Distributor adjustments and repairs are most commonly performed on the components within the upper half of the distributor, such as the rotor and the distributor cap. However, the shaft of the distributor, which enters the engine and contacts the oil pump’s shaft and the camshaft, is also prone to wear. Although repairing the distributor is an option, it is usually more cost-effective to simply replace the distributor with a new one. Fortunately, Chevy distributors are fairly simple to replace.
Remove the negative battery cable from the negative battery post with a wrench.
Remove the spark plug from the number one cylinder with a deep-set socket connected to a socket wrench. Each cylinder is assigned a number which corresponds to a metal electrode within the distributor cap. The precise location of the number one cylinder varies depending on the engine, so consult the engine manual to identify the number one cylinder.
Attach a deep-set socket to the bolt located in the center of the vibration dampener, located just below the water pump. Cover the spark plug hole for the number one cylinder with a thumb then slowly twist the vibration dampener with the wrench. A single line is scribed into the dampener. As the line approaches the tip of the timing pointer, note whether a puff of air escapes past the spark plug hole. If air does escape, continue turning the vibration dampener until the line on the dampener aligns with the tip of the timing pointer. If no puff of air is detected, rotate the vibration dampener one full revolution until the line on the dampener aligns with the tip of the timing pointer. This is referred to as the “top-dead-center” position.
Transfer the distributor wires to the top of the replacement distributor’s cap. Place the back of the new distributor cap against the front of the old distributor cap. Pull each wire off of the old cap and plug the wires into the same terminals on the new distributor cap. Remove the distributor cap and note the direction that the metal tip of the rotor faces. When the replacement distributor is installed, that distributor’s rotor must point in the same direction.
Remove the existing distributor from the engine. Disconnect the ignition wire which leads from the side of the distributor with an ignition wrench then pull the rubber hose off of the vacuum-advance canister, also located on the side of the distributor. At the bottom of the distributor is a metal set-piece with a bolt through the center of it. That set-piece bolts to the engine and grasps a lip at the bottom of the distributor, thereby holding the distributor in place. Remove the bolt from the set-piece and pull the distributor out of the engine.
Lower the replacement distributor halfway into the engine then turn the rotor until the metal tip on the end of the rotor points in the same direction as the rotor from the old distributor. Lower the distributor into the engine and install the metal set-piece with a wrench once the rotor is properly positioned. Do not tighten the bolt which holds the set-piece in place as the distributor will probably need to be twisted to time the engine. Reconnect the vacuum advance hose to the vacuum canister on the distributor, followed by the distributor’s ignition coil wire.
Attach the distributor cap to the distributor then install the spark plug back into the number one spark plug cylinder with a deep-set socket connected to a socket wrench.
Consult the engine manual to determine the number of degrees at which the engine must be timed. Locate and mark that number on the engine’s timing pointer, located just above the vibration dampener, with a piece of chalk. Attach a timing light to the engine and turn the engine on. Point the timing light at the chalk mark on the timing pointer and observe the flash of the light. The chalk mark must align with the groove cut into the vibration dampener. If necessary, rotate the distributor until the marks align then tighten the bolt on the distributor’s set-piece. Turn the engine off and disconnect the timing light, then reattach the negative battery cable to the battery.
