Operation Manual

CYLINDER AND PISTONS
5-32
3. Measure:
• Piston ring end gap
Out of specification → Replace the piston
ring set.
TIP
The oil ring expander spacer’s end gap cannot
be measured. If the oil ring rail’s gap is exces-
sive, replace all three piston rings.
EAS24440
CHECKING THE PISTON PINS
The following procedure applies to both of the
piston pins.
1. Check:
• Piston pin
Blue discoloration/grooves → Replace
the piston pin and then check the lubrica-
tion system.
2. Measure:
• Piston pin outside diameter “a”
Out of specification → Replace the piston
pin.
3. Measure:
• Piston pin bore inside diameter “b”
Out of specification → Replace the pis-
ton.
4. Calculate:
• Piston-pin-to-piston-pin-bore clearance
Out of specification → Replace the piston
pin and piston as a set.
Piston ring
Top ring
End gap (installed)
0.25–0.35 mm (0.0098–0.0138
in)
Limit
0.60 mm (0.0236 in)
2nd ring
End gap (installed)
0.35–0.50 mm (0.0138–0.0197
in)
Limit
0.75 mm (0.0295 in)
Oil ring
End gap (installed)
0.10–0.35 mm (0.0039–0.0138
in)
a. 40 mm (1.57 in)
Piston pin outside diameter
15.991–16.000 mm (0.6296–
0.6299 in)
Limit
15.971 mm (0.6288 in)
Piston pin bore inside diameter
16.002–16.013 mm (0.6300–
0.6304 in)
Limit
16.043 mm (0.6316 in)
• Piston-pin-to-piston-pin-bore clearance =
Piston pin bore inside diameter -
Piston pin outside diameter
Piston-pin-to-piston-pin-bore
clearance
0.002–0.022 mm (0.0001–
0.0009 in)