Specifications

1-14
GROUP 1-ENGINES AND EXHAUST SYSTEMS
Assemble the lifter assembly and
check for freeness of operation by
pressing down on the push rod cup.
The lifters can also be checked with a
hydraulic tester to test the leak-down
rate. Follow the instructions of the
test unit manufacturer.
TIMING CHAIN
Clean all parts in solvent and dry
them with compressed air. Inspect
the chain for broken links and the
sprockets for cracks, and worn or
damaged teeth. Replace all the com-
ponents if any one item needs re-
placement.
CAMSHAFT
CLEANING AND INSPECTION
Clean the camshaft in solvent and
wipe dry. Inspect the camshaft lobes
for scoring, and signs of abnormal
wear. Lobe wear characteristics may
result in pitting in the general area of
the lobe. This pitting is not detri-
mental to the operation of the cam-
shaft, therefore, the camshaft should
not be replaced until the lobe lift
loss has exceeded 0.005 inch.
The lift of camshaft lobes can
only be checked with the camshaft
installed in the engine. Refer to
"Camshaft Lobe Lift."
Check the distributor drive gear
for broken or chipped teeth.
REPAIRS
Remove light scuffs, scores, or
nicks from the camshaft machined
surfaces with a smooth oil stone.
CRANKSHAFT
CLEANING
Handle the crankshaft with care
to avoid possible fractures or dam-
age to the finished surfaces. Clean
the crankshaft with solvent, then
blow out all oil passages with com-
pressed air.
INSPECTION
Inspect main and connecting rod
journals for cracks, scratches,
grooves, or scores.
Measure the diameter of each
journal in at least four places to de-
termine out-of round, taper, or un-
dersize condition (Fig. 21).
On engines used with a manual-
shift transmission, check the fit of
the clutch pilot bushing in the bore
of the crankshaft. The bushing is
pressed into the crankshaft and
PILOT BUSHING
Telescope Gauge
FLYWHEEL A132O-A
FIG. 22-Clutch Pilot Bushing
Wear Check
should not be loose. Inspect the
inner surface of the bushing for wear
or a bell-mouth condition. Check the
ID of the bushing (Fig. 22). Replace
the bushing if worn or damaged.
Inspect the pilot bearing, when
used, for roughness, evidence of
overheating or loss of lubricant. Re-
place if any of these conditions are
found.
REPAIRS
Dress minor imperfections with an
oil stone. Reface severely marred
journals.
If the journals exceed the wear
limit, they should be refinished to
size for the next undersize bearing.
Refinishing Journals. Refinish the
journal to give the proper clearance
with the next undersize bearing. If
the journal will not "clean up" to
give the proper clearance with the
maximum undersize bearing avail-
able, replace the crankshaft.
Always reproduce the same jour-
nal shoulder radius that existed
originally. Too small a radius will
result in fatigue failure of the crank-
shaft. Too large a radius will result
in bearing failure due to radius ride
of the bearing.
After refinishing the journals,
chamfer the oil holes, then polish
the journal with a No. 320 grit
polishing cloth and engine oil.
Crocus cloth may be used also as a
polishing agent.
CONNECTING RODS
The connecting rods and related
parts should be carefully inspected
and checked for conformance to
specifications. Various forms of en-
gine wear caused by these parts can
be readily identified.
A shiny surface on the pin boss
side of the piston usually indicates
that a connecting rod is bent or the
piston pin hole is not in proper re-
lation to the piston skirt and ring
grooves.
Abnormal connecting rod bear-
ing wear can be caused by either a
bent connecting rod, an improperly
machined crankpin, or a tapered
connecting rod bore.
Twisted connecting rods will not
create an easily identifiable wear
pattern, but badly twisted rods will
disturb the action of the entire pis-
ton, rings, and connecting rod as-
sembly and may be the cause of
excessive oil consumption.
CLEANING
Remove the bearings from the rod
and cap. Identify the bearings if they
are to be used again. Clean the con-
necting rod in solvent, including the
rod bore and the back of the inserts.
Do not use a caustic cleaning solu-
tion. Blow out all passages with com-
pressed air.
INSPECTION
Inspect the connecting rods for
signs of fractures and the bearing
bores for out-of-round and taper.
If the bore exceeds the recom-
mended limits and/or if the con-
necting rod is fractured, it should
be replaced.
Check the piston pin to connect-
ing rod bushing clearance. Replace
the connecting rod if the bushing is
so worn that it cannot be reamed or
honed for an oversize pin.
Replace defective connecting rod
nuts and bolts.
After the connecting rods are as-
sembled to the piston, check the con-
necting rods for bend or twist on a
suitable alignment fixture. Follow the
instructions of the fixture manufac-
turer. If the bend and/ or twist is ex-
cessive, the connecting rod should be
straightened or replaced.
PISTONS, PINS, AND RINGS
CLEANING
Remove deposits from the piston
surfaces. Clean gum or varnish from
the piston skirt, piston pins, and rings
with solvent. Do not use a caustic
cleaning solution or a wire brush to
clean pistons. Clean the ring grooves
with a ring groove cleaner (Fig. 23).
Make sure the oil ring slots (or holes)
are clean.