Westerbeke W-46 - Page 31

INSPECTION/REPAIR
c. Grinding the crankshaft.
The crankshaft· journals and crankpins must be refinished to a
dimension smaller by 0.100 .teO 0~120mm (0.00394 to 0.00472in.)
than the undersize of bearings to be used.
Example: If 0.50mm (0.01969in.) undersize bearings are to
be used:
The journals must be refinished to
65-0.5-(0.100 to 0.120)
[2.55905-0.01969-(0.00394 to 0.00472in.)
The crankpins must be refinished to
58-0.5-(0.100 to 0.120)
[2.28346-0.01969-(0.00394 to 0.00472in.)
When grinding the crankpins and journals, be sure to reproduce
the same fillet radius (shoulder radius) as the original one.
Too small a radius of fillet will result in fatigue/failure of
crankshaft while too large a fillet radius will cause the
bearing to ride on the radius and thereby result in a bearing
failure.
CAUTION
Be extremely careful not to grind off the radius part beyond
the desired dimension. An over-ground radius part can be
corrected only by grinding off the shoulder face. If this
occurs, it will present problems in obtaining a proper end
clearance.
Also check the crankpin and journals for hardness. They should
have a hardness of 620 or more according to the Vickers Hard-
ness Number. If necessary,
re-harden the crankpins and Specifications Unit: mm (in.)
journals, and check them for
cracks by conducting a
magnaflux (magnetic
particle) test.
3. End Play.
Check the
play, as
thickness
bearing.
reached
plate.
Item
Journal width
for thrust
bearing
crankshaft for end
shown, by using a
guage at the thrust
If the limit is
replace the thrust
Specifications
Unit:
mm (in.)
Standard
Repair
limit
0.100-0.189
0.3
(0.00394- 0.00744) (0.012)
29
Undersize Journals to be refinished to
0.25
64
75-0.015 (2 54921-0.00059)
(0.0098)
. -0.035 . -0.00138
0.50
64 5 -0.015 (2 53937-0.00059)
(0.0197}
. -0.035 . -0.00138
Checking crankshaft end play