Chevrolet 70 1969 Series, Shop Manual

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ENGINE ELECTRICAL 6Y-13
With pointer and timing mark aligned, rotor
segment should point toward mark made on dis­
tributor body in Step 1 above. Instead, rotor seg­
ment may point 180 degrees away from mark; in
this case engine must be rotated one complete
revolution and timing mark realigned.
3. With timing mark and pointer aligned and
with rotor segment pointing to No. 1 spark plug
wire, points should just begin to open. Loosen dis­
tributor mounting clamp cap screw and turn dis­
tributor housing clockwise until points close. Re­
move high tension wire from center socket in dis­
tributor cap. Turn on ignition switch and hold end
of high tension wire (still connected to coil) 1/4-
inch from a ground; then turn distributor housing
counterclockwise until a spark jumps the gap be­
tween high tension wire and ground. When spark
occurs, points are open. Hold distributor in this
position and tighten mounting clamp cap screw.
Turn ignition switch off and install distributor cap.
Install high tension wire in center socket in cap.
M A N U A L A D V A N C E A D J U S T M E N T
1. After engine has been thoroughly warmed
up, drive vehicle using grade of fuel expected to be
used in service. Engine should not ping or knock
excessively under load and full throttle.
2. If knock is evident, loosen distributor
mounting clamp cap screw (fig. 3) and turn dis­
tributor housing clockwise to retard spark until
knock is eliminated.
N O T E : Manual advance should be set to obtain
the best possible engine performance with the par­
ticular grade of gasoline being used.
DISTRIBUTOR
Distributor is mounted on top center of cylin­
der block at rear end and is driven by the engine
camshaft by means of spiral cut gears. A gasket
is used between flange on distributor housing and
cylinder block. Distributor is held in place by a
mounting clamp and cap screw (fig. 3). Drive gear,
secured on lower end of distributor shaft by a
rivet, has a hexagonal opening in lower end which
engages end of oil pump shaft to drive the oil pump.
Model number is stamped on the housing.
Figure 3— Distributor and Ignition Coil Installed ITypicalI
CONTACT POINT REPLACEMENT
R E M O V A L
1. Release distributor cap hold-down screws,
remove cap and place it out of work area.
2. Remove rotor.
3. Pull primary and condenser lead wires
from contact point quick-disconnect terminal (fig. 4).
4. Remove contact set attaching screw, lift
contact point set from breaker plate.
5. Clean breaker plate of oil, smudge and dirt.
Figure 4 — Breaker Plate and Attaching Parts
R evised 1968
CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L