How to Make Sure Timing Is on a Distributor

Distributor timing serves an important automotive function. If the spark inside the distributor cap does not synchronize with the precise opening and closing of the intake and exhaust valves, poor engine performance results. The gears on the distributor shaft must align with the gears on the camshaft for the precise timing to take place. A DIY repair person can make sure the two systems are aligned properly by performing a simple alignment test involving the rotor position inside the distributor.

Instructions

1

Place the vehicle transmission in "Park" for an automatic and neutral for a standard. Apply the emergency brake and raise the hood. Locate the crankshaft pulley, also called the harmonic balancer, at the front lower part of the engine. Find the timing notch on the pulley, which is represented by a line. Have an assistant quickly the bump the engine over by turning the ignition key on and off rapidly. Look for the small timing tab with marked lines sitting slightly above the crankshaft pulley. The tab will have lines representing degrees. Align the crankshaft notch with the "0" (zero) degree line on the tab.

2

Consult your owner's service manual for a diagram of your vehicle's firing order and plug wire position. Locate the position of the number 1 spark plug wire and the distributor cap terminal it attaches to. Many number 1 plug wires are located at the front of the engine on either the right- or left-hand side. Trace the wire back to the terminal on the top of the distributor cap.

3

Note the number 1 terminal on the cap. Use chalk to mark a line on the distributor body directly in line and below the number 1 cap terminal. Do not mark the distributor cap -- only the top of the distributor body. Use a screwdriver to remove the distributor cap, by removing the screws or turning the screws until the cap retainer pins face outward.

4

Pull the distributor cap off and lay it aside, but keep the plug wires attached to it. Look at the position of the rotor electrode. It should be facing directly over your chalk mark. If it does not line up, instruct your assistant to quickly "bump" the ignition key on and off to rotate the crankshaft one full 360-degree turn until the tab and crankshaft marks realign.

5

Examine the rotor electrode again. It should be directly above the number 1 cylinder chalk mark on the distributor body. If it appears so, it means the distributor timing is set correctly. If the rotor electrode does not align with the number 1 firing position, it means the distributor timing is off and will have to be reset.