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8-52
IGNITION SYSTEM
IGNITION TIMING
To obtain maximum engine performance, the dis-
tributor must be correctly positioned on the engine
to
give the proper ignition timing.
The ignition timing test will indicate the timing of
the spark at NO. 1 cylinder at idle (only).
Test procedures are as follows:
(1) Disconnect the vacuum hose at the distributor.
(2)
Connect the secondary lead of the Power Tim-
ing Light to the NO. 1 spark plug, red primary lead
to the positive terminal of the battery and the black
primary lead to the negative battery terminal.
NOTE: Do not puncture the wires, boots or nipples
with test probes. Always use adapters. Puncturing
spark plug wires with a probe will damage the wires.
The probe can separate the conductor and cause
high resistance. In addition, breaking the rubber
insulation may permit secondary current to arc to
ground.
(3)
Start the engine and set the idle to specifica-
tions, engine at normal operating temperature (trans-
mission in neutral).
(4)
Using a timing light, observe the positions of
the timing mark on the crankshaft damper and check
against the specifications.
(5)
Loosen the distributor hold down clamp screw
and rotate the distributor housing so that the speci-
fied timing mark on damper aligns with the specified
"BTC" mark on the timing plate. Moving the distrib-
utor "clockwise" advances the timing and "counter-
clockwise" retards the timing.
(6)
Tighten the distributor hold down clamp screw
after the timing has been
set and recheck the timing
adjustment with a Power Timing Light.
vacuum hose to the distributor.
(7) When the ignition timing is correct, connect the
NOTE: As the engine speed is increased, the timing
mark should move down on the vibration dampener
below the pointer if advance units are functioning.
DISTRIBUTOR
(1) Disconnect the vacuum hose at the distributor.
(2) Disconnect the primary lead wire at the coil.
(3)
Unfasten the distributor cap retaining clips and
lift
off the distributor cap.
(4)
Scribe a mark on the edge of the distributor
housing to indicate the position of the rotor as refer-
ence when reinstalling the distributor.
(5)
Remove the distributor hold-down clamp screw
and the clamp.
(6)
Carefully
lift
the distributor from the engine.
Shaft and Bushing Wear Test
(1)
Remove the distributor rotor.
(2)
Disconnect the primary lead wire at the distrib-
utor terminal. DO NOT LOOSEN the inner nut that
holds the movable contact arm tension spring to the
terminal post.
(3)
Clamp the ribbed section of the distributor
housing lightly in a vise equipped with soft jaws and
attach the dial indicator
to
the body of the distributor
with the indicator plunger arm resting against the
movable contact arm at the rubbing block and with
the rubbing block of the contact arm on the highest
point of the cam lobe (Fig. 1).
Removal
P
-.-----
TOOL
62x326
Fig. 1-Shaft
and Bushing Wear rest
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