piston ISUZU TF SERIES 2004 Repair Manual

ENGINE MECHANICAL 6A – 59

PISTON AND CONNECTING ROD



RTW46ALF000301


Disassembly Steps
1.
Connecting rod bearing 4.
Piston pin
2.
Piston ring 5.
Connecting rod
3.
Piston pin snap ring 6.
Piston

6A – 60 ENGINE MECHANICAL


RTW36ASH001501
Disassembly
1. Connecting Rod Bearing
If the connecting rod bearings are to be reinstalled, mark
their fitting positions by tagging each bearing with the
cylinder number from which it was removed.





2. Piston Ring
1. Clamp the connecting rod in a vise.
Take care not to damage the connecting rod.
2. Use a piston ring replacer to remove the piston rings.
Piston Ring Replacer
Do not attempt to use some other tool to remove the
piston rings. Piston ring stretching will result in
reduced piston ring tension.





3. Piston Pin Snap Ring
Use a pair of pliers to remove the piston pin snap rings.





RTW36ASH001601
4. Piston Pin
5. Connecting Rod
6. Piston
Tap the piston pin out with a hammer and a brass bar.
If the pistons and piston pins are to be reinstalled, mark
their installation positions by tagging each piston and piston
pin with the cylinder number from which it was removed.
015RW041
F06MV015

6A – 74 ENGINE MECHANICAL










Piston Grade Selection
Measure the cylinder liner bore after installing the cylinder liner.
Then select the appropriate piston grade for the installed
cylinder liner.
1. Measure the cylinder liner bore.
Refer to "Cylinder Liner Bore Measurement"


Cylinder Liner Bore (Service Part) Grade mm (in)
Grade Bore measurement
AX 93.035-95.050
(3.6628-3.6634) 4JA1T(L)
4JA1TC
CX 93.051-95.066
(3.6634-3.6640)
AX 95.435-95.450
(3.7573-3.7579)
4JH1TC
CX 95.451-95.466
(3.7579-3.7585)

NOTE:
It is most important that the correct piston grade be
used. Failure to select the correct piston grade will
result in engine failure. Always measure the cylinder
bore and select the correct piston grade.

ENGINE MECHANICAL 6A – 75










































2. Measure the piston diameter.


Piston Measuring Point mm (in)
4JA1T(L)
4JA1TC 78 (3.07)
4JH1TC 70 (2.76)


Piston Grade (Service Part) mm (in)
AX 92.949 - 92.964
(3.6549 - 3.6600)
4JA1T(L)
4JA1TC
CX 92.965 - 92.980
(3.6600 - 3.6606)
AX 95.359 - 95.374
(3.7542 - 3.7548)
4JH1TC
CX 95.375 - 95.390
(3.7548 - 3.7555)


Cylinder Liner and Piston Clearance mm (in)
4JA1T(L)
4JA1TC 0.041-0.071 (0.0016-0.0027)
4JH1TC 0.047-0.065 (0.0019-0.0026)

NOTE:
Cylinder liner kit clearances are preset. However, the
cylinder liner installation procedure may result in
slight decreases in cylinder liner clearances. Always
measure the cylinder liner clearance after installation
to be sure that it is correct.



TAPPET AND PUSH ROD
Visually inspect the tappet contact surfaces for pitting,
cracking, and other abnormal conditions. The tappet must be
replaced if any of these conditions are present.
Refer to the illustration at the left.
1. Normal contact
2. Cracking
3. Pitting
4. Irregular contact Uneven contact
5. Irregular contact One-sided contact

NOTE:
The tappet surfaces are spherical. Do not attempt to
grind them with an oil stone or similar tool in an effort
to repair the tappet. If the tappet is damaged, it must
be replaced.


015LX021
014RY00028

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

6A – 96 ENGINE MECHANICAL
PISTON AND CONNECTING ROD




RTW46ALF000301


Reassembly Steps
1.
Piston 5.
Piston pin snap ring
2.
Connecting rod 6.
Piston ring
3.
Piston pin snap ring 7.
Connecting rod bearing
4.
Piston pin