Westerbeke 8.0KW-60Hz Service Manual page 29

ENGINE-DISASSEMBLY, INSPECTION AND ASSEMBLY
5
PISTON RINGS
MARK THE CYLINDER ON
THE SIDE OF THE CONNECTING
ROO BIG END TO IDENTIFY
WHEN REASSEMBLING.
CYLINDER
NUMBER
3UPPER
~
.
BEARING~V
2LDWE~~'
BEARING
PISTON PIN REMOVAL
OIL RING
1
4
PISTON AND
CONNECTING ROD
J
W~'"
NUMBERS INDICATE THE
SUGGESTED ORDER OF
DISASSEMBLY
1
CONNECTING ROD
NUT AND BEARING
CAP
1. Insert the Push Rod (special tool) from the front arrow
mark side, then fit guide D.
2. Mount the piston and connecting
rod
assembly on the
Piston
Pin
Setting Base (special tool) with the piston's
front mark pointing upward.
3. Remove the piston pin using a press.
NOTE:
After removing the piston pin, keep the piston,
piston pin,
and
connecting rod together. Do not allow
pistons, piston pins, and connecting rods from different
cylinders to become mixed up.
a-PUSHROD
FRONT ....
,._~
PISTON RINGS· INSPECTION
1. Check the piston ring side clearance. If the clearance
exceeds the specified limit, replace the ring or piston, or
both.
STANDARD VALUE:
NO.1 RING:
NO.2 RING:
0.03· 0.07mm (.00118 •. 00275In)
0.02' 0.06mm (.00078 •. 0023in)
CHECKING THE SIDE CLfARANCE
2. Insert the piston ring into the cylinder bore and push it
down with a piston. Ensure that the pistons crown is in
contact with the ring so that the ring is at 90" to the
cylinder wall. Then measure the end gap with a thickness
gauge. If the gap is too large, replace the piston ring.
STANDARD VALUE:
NO.1 RING:
NO.2 RING:
OIL RING
LIMITS:
NO.1 RING:
NO.2 RING:
OIL RING
0.20· 0.35mm (.00788 •• 013in)
0.35· 0.50mm (.013 •. 019In)
0.20· 0.50mm (.00788 •. 019In)
0.8mm (.031In)
0.8mm (.031In)
1.0mm (.039in)
RING
CYLINOER-_.r-~"'""~
BORE
MEASURING PISTON RING END GAP
PIN
CYLINDERL----:::=J~~;~;~~~_
BORE
GAP
PISTON
GUIDE
REMOVING THE
PISTON PINS
3. Check the piston rings for damage, wear, seizure and
bends, replacing the rings if anything unusual is noted.
Always replace the piston rings when installing a new
piston.
NOTE: If
replacing piston rings, check the piston ring
gaps. New rings are packaged with detailed instructions
that often supersede the service manual text.
~ WESTERBEKE
Engines & Genefa/OfS
22