SELVA MARINE Kingfish 25, Service Manual

Page: 206 / 398

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7
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
.
Checking the piston ring groove
1. Measure the piston ring grooves.
Checking the piston ring side
clearance
1. Measure the piston ring side clearance.
Checking the piston pin boss inside
diameter
1. Measure the piston pin boss inside diam-
eter
a
.
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)
a
b
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)
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)
a
b
c
b
a
Cylinder block