Yanmar 3YM30, Service Manual

Page: 141 / 231

5. Inspection and servicing of basic engine parts
121
5.4 Connecting rod
The connecting rod is made of high-strength forged
carbon steel.
The large end with the aluminium metal can be
separated into two and the small end has a 2-layer
copper alloy coil bushing.
5.4.1 Inspecting the connection rod
(1) Twist and parallelism of the large and small
ends
Insert the measuring tool into the large and small ends
of the connecting rod. Measure the extent of twist and
parallelism and replace if they exceed the tolerance.
mm
Standard Limit
Connecting rod
twist and
parallelism
Less than 0.03
per 100 mm
0.08
Piston pin bushing
Crank pin metal
Connecting rod bolt
Connecting rod
Connecting rod
(bid end cap)
(Twist and parallelism measurement)
Mandrel
Parallelism
Twist
100 mm
100 mm
Connecting rod
aligner
Twist measurement using
a connecting rod aligner
( )