Isuzu NHR 4J Series Workshop Manual page 79

6A – 12 GENERAL ENGINE MECHANICAL
1. Valve Guide Clearance
• Measure the valve stem diameter with a micrometer.
If the valve stem diameter is less than the specified
limit, the valve and the valve guide must be replaced
as a set.
Diameter of
Valve stem
6A-12-1.tif
• Measure the inside diameter of the valve guide with a
micrometer.
• Subtract the measured outer diameter of the valve
stem from the measured inner diameter of the valve
guide. If the valve exceeds of the valve guide.
If the valve exceeds the specified limit, the valve and
the valve guide must be replaced as a set.
Valve Guide Clearance
Inlet clearance
Exhaust clearance
Standard
7.946 - 7.961
Inlet
(0.3128 - 0.3134)
7.921 - 7.936
Exhaust
(0.3118 - 0.3124)
Standard
0.039 - 0.069
(0.0015 - 0.0027)
0.064 - 0.096
(0.0025 - 0.0038)
mm (in)
Limit
7.880
(0.310.2)
7.850
(0.3091)
mm (in)
Limit
0.200
(0.0079)
0.250
(0.0098)