Isuzu NHR 4J Series, Workshop Manual

Page: 80 / 406

GENERAL ENGINE MECHANICAL 6A – 13
Valve Guide Replacement
1. Using special tool, drive out the valve guide from the
combustion chamber side.
Valve guide replacer: 9-8523-1212-0
2. Apply engine oil to the outside of the valve guide.
Using special tool, drive in a new valve guide from
cylinder head upper face side, and check the valve
guide height.
Valve guide replacer: 9-8523-1212-0
Height
mm (in)
13 (0.51)
NOTE:
If the valve guide has been removed, both the valve
and the valve guide must be replaced as a set.
Valve Thickness
1. Measure the valve thickness
2. If the measured value is less than the specified limit
the valve and the valve guide must be replaced as a
set.
Valve Thickness mm (in)
Standard Limit
Inlet 1.79 (0.0705)
4JB1
4JB1T
4JB1TC Exhaust
1.83 (0.0720)
1.5 (0.06)
Inlet 1.41 (0.0555)
4JG2
Exhaust 1.39 (0.0547)
1.1 (0.043)
Contact surface angle on valve seat on valve
1. Measure contact surface angle on valve seat.
2. If the measured value exceeds the limit, replace valve
guide and valve seat as a set.
Standard Degrees
45°
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