Chevrolet 10 Series 1970 Service Manual page 416

ENGINE-ELECTRICAL 6Y-24
Maintain tight c o v e r bands o r plugs on the d is-
tributor " sp in n er"
vacuum exists in this cham ber, dirt could be drawn
DISTRIBUTOR CONTACT POINTS
Cleaning
D irty contact points should be d ressed with a few
strokes o f a clean, fin e-cu t contact file . The file should
not be used fo r other m etals and should not be allow ed to
becom e grea sy o r d irty . N e v e r use em ery cloth to clean
contact points. Contact su rfaces, a fte r considerable use,
may not appear bright and smooth, but this is not n eces­
s a rily an indication that they a re not functioning sa tis­
fa c to rily . Do not attempt to rem ove all roughness nor
d ress the point su rfaces down smooth;
scale or dirt„
Badly burned o r pitted contact points should be r e ­
placed and the cause o f trouble determ ined so it can be
elim inated. High resista n ce o r loose connections in the
condenser circu it, o il o r foreig n m ateria ls on the contact
surfaces, im p rop er point adjustment or high voltages may
cause oxidized contact points. Check fo r these conditions
where burned contacts
balance condition in the ignition system , often the resu lt
o f too much o r too little condenser capacity, is indicated
where point pitting is encountered.
C A M LU B R IC A T O R
B R EA K ER PLATE
A T T A C H IN G S C R E W S
F ig . 2 i — Breaker P late and A tta c h in g Parts
com partm ent. Since a p artial
SERVICE OPERATIONS
m e re ly rem ove
a re experienced. An o u t-o f­
C O N T A C T SET
A T T A C H IN G
S C R E W
Q U IC K
D IS C O N N E C T
T ER M IN A L
thru a leaking co v e r band and upset the operation o f
the spinner valve,
Fig. 3 i—C h e ckin g Breaker Arm S pring Tension
Replacement
Four and Six Cylinder Engine Distributor
1. R elease distribu tor cap hold-down screw s, rem ove
cap and place it out o f work area.
2. R em ove rotor.
3. P u ll p rim a ry and condenser lead w ire s from contact
point quick disconnect term inal (fig . 2i).
4. R em ove contact set
point set from brea k er plate.
5. Clean break er plate o f o il smudge and dirt.
6. P la c e new contact point assem bly in position on
brea k er plate, install attaching screw .
CAUTIO N: C arefu lly wipe p ro tec tiv e film from
point set p r io r to installation.
NOTE: P ilo t on contact set must engage m atch­
ing hole in b rea k er plate.
7. Connect p rim a ry and condenser lead w ire s to quick
disconnect term in al on contact point set.
8. Check and adjust points fo r p rop er alignm ent and
break er arm spring tension (fig. 3i). Use an aligning
tool to bend stationary contact support if points need
alignm ent.
NOTE: The contact point p ressu re must fa ll
within specified lim its . Weak tension w ill cause
chatter resulting in arcin g and burning o f the
points and an ignition m iss at high speed, while
exc es siv e tension w ill cause undue w ear o f the
contact points, cam and rubbing block. B reak er
arm spring tension should be 19-23 ounces. The
contact point pressu re should be checked with a
spring gauge. The scale should be hooked to the
b rea k er le v e r and the pull exerted at 90 d egree s
to the b reak er le v e r as shown in F igu re 5i. The
reading should be taken just as the points sepa­
rate. The p ressu re can be adjusted by bending
attaching screw , lift contact
CHEVROLET TRUCK SERVICE MANUAL