Operation Manual

4-23
CYLINDER AND PISTON
2. Position:
• Piston ring
(in cylinder)
Insert a ring into the cylinder and
push it approximately 40mm (1.57 in)
into the cylinder. Push the ring with
the piston crown so that the ring will
be at a right angle to the cylinder
bore.
a. 40 mm (1.57 in)
3. Measure:
• Ring end gap
Out of specification → Replace.
You cannot measure the end gap on
the expander spacer of the oil control
ring. If the oil control ring rails show
excessive gap, replace all three rings.
CHECKING THE PISTON PIN
1. Inspect:
• Piston pin
Blue discoloration/grooves → Re-
place, then inspect the lubrication
system.
2. Measure:
• Piston pin-to-piston clearance
Measurement steps:
a. Measure the outside diameter
(piston pin) "a".
If out of specification, replace the
piston pin.
b. Measure the inside diameter (pis-
ton) "b".
c. Calculate the piston pin-to-piston
clearance with the following for-
mula.
d. If out of specification, replace the
piston.
INSTALLING THE PISTON RING
AND PISTON
1. Install:
• Piston ring
Onto the piston.
• Be sure to install the piston rings so
that the manufacturer's marks or
numbers are located on the upper
side of the rings.
• Lubricate the piston and piston
rings liberally with engine oil.
2. Position:
•Top ring
•2nd ring
•Oil ring
Offset the piston ring end gaps as
shown.
a. Top ring end
b. 2nd ring end
c. Oil ring end (upper)
d. Oil ring
e. Oil ring end (lower)
End gap:
Standard <Limit>
Top
ring
0.20–0.30
mm
(0.008–0.01
2 in)
0.55 mm
(0.022 in)
2nd
ring
0.35–0.50
mm
(0.014–0.02
0 in)
0.85 mm
(0.033 in)
Oil
ring
0.20–0.50
mm
(0.008–0.02
0 in)
—
Outside diameter (piston
pin):
17.991–18.000 mm
(0.7083–0.7087 in)
Inside diameter (piston):
18.004–18.015 mm
(0.7088–0.7093 in)
Piston pin-to-piston clearance =
Inside diameter (piston) "b" -
Outside diameter (piston pin)
"a"
Piston pin-to-piston
clearance:
0.004–0.024 mm
(0.00016–0.00094 in)
<Limit>:0.07 mm (0.003
in)
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