Turn the ignition switch on.
DISTRIBUTOR TESTS ON VEHICLE
If the voltmeter reading is 0.25 volt or less, the primary circuit
DISTRIBUTOR SHAFT END PLAY
from coil to ground is satisfactory.
If the shaft end play is not to specifications, check the location of
If the voltmeter reading is greater than 0 25 volt. test the
the gear on the shaft. The shaft end play can be checked with the
voltage drop between each of the following:
distributor installed on the engine.
· The coil and the breaker point connections of the coil to
Mount a dial indicator on the distributor so that the indicator tip
distributor primary wire.
rests on the top of the distributor shaft.
· The movable breaker point and the breaker plate.
Push the shaft down as far as it will go and set the dial indicator
· The breaker plate and the distributor housing.
· The distributor housing and engine ground.
Pull the distributor shaft upward as far as it will go and read the
Turn the ignition switch off. Disconnect the voltmeter leads
end play. The end play should be within specifications with the
distributor removed or installed.
Check the coil on a coil tester by following the manufacturer's
instructions Check for ohms resistance both primary and secondary
Disconnect the distributor primary wire at the coil. Connect a
Also check the amperage draw both with the engine idling and
short jumper wire to the DIST terminal of the coil and the distributor
stopped. These checks should all fall within ,specifications
primary wire Connect the red lead to the jumper wire.
Connect the black lead to a good ground on the engine.
Dwell Angle Check
The secondary wires include the wires connecting the distributor
Disconnect the distributor vacuum line. Connect the tester.
cap to the spark plugs and the wire connecting the center terminal of
Turn the test control knob to the set position.
the distributor cap to the center terminal of the Ignition coil.
Adjust the set control knob until the needle on the dwell meter
These wires are the radio resistance-type which filter out the
lines up with the set line.
high frequency electrical impulses that are the source of ignition noise
Start the engine and let it idle.
interference. The resistance of each wire should not exceed 5000
Turn the cylinder selector to the figure corresponding to the
ohms per inch. When checking the resistance of the wires or
number of lobes on the cam of the distributor.
setting ignition timing, do not puncture the wires with a probe.
Read the dwell angle on the dwell meter and compare the
The probe may cause a separation in the conductor.
reading to specifications.
Turn off the engine.
When removing the wires from the spark plugs, grasp and twist
If the dwell angle was below the specified amount, the breaker
the moulded cap. then pull the cap off the spark plug Do not pull on
point gap is too large. If the dwell angle was above the
the wire because the wire connection inside the cap may become
specified amount, the breaker point gap is too small.
separated or the insulator may be damaged.
If the dwell is to specifications, turn the test selector knob to the
To check the spark intensity at the spark plugs, proceed as follows:
OFF position and disconnect the tester leads and jumper wire: then
Disconnect a spark plug wire. Check the spark intensity of
connect the distributor vacuum line.
one wire at a time
Install a terminal adapter in the terminal of the wire to be
checked. Hold the adapter approximately 3/16 inch from the
exhaust manifold and crank the engine, using a remote starter
switch. The spark should jump the gap regularly.
If the spark intensity of all the wires is satisfactory, the coil,
Dwell Angle Adjustment
condenser, rotor, distributor cap and the secondary wires are
If the dwell angle is not within specifications, proceed as follows:
Remove the coil high tension lead from the distributor and
If the spark is good at only some wires, check the resistance of
the faulty leads.
Remove the distributor cap and place it out of the way.
If the spark is equal at all wires, but weak or intermittent, check
Connect an auxiliary starter switch in the circuit.
the coil, distributor cap and the coil to distributor high tension wire.
Loosen the breaker point assembly retaining screw near the
breaker point contacts.
With the ignition on, crank the engine with an auxiliary starter
Release the auxiliary starter switch and tighten the breaker point
assembly attaching screw.
Spark Plug Test
Since the adjustrnent may have changed when the attaching
Inspect, clean, file the electrodes and gap the plugs. After the
screw was tightened, crank the engine again with the auxiliary
proper gap is obtained, check the plugs on a testing machine.
starter switch and check the dwell. When the dwell is properly
Compare the sparking efficiency of the cleaned and gapped plug with
adjusted, remove the jumper wire, auxiliary starter switch and
a new plug. Replace the plug if it fails to meet 70 percent of the new
tester leads and install the distributor cap and coil high tension
Connect the distributor vacuum line.