Chevrolet Corvette 1963 Repair & Tune-Up Manual page 123

116 ENGINE AND ENGINE REBUILDING
#1 CYLINDER
AT T.D.C.
#6 CYLINDER
AT T.D.C.
1980 and later timing mark alignment
isfactory repair. Remember that the total de-
flection of the chain (installed) should not ex-
ceed about Va".
Most engines are equipped with the nylon-
toothed camshaft sprocket. If you drive the
car hard, or if the original sprocket failed pre-
maturely, it may be wise to replace the ny-
lon-toothed sprocket with the hardened-iron
sprocket available through Chevrolet deal-
ers. Make sure that you explain your inten-
tions when purchasing the timing compo-
nents, so that the chain and gears are properly
matched. An all-metal cam gear produces a
little more noise than the nylon-toothed gear,
but will last considerably longer.
When installing the new timing compo-
nents, be sure to align the timing marks of
both the cam gear and crank gear. DO NOT
rotate the engine while the timing chain is
removed. Torque the camshaft sprocket bolts
to 20 ft. Ibs. and install the timing cover as
previously outlined.
Camshaft
REMOVAL AND INSTALLATION
Remove the radiator and shroud. Remove the
fan and fen pulley. Use a gear puller to re-
move the harmonic balancer. Remove the oil
pan, water pump, and the timing chain cover.
On the top of the engine, remove the bat->
tery cables, carburetor(s)/fuel injection unit,
(on 1982 and later models, remove the TBI
units and the TBI mounting plate as an as-
sembly), distributor shielding, and distribu-
tor. Be sure to mark the distributor so that it
will not be necessary to retime the engine.
When the intake manifold has been cleared
of obstructions, remove it to expose the valve
lifters. Cover the open area and remove the
fuel pump and push rod.
Remove the rocker arm covers and rocker
arms and withdraw the pushrods and lifters.
Keep the pushrods and lifters in order so that
they can be returned to their original posi-
tions. Remove the grille, timing chain, and
camshaft sprocket. Loosen the engine side
mount through bolts and jack up the front of
the engine slightly. This is necessary for the
camshaft to clear the radiator brace. Run two
5
/ie-18x4 in. bolts into the camshaft from the
engine. Do not rotate the crankshaft until the
camshaft has been replaced and the sprocket
and chain correctly installed and aligned.
Alignment procedures are the same as those
shown within the previous Timing Chain re-
placement procedure.
Reverse the operation to complete the re-
placement. Lubricate the cam and lifters with
E.O.S. additive before installation. Make an
initial and final valve adjustment as previ-
ously described.
INSPECTION
Completely clean the camshaft with solvent,
paying special attention to cleaning the oil
holes. Visually inspect the cam lobes and
bearing journals for excessive wear. If a lobe
is questionable, have the cam checked at a
reputable machine shop; if a journal or lobe
is worn, the camshaft must be reground or
replaced. Also have the camshaft checked for
straightness on a dial indicator.
NOTE: If a cam journal is worn, there is a
good chance that the bushings are worn.
Camshaft Bearings
REMOVAL AND INSTALLATION
If excessive camshaft wear is found, or if the
engine is being completely rebuilt, the cam-
shaft bearings should be replaced. A special
puller tool is necessary.
NOTE: The front and rear bearings should
be removed last, and installed first. Those
bearings act as guides for the other bear-
ings and pilot.
1. Drive the camshaft rear plug from the
block.
2. Assemble the removal puller tool with
its shoulder on the bearing to be removed.
Gradually tighten the puller nut until the
bearing is removed.
3. Remove the remaining bearings, leav
ing the front and rear for last. To remove
these, reverse the position of the puller, so