idosubaru Posted September 2, 2008 Share Posted September 2, 2008 I know this sounds like a noob question. But I've always wondered how two pieces of metal rotate around thousands of times without completely destroying each other? How do they continually make contact without wearing faster than they do? Seems they would just destroy each other rather quickly. Okay end dumb question of the day. Quote Link to comment Share on other sites More sharing options...
screwbaru2 Posted September 2, 2008 Share Posted September 2, 2008 I think its the soft metal, copper? There's a lot of flex and they're barely touching. Quote Link to comment Share on other sites More sharing options...
robm Posted September 2, 2008 Share Posted September 2, 2008 The contacts don't touch. The spark jumps the gap. The gap is very small, so it doesn't rob much voltage, or burn the contacts too much. Eventually, they do get burnt, and that is why you put on a new cap and rotor. Quote Link to comment Share on other sites More sharing options...
idosubaru Posted September 3, 2008 Author Share Posted September 3, 2008 ah ha - they don't touch. i was wondering that. interesting then that the spark gets to jump that many times. at least at the cap and at the plug. so the distributor contacts only get warn down from the spark then? seems the distributor contacts wear quicker than the rotor? seems like it should be the other way around since the rotor is doing 4 or 6 times as much sparking as one disty contact? Quote Link to comment Share on other sites More sharing options...
robm Posted September 3, 2008 Share Posted September 3, 2008 Probably because it is easier on the metal for the arc to leave it than for it to arrive, if that makes sense. Look at how spark plugs wear, it is a similar effect there. Also, the rotor contact is wider than the target contact, and the point the spark leaps varies a bit with the ignition timing. And remember, the gap is really small, like a few thousandths of an inch, so it is no sweat for a coil to pump the spark over it, when it is designed to jump a spark 40 thou at very high pressure. Quote Link to comment Share on other sites More sharing options...
bigjim5551212 Posted September 3, 2008 Share Posted September 3, 2008 there are 2 lots of sparks in the ignition system, 3 if you count bad points. points, distributor cap, spark plugs. Quote Link to comment Share on other sites More sharing options...
zukiru Posted September 3, 2008 Share Posted September 3, 2008 assuming you have points... great topic! Quote Link to comment Share on other sites More sharing options...
idosubaru Posted September 3, 2008 Author Share Posted September 3, 2008 great topic!hey don't make fun of me drew!! (hands to face..walking towards corner of room.....) Quote Link to comment Share on other sites More sharing options...
zukiru Posted September 3, 2008 Share Posted September 3, 2008 I think this beats my stock EA mpfi EJ thread, yeah? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted September 3, 2008 Author Share Posted September 3, 2008 I think this beats my stock EA mpfi EJ thread, yeah?define "beats", that could be taken either way! Quote Link to comment Share on other sites More sharing options...
zukiru Posted September 3, 2008 Share Posted September 3, 2008 exactly... Quote Link to comment Share on other sites More sharing options...
robm Posted September 3, 2008 Share Posted September 3, 2008 The spark on the points side doesn't really count. It is a different current there, that is the low voltage side of the coil. It is like a transformer. Well set-up points shouldn't spark very much, if at all, that is what the "condensor" (capacitor) is for, to cut down the arc at the points. Since that is a high current spark, it really eats the contacts. Points don't last long without the capacitor. Quote Link to comment Share on other sites More sharing options...
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