In a message dated 97-07-27 16:13:03 EDT, amace@unix2.nysed.gov (Andrew Mace)
writes:
> Which wire goes where on the coil depends upon whether you've gone with
> positive or negative earth. Regardless, though, you'd get spark
> sufficient to power the engine.
>
> My guess is that the surface of the contact points might be dirty if old
> or perhaps covered with a bit of a protectant if new. Either way,
> cleaning those up might help. Also, if you've recently replaced or
> renewed these, depending on the brand, it's easy enough (been there, done
> that) to get the little wire and various bits of nylon washers and
> insulators on the wrong way so that current doesn't flow.
>
> Just a couple of quick thoughts.
>
> --Andy
Andy's right. Check as he said. In addition, I just finished some research
on coil polarity. Here's what I found.
The original coils had the markings "SW" and "CB" on the "primary" terminals
(the two on the outside top of the coil). SW was supposed to be connected to
the ignition SWitch and CB to the Contact Breaker, also known as the points.
The new coils have "+" and "-" on them.
For POSITIVE GROUND cars, the negative "-" should be connected to the wire
from the ignition switch and the "+" should be connected to the points.
(Mine was backwards because I worked the problem by myself in '91 and came
up with the wrong answer. BUT everything still worked - my plugs were just
firing with the spark jumping the wrong way.)
If you have a NEGATIVE GROUND car then connect the positive "+" coil terminal
to the wire from the ignition switch and the negative "-" coil terminal to
the points.
The main point of all this is that you want the center (secondary or high
voltage) terminal of the coil to be negative. If you connect it as above
(depending on which type of ground you have) the wire (in the center of the
coil) coming from the high voltage side of the coil will be negative (what
you want). When you connect that wire to the distributor cap then through
the rotor to the spark plugs the electrons will "boil off" the center
electrode of the spark plug because the center electrode is negative (also
what you want).
There is a good article on p.44 of British Car magazine for Jun/Jul '97 which
goes into more detail. I verified the article with several other sources,
but the article explains the whole idea very simply.
Hope this helps. In any case please let us know what you find that solves
your problem. Cheers.
Art Kelly '64 TR4 CT33118L (positive ground)
VTR TR4 vehicle consultant
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