CRANKSHAFT
Inspect the bearing journals.
If
they are scored and
cannot be smoothed out by dressing down, the bear-
ing journals should be refinished to use nearest avail-
able undersize bearings or a new crankshaft should
be installed. If a worn main bearing journal cannot be
fitted with an available precision type undersize bear-
ing, then refinish
it
to the next undersize. If a worn rod
journal cannot be fitted by installing new bearing
inserts (forged rod), then refinish
it
to take the next
corresponding undersize bearing insert available.
Whenever making major repairs on the engine, always
inspect the drilled passages of the crankshaft. Clean
them to remove any foreign material and to assure
proper lubrication of the connecting rods.
Shot Peening:
On older model engines, shot peening
is required to prevent failures. When the shaft is
machined, followthedatatoshot peen each crankpin
fillet.
1. Almen gauge reading: 0.01 2A
2.
Mask off connecting rod bearing areas.
3.
Peen with 0.019 inch (0.49 mm) diameter cast
steel shot.
4.
Peen for
30
seconds on each crankpin fillet.
Undersize bearings and connecting rods are availa-
ble to rework the shaft to 0.010,0.020, and
0.030
inch
undersize.
BEARINGS
With camshaft and crankshaftremoved, usea microme-
ter to measure diameter of bearing journals. Use a dial
bore gauge or a telescopic gauge and micrometer to
measure inside diameter of bearings. Refer to
Dimen-
sion
and
Clearance Section
to determine if clearances
are within specifications.
Any bearing that is scored, chipped, pitted
beyond the specified limits must be replaced.
or worn
7/32"
(5.6
mrn)
FROM
OUTSIDE
ALIGN HOLE IN
BEARING
------------
WITH
HOLE
'
IN
BEARING
BORE
CAPSHAFT BEARING
FIGURE
71.
FRONT
CAMSHAFT
BEARING
Removal of the camshaft bearings requires complete
disassembly of the engine. Use a press or a suitaliie
driver to remove bearings. Support casting to avoid
distortion and to avoid damaging the bearing bore dur-
ing removal and installation.
Replacement camshaft bearings are precision type
which do not require line reaming or line boring after
installation. Clean outside
of
the bearing and bearing
bore in the block. Before installing cam bearings use
Locktite Bearing Mount
on
outside diameter of bearing.
Use a combination bearing driver to install bearings.
Place the bearing
on
the crankcase over the bearing
bore with the lubricating hole (front only) in the proper
position. Be sure to start the bearing straight. Press in
the front bearing flush with the outside end of the bear-
ing bore. Front cam bearing oil hole must line up with
oiling hole in cyliner block (Figure 71). Press in the rear
camshaft bearing until past the ignition plunger hole.
Lubricate bearing surfaces with oil after installing.
New crankshaft main bearings are precision type which
do
not
require line reaming or line boring after installa-
tion. Use a press or asuitable driver to remove bearings.
Support casting to avoid distortion and to avoid damag-
ing the bearing bore during removal and installation.
Before installing main bearings, expand bearing bore by
placing the casting in an oven heated to
2OOOF
(94°C).
If
practical, cool the precision bearing to shrink
it.
..
Before installing the front main bearing, use the towelette
included with the bearing kit to clean the outside of the
bearing and bearing bore in the block.
-1
Breathing vapor from towelette and
prolonged
contact
with skin can
be
harmful. Be sure area is well ventilated.
51
To Next Page
Loading...
Need help?
General
