Buick LeSabre 1965 Service Manual page 608

1 0 - 3 8 IGNITION TIMING
ELECTRICAL SYSTEMS
FLYWHEEL DEGREES
TIMING
ITOTAL ADVANCE 1
AUTOMATIC
ADVANCE
DISTRIBUTOR SPARK ADVANCE
425CU.IN. ENGINE
(2-4 BBLCARB; AUTOMATIC TRANSMISSION)
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Figure 10-39—Distributor Spark Advance Chart-425 Engine with Dual 4-Bbl. and Auto. Trans.
NOTE: The service replacement
contact point set has the breaker
spring tension and point alignment
adjusted at the factory.
a. Removal of Contact
Point Set
1. Remove distributor cap by in-
serting a screwdriver in upper
slotted end of cap retainers, press
down and turn 90° counterclock-
wise. Push distributor cap aside
and remove rotor. Disconnect the
condenser and primary leads from
their terminal by loosening the
retaining screw.
2. Loosen two screws and lock
washers which hold the contact
point set in place. Then remove
point set.
b. Installation of Contact
Point Set
1. Apply a thin layer of high
temperature cam and ball bearing
lubricant to cam.
2. Slide contact point set over
boss on breaker plate and under
the two screw heads. Tighten two
screws and lock washers.
3. Install condenser and primary
leads.
NOTE: Leads must be properly
positioned so they will not come
in contact with bottom of weight
base or rotor.
4. If engine does not start readi-
ly, position contact arm rubbing
block on peak of cam lobe, insert
a 1/8" Allen wrench in adjusting
screw and turn screw in (clock-
wise) until contact points just
close. Then back s c r e w out
(counterclockwise) 1/2 turn (180°)
to obtain a point gap of approxi-
mately .016" for a preliminary
setting.
c. Adjustment of Contact
Points—Engine Running
NOTE: When adjusting contact
point dwell angle, always follow
the instructions which come with
the dwell meter.
1. Connect dwell tester leads:
red to distributor side of coil,
black to ground.
2. Turn selector switch to posi-
tion for 8-lobe cam. Turn ignition
switch on.
3. Start engine. Lift adjustment
window and insert 1/8" Allen
wrench in adjusting screw. See
Figure 10-41. Set dwell angle at
30 degrees.
4. After adjusting dwell angle,
always check ignition timing.
10-35 IGNITION TIMING
The timing mark is a groove
filled with yellow paint, which is
on the rear edge of the harmonic
balancer. On 401 and 425 engines,
the timing indicator, a part of the
timing chain cover, has three
ridges outlined with yellow paint.
These ridges indicate U. D. C.