Chevrolet 10 Series 1970 Service Manual page 326

ENGINE 6-4
LO C A T O R
(R O U N D )
C E N T R IF U G A L
A D V A N C E
M E C H A N IS M
C A M
L U B R IC A TO R
R E PLA C E M E N T
A D J U S T S Q U A R E LY
A N D JUST
T O U C H IN G LOBE
O F C A M
F ig . 5 —D is trib u to r (V 8)
• D irty points should be cleaned with a clean point
file .
Use only a few strokes o f a clean, fine-cu t con­
tact file . The file
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 or sandpaper to
clean contact points since p a rtic le s w ill embed and
cause arcin g and rapid burning of points. Do not
attem pt to rem ove a ll roughness nor d re s s the
point su rfaces down smooth. M e re ly rem ove scale
o r dirt.
• Clean cam lobe with cleaning solvent and rotate
cam lu bricator w ick
applicable).
• Replace points that are burned o r badly pitted.
NOTE:
W here p rem atu rely
pitted points a re encountered, the ignition sys-
LATERAL
M ISA LIG N M EN T
CORRECT LATERAL MISALIGNMENT BY
BENDING FIXED CONTACT SUPPORT
NEVER BEND BREAKER LEVER
Fig . 6 —P o in t A lig n m e n t
LO C A T O R
(S Q U A R E )
C A M
LU B R IC A TO R
C A U T IO N !
N E VE R O IL
C A M L U B R IC A T O R —
REPLACE W IC K
W H E N N E C E SSA R Y
should not be used on other
end fo r end (o r 180° as
burned o r badly
PROPER
LA TER A L A LIG NM ENT
tem and engine should be checked to determ ine
the cause o f trouble so that it can be elim inated.
Unless the condition causing point burning or
pitting is corrected , new points w ill provid e no
b etter s e rv ic e than the old points.
Section 6Y fo r an analysis o f point burning or
pitting.
• Check point alignm ent (fig . 6) then, adjust d is tr i­
butor contact point gap to .019" (new points) o r
.016" (used points).
must be on high point o f lobe during adjustment.
NOTE:
If contact points have been in s e rv ic e ,
they should be cleaned with a point file b efo re
adjusting with a fe e le r gauge.
• Check distribu tor
point p ressu re) with a spring gauge hooked to
brea k er le v e r at the contact and pull exerted at 90
d eg rees to the break er le v e r . The points should be
closed (cam fo llo w e r between lobes) and the rea d ­
ing taken just as the points separate. If not within
lim its , replace.
E x cessive point pressu re w ill cause ex cessive
w ear on the points, cam and rubbing block. Weak
point p ressu re perm its
resu lting in arcing and burning o f the points and
an ignition m iss at high speed.
4. Install ro to r and distribu tor cap. P r e s s a ll w ire s
firm ly into cap tow ers.
Service Battery and Battery Cables
1. M easure the sp ecific g ra vity o f the ele c tro ly te in
each c e ll (fig. 7). If it is below 1.230 (co rrected to
80°F.) rech arge with a slow
d esired , further check battery.
2. Connect a voltm eter a cro ss the battery term in als
and m easure the term in al voltage o f the battery
during cranking (disconnect the co il p rim a ry lead
at the negative term in al during this check to preven t
engine from firin g ). If the term in al voltage is less
than 9.0 volts at room tem peratu re, approxim ately
80° ± 20°F., the battery should be further checked.
See Section 6Y fo r further tests.
F ig . 7 —Testing S p e c ific G r a v ity o f B atte ry
R e fe r to
B rea k er arm rubbing block
point spring tension (contact
bouncing o r clatterin g,
rate ch arger, o r if
CHEVROLET TRUCK SERVICE MANUAL