> I sent the following message to the list yesterday and it never seemed to
> come through so I am sending it again. It didn't show up on my mail so if
> you did already get it...sorry for the duplication.
>
> While trying to trace the problem of why my Tach would not work, I found
> the problem in my coil connection. About 8 months ago I switched a coil
> from a series II into my series V paying close attention to the physical
> position of the connections from the series II(not looking at the + or -).
> 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? Do I need to
> reset timing or anything?
>
> This is a pretty forgiving car if you can make a mistake like that and
> still run the car!
It really isn't surprising that the car will run; most will run with the polarity of the coil primary reversed. There is a difference in the spark--I think it is easier for the spark to jump the gap in the plug with the proper coil polarity, but any difference probably would not show up except in really adverse conditions. It is very unlikely you have hurt anything, and you should not have to reset timing.
But just to make sure you now have it right: The + terminal on the coil should now be connected to the ignition of your negative ground car, and the - terminal should be connected to the distributor points. If the coil is marked CB and B or something like that, and you know it is a coil intended for positive ground, the CB (contact breaker) post should go to the ignition of a negative ground car.
There is a test you can do with a pencil to see if the polarity is right, but I can't remember which way it goes. Somebody else may know.
Ray Gibbons Dept. of Molecular Physiology & Biophysics Univ. of Vermont College of Medicine, Burlington, VT gibbons(at)northpole.med.uvm.edu (802) 656-8910