Checking The Piston Ring End Gap; Checking The Piston Ring Groove; Checking The Piston Ring Side Clearance; Checking The Piston Pin Boss Inside Diameter - SELVA MARINE Kingfish 25 Service Manual

Checking the piston ring end gap

1. Level the piston ring 1 in the cylinder
with a piston crown at the specified mea-
suring point a.
2. Measure the piston ring end gap b.
a
b
Measuring point a (reference data):
20 mm (0.79 in)
Piston ring end gap b (reference data):
Top ring:
0.150–0.300 mm (0.0059–0.0118 in)
2nd ring:
0.300–0.500 mm (0.0118–0.0197 in)
Oil ring:
0.200–0.700 mm (0.0079–0.0276 in)

Checking the piston ring groove

1. Measure the piston ring grooves.
1
a
b
c
Piston ring groove:
Top ring a:
1.210–1.230 mm (0.0476–0.0484 in)
2nd ring b:
1.510–1.530 mm (0.0594–0.0602 in)
Oil ring c:
2.520–2.540 mm (0.0992–0.1000 in)
Checking the piston ring side
clearance
1. Measure the piston ring side clearance.
Piston ring side clearance:
Top ring a:
0.020–0.060 mm (0.0008–0.0024 in)
2nd ring b:
0.020–0.060 mm (0.0008–0.0024 in)
Oil ring c:
0.040–0.180 mm (0.0016–0.0071 in)
Checking the piston pin boss inside
diameter
1. Measure the piston pin boss inside diam-
eter a.
a
Cylinder block
a
b
c
7
b
7-58