Chevrolet 30 Series 1967 Service Manual page 370

ENGINE-ELECTRICAL 6Y-22
F ig . 8 i—Inaccurate Gauging of Rough Points
adequate lubrication for cam. Do not apply ad­
ditional grease to cam surface.
7. Start engine and check point dwell and ignition
timing.
SETTING DWELL ANGLE
Four and Six Cylinder Engine Distributors
The point opening of new points can be checked with a
feeler gauge, but the use of a feeler gauge on rough or
uncleaned used points is not recommended since accurate
mechanical gauging cannot be done on such points (fig.
Contact points must be set to the proper opening.
Points set too close may tend to burn and pit rapidly.
Points with excessive separation tend to cause a weak
spark at high speed. Proper point setting for all models
are:
.019" for new points
.016" for used points
F ig . lO i—Setting Point O pening
New points must be set to the larger opening as the
rubbing block will wear down slightly while seating to the
cam. Contact points should be cleaned before adjusting if
they have been in service.
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.
i).
3. Loosen the contact support lock screw.
8
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.
. After checking and adjusting the contact point opening
6
to specifications, the cam angle or dwell should be
checked with a dwell angle meter if such equipment
is available
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 variation
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
(see Specifications for proper dwell
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