Chevrolet 10 Series 1970 Service Manual page 419

a. W ith the distribu tor mounted on a distribu tor
testing machine, connect the dwell m eter to the
distributor p rim a ry lead.
b. Turn the adjusting
dw ell angle to 30 d egrees.
2. T e s t Light Method:
a. W ith the distribu tor mounted in a vis e , connect a
testing lamp to the p rim a ry lead.
b. Rotate the shaft until one o f the circu it breaker
cam lobes is under the center o f the rubbing
block of the b reak er le v e r.
c. Turn the adjusting screw clockw ise (fig. 9i) until
the lamp lights, then give the wrench 1/2 turn in
the opposite direction (cou n ter-clock w ise) to ob­
tain the p ro p er dwell angle.
DISTRIBUTOR CONDENSER
Performance Diagnosis
T h e fo llo w in g fou r fa c to r s a ffe c t c o n d en ser p e r f o r m ­
a n ce , and each fa c to r m ust b e c o n s id e r e d in m aking any
c o n d e n s e r te s t.
1. Breakdown - A . failu re o f the insulating m ateria l. A .
d ire c t short between the m etallic
condenser. T h is prevents any condenser action.
2. Low Insulating Resistance
tion resistan ce' p revents the condenser from holding
a charge. A ll condensers are
which, up to a certain lim it, is not objectionable.
3. High S e rie s Resistance - E xcessive
the condenser c ircu it due to broken strands in the
condenser leak or to a d efective connection. This
w ill cause burned points and ignition failu re upon
in itial starts and at high speeds.
4. Capacity - Capacity is determ ined by the area o f the
m etallic elem ents and the insulating and im p reg ­
nating m aterials.
F or a com plete check o f the condenser, use a te ster
which w ill check fo r all o f the above conditions. Follow
the instructions g i v e n
test equipment. Condenser capacity should be .18-.23
m icro fa ra d s.
Replacement
Four and Six Cylinder Engine Distributor (Fig. 2i)
1. R e lea s e distributor cap hold-down screw s, rem ove
cap and place it out o f the work area.
2. R em ove rotor.
3. Disconnect condenser lead w ire from contact point
quick-disconnect term in al.
4. Rem ove condenser attaching screw , lift condenser
fro m b reak er plate and wipe break er plate clean.
5. Install new condenser using r e v e r s e of procedure
outlined above.
Eight Cylinder Engine Distributor
1. Rem ove distribu tor cap.
2. Loosen condenser lead attaching screw (fig . 4i) and
lift out condenser lead clip.
3. Rem ove screw holding condenser bracket to break er
plate and slide condenser from bracket.
4. T o replace condenser r e v e r s e the above procedure.
NOTE: Make sure that new condenser lead is
installed in prop er position (fig . 6i).
s crew (fig. 9i) to set the
elem ents o f the
(Leakage) - Low insula­
subject to leakage
resistan ce in
by the m anufacturer of
DISTRIBUTOR
Removal
1. R elease the distributor cap hold-down screw s, r e ­
m ove the cap and place it clea r o f the work area.
NOTE: If n ecessary,
from the distributor cap a fter firs t m arking the
cap tow er for the lead to No. 1 cylin der. Th is
w ill aid in the reinstallation of leads in the cap.
2. Disconnect the distributor p rim a ry lead from the coil
term inal.
3. Scribe a realignm ent mark on the distributor bowl
and engine in line with the rotor segment.
4. Disconnect external connections (vacuum line, d rive
cables, etc.) rem ove the distributor hold-down bolt
and clamp, rem ove the distributor from the engine.
Note position o f vacuum advance mechanism re la tive
to the engine.
CAUTIO N: A void rotating the engine with the
distribu tor rem oved as the ignition tim ing w ill
be upset.
DISASSEMBLY
It is advisable to place the distributor in a distribu tor
testing machine o r synchroscope p rio r to disassem bly.
When mounting d istribu tors fo r tests, fir s t secure the
g e a r in the test d rive mechanism, then push the d is trib ­
utor housing downward toward the gear to take up any end
play between the gear and the housing.
NOTE: When
their low er shaft support bushing located in the
engine block
adapter should be used to insure the shaft w ill
run true in its housing.
T est the distribu tor fo r variation o f spark, c o rre c t
centrifu gal and vacuum advance and condition of contacts.
T h is test w ill g ive valuable inform ation on distributor
the
condition and indicate parts replacem ent which may be
n ecessary. Check the area on the brea k er plate just b e­
neath the contact points. A smudgy line indicates that oil
o r crankcase vapors
points.
Four and Six Cylinder Engines
R e fe r to Figure lOi.
1. Rem ove the rotor.
2. Rem ove t h e
screw s, detach the unit from the distribu tor housing.
3. Disconnect the p rim a ry and condenser leads from
the contact point quick disconnect term in a l, rem ove
the contact point set attaching screw , condenser at­
taching screw .
from the break er plate.
4. Rem ove the break er plate attaching screw s, rem ove
the break er
(fig. lOi).
NOTE: Do not disassem ble breaker plate any
further.
5. R em ove the r o ll pin retaining the driven gear to the
mainshaft, slide the gea r from the shaft.
ENGINE-ELECTRICAL 6Y-27
rem ove secondary leads
testing distributors that
(6 cylin der engines, a
have been present between the
vacuum control assem bly
Rem ove the point set and condenser
plate from the distribu tor
CHEVROLET TRUCK SERVICE MANUAL
have
special
retaining
housing