Distributor Rotor Replacement

Technology often improves performance and efficiency. Automotive ignitions received a notable technological advance in the Seventies when "points" type systems began giving way to more-modern electronic ignitions. Before then, many grizzled old-timers were local legends for their points "twiddling" skills. These spark masters would file the ignition points to remove carbon buildups, expertly set the point gap, adjust the dwell through a slide-up door in the distributor cap and perform others acts of black science that sent the spark to the plug at precisely the time the fuel arrived. As a result, engine "miss" was cured.

Pointless
Electronics advances simplified ignition systems. Old-fashioned points, condensors and breaker plates were replaced by a rotor. This simpler and more efficient setup consists of a rotor that spins atop the distributor's shaft. As it spins, the rotor's metal tip contacts terminals on the distributor cap. The terminals route the spark through the appropriate wire to the proper spark plug.

The good news: Distributor rotors are easy to replace by the average home mechanic.
Unfortunately, all moving parts eventually wear out. Just as ignition points corrode and decay, rotors' metal tips grind down over time, resulting in improper contact with the distributor cap. Further, rotor bodies are usually made of plastic, so heat and vibration can cause cracks over time. The good news: Distributor rotors are easy to replace by the average home mechanic.


Often, the most time-consuming part of the job is removing the distributor cap to access the rotor. Distributors are sometimes obscured by other components or even recessed under the cowl, snug against the firewall. Once the cap is popped, though, the old rotor is simply detached and replaced with the new. (A service manual will mention the specifics for your vehicle.)


This "pointless" procedure can smooth the car's idle, clean tailpipe emissions and restore lost fuel economy.