Isuzu NHR 4J Series, Workshop Manual

Page: 92 / 406

GENERAL ENGINE MECHANICAL 6A – 25
Oil Clearance
1. Use either a vernier caliper or a dial indicator to
measure the rocker arm inside diameter.
Rocker Arm Inside Diameter mm (in)
Standard Limit
19.036 - 19.060
(0.7494 - 0.7503)
19.100 (0.7519)
2. Measure the rocker arm shaft outside diameter.
If the measured value exceeds the specified limit,
replace either the rocker arm or the rocker arm shaft.
Rocker Arm and
Rocker Shaft Clearance
mm (in)
Standard Limit
0.06 - 0.08
(0.0024 - 0.0031)
0.10 (0.0039)
3. Check that the rocker arm oil port is free is
obstructions.
If necessary, use compressed air to clean the rocker
arm oil port.
Rocker Arm Correction
Inspection the rocker arm valve stem contact surface for
step wear
!
and scoring
"
.
If the contact surfaces have light step wear or scoring,
they may be honed with an oil stone.
If the step wear or scoring is severe, the rocker arm must
be replaced.
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