Isuzu NHR 4J Series Workshop Manual page 118

4JG2
Compression
ring
Oil ring
Piston pin
Visually inspect the piston pin for cracks, flaws, and other
damage and replace if necessary.
1. Use a micrometer to measure the piston pin outside
diameter in both directions at three different positions.
If the measurement exceed the specified limit the
piston pin must be replaced.
Piston pin outside diameter
4JB1 /
6A-51-1.tif
4JB1T
4JB1TC
4JG2
2. Measure the inside diameter of the connecting rod
small end. If the clearance between the small end and
pin does not conform to the specified value, the
connecting rod or bushing and pin must be replaced.
Clearance
3. Insert the piston pin into the piston and rotate it. If the
6A-51-2.tif
pin rotates smoothly with no backlash, the clearance is
normal. If there is backlash or roughness, measure the
clearance. If the clearance exceeds the specified limit,
the piston and the piston pin must be replaced.
Clearance
GENERAL ENGINE MECHANICAL 6A – 51
Standard
1st 0.09-0.13
(0.0035 - 0.0051)
2nd 0.05 - 0.07
(0.0020 - 0.0028)
0.03-0.07
(0.0012-0.0028)
Standard
30.995 - 31.000
(1.2202 - 1.2204)
33.995 - 34.000
(1.3384 - 1.3386)
Standard
0.008 - 0.020
(0.0003 - 0.0008)
Standard
0.002 - 0.004
(0.00008 - 0.00016)
mm (in)
Limit
0.15
(0.0059)
mm (in)
Limit
30.970 (1.2190)
33.970 (1.3374)
mm (in)
Limit
0.05
(0.0020)
mm (in)
Limit
0.04
(0.0016)