Chevrolet 10 Series 1968, Service Manual, Page: 350 / 713

ENGINE 6-3
ADJUST DWELL
ANGLE SETTING OR
POINT OPENING
F ig . 3—Distributor (In Line)
2. Clean rotor and inspect for damage or deterioration.
Replace rotor where necessary.
3. Replace brittle, oil soaked or damaged spark plug
wires. Install all wires to proper spark plug. Proper
positioning of spark plug wires in supports is im ­
portant to prevent cross-firing.
4. Tighten all ignition system connections.
5. Replace or repair any wires that are frayed, loose
or damaged,,
M agnetic Pulse (B re a k e rle ss) D istributor
There are no moving parts in the ignition pulse amp­
lifie r, and the distributor shaft and bushings have
permanent type lubrication, therefore no periodic main­
tenance is required for the magnetic pulse ignition
system. Refer to Section 6Y for an analysis of problems
and/or repair procedures encountered on the Transis­
torized (Magnetic Pulse) ignition system.
Standard (Breaker Point) Distributor (Figs. 3 or 4)
1. Check the distributor centrifugal advance mechanism
by turning the distributor rotor in a clockwise direc­
tion as far as possible, then releasing the rotor to
see if the springs return it to their retarded position.
If the rotor does not return readily, the distributor
must be disassembled and the cause of the trouble
corrected.
2. Check to see that the vacuum control operates freely
by turning the movable breaker plate counterclock­
wise to see if the spring returns to its retarded
position. Any stiffness in the operation of the vacu­
um control will affect the ignition timing. Correct
any interference or binding condition noted.
3.
Examine distributor points and clean or replace if
necessary. /
• Contact points with an overall gray color and
only slight roughness or pitting need not be
replaced.
• Dirty points should be cleaned with a clean point
file.
Use only a few strokes of a clean, fine-cut con­
tact file. The file should not be used on other
metals and should not be allowed to become greasy
or dirty. Never use emery cloth or sandpaper to
Fig. 4—Distributor (T yp ica l V8)
clean contact points since particles will embed and
cause arcing and rapid burning of points. Do not
attempt to remove all roughness nor dress the
point surfaces down smooth. Merely remove scale
or dirt.
• Clean cam lobe with cleaning solvent, lubricate
cam lobe with "Delco Remy Cam and Ball Bearing
Lubricant" or its equivalent and rotate cam lub­
ricator wick 1/2 turn.
• Replace points that are burned or badly pitted.
NOTE:
Where prematurely burned or badly
pitted points are encountered, the ignition sys­
tem and engine should be checked to determine
the cause of trouble so it can be eliminated.
Unless the condition causing point burning or
pitting is corrected, new points will provide no
better service than the old points. Refer to
Section 6Y for an analysis of point burning or
pitting.
• Check point alignment (fig. 5) then, adjust distri­
butor contact point gap to .019” (new points) or
.016" (used points). Breaker arm rubbing block
must be on high point of lobe during adjustment.
NOTE:
If contact points have been in service,
they should be cleaned with a point file before
adjusting with a feeler gauge.
• Check distributor point spring tension (contact
point pressure) with a spring gauge hooked to
breaker lever at the contact and pull exerted at 90
degrees to the breaker lever. The points should be
closed (cam follower between lobes) and the read­
ing taken just as the points separate. If not within
limits, replace.
ROTOR
CAM
LUBRICATOR
REPLACEMENT
CAUTION!
NEVER OIL
CAM LUBRICATOR —
REPLACE WICK
WHEN NECESSARY
ADJUST SQUARELY
AND JUST
TOUCHING LOBE
OF CAM
LOCATOR
(RO U N D )
CENTRIFUGAL
ADVANCE
MECHANISM
CAM
LUBRICATOR
LOCATOR
(SQ U AR E)
CHEVROLET TRUCK SERVICE MANUAL