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Isuzu engine 4j series. Manual - part 31

6A – 60

GENERAL ENGINE MECHANICAL

4JG2

mm (in)

Liner

outside

Grade

Cylinder bore

diameter average

Liner outside

diameter

Liner

bore

Grade

Service liner bore measurement

95.435 (3.7573) - 95.450 (3.7579)

97.001 - 97.010

(3.8189 - 3.8193)

97.011 - 97.020

(3.8193 - 3.8197)

95.451 (3.7579) - 95.466 (3.7585)

95.435 (3.7573) - 95.450 (3.7579)

97.011 - 97.020

(3.8193 - 3.8197)

97.021 - 97.030

(3.8197 - 3.8201)

95.451 (3.7579) - 95.466 (3.7585)

95.435 (3.7573) - 95.450 (3.7579)

97.021 - 97.030

(3.8197 - 3.8201)

97.031 - 97.040

(3.8201 - 3.8205)

95.451 (3.7579) - 95.466 (3.7585)

95.435 (3.7573) - 95.450 (3.7579)

97.031 - 97.040

(3.8201 - 3.8205)

97.041 - 97.050

(3.8205 - 3.8209)

95.451 (3.7579) - 95.466 (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.

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.

Cylinder Liner Installation

1. Cylinder Liner Installation Using The Special Tool.

1) Use new kerosene or diesel oil to thoroughly clean

the cylinder liners and bores.

2) Use compressed air to blow-dry the cylinder liner

and bore surfaces.

Cylinder Liner Installer: 5-8840-2313-0 (4JG2)

: 5-8840-2040-0 (4JB1 / 4JB1T/

4JB1TC)

NOTE:

All foreign material must be carefully removed from
the cylinder liner and the cylinder bore before
installation.

3) Insert the cylinder liner

into the cylinder body

from the top of the cylinder body.

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GENERAL ENGINE MECHANICAL 6A – 61

4) Set the cylinder liner installer 3 to the top of the

cylinder liner.
Position the cylinder body so that the installer
center is directly beneath the bench press shaft
center 4.

Cylinder Liner Installer: 5-8840-2313-0 (4JG2)

: 5-8840-2040-0 (4JB1/4JB1T/

4JB1TC)

NOTE:

Check that the cylinder liner is set perpendicular to
the bench press and that there is no wobble.
5) Use the bench press to apply a seating force of 500 kg

(1,102.5 lb/4,900 N) to the cylinder liner.

6) Apply a force 2,500 kg (5,512.5 lb/24,500 N) to fully

seat the cylinder liner.

7) After installing the cylinder liner, measure the cylinder

liner projection.

8) After installing the cylinder liner, measure the cylinder

liner projection.
Refer to “Cylinder Liner Projection Inspection” in this
Section.
Measure the cylinder liner bore inside diameter and
select the appropriate piston grade.

REASSEMBLY

16. Cylinder Block

15. Tappet

14. Camshaft

•

Apply a coat of engine oil to the tappet and the cylinder
body tappet insert holes.

•

Locate the position mark applied at disassembly (if the
tappet is to be reused).

•

Apply a coat of engine oil to the camshaft and the
camshaft bearings.

•

Install the camshaft to the cylinder body.
Take care not to damage the camshaft bearings.

13. Crankshaft

12. Main Bearing Cap

11. Crankshaft Rear Oil Seal

10. Cylinder Block Rear Plate

9. Flywheel

Above works refer to “CRANKSHAFT” Section in this
manual.

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6A – 62

GENERAL ENGINE MECHANICAL

8. Piston and Connecting Rod

1) Try to insert the piston pin into the piston pin hole with

normal finger pressure.
Weigh each piston and connecting rod assembly.
Select piston and connecting rod combinations so that
the weight variation of the different assemblies is held
within the specified limits.

g (oz)

Variance in weight

after assembly

Less than 3

(0.1058)

2) Clamp the connecting rod in a vise.

Take care not to damage the connecting rod.

3) Use a pair of pliers to install the piston pin snap ring to

the piston.

NOTE:

When changing piston/connecting rod combinations,
do not change the piston/piston pin combination.

4) Install the piston to the connecting rod.

The piston head front mark

and the connecting rod

“ISUZU” casting mark

must be facing the same

direction.

5) Apply a coat of engine oil to the piston pin and the

piston pin hole.
Use your fingers to force the piston pin into the piston
until it makes contact with the snap ring.

6) Use your fingers to force the piston pin snap ring into

the piston snap ring groove.
Check that the connecting rod moves smoothly on the
piston pin.

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GENERAL ENGINE MECHANICAL 6A – 63

7) Install the piston rings with the piston ring expander.

The compression ring must be set with the 1N, 2N
mark (4JG2) facing up.
Discrimination mark is painted as shown in the
illustration.

8) Use a piston ring replacer to install the three piston

rings.
Piston Ring Replacer:
Install the piston rings in the numerical order shown in
the illustration.

Oil ring

2nd compression ring

1st compression ring

NOTE:

Install the compression rings with the stamped side
facing up.

Insert the expander coil into the oil ring groove so that
there is no gap on either side of the expander coil
before installing the oil ring.

9) Apply engine oil to the piston ring surfaces.
10) Check that the piston rings rotate smoothly in the

piston ring grooves.

11) Position the piston ring gaps as shown in the

illustration.

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