4.2L Distributor Component Replacement - Jeep 1987 Wrangler Workshop Manual

ELECTRICAL
IGNITION SYSTEM - MOTORCRAFT (6-Cyl. Engine)
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Slide the distributor shaft down into the engine
and position the distributor vacuum advance
mechanism housing in approximately the same
location (in relation to the surrounding engine
components) as when removed. Align the scribe
mark on the distributor housing with the
corresponding scribe mark on the cylinder
block.
NOTE: It may be necessary to rotate the oil
pump shaft with a long flat-blade screwdriver to
engage the oil pump drive tang, but the rotor
should align with the position of the No. 1
terminal when the distributor shaft is down in
place.
Install the distributor holddown clamp and bolt,
but do not tighten the bolt.
CAUTION: If the distributor cap is incorrectly
positioned on the distributor housing, the cap or
rotor may be damaged when the engine is
rotated.
Install the distributor cap with the ignition wires
on the distributor housing. Ensure the pickup
coil wire rubber grommet in the distributor
housing aligns with the depression in the
distributor cap and that the cap fits on the rim of
the distributor housing.
NOTE: Two different diameter screws are used
to retain the distributor cap.
Apply AMC/Jeep Silicone Dielectric Compound,
or equivalent, to the connector terminal blades
and cavities. Connect the distributor primary
wiring connector.
CAUTION: Do not puncture the spark plug wires
or boots to make a connection. Use the proper
adapters.
Connect a timing lamp to the No. 1 spark plug.
NOTE: The timing case cover has a socket
adjacent to the timing degree scale for use with a
magnetic timing probe. Ignition timing may be
checked by inserting the probe through the
socket until it rests on the vibration damper.
The probe is calibrated to compensate for the
probe socket location, which is 9 . 5 ° ATDC.
Eccentricity of the damper will properly space
the magnetic probe. The timing degrees are
indicated on a meter.
WARNING: Use extreme caution when the
engine is operating. Do not stand in a direct line
with the fan. Do not put hands near the pulleys,
belts, or fan. Do not wear loose clothing.
Operate the engine at the specified idle RPM
and observe the timing degree scale and index
with a timing lamp. Rotate the distributor
housing as needed to align the timing index on
the vibration damper pulley with the correct
mark on the timing degree scale.
Refer to the Emission Control Information Label
or to Chapter B - Engines - General Service and
Diagnosis for ignition timing specifications.
When the ignition timing is correct, tighten the
distributor holddown bolt and recheck the timing
to ensure it did not change.
Disconnect the timing lamp and connect the
vacuum hose to the distributor vacuum advance
mechanism.
4.2L DISTRIBUTOR COMPONENT
REPLACEMENT
When replacing the pickup coil assembly (8),
trigger w h e e l (3) or v a c u u m a d v a n c e
mechanism (9), it is not necessary to remove the
distributor from the engine. It is necessary to
check ignition timing if the pickup coil assembly
or vacuum advance mechanism is replaced.
C-98