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24
Chapter I-General Eng ine Repair
OVERLAY GONE
Fig. 35-Bearing failure-Tapered Journal
shaft
counterweight
adjoining
the bearing which is
being checked
for clearance.
The
shaft
can
also be
supported
by
a
thin rubber pad between the
cap
insert
and
the journal
of
two bearings that
are
not being
checked.
Tighten these bearing
cap
bolts just enough
to
hold the
crankshaft
up
against
the upper bearing
inserts.
NOTE:
It
is
n
ecessary
to
support
the
weight of
the
crankshaft
when
checking
,nain
bearing clearances,
in order
to prevent
the weight of
the crankshaft
front
compressing
the Plastigage, therelJY providing an
erroneous reading.
Place
a
piece
of
Plastigage, the
full
width
of the
bearing
cap
insert,
on
the
bearing surface (or on
the
crankshaft journal if
the engine
is inverted)
about
Fig.
36-Beoring Showing Radius Ride
Fig
.
37-Bearing
Bright
Spots-Improper Seating
V.-inch off center.
Install the
cap and
tighten
the
bolts
to
specifications.
CAUTION: Do not turn the
crankshaft
while the
Plastigage
is
in
place
.
R
emove
the
cap, and check the
width of the Plasti-
gage,
at
the widest
point,
with
the Plastigage
scale (fig.
38).
If
the clearance is
not
within
limits, try
another
selective fit bearing
to bring the clearance
within the
desired limit. Red marked bearings increase clearance,
blue marked bearings
decrease
clearance. If the
various
selective
fit bearings do not bring the clearance
within
specifications,
it
will be
necessary to
regrind
the crank-
shaft
journals
and
install
undersize
bearing inserts.
NOTE:
Normally,
Ina
in
bearing
journals
wea
r evenly
and are not out-oj-round.
However,
if
a bearing is
being
fi-
tted
to an out-o I-round
journal,
be sure to
fit
th.e
bearing to the
maximum
diameter of
the
journal.
If
the
bearing
is fitted to the minimum
dia-
fig. 3B-Measuring Plosfigoge
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