s
g
11
e
g
s,
n
he
;a-
nd
he
1al
ed
led
lial
the
Main bearings
and
connecting-rod bearings
(1) Inspect
the
bearing shells, paying particular
attention
to
the
tri-metal surface for evi-
dence
of
flaking. Burnt,
pitted
or
wiped
shells and shells showing
bad
contact
pattern
must
be replaced.
(2)
Mike
the
main bearings and connecting-rDd
bearings and also
the
crankshaft
journals
and crankpins
to
determine,
on
the
basis
of
ID readings and OD readings,
the
amount
of
oil clearance available in
each
fit. (A press
gauge can be used instead.)
Measuring main bearing I D
Measuring connecting rod (crankpin) bearing
When reading
the
bearing ID,
whether
it
is
a main bearing
or
a crankpin bearing, be
sure
that
the
bearings shells are tight in the
usual manner,
with
the
cap bolts
torqued
to
the
specification.
If
the
clearance
determined
by
computing
with
the
ID and
OD readings exceeds
the
limit, replace the
bearings or,
if
mere
bearing replacement
does
not
produce
the
specified clearance,
ENGINE
grind
the
crankshaft journals and crankpins
to the
next
undersize and use
the
undersize
bearings.
Timing gears
and
hydraulic
pump
gear
Inspect these gears for
tooth
contact
pattern,
tooth
wear and damage and,
as
necessary,
replace them. Inspect
the
Oldham coupling
groove formed
of
the
end
of
the
pump
gear;
if
this groove is disfigured
or
damaged, replace
the
gear.
Camshaft
(1)
If
the
running clearance between
the
camshaft journal and its hole provided in
the
block is
too
large,
then
either
the
camshaft
or
the
block
must
be replaced.
This clearance is
to
be
determined
by
measuring
journal
diameter
and hole dia-
meter.
(2)
Visually inspect
the
cam faces for damage,
and check each cam for cam height by
miking. Replace the camshaft
if
any
of
the
cams
is
in bad
condition
in regard
to
cam
height and face.
Measuring cam height on engine camshaft
Fuel-injection-pump camshaft
Inspect and check this camshaft
as
in
the
case
of
engine camshaft. Additionally, inspect
the
shaft
end, which is shaped for Oldham coupling:
the
camshaft
must
be replaced
if
the
coupling
end is disfigured.
2-21
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