engine ISUZU TF SERIES 2004 Workshop Manual

ENGINE MECHANICAL 6A – 77



CAMSHAFT
Visually inspect the journals, the cams, the oil pump drive gear,
and the camshaft bearings for excessive wear and damage.
The camshaft and the camshaft bearings must be replaced if
these conditions are discovered during inspection.














Camshaft Journal Diameter
Use a micrometer to measure each camshaft journal diameter
in two directions (1 and 2). If the measured value is less than
the specified limit, the camshaft must be replaced.


Camshaft Journal Diameter mm (in)
Standard Limit
49.945 - 49.975
(1.9663 - 1.9675) 49.60 (1.953)














Cam Height
Measure the cam height (H) with a micrometer. If the
measured value is less than the specified limit, the camshaft
must be replaced.


Cam Height (H) mm (in)
Standard Limit
42.016 (1.6542) 41.65 (1.640)



















Camshaft Run-Out
1. Mount the camshaft on V-blocks.
2. Measure the run-out with a dial indicator.
If the measured value exceeds the specified limit, the
camshaft must be replaced.


Camshaft Run-Out mm (in)
Standard Limit
0.02 (0.0008) 0.10 (0.004)

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6A – 78 ENGINE MECHANICAL
Camshaft and Camshaft Bearing Clearance
Use an inside dial indicator to measure the camshaft bearing
inside diameter.


Crankshaft Bearing Inside Diameter mm (in)
Standard Limit
50.00 - 50.03
(1.968 - 1.970) 50.08 (1.972)
If the clearance between the camshaft bearing inside diameter
and the journal exceeds the specified limit, the camshaft
bearing must be replaced.


Camshaft Bearing Clearance mm (in)
Standard Limit
0.055 (0.0022) 0.12 (0.005)










Camshaft Bearing Replacement
Camshaft Bearing Removal
1. Remove the cylinder body plug plate.
2. Use the bearing replacer to remove the camshaft bearing.
Bearing Replacer: 5-8840-2038-0










Camshaft Bearing Installation
1. Align the bearing oil holes with the cylinder body oil holes.
2. Use the replacer to install the camshaft bearing.
Bearing Replacer: 5-8840-2038-0



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ENGINE MECHANICAL 6A – 79




CRANKSHAFT AND BEARING
Inspect the surface of the crankshaft journals and crankpins for
excessive wear and damage.
Inspect the oil seal fitting surfaces for excessive wear and
damage.
Inspect the oil ports for obstructions.

NOTE:
To increase crankshaft strength, tufftriding (Nitrizing
Treatment) has been applied. Because of this, it is not
possible to regrind the crankshaft surfaces.
Therefore, under size bearing are not available.























Crankshaft Run-Out
1. Set a dial indicator to the center of the crankshaft journal.
2. Gently turn the crankshaft in the normal direction of
rotation.
Read the dial indicator as you turn the crankshaft.
If the measured value exceeds the specified limit, the
crankshaft must be replaced.


Crankshaft Run-Out mm (in)
Standard Limit
0.05 (0.002) or less 0.08 (0.003)















Bearing Spread
Use a vernier caliper to measure the bearing spread.
If the measured value is less than the specified limit, the
bearing must be replaced.


Bearing Spread mm (in)
Limit
4JA1T (L),
4JA1TC 64.5 (2.54)
Creankshaft Bearing
4JH1TC 74.5 (2.93)
Connecting Rod Bearing 56.5 (2.22)


015LX061
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6A – 80 ENGINE MECHANICAL

Crankshaft Journal and Crankpin Diameter
1. Use a micrometer to measure the crankshaft journal
diameter across points 1 - 1 and 2 - 2.
2. Use the micrometer to measure the crankshaft journal
diameter at the two points (3 and 4).
3. Repeat Steps 1 and 2 to measure the crankpin diameter.
If the measured values are less than the specified limit, the
crankshaft must be replaced.


