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ENGINE-ELECTRICAL 6Y-22
ADJUST DWELL
ANGLE SETTING OR
POINT OPENING
Fig. lOi—Settihg Point Opening
To adjust the contact point opening:
1. If necessary, align points (fig. 9i) by bending the
fixed contact support. Do not bend the breaker lever.
Do not attempt to align used points; replace them
where serious misalignment is observed. Use an
aligning tool if available.
2. Turn or crank the distributor shaft until the breaker
arm rubbing block is on the high point of the cam
lobe. This will provide maximum point opening.
3. Loosen the contact support lock screw.
4. Use a screw driver (fig. lOi) to move the point sup-
port to obtain a .019" opening for new points and a
.016" opening for used points.
5. Tighten the contact support lock screw and recheck
the point opening.
6. After checking and adjusting the contact point open-
ing to specifications, the cam angle or dwell should
be checked with a dwell angle meter if such equip-
ment is available (see Specifications for proper dwell
angle). If the cam angle is less than the specified
minimum, check for defective or misaligned contact
points or worn distributor cam lobes. The variation
in cam angle readings between idle speed and 1750
engine rpm should not exceed 3°. Excessive varia-
tion in this speed range indicates wear- in the
distributor.
NOTE:
Cam angle readings taken at speeds
above 1750 engine rpm may prove unreliable
on some cam angle meters.
Eight Cylinder Engine Distributor
On the Vehicle
With the engine running at idle and operating tempera-
tures normalized, the dwell is adjusted by first raising
the window provided in the cap and inserting a "Hex"
type wrench into the adjusting screw head (fig. Hi).
WINDOW
r- "HEX" TYPE
WRENCH
ADJUSTING
SCREW
Fig. -lli—Adjusting Dwell Angle
1.
Preferred Method - Turn the adjusting screw until
the specified dwell angle is obtained as measured in
degrees (28° to 32°, 30° preferred) by a dwell angle
meter.
2. Alternate Method - Turn adjusting screw in (clock-
wise) until the engine begins to misfire, then turn
screw 1/2 turn in the opposite direction (counter-
clockwise). This will give the approximate dwell
angle required.
(Use only when meter is not
available.)
Off 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. lli) 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. lli) until
the lamp lights, then give the wrench 1/2 turn in
the opposite direction (counter-clockwise) to ob-
tain the proper dwell angle.
DISTRIBUTOR CONDENSER
PERFORMANCE DIAGNOSIS
The following four factors affect condenser perform-
ance, 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 insula-
tion 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
CHEVROLET CHASSIS SERVICE MANUAL
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