Since the advent of cars in 20th century, gasoline powered motor vehicles have always needed an accurate way to transmit an electrical spark to all engine cylinders. Diesel powered cars make an exception here because they do not rely on spark plugs to ignite fuel-air mixture. The spark has for the last 100 years, been delivered by an ignition distributor which is mechanically timed or linked to engine rotation system. That way, the spark is always sent at the exact second it is needed without fail. In light of this concept, it is safe to conclude that without a performance ignition distributor, your Porsche won’t start. But there is much more into these small components than what meets the eye. Read on to learn more.
The distributor has a shaft at the center complete with a rotor at the top. The rotor spins under the distributor cap, which has a number of terminals around it. Note that in any distributor, the number of terminals is always proportional to the number of cylinder count.
How It Works
Electricity travels through the distributor cap as the rotor passes under the terminals. Under the cap on a plate sits a set of points as well as the condenser. The closing and opening of the points helps to create high energy sparks from the ignition coil.
The distributor also has a shaft which may be driven a camshaft or a gear on the crankshaft. The amount of time needed for sparks to be delivered to each plug changes as speed changes. In Porsche models, this is made possible by electronic controls.
Nearly all distributors used with electric fuel injection Porsche engines do not have centrifugal and vacuum advance mechanisms. That’s because Porsche models use chip controlled distributors. This means that timing advance is always electronically controlled by an engine computer. Timing can therefore be adjusted accurately based on several factors and not just intake manifold vacuum or rpms. Note that Porsche has taken a different approach where they eliminate hardware for vacuum pressure and centrifugal advance. This creates a more reliable distributor complete with fewer moving parts that hardly wear out.
At some point, they wear out just like all other car components. Wear out mostly affects bushings that surround the main distributor shaft. This causes the rotating shaft to wobble. If left unattended wobbling can go on until sparks won’t flow properly. This will in turn cause inconsistent engine performance because rpms will change. In cases where the wobble worsens, the reluctor wheel will be forced to collide with the coil. Total failure will then be imminent and the car won’t simply start or move. Oil may even squeeze up the shaft where it does not belong and cause more problems. Fortunately, there is something you can always do. Take your car for scheduled maintenance. Then replace the distributor as often as your mechanic recommends. This will save you money, as fixing any distributor related glitch on time is always affordable compared to replacing and repairing a damaged one.