Advertisement
9-12
GROUP
9-
IGNITION SYSTEM
CONDITION
CAUSED IY
Contacts should be replaced if the contact surfaces
are severely black, extremely dirty or show evidence
of excessive oil or grease; such as to cause the
voltage drop across the points to exceed 250 Milli
Volts, when the points are closed 'lllld the ignition
switched on.
Incorrect
alignment.
Incorrect voltage regulator setting.
Radio condenser installed to the distributor side
of the coil.
EXCESSIVE METAL
TRANSFER OR PITTING
Ignition condenser of improper capacity.
Extended operation of the engine at speeds other
than normal.
FIG. 20-
Breaker Point Inspection
The breaker point assembly con-
sists of the stationary point bracket
assembly,
breaker arm and the pri-
mary wire terminal.
Breaker points should be inspected,
cleaned and adjusted as necessary.
Breaker points can be cleaned with
chloroform and a stiff bristle brush.
Replace the breaker point assembly
if the contacts are badly burned or
excessive metal transfer between the
points is evident (Fig. 20). Metal
transfer is considered excessive when
it equals or exceeds the gap setting.
SECONDARY WIRING
Wipe the wire with a damp cloth
and check for fraying, breaks or
cracked insulation. Inspect the ter-
minals and weather seals for loose-
ness or corrosion. Replace any wires
that are not in good condition.
COIL
Wipe the coil with a damp cloth
and check for any cracks or other de-
fects.
DISTRIBUTOR CAP
Clean the distributor cap with a
soft bristle brush and mild cleaning
solvent or mineral spirits. Dry the
cap with compressed
air.
Inspect the
cap for cracks, burned contacts, per-
manent carbon tracks or dirt or cor-
rosion in the sockets. Replace the cap
if it is defective.
FIG. 21-
Cleaning Spark
Plug Electrode
ROTOR
Clean the rotor with a soft bristle
brush and mild cleaning solvent or
mineral spirits. Dry the rotor with
compressed air. Inspect the rotor for
cracks or burning. Replace the rotor
if it is defective.
DISTRIBUTOR VACUUM
CONTROL VALVE
Check that all vacuum lines are
correctly fitted and free from leaks.
Inspect valve for correct operation
as outlined in Part 2 prior to attempt-
ing any engine tuning procedures.
DISTRIBUTOR VACUUM
ADVANCE CONTROL VALVE
The distributor vacuum advance
control valve shown in
.
Fig. 23 is
fitted to 250 C.I.D. IV engines equip-
ped with air conditioning and to all
250 C.I.D. 2V, 302 C.I.D. and 351
C.I.D.
engines.
DESCRIPTION
The temperature sensitive vacuum
control valve is located in the engine
coolant outlet. Its function is to
regulate the ignition spark control
vacuum applied to the distributor at
engine idle.
OPERATION
During extended idle periods,
under high ambient temperature
conditions with the air conditioner
operating, the valve regulates the
ignition timing according to engine
temperature.
As the engine coolant temperature
rises above normal the vacuum
control valve is progressively opened
so applying vacuum to the dis-
tributor spark control unit and
advancing the ignition timing.
This has the effect of:
1. Increasing the engine idle speed.
2. Increasing the air flow through
the radiator.
3. Increasing coolant flow through
the engine.
4. Increasing thermal efficiency.
B 3104-A
FIG 22 - Distributor Vaccum
Control Valve
·
DISTRIBUTOR VACUUM
CONTROL VALVE TEST
(TEMPERATURE SENSING
VALVE)
1. Make certain that all vacuum
hoses are properly routed and in-
stalled.
2. Attach a tachometer to the en-
gine.
3. Bring the engine up to operating
temperature and be certain that the
choke plate is in the vertical position.
Engine must not be overheated.
4. Note the engine idle rpm with
transmission in neutral and carburettor
throttle in the curb idle positiorr.
5. Disconnect
·
the vacuum hose
from the intake manifold at the tern-
Advertisement
