Chevrolet Light Duty Truck 1973, Service Manual

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6 Y -3 8 ENGINE ELECTRICAL
Fig. 1 8 i— S e ttin g P o in t O p e n in g
“HEX” type wrench into the adjusting screw head. (fig.
19i).
1. Preferred Method - Turn the adjusting screw until
the specified dwell angle is obtained as measured in
degrees (29° to 31°, 30° preferred) by a dwell angle
meter.
2. Alternate Method - Turn adjusting screw in
(clockwise) until the engine begins to misfire, then
turn screw 1 /2 turn in the opposite direction
(counterclockwise). This will give the approximate
dwell angle required. (Use only when meter is not
avaiable.)
O ff the Vehicle
1. Distributor Test Method:
a. With the distributor mounted on a distributor
testing machine, connect the dwell meter to the
distributor primary lead.
b. Turn the adjusting screw (fig. 19i) to set the
dwell angle to 30 degrees.
2. Test Light Method:
a. With the distributor mounted in a vise, connect
a testing lamp to the primary lead.
b. Rotate the shaft until one of the circuit breaker
cam lobes is under the center of the rubbing
block of the breaker lever.
c. Turn the adjusting screw clockwise (fig. 19i) until
the lamp lights, then give the wrench 1/2 turn in
the opposite direction (counter-clockwise) to
obtain the proper dwell angle.
Distributor Condenser
Performance Diagnosis
Fig. 19 i —A d ju s tin g D w e ll A n g le
The following four factors affect condenser performance
and, each factor must be considered in making any
condenser test.
1. Breakdown - A failure of the insulating material. A
direct short between the metallic elements of the
condenser. This prevents any condenser action.
2. Low Insulating Resistance (Leakage) - Low
insulation resistance prevents the condenser from
holding a charge. All condensers are subject to
leakage which, up to a certain limit, is not
objectionable.
3. High Series Resistance - Excessive resistance in the
condenser circuit due to broken strands in the
condenser leak or to a defective connection. This
will cause burned points and ignition failure upon
initial starts and at high speeds.
4. Capacity - Capacity is determined by the area of
the metallic elements and the insulating and
impregnating materials.
For a complete check of the condenser, use a tester
which will check for all of the above conditions. Follow
the instructions given by the manufacturer of the test
equipment. Condenser capacity should be 18-: 23
microfarads.
Replacement
Six Cylinder Engine D istributor (Fig. 13i)
1. Release distributor cap hold-down screws, remove
cap and place it out of the work area.
2. Remove rotor. On Van models, also remove dust
shield.
3. Disconnect condenser lead wire from contact point
quick-disconnect terminal.
4. Remove condenser attaching screw, lift condenser
from breaker plate and wipe breaker plate clean.
5. Install new condenser using reverse of procedure
outlined above.
LIGHT DUTY TRUCK SERVICE MANUAL