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IGNITION SYSTEM
8-49
Vacuum Advance Curve
If only the vacuum advance curve is to be checked,
connect the tester vacuum pump hose to the distrib-
utor vacuum advance unit and perform operations
1 through 4 under "centrifugal Advance Curve."
Then proceed as follows:
(1) Turn tester vacuum pump "ON." Adjust vac-
uum pump regulator to vacuum test specifications. See
"Specifications" and observe arrow flashes on tester
degree ring to determine degrees of advance.
(2)
If the vacuum advance is below or above speci-
fications, replace the vacuum advance unit. Retest the
vacuum advance curve.
INSTALLATION OF DISTRIBUTOR
(1) Position the distributor on the engine. Make
certain the rubber "0" ring seal is in the groove of
the distributor shank.
(2)
Carefully engage the distributor drive gear with
the camshaft drive gear so that when the distributor
is installed properly, the rotor will be in line with the
previously scribed line on the cylinder block.
NOTE: If the engine has been cranked while
dis-
tributor is removed, it will be necessary to estab-
lish the proper relationship between the distributor
shaft and the Number 1 piston position as follows:
(3)
Rotate the crankshaft until the number one
piston is at the top of the compression stroke. The
mark on the inner edge of the crankshaft pulley
should be in line with the "0" (TDC) mark on the
timing chain case cover.
(4) Rotate the rotor to a position just ahead of
the number one distributor cap terminal.
(5) Lower the distributor into the opening, en-
gaging the distributor gear with the drive gear on the
camshaft. With the distributor fully seated on the en-
gine, the rotor should be under the cap number 1 tow-
er with the ignition contacts just separating.
(6)
Install the distributor cap (make sure all high
tension wires "snap" firmly in the cap towers).
(7) Install the hold-down arm screw and tighten it
finger tight.
(8)
Attach the primary lead wire to the coil.
NOTE:
Do
not connect the distributor vacuum hose
at this time.
(9)
Connect the secondary lead of the Power Tim-
ing Light to the Number 1 spark (using the proper
adaptor) 'and the 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 cable cap nipples or
spark plug covers to make a contact. Use the proper
adapters.
(10)
Start the engine and run at idle speed.
(11)
Rotate the distributor housing so that the tim-
ing mark on the crankshaft damper is aligned with
the "BTC" mark on the chain case cover. Refer
to
"Specifications" (Moving the distributor housing
counter-clockwise advances the timing and clockwise
retards the timing.)
(12) Tighten the distributor hold down arm screw
after timing has been set and recheck the timing ad-
justment with a Power Timing Light.
(13) When the timing is correct, connect the vac-
uum hose to the distributor.
(14) Remove the timing light from the engine.
Ignition Timing (with
C-744
Test Lamp)
(1)
Connect the C-744 test lamp between the dis-
tributor primary terminal and the battery positive
post.
(2)
Turn the engine until the number
6
exhaust
valve is just closing; continue turning the engine
slowly until .the specified degree mark on the crank-
shaft pulley is at the pointer.
(3)
Loosen the distributor clamp bolt so that the
distributor housing can be rotated with a slight drag,
then turn the distributor in the normal rotation un-
til the test lamp lights.
(4)
Turn the distributor against normal distribu-
tor rotation until the test lamp goes out.
NOTE:
If
the test lamp lights immediately when
connected, turn the distributor against normal
dis-
tributor rotation until the light goes out.
(5)
Tighten the distributor clamp bolt securely and
remove test lamp.
If
the operation is performed
properly the engine is timed to specifications.
NOTE:
If
the engine i s turned beyond the timing
mark, continue turning the engine for two full
revolutions of the crankshaft; this will place the
distributor rotor in approximately the initial posi-
tion.
CAUTION:
DO
NOT reverse the rotation of the
crankshaft if you have passed the timing mark as
this would affect valve timing and distributor tim-
ing.
IGNITION
COIL
The ignition coil is designed to operate with an ex-
ternal ballast resistor. When testing the coil for out-
put, include the resistor in tests. Inspect the coil for
external leaks and arcing.
Test the coil according to the coil tester Manufac-
turer's instructions. Test the coil primary resistance.
Test the ballast resistor resistance. Test the coil sec-
ondary resistance. Replace any coil or ballast resistor
that does not meet specifications.
Every time an ignition coil
is
replaced because
of
a burned tower, carbon tracking, or any evidence of
arcing at the tower, the nipple or boot on the coil
end of the secondary lead should be replaced. Any
arcing at the tower will carbonize the nipple
so that
placing it on a new coil will invariably cause another
coil failure.
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