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Sharp edges-- why... Posted by JimBlake [Email] (#141) [Profile/Gallery] (more from JimBlake) on Tue, 15 Jul 2003 06:21:40 In Reply to: Re: Spark plugs---Sharp edges--, Paco, Tue, 15 Jul 2003 05:22:18 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Interesting observations from all you guys... For Paco, here's why.
Before the gap ionizes, it's not at all like current flowing through a material with uniform resistivity. There's no current across the gap, but the charge carriers (electrons & holes) are collecting on the electrodes waiting to jump. They repel each other and they're attracted to the opposite charge. So if the electrodes were pointed they would all try to sit at the pointy end. That helps concentrate the field that's building up across the gap. When it gets strong enough to ionize the 'air' in the gap, the spark fires.
If the electrodes are round & smooth, it should take higher voltage before the spark fires. Pt plugs have a (+) electrode that's pointy. Cu plugs (+) electrode starts out having a square end with a sharp corner/edge around it, but erodes & gets rounded. Dean's saying that the DI cassette has enough power to deal with that, TG says he can tell the difference. Either way, brand new plugs are pretty cheap & easy to put in.
posted by 12.28.24...
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