Engine Electrical
Distributor Rotor
A distributor rotor spins inside the distributor cap and sends spark from the coil to each spark plug terminal in turn. We carry 39 distributor rotors from $4 to $47 for 1954-2005 vehicles, from AC Delco, Standard Motor Products, Forecast and MSD, with fits for the Chevrolet Camaro and Corvette, Ram 1500, Porsche 944, Nissan 300ZX and Land Rover Discovery.
Shop distributor rotor by vehicle
How rotors wear
Each time spark jumps from the rotor tip to a cap terminal, it burns away a tiny amount of metal. Over many miles the tip erodes and the gap grows, which weakens spark. Look for a burned or pitted tip, cracks in the body, or carbon tracks. Symptoms of a worn rotor include misfires, rough running and hard starting. A rotor that breaks or slips on the shaft can stop the engine completely.
Matching your distributor
Rotors are designed for a specific distributor, so the shape, the shaft fit and the attachment must match. Some push onto the shaft, while others are held by screws or bolts, and some listings include those bolts. Colors include blue, black, red and white, which mostly reflects the brand and material. Choose your year, make and model, check the fitment table for engine, and compare with your old rotor before installing it.
Replace with the cap
Install a new rotor whenever you replace the distributor cap, since both wear at the spark gap. Remove the cap with the wires still attached, lift or unscrew the old rotor, and fit the new one in the same position, using the locating tab or flat on the shaft. Tighten any screws gently. Check that the rotor does not touch the cap terminals when the cap goes back on.
Distributor Rotor questions
How often should I replace the distributor rotor?
Follow the interval in your owner's manual or service schedule, often at a tune-up with the cap. Replace it sooner if the tip is burned or the body is cracked.
Can a bad rotor cause no start?
Yes. A cracked rotor, a broken tip, or one that has slipped on the shaft can stop spark reaching the plugs, leaving an engine that cranks but does not start.
Are all rotors for the same engine interchangeable?
No. Rotors are built for specific distributors, and one engine may have used different distributors over its run. Check the fitment table and compare the shape of your old rotor.