Distributor Assembly Replacement

DISTRIBUTOR REPLACEMENT

Removal

Unfasten the distributor cap retaining screws. Remove the distributor cap with the coil and spark plug wires connected and position aside.

Disconnect and plug the distributor vacuum advance hose.

Disconnect the distributor primary wiring connector.

Scribe a mark on the distributor housing in line with the tip of the rotor. Scribe a mark on the distributor housing near the clamp and continue the scribe mark onto the engine block in line with the distributor housing mark. Note the position of the rotor and distributor housing in relation to the surrounding engine components as reference points for installing the distributor.

Remove the distributor holddown bolt and clamp.

Withdraw the distributor carefully from the engine.

Installation

Clean the distributor mounting area of the cylinder block.

Install a replacement distributor mounting gasket in the counterbore of the cylinder block.

Position the distributor shaft in the cylinder block. If the engine was not rotated while the distributor was removed, perform the following.

- align the rotor tip with the mark scribed on the distributor housing during removal; turn the rotor approximately 1/8-turn counterclockwise past the scribe mark

CAUTION: Assure that the distributor shaft fully engages the oil pump drive gear shaft. It may be necessary to slightly rotate (bump) the engine while applying downward hand force on the distributor body to fully engage the distributor shaft with the oil pump drive gear shaft.

- slide the distributor shaft down into the engine; align the scribe mark on the distributor housing with the corresponding scribe mark on the cylinder block

NOTE: It may be necessary to move the rotor and shaft slightly to start the gear into mesh with the camshaft gear and to engage the oil pump drive tang, but the rotor should align with the scribe mark when the distributor shaft is down in place.

- install the distributor holddown clamp and bolt, but do not tighten the bolt

If the engine was rotated while the distributor was removed, it will be necessary to establish timing according to following procedure.

- remove the No.1 sparkplug; hold a finger over the spark plug hole and rotate the engine until compression pressure is felt; slowly continue to rotate the engine until the timing index on the vibration damper pulley aligns with the top dead center (TDC) mark (0 degree) on the timing degree scale; always rotate the engine in direction of normal rotation; do not turn the engine backward to align the timing marks

- turn the distributor shaft until the rotor tip points in the direction of the No.1 terminal in the distributor cap; turn the rotor 1/8-turn counterclockwise past position of the No.1 terminal

- slide the distributor shaft down into the engine and position the distributor vacuum advance mechanism housing in approximately the same location (in relation to 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 with the starter motor.

Install the distributor cap (with ignition wires) on the distributor housing. Ensure that the pickup coil wire rubber grommet in the distributor housing aligns with the depression in the distributor cap and that the cap fits on rim of the distributor housing.

NOTE: Two different diameter screws are used to retain the distributor cap.

Apply AMC 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 the connection. Use proper adapters.

Connect the timing light 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 'me with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.

Operate engine at the specified idle rpm and observe the timing degree scale and index with a timing light. Rotate the distributor housing as needed to align the timing index on the vibration damper pulley with correct mark on the timing degree scale. Refer to the specifications in this chapter for ignition timing information. When the ignition timing is correct, tighten the distributor holddown bolt and recheck the timing to ensure it did not change.

Disconnect the timing light and connect the vacuum hose to the distributor vacuum advance mechanism.