Westerbeke W-46 - Page 24

INSPECTION/REPAIR
6. Replacing piston rings.
If the rings are replaced, the
gap width will exceed the stan-
dard value, but this is not
important, provided that the
service limit is not exceeded.
7. Piston pin bosses.
Check the piston pin bosses by
referring to the text which
follows.
Piston Pins, Piston Pin Bosses and
Piston Pin Bushings
1. Check the pin clearance in the
pin boss of the piston by com-
puting the difference between
the two diameter readings, one
taken on the pin and the other
in the boss. If the computed
difference (clearance) exceeds
the repair limit, replace the
piston pin with a new one.
Specifications
Unit: mm (in )
Item
Standard
Repair
limit
25
0
Piston pin
-0.006
diameter
<
0
·
984
_g.00024)
EB
Use a micrometer to measure piston
pin bushing and piston pin
2. Check the clearance of the pin in the bushing fitted to the small
end of the connecting rod by computing the difference between the
two diameter readings. If the computed difference (clearance)
exceeds the repair limit, replace the pin or the bushing,
whichever is badly worn.
Specifications
Unit· mm (in )
Item Standard
Repair
limit
Piston pin boss
25 +0.010
0
ID
(0.984 ~.00039)
Piston pin clear-
0-0.016
0.05·
ance in piston
(0- 0.00063)
(0.0020)
pin boss
Piston pin
25 +0.045
-0.020
bushingiD
(0 984+0'.00177)
• -0.00079
Piston pin clearance
0.020-0.051
0.08
(0.00079-
in piston pin bushing
0.00201)
(0.0031)
22