2193)


Piston Pin and Piston Clearance
Use and inside dial indicator to measure the piston pin hole (in
the piston).


Piston Pin Hole mm (in)
4JA1T (L) 31.002-31.010 (1.2206-1.2208)
4JA1TC, 4JH1TC 31.005-31.013 (1.2207-1.2210)


Piston Pin and Piston Pin Hole Clearance mm (in)
4JA1T (L) 0.002-0.015 (0.00008-0.0006)
4JA1TC, 4JH1TC 0.005-0.018 (0.0002-0.0007)



















CYLINDER HEAD GASKET SELECTION
Cylinder head gasket is determined by the piston head
projection from the cylinder body upper surface, in order to
improve engine performance.
Three types of gasket are provided by the difference of
thickness. Select the adequet one out of three grades of
gasket, according to the following procedure.
Before measurement, clear off carbon from the piston head
and cylinder body surface and also clean the place where a
gasket was installed.
015LX026
015RW048
011LX011

ENGINE MECHANICAL 6A – 89


RTW36ASH001701
Piston Head Projection Measuring Point
1. Use a dial indicator to measure the piston projection
amount.
2. Refer to the illustration for the piston head projection
measuring positions.
All measuring positions should be as close as possible to
the cylinder liner.



3. Measure the points 1, 2, 3, 4 and obtain two differences 1-
2 and 3-4 on each cylinder.
Calculate the average value of the piston head projection
on each cylinder.
4. Obtain the maximum value in the four cylinders.
5. Determine the gasket grade required to the maximum
value described above in accordance with the following
table.

Cylinder Head Gasket Combination mm (in)

Cylinder Head Gasket Combination
4JA1T (L), 4JA1TC mm (in)
Gasket Grade Mark Piston Projection Gasket Thickness
(Reference)
A 0.718-0.773
(0.0283-0.0304) 1.6
(0.0630)
B 0.773-0.819
(0.0304-0.0322) 1.65
(0.0650)
C 0.819-0.874
(0.0322-0.0344) 1.70
(0.0669)


4JH1TC mm (in)
Gasket Grade Mark Piston Projection Gasket Thickness
(Reference)
A 0.215-0.265
(0.0085-0.0104) 1.3
(0.5118)
B 0.265-0.315
(0.0104-0.0124) 1.35
(0.5315)
C 0.315-0.365
(0.0124-0.0144) 1.4
(0.5512)
NOTE:
Difference of the each piston projection and must be
equal or within 0.1 mm (0.004 in).


011RY00027
011RY00030

6A – 90 ENGINE MECHANICAL






CONNECTING ROD
Connecting Rod Alignment
Use a connecting rod aligner to measure the distortion and the
parallelism between the connecting rod big end hole and the
connecting rod small end hole.
If either the measured distortion or parallelism exceed the
specified limit, the connecting rod must be replaced.


Connecting Rod Alignment Per Length of 100 mm (3.94 in)
mm (in)
Standard Limit
Distortion 0.08 (0.003) or Less 0.20 (0.008)
Parallelism 0.05 (0.002) or Less 0.15 (0.006)


Connecting Rod Side Face Clearance
1. Install the connecting rod to the crankpin.
2. Use a feeler gauge to measure the clearance between the
connecting rod big end side face and the crankpin side
face.
If the measured value exceeds the specified limit, the
connecting rod must be replaced.


Connecting Rod Big End and Crankpin Side Face Clearance
mm (in)
Standard Limit
0.23 (0.009) 0.35 (0.014)


Piston Pin and Connecting Rod Small End
Bushing Clearance
Use a caliper calibrator and a dial indicator to measure the
piston pin and connecting rod small end bushing clearance.
If the clearance between the piston pin and the connecting rod
small end bushing exceeds the specified limit, replace the
piston pin and/or the connecting rod.


Piston Pin and Connecting Rod Small End
Bushing Clearance
mm (in)
Standard Limit
4JA1T (L) 0.008-0.020
(0.003-0.0008) 0.050 (0.002)
4JA1TC,
4JH1TC 0.005-0.018
(0.0002-0.0007) 0.050 (0.002)

015LX034
011RY00029
015LX028