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.
POINT ALIGNMENT, DWELL,
DWELL VARIATION, AND CAM LOBE AC-
Proper tension of the breaker point spring is an
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-
gine. Excessive spring tension can cause rapid
a. With test leads connected to the distrib-
rubbing-block, cam, and contact wear while in-
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
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
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
adjust the point spacing until the dwell
m e t e r indicates the specific degrees of
Spring tension scale reads in either
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
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.
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-
formation on point-dwell and point-gap
e. Note reading on tension scale under the
``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
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.