Figure 11B-88. Removing Upper Main
Bearing Shell
by-pass valve to make sure it is operat-
ing freely.
F i g u r e 11B-89. Removing Upper Rear
After removal, clean the bearings and
M a i n Bearing Shell
pitting,
for
scoring,
inspect
them
flaking, etching, loss of babbitt or signs
ings is in no way impaired and they will
of
overheating
(see
Figure
11B-90).
give many additional hours of trouble
The lower bearing shells, which carry
free operation.
the load, will normally show signs of dis-
tress before the upper bearing shells.
Inspect the backs of the bearing shells
babbitt plated bearings may
However,
for bright spots which indicate they have
develop minute cracks or small isolated
b e e n moving in the bearing caps or bear-
cavities o n t h e b e a r i n g s u r f a c e d u r i n g
are
ing
supports.
If
such
spots
These are character-
engine operation.
present, discard the bearing shells.
istics of and are not detrimental to this
type of bearing. They should not be re-
Measure the thickness of the bearing
minor
surface
these
placed
for
shells at point "C", 90 from the parting
imperfections since function of the bear-
F i g u r e 11B-90. Comparison of Main Bearing Shells
11B-58