Isuzu engine 4j series. Service manual - part 20

6A – 16

  GENERAL ENGINE MECHANICAL

REASSEMBLY

6. Valve Guide

•

Apply engine oil to the outside of the valve guide.
Using special tool, drive in a new valve guide from the
rocker arm shaft side.
Valve guide replacer: 9-8523-1212-0

5. Valve Guide Oil Seal

•

Using special tool, drive in a new oil seal
Oil special tool, drive in a new oil seal
Oil seal installer: 5-8840-2033-0

4. Valve

•

Apply engine oil to the outside of the valve stem.

3. Valve Spring

•

Attach the valve seat to the upper spring seat. The
painted area of the valve spring should be facing
downward.

2. Split Collar

•

Use a spring compressor to push the valve spring into
position.

•

Install the spring seat split collar.

•

Set the split collar by tapping lightly around the head of
the collar with a rubber hammer.

Valve spring compressor: 9-8523-1423-0 (J-29760)

1. Rocker Arm Assembly

N∙m (kg∙m/lb∙ft)

                                                                                                                   

54 (5.5/40)

                                                                                                                   

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GENERAL ENGINE MECHANICAL   6A – 17

CAMSHAFT, TAPPET

DISASSEMBLY

1. Cylinder Head Assembly

2. Flywheel

3. Cylinder Block Rear Plate

4. Oil Pan Assembly

5. Oil Pump Assembly

6. Camshaft Timing Gear (Gear Drive Model)

•

Remove the camshaft timing gear bolt from the
camshaft.

NOTE:

Hold the camshaft stationary to prevent the camshaft
from turning.
•

Use the universal puller 

!

 to pull out the camshaft

timing gear 

"

.

•

Universal Puller: 5-8521-0002-0
Remove the thrust plate 

#

.

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6A – 18

  GENERAL ENGINE MECHANICAL

6a. Camshaft Timing Pulley (Belt Drive Model)

•

Use the timing pulley puller 

"

 to remove the pulley.

Timing Pulley Puller: 5-8840-0086-0

•

Remove the stopper bolt.

7. Camshaft Thrust Plate (Gear Drive Model)

7a. Camshaft Pulley Center (Belt Drive Model)

8. Camshaft

9. Tappet

INSPECTION AND REPAIR

Make the necessary adjustment, repairs, and part
replacements if excessive wear or damage is discovered
during inspection.

1. Measure the Camshaft Thrust Clearance

•

Use a dial indicator to measure the camshaft end play.
This must be done before removing the camshaft
gear.
If the camshaft end play exceeds the specified limit,
the thrust plate must be replaced.

Camshaft End Play

mm (in)

Standard

Limit

0.08 (0.0031)

0.2 (0.0079)

2. Camshaft Journal Diameter

•

Use a micrometer to measure each camshaft journal
diameter in two directions 

!

 and 

"

. If the measured

value is less than the specified limit, the camshaft
must be replaced.

Journal Diameter

mm (in)

Standard

Limit

49.945 - 49.975 (1.9663 - 1.9675)

49.60 (1.9528)

3. 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

mm (in)

Standard

Limit

42.02 (1.6543)

41.65 (1.6398)

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GENERAL ENGINE MECHANICAL   6A – 19

4. Camshaft Run-Out

•

Mount the camshaft on V-blocks.

•

Measure the run-out with a dial indicator.
If the measured value exceeds the specified limit, the
camshaft must be replaced.

Run-Out

mm (in)

Standard

Limit

0.02 (0.008) or less

0.10 (0.0039)

5. Camshaft and Camshaft Bearing Clearance

•

Use an inside dial indicator to measure the camshaft
bearing inside diameter.

Camshaft Bearing Inside Diameter

mm (in)

Standard

Limit

50.00 - 50.03

(1.9685 - 1.9696)

50.08 (1.9716)

Camshaft Bearing Clearance

mm (in)

Standard

Limit

0.025 - 0.085

(0.0010 - 0.0033)

0.12 (0.005)

•

If the clearance between the camshaft bearing inside
diameter and the journal exceeds the specified limit,
the camshaft bearing must be replaced.

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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