Ford COUGAR 1968 Shop Manual page 435

PART 9-1
-
General Ignition Service
DISTRIBUTOR SPARK
ADVANCE TEST-ARE236
AND ARE14-16 TESTERS
The spark advance is checked to
determine if the ignition timing ad-
vances in proper relation to engine
speed and load.
Check the contact dwell. If the
contact'dwell is not within specifica-
tions, adjust the breaker points.
Check the breaker arm spring
tension and adjust it, if necessary.
The dual advance distributor has
two independently operated spark
advance systems. Each system is ad-
justed separately.
Adjust the centrif-
ugal advance before adjusting the
vacuum advance.
Centrifugal Advance
1. Operate the distributor in the
direction of rotation (counterclockwise)
and adjust the speed to the initial
rpm setting listed in the specifications.
Move the protractor scale s o that one
of the flashes lines up with the zero
degree mark.
2. Slowly increase the rpm to the
setting specified for the first advance
reading listed in the specifications.
If the correct advance is not indi-
cated a t this rpm, stop the distribu-
tor and bend one spring adjustment
bracket to change its tension (Fig.
14). Bend the adjustment bracket
away from the distributor shaft to
decrease advance (increase spring
tension) and toward the shaft to in-
crease advance (decrease spring ten-
sion). After the adjustment is.made,
identify the bracket.
3. After an adjustment has been
made to one spring, check the mini-
mum advance point again.
4. Operate the distributor a t the
specified rpm to give an advance
just below the maximum. If this ad-
vance is not to specifications, stop
the distributor and bend the other
spring bracket to give the correct
advance.
5. Check the advance a t all rpm
settings listed in the specifications.
Operate the distributor both up and
down the rpm range.
V a c u u m Advance (Single or
Dual
D i a p h r a g m )
1. Connect the test set vacuum
SPACING WASHERS
8201 1-8
FIG. 15
- Vacuum Advance
Adjustment
4. If the advance is incorrect,
change the calibration washers be-
tween the vacuum chamber spring
and nut (Fig. 15). After installing or
removing the washers, position t h e
gasket in place and tighten the nut.
The addition of a washer will de-
crease advance and the removal of a
washer will increase advance.
5. After one vacuum setting has
been adjusted, the others should be
checked. Do
not change the original
rpm setting when going to a differ-
ent vacuum setting. If the other set-
tings are not within limits, there is
incorrect spring tension, leakage in
the vacuum chamber and/or line, or
the wrong fibre stop has been in-
stalled in the vacuum chamber of
the diaphragm housing.
T o check the diaphragm for leak-
age, (either, or both on dual diaphragm
distributors).
Install the distributor on a dis-
tributor tester. Do not connect the
vacuum line to the distributor.
Remove the vacuum line from the
distributor. Adjust the vacuum pres-
sure of a distributor tester to its
maximum position. Hold your hand
over the end of the tester's vacuum
hose and note the maximum reading
obtained. Do
not exceed
2 5
inches
Hg.
If the maximum. reading is 25
inches Hg or less, connect the test-
er's vacuum line to the vacuum fit-
ting on the diaphragm to be tested
without changing any of the adjust-
ments.
The maximum gauge reading
should not be less than it was above.
If it is less, the diaphragm is leaking
and should be replaced.
DISTRIBUTOR DUAL
D I A P H R A G M TEST
line to the fitting on the diaphragm.
2.
Set the test set a t 0 degrees
V a c u u m Advance
2. Using a tachometer, increase
the idle speed by setting on the first
step of the fast idle cam.
3. Using a timing light observe
ignition timing setting.
4. Connect the carburetor vacuum
line to the outer diaphragm. The tim-
ing should advance immediately. Ad-
just if necessary.
V a c u u m Retard
1. Readjust the engine idle speed
to 550-600 rpm.
2. Using a timing light observe
the spark timing.
3. Remove the plug from the mani-
fold vacuum line and connect the line
to the inner diaphragm.
4. The timing should retard im-
mediately. Replace the dual diaphragm
unit if the retard portion is out of
calibration, the advance portion can-
not be calibrated to specifications, or
either of the diaphragms are leaking.
DISTRIBUTOR VACUUM
ADVANCE CONTROL
VALVE (DECELERATION
VALVE) TEST
1. Connect a tachometer to the
engine and bring engine to normal
operating temperature.
2. Connect a vacuum gauge to the
distributor vacuum line. Be sure the
tee has the same inside diameter as
the distributor vacuum line to pre-
vent false pressure readings.
3. If the engine is equipped with
a dash pot, take the plunger in a de-
pressed position so that it does not
contact the throttle lever a t idle
speed.
4. Clamp closed the vacuum line
that connects, the deceleration valve
to the intake manifold.
5. Remove the distributor vacuum
tube a t the distributor and clamp the
hose closed.
6. With engine operating at spe-
cified idle rpm (transmission in neu-
tral and parking brake on), set the
ignition timing to specifications.
7. If necessary, adjust carbure-
tor to obtain specified engine speed
and air-fuel mixture. The distributor
vacuum must be below six inches of
mercury a t idle speed.
8.
Remove the clamps from the
vacuum tubes and reconnect the vacuum
tube to the distributor. Remove the
distributor vacuum advance control
valve cover (Fig. 16).
advance, 0 vacuum, and a t 1000 rpm. 1. Disconnect the vacuum lines 9. Increase -engine speed to 2000
3.
Check the advance a t the first from both the outer and inner dia- rpm in neutral and hold speed approxi-
vacuum setting given in the specifi- phragms. Plug the line removed from mately five s e c ~ n d s . Re!ease the
cations. the inner diaphragm. throttle and note the distributor