Ignition Systems; Periodic M Aintenance; Distributor Contact Points - Chevrolet 10 1971 Series Chassis Service Manual

M a inte na nce and A d j u s t m e n t s ....................................................... 6Y-15
P e r io d ic M a in te n a n c e ....................................................................6Y-15
Service O p e r a t io n s .............................................................................6Y-15
D is tr ib u to r C ontact P o in t s ...........................................................6Y-15
C l e a n in g ......................................................................................... 6Y-15
R e p l a c e m e n t ................................................................................ 6Y-15
Setting D w ell A n g l e ....................................................................6Y-16
D is tr ib u to r C o n d e n se r....................................................................6Y-18
P e rfo rm a n c e D i a g n o s is .......................................................... 6Y-18

PERIODIC M AINTENANCE

The distributor breaker points and spark plugs are the
only ignition system components that require periodic
service. The remainder of the ignition system requires
only periodic inspection to check operation of the units,
tighteness of the electrical connections, and condition of
the wiring. When checking the coil, test with a reputable
tester.
Breaker type distributors are equipped with cam
lubricator and should have the wick replaced at the same
time contact point set is replaced. It is not necessary to
lubricate the breaker cam when using a cam lubricator.
Do not attempt to lubricate the wick - Replace when

DISTRIBUTOR CONTACT POINTS

Cleaning
Dirty contact points should be dressed with a few
strokes of a clean, fine-cut contact file. The file should
not be used for other metals and should not be allowed to
become greasy or dirty. Never use emery cloth to clean
contact points. Contact surfaces, after considerable use,
may not appear bright and smooth, but this is not neces­
sarily an indication that they are not functioning satis­
factorily. Do not attempt to remove all roughness nor
dress the point surfaces down smooth; merely remove
scale or dirt.
Badly burned or pitted contact points should be replaced
and the cause of trouble determined so it can be elimi­
nated. High resistance or loose connections in the con­
denser circuit, oil or foreign materials on the contact
surfaces, improper point adjustment or high voltages may
cause oxidized contact points. Check for these conditions
where burned contacts are experienced. An out-of-balance
condition in the ignition system, often the result of too
much or too little condenser capacity, is indicated where
point pitting is encountered.

IGNITION SYSTEMS

Page
MAINTENANCE A N D ADJUSTMENTS
SERVICE OPERATIONS
IN D E X
R e p l a c e m e n t ................................................................................6Y-18
D i s t r i b u t o r .........................................................................................6Y-18
R e m o v a l .........................................................................................6Y-18
D i s a s s e m b l y ................................................................................6Y-19
C le an in g and I n s p e c t io n .......................................................... 6Y-20
A s s e m b l y ......................................................................................6Y-20
I n s t a l l a t i o n ...................................................................................6Y-20
Spark P lu g and W ir e S e r v i c e .................................................... 6Y-21
necessary. When installing a new wick, adjust its position
so the end of the wick just touches the lobe of the breaker
cam.
Distributor shaft lubrication is accomplished by a res­
ervoir of lube around the mainshaft in the distributor body
or through a hinge cap oiler on governor type units.
Spark plugs should be removed, inspected, cleaned and
regapped at tune-up. Defective plugs should be replaced.
The low and high tension cables should be examined
carefully for brittle or cracked insulation and broken
strands. Defective insulation will permit missing or
cross firing of the engine. Connections should be clean
and tight.
Replacement
Six Cylinder Engine Distributor
1. Release distributor cap hold-down screws, remove
cap and place it out of work area.
2. Remove rotor and dust shield.
3. Pull primary and condenser lead wires from contact
point quick disconnect terminal (fig. li).
4. Remove contact set attaching screw, lift contact point
set from breaker plate.
5. Clean breaker plate of oil smudge and dirt.
6. Place new contact point assembly in position on
breaker plate, install attaching screw.
Pilot on contact set must engage match­
NOTE:
ing hole in breaker plate.
7. Connect primary and condenser lead wires to quick
disconnect terminal on contact point set.
8. Check and adjust points for proper alignment and
breaker arm spring tension (fig. 2i). Use an aligning
tool to bend stationary contact support if points need
alignment.
ENGINE-ELECTRICAL 6Y-15
Page
10-30 CHEVROLET TRUCK SERVICE MANUAL