When your distributor cap or rotor goes bad you could be left stranded and unable to start your vehicle. The rotor is a whirling dervish of power distribution, transferring energy from the ignition coil, through the distributor cap, and finally to the spark plugs which initiate combustion. In other words, you need the distributor’s parts to function properly in order to start your car.

You may also experience other issues if the rotor or cap malfunctions, such as the car shaking or the engine struggling to turn over when you turn the key. Time, wear, and tear can affect the electrical contacts and other components of these crucial parts and cause failure. If it’s time to shop for a new distributor rotor and/or cap, there are some factors to take into consideration.

How to make sure you’re getting a good quality distributor cap

  • Look for brass terminals. Aluminum terminals are cheaper but they tend to be more unreliable and don’t last as long.

  • Don’t sacrifice function for appearance. Some distributor caps may be slick looking but cost more than a more durable, plainer model.

  • Look for a warranty – you want a minimum of at least 3000 miles or 90 days in case there’s a problem with the part.

How to make sure you’re getting a good quality distributor rotor

  • Go for the brass contacts here too.

  • Choose a distributor rotor that minimizes electric over-arcing. This extends the life of the rotor.

  • Look for corrosion-resistant springs in spring-loaded rotors.

  • Choose a rotor that is impact-resistant, particularly if you’re an off-roader or engage in other high-intensity driving.

  • Make sure there’s a warranty. The better the part, typically the better the warranty. This is where you’ll have to balance your budget with quality and guarantee.

YourMechanic supplies top-quality distributor caps and rotors to our certified mobile technicians. We can also install distributor caps and rotors that you've purchased. Click here for a distributor cap/ rotor replacement.

This article originally appeared on YourMechanic.com as How to Buy a Good Quality Distributor Rotor and Cap and was authored by Valerie Johnston.


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