Isuzu NHR 4J Series, Workshop Manual

Page: 119 / 406

6A – 52 GENERAL ENGINE MECHANICAL
Bushing replacement
Removal: Use a suitable bar and bench press or
hammer.
Installation: Use a suitable bar and bench press.
NOTE:
Align the bushing with the connecting rod oil port.
After installing a new bushing, finish the bushing bore
with a pin hole grinder.
Connecting rods
1. Check the connecting rod alignment with a connecting
rod aligner.
If either the bend or the twist exceeds the specified
limit, the connecting rod must be replaced.
mm (in)
Standard Limit
Bend per 100 (3.94) 0.08 (0.0031) or less 0.20 (0.0079)
Twist per 100 (3.94) 0.05 (0.0020) or less 0.15 (0.0059)
2. Measure the connecting rod thrust clearance.
Use a feeler gauge to measure the thrust clearance at
the big end of the connecting rod.
If the clearance exceeds the specified limit, the
connecting rod must be replaced.
Thrust Clearance mm (in)
Standard Limit
0.230 (0.0091) 0.350 (0.0138)
3. Measure the oil clearance between the connecting rod
and the crankshaft by:
1) Remove the connecting rod cap nuts and the rod
caps.
Arrange the removed rod caps in the cylinder
number order.
2) Clean the rod bearings and the crankshaft pins.
3) Carefully check the rod bearings.
If even one bearing is found to be damaged or
badly worn, the entire bearing assembly must be
replaced as a set. Reinstall the bearings in their
original positions.
Apply plastigage to the crank pin.
4) Reinstall the rod caps to their original positions
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