Sometimes it amazes us that this stuff works as well as it does. Take, for example, your BMW Distributor Rotor . A little plastic disc with an electrode on it spins at thousands of RPMs, and passes tens of thousands of volts across a tiny gap four, six, eight, or even twelve times for each revolution. Kind of boggles the mind, doesn't it? Granted, the BMW distributor rotor is going the way of leaded gas now that distributorless ignition systems are becoming more common. But there are a lot of older BMWs on the road that perform very well thanks to, or in spite of, their BMW distributor rotor.

Obviously, with a job like it has, the BMW distributor rotor doesn't last forever. In fact, along with spark plugs, the distributor cap, and the plug wires, it's one of the normal "tune-up" items that require replacement at certain intervals. All that sparking takes a toll on the metal and plastic components, and as the gap gets wider, the spark gets weaker. So install a new BMW distributor rotor as part of your maintenance schedule, and consider this when you do: That little chunk of plastic and metal gets you home every evening.