NOTE
NOTE
On distributors equipped with two
On distributors where two sets of
sets of breaker points, one set must
breaker points are used test the re-
be held open while testing the other
sistance of each set of points sepa-
set. A thick piece of clean fiber may
rately by holding or blocking one set
be placed between the contacts to
o p e n while testing the other set.
hold them open.
BREAKER POINT SPRING TENSION TEST.
BREAKER
POINT ALIGNMENT, DWELL,
DWELL VARIATION, AND CAM LOBE AC-
Proper tension of the breaker point spring is an
CURACY.
important factor in obtaining normal breaker as-
sembly life and maintaining full ignition system
T h e breaker point alignment is checked as
efficiency throughout the speed range of the en-
follows :
gine. Excessive spring tension can cause rapid
a. With test leads connected to the distrib-
rubbing-block, cam, and contact wear while in-
u t o r (as in the Distributor Resistance
sufficient spring tension may allow the points to
Test), turn tach-dwell switch to position
bounce at high speeds which generally results in
which corresponds to type of distributor
arcing and burning of the points and causes the
being tested (4, 8 or 6 cylinder).
engine to misfire. (See Figure 5)
b. Place RPM toggle switch in the 2500 rpm
position.
Procedure:
c. A d j u s t distributor speed to 1000 rpm.
d. Observe the slight arc appearing between
a. Turn small knob in center of spring ten-
the breaker points. If the points are prop-
sion scale until the adjustable "riding"
erly aligned the arcing will appear in the
pointer engages the pointer of the ten-
center of the contacts when viewed from
sion scale and moves it to the zero mark.
above or from the side.
b. With dwell meter calibrated and distrib-
e. R e d u c e distributor speed to 200 rpm.
utor test leads connected to distributor as
for distributor resistance test, place hook
BREAKER POINT DWELL.
of tension scale over movable lever near
the contact point. (See Figure 5.)
A d j u s t the breaker point dwell as follows:
Observe the dwell meter and if necessary
NOTE
adjust the point spacing until the dwell
m e t e r indicates the specific degrees of
Spring tension scale reads in either
dwell.
direction from zero and maybe used
(1) O n distributors equipped with dual
to push the point lever-arm when
points it will be necessary to adjust
necessary.
t h e dwell on each set individually.
To isolate each set for adjustment, the
c. Slowly pull spring tension tester at right
other set may be blocked open by in-
angles to point lever-arm and gradually
serting a clean piece of fiber between
increase the pull exerted.
the contacts.
d. Watch dwell meter for indication of con-
(2) S e e CONTACT POINT GAP AND
tact separation by the reading falling to
DWELL paragraph for additional in-
zero.
formation on point-dwell and point-gap
e. Note reading on tension scale under the
adjustment.
``riding" pointer, Compare reading with
distributor test specifications.
BREAKER POINT DWELL VARIATION.
f. Hold points open to approximately the rec-
ommended gap with the spring tension
The breaker point dwell variation is checked as
scale and slowly let them close. If scale
follows :
reading decreases noticeably from pre-
a. While watching dwell meter, vary the dis-
vious reading before the points close, it is
tributor speed from 200 to 1750 rpm. A
p r o b a b l e the pivot requires lubrication
dwell variation in excess of 2 degrees in-
dicates worn distributor shaft or bushings.
