Yanmar 3TNV82A Service Manual page 205

Crankshaft and Camshaft Components
5. Subtract the piston measurement from the
greatest measurement acquired during cylinder
inspection (see Inspection of Cylinder Block on
page 6-78) to obtain piston-to-cylinder
clearance. Record the measurements. See
Piston on page 6-15 for specifications.
6. Measure the diameter of the wrist pin bore on
both sides of the piston (Figure 6-112). See
Piston on page 6-15 for specifications. Record
the measurements.
Figure 6-112
7. Measure the outside diameter of the wrist pin in
three places and at 90° (Figure 6-113). See
Piston on page 6-15 for specifications. Record
the measurements.
Figure 6-113
8. Using a micrometer, measure the thickness of
each piston ring. See Piston Ring on page 6-17
for specifications. Record the measurements.
Notes:
• On an engine with low hours, the pistons,
piston rings and cylinders may be reused if they
are found to be within specifications.
TNV DI Service Manual
• On an engine with high hours, the pistons rings
should be replaced and the cylinder honed
(see Honing and Boring on page 6-83) or
replaced. The piston should be replaced as
necessary.
9. Place each compression piston ring in the
groove as shown (Figure 6-114). Use a feeler
gauge to measure the clearance between the
piston ring and the piston ring land. Record the
measurements. See Piston Ring on page 6-17
for specifications. Replace the piston if not
within specification.
0000237
0001889
ENGINE
0001892
Figure 6-114
6-79