4jh1 ISUZU TF SERIES 2004 Workshop Manual

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
015RY00007

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.



015RY00012
015RY00013 015RY00011

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
015LX060

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

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