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PART 1-3
-
MEDIUM AND HEAVY DUTY V-8 ENGINES
1-69
INSTAlliNG P!o,tigage
1 5.58_8
FIG.
68-lnstalling
and
Measuring
Plastigoge-
Engine in Chassis
engine is on
a
work
stand,
omit step
I
and follow
steps
2-5. In step 4,
if
the
engine is on a work
stand
it
is not
necessary
to
support
the
crankshaft
because the engine wi
ll
be inverted.
Also in
step
4 place the
Plastigage
on
the
crankshaft journal (Fig. 67) in-
stead of on the bearing
su
rface
if the
engine is on a work stand.
1.
Drain
the crankcase.
Remove
the
oil level dipstick, the oi
l
pan, the
oil pump and
pick-up
tube assembly.
and the intermediate
drive shaft.
2.
Replace
onc bearing at a time,
h~aving
the other
bearings securely
fastened.
Remove
the
main
bearing
cap
10
which new bearings are to be
installed.
Insert
the upper bearing re-
moval tool (tool 633
1)
in
the
oil hole
in the crankshaft.
Rotate
the crank-
shaft
in
the
direction
of engine rota-
tion
to
force the bearing out of the
block.
3.
To
install the upper
main
bear-
ing,
place
the
plain
end
of
the bearing
over the
shaft
on the locking
tang
side
of the block. Using tool 6331.
rotate the crankshaft in the opposite
direction
of engine rotation until the
bearing
seats
itself. Remove
the
tool.
Replace
the cap bearing. Clean the
crankshaft journal and bearings.
4.
Support Ihe crankshaft so its
weight will nOI compress
the
Plasti-
:age and provide an erroneous read-
.
ng. Position
a
small jack
so it
will
bear against the counterweight ad-
joining
the
bearing which is being
checked.
Place a piece of Plastigage
on the bearing
surface
the full
width
of the bearing
cap
and about
!4
inch
off
center
(Fig. 68). Insta
ll
the
cap
and tighten
the
bolts to
specifications.
Do
not
tum
the
crdnkshaft while
the
P lastigage is
in
place.
Remove
the
cap, then
using
the
Plasligage
scale,
check the width of Ihe Plasligage at
the widest point in order to
get
mini-
mum clearance. Check
Ihe
Plasligage
at
the
narrowest
point
in order 10 get
the maximum clearance. The diffe r-
ence between the two readings is Ihe
taper.
If the clearance is less than the
specified
limits, try two red bearing
halves
or a combination
o
f
red and
blue
dependi ng upon
the
condition.
If
the
standard
bearings do
not
bring
the clearance
within
the desired lim-
its, refinish
the crankshaft journal.
then
install
undersize
bearings.
S. After the bearing has been
checked
and found to be satisfactory.
apply a
light
coat
of
engine
oi
l
to the
journal
and
bearings, then install the
bearing cap. Tighten the cap bolts
to
specifications.
6.
If the rear main bearing is
re-
placed,
replace
the retainer
seal
(292
engine) or
lower
seal
in the
cap (302
or
332 engine)
and
the
side seals.
The
upper oil
seal
(in the block) can-
not
he
replaced
with
the
crankshaft
installed.
7. Install the
intermediate
drive
shaft
,
oil pump, and inlet tube and
SCFeen
assembly. Install the oil pan.
Fi
ll
the crankcase.
8. Operate
the engine
at
fast idle
and check for oi[ pressure
and
oil
leaks.
CONNECTING ROD BEARING
REPLACEMENT
L
Drain
the crankcase.
Remove
the oi
l
level
dip Slick,
the
oil
pan,
the
oi
l
pump and
pick-up
tube assembly.
and the intermediate drive shaft.
Re-
move
the cap from the connecting
rod
to which new bearings
are to be
installed
and
remove the
bearing
in-
sert
. Push
the piston up
in
the cylin-
der,
then
remove
the
bearing
insert
from
the
connecti ng rod. Clean
the
crankshaft
journals,
the cap, and the
upper half
of
Ihe
bearing bore.
2.
Install the new bearings
in
the
connecting rod
a
nd
cap.
Pull the
con-
necting
rod assembly dow
n
finn[y
on
the
crankshaft
journal. Place
a
piece
of
P[astigage o
n
the
lower
bearing
su
rface, the full width
of
the
cap and
about
!4
inch off center.
Install the
cap and tighten the connecting rod
nuts
to
45-50
foot-pounds
to rque.
Do
not
turn
the
crankshaft while the
P)astigage
is in
place.
3,
Remove the cap,
then
using the
Plastigage
scale check the width of
the
Plastigage at
the
widest
point
in
order 10 get
the minimum clearance.
Check the Plastigage at
the
narrow-
est point in order
10
gel the
maximum
clearance.
The
difference belween the
two
readings is the taper.
If
the clearance
is less than the
specified
limits,
try
two
red
bearing
halves or a combination of red
and
blue
depending upon the condition.
If
the
standard bearings
do
not bri ng
the clearance within the desired lim-
its, refinish the crankshaft journal,
then
install undersize bearings.
After the bearing clearance
has
been
checked and
found
to
be satis-
factory,
apply a
light
coat of engine
oil
10
the journal and bearings,
then
install the connecting
rod
cap.
Tight-
en the nuts to 45-50 foot-pounds
torque.
4_ Repeat
the procedure for the
remaining connecting
rods
that
re-
quire
new
beari ngs.
S.
After all
the
bearin
gs
Ihal
required
replacement
have
been
re-
placed, inslall the
intermediate drive
shaft. oil
pump.
and
inlet
tube and
screen
assembly.
Install
the oi
l
pan.
Fill
Ihe crankcase .
6.
Operate Ihe
engine at
fast
id
le
and
check for
oil
pressure
and
oil
leaks.
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