Crankshaft Journal and Diameter mm (in)
Standard Limit
4JA1T (L),
4JA1TC 59.921-59.928
(2.3591-2.3594) 59.91 (2.3586)
4JH1TC 69.917-69.932
(2.7526-2.7532) 69.91(2.7524)


Crankpin Diameter mm (in)
Standard Limit
52.915 - 52.930
(2.0833 - 2.0839) 52.90 (2.083)


Crankshaft Journal and Crankpin Uneven Wear mm (in)
Standard Limit
0.05 (0.002) or less 0.08 (0.003)


Crankshaft Journal and Crankpin Diameter
If the clearance between the measured bearing inside diameter
and the crankshaft journal diameter exceeds the specified limit,
the bearing and/or the crankshaft must be replaced.


Crankshaft Journal and Bearing Clearance mm (in)
Standard Limit
0.032 - 0.077
(0.0013 - 0.0030) 0.110 (0.0043)


015RY00008
015RY00009

ENGINE MECHANICAL 6A – 81

Connecting Rod Bearing Inside Diameter
1. Install the bearing to the connecting rod big end.
2. Tighten the bearing cap to the two step of anglar tightening
method.


Connecting Rod Bearing Cap Bolt Torque N·m (kg·m/Ib ft)
4JA1T (L),
4JA1TC 78-88 (8.0/57 – 9.0/65)
1st step ; 29.0–29.2 (3.00/22.0–3.01/22.2)4JH1TC
2nd step ; 45
-60

3. Use an inside dial indicator to measure the connecting rod
bearing inside diameter.



Crankpin and Bearing Clearance
If the clearance between the measured bearing inside diameter
and the crankpin exceeds the specified limit, the bearing
and/or the crankshaft 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
(0.0011-0.033) 0.100 (0.0039)






Clearance Measurements (With Plastigage)
Crankshaft Journal and Bearing Clearance
1. Clean the cylinder body, the journal bearing fitting surface,
the bearing caps, and the bearings.
2. Install the bearings to the cylinder body.
3. Carefully place the crankshaft on the bearings.
4. Rotate the crankshaft approximately 30
to seat the
bearing.
5. Place the Plastigage (arrow) over the crankshaft journal
across the full width of the bearing.
6. Install the bearing caps with the bearing.








7. Tighten the bearing caps to the specified torque.


Crankshaft Bearing Cap Bolt Torque mm (in)
167 (17/123)
Do not allow the crankshaft to turn during bearing cap
installation and tightening.
8. Remove the bearing cap.



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6A – 82 ENGINE MECHANICAL




































9. 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 limit, perform the
following additional steps.
1. Use a micrometer to measure the crankshaft outside
diameter.
2. Use an inside dial indicator to measure the bearing
inside diameter.
If the crankshaft journal and bearing clearance
exceeds the limit, the crankshaft and/or the bearing
must be replaced.


Crankshaft Journal and Bearing Clearance mm (in)
Standard Limit
0.032 - 0.077
(0.0013 - 0.0030) 0.110 (0.0043)
































Crankpin and Bearing Clearance
1. Clean the crankshaft, the connecting rod, the bearing cap,
and the bearings.
2. Install the bearing to the connecting rod and the bearing
cap.
Do not allow the crankshaft to move when installing the
bearing cap.
3. Prevent the connecting rod from moving.
4. Attach the Plastigage to the crankpin.
Apply engine oil to the Plastigage to keep it from falling.
5. Install the bearing cap and tighten it to the two step of
anglar tihtening method.
Do not allow the connecting rod to move when installing
and tightening the bearing cap.


Connecting Rod Bearing Cap Bolt Torque N·m (kg·m/Ib ft)
4JA1T (L),
4JA1TC 78-88 (8.0/57 – 9.0/65)
1st step ; 29.0–29.2 (3.00/22.0–3.01/22.2)4JH1TC
2nd step ; 45
-60

015LX129
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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
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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
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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)



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015LX023
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