Re: Accidental + - Conversion! Coil!!

John Souders (frodo4(at)ix.netcom.com)
Wed, 5 Jun 1996 15:38:51 -0700

You wrote: >
>..............>>>>.
>I connected it up in the same way it was connected on the series II.
I >hadn't been thinking about the difference in + or - earth so I ended
up >installing it incorrectly on the series V with the connections set for
a >positive earth car.
>
>What I don't understand is why the engine ran just fine with the
>terminations wrong. I've been driving it for about 8 months that way.
I >switched it back and the engine still works and also now the tach
works. >Does anyone know why the engine would work with the coil terminations
>reversed and have I done any damage to anything because of it?

Have no fear - you have done no damage. Coils dont contain anything that is polarity sensetive.

What you ended up doing by reversing the connections was to reverse the direction of the spark at the plugs. Not timing or anything else.

You see - when electrons leave a surface to jump the gap to the other terminal on the spark plug, they are a lot more willing to leave a hot surface than a cooler one. The coil is arranged such that the negative connection to the high voltage side of the coil (nothing to do with the negative ground for the 12 volts) is connected to the hotter point on the plug ie the center of the plug. But the spark is also capable of jumping the other way - note I said that it is only easier for the spark to jump from the hot surface.

On a very high compression engine, or one where the plug wires are not so good, you might experience misfiring etc with the coil reversed. For the Alpine the demands are not so great, and you dont notice the diffence.

Dont worry - no harm done.

John Alpine IV