Camshaft; Camshaft Gear Runout; Camshaft Gear Backlash Check - Ford 1956 Truck Shop Manual

22
Chapter l-General Engine Overhaul, Inspection, and Repair
REFERENCE POINT
•
TAKE UP SLACK ON lEFT sIDe OF CHAIN. ESTABLISH A REFERENCE
POINT AND MEASURE DISTANCE A. THEN. TAKE UP SLACK ON
RIGHT SIDE OF CHAIN AND FORCE lEFT SIDE OF CHAIN OUT
WITH
HiE
FINGERS AND MEASURE DISTANCE B. DEflECTION
IS A. MINUS 8. 6608
Fig. 26-Timing Chain Dellection-Typical
shaft to move all the slack to the left side. With the
fingers, move the chain toward the original reference
point and measure the distance between the reference
point and the chain. If the difference between the two
measurements (which is the slack) exceeds '/. inch,
replace the timing chain and/or sprockets.
Inspect the sprockets for worn or damaged teeth and
the chain for broken links. Replace the sprockets or
the timing chain as deemed necessary by inspection.
However, it
is
recommended that all the components
be replaced if anyone
item needs replacement
Fig. 27-Camshalr Gear Sack/ash Check
Fig.
28-Cam.halr Gear Runour
b. Timing Gears.
The following checks apply to the 302 and 332 cubic
inch engines.
(1) BACKLASH.
Check the backlash between the
camshaft gear and the crankshaft gear with a dial in-
dicator (fig. 27). Hold the gear firmly against the block
while making the check. The backlash limits are listed
in the Specification Section.
(2) RVNOVT CHECK. Check the camshaft and
crankshaft gear runout with a dial indicator (fig. 28).
The camshaft gear run out should not exceed 0.008 inch
and the crankshaft gear runout should not exceed 0.007
inch. If the gear runout is excessive, remove the gear
and clean any burrs from the shaft, or replace the gear
and/or gears. It is good practice to replace both gears
when either gear needs replacing.
(3) INSPECTION. Clean the gears
in solvent. Note
the condition of the gear teeth. If the teeth are scored
or the contact pattern on the teeth is uneven, replace
the gear and/or gears.
c. Camshaft.
The camshaft should be replaced when any lobe
(intake or exhaust) is worn to such an extent that the
lift loss exceeds 0.005 inch. The tappet which mates
with the worn lobe must also be replaced.
(1) CAlif LOBE LIFT CHECK. This procedure is
similar to the procedure for checking valve timing.
Loosen the valve rocker arm adj usting screw, then slide
the rocker arm assembly to one side and secure it in