Isuzu 4ja1, Workshop Manual

Page: 90 / 564

6A – 68 ENGINE MECHANICAL
ROCKER ARM SHAFT AND ROCKER ARM
Rocker Arm Shaft Run-Out
1. Place the rocker arm shaft on a V-block.
2. Use a dial indicator to measure the rocker arm shaft
central portion run-out.
If the run-out is very slight, correct the rocker arm shaft
run-out with a bench press. The rocker arm must be at cold
condition.
If the measured rocker arm shaft run-out exceeds the
specified limit, the rocker arm shaft must be replaced.
Rocker Arm Shaft Run-Out mm (in)
Limit
0.3 (0.012)
Rocker Arm Shaft Outside Diameter
Use a micrometer to measure the rocker arm fitting portion
outside diameter.
If the measured value is less than the specified limit, the rocker
arm shaft must be replaced.
Rocker Arm Shaft Outside Diameter mm (in)
Standard Limit
18.98–19.00 (0.747–0.748) 18.90 (0.744)
Rocker Arm Shaft and Rocker Arm 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
19.010–19.030
(0.748–0.749)
19.100 (0.752)
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 Shaft and Rocker Arm Clearance mm (in)
Standard Limit
0.01–0.05
(0.0004–0.0020)
0.20 (0.008)
015LX009
014RY00024
015LX008