Hi MYLDN!!
On Fri, 4 Apr 1997 MYLDN@aol.com wrote:
> Hey all, what are all the steps in converting an MGA from poss ground to neg
> ground and are there any bad side effects?
Well now, You have to think of the things that would be polarity
sensitive, and then deal with each one seperately.
1. You must polarize the generator. This is a painless procedure IF you
follow the shop manual. No, I don't remember exactly how to do it; but
it's in the book!! Basically, you are "zapping" the magnetic fields
inside the generator by jumpering from battery positive to a
generator terminal on the voltage regulator.
2. You must polarize the coil. Just switch the leads around on the
primary connections. What you are doing is getting the spark to jump
the "easiest" way; which I think is from the cooler side electrode to
the hotter centre electrode. If this isn't done, the coil hasn't enough
voltage to fire the mixture under wot/high rpm conditions (it will
either miss, or just crap out).
3. You must polarize the fuel pump, IF it contains a spark suppression
diode. The diode shorts out the fuel pump coil's inductive "kick", so
the fuel pump points will last much longer. If you hook up a diode pump
with reverse polarity, you have a dead short, which lets out the blue
smoke from the components. Smokeless parts don't work anymore...
There's an EXELLENT tech article one of the mg web pages out of england.
All you have to do is reverse the diode connections in the pump switch
gear.
4. You must check your radio. Some of the older radios had a polarity
reversal plug in the side of the case. You just had to pull the plug,
orient it for the neg ground position, and plug it back in. If you have
a pos ground chassis, without the plug, it could be very expensive to
convert it; the best way to approach it, is to have an electronics
friend look it over.
5. Everything else is transparent to the polarity; ie resistive loads
"don't care", and the heater/wiper/starter motors aren't polarity
sensitive because they have field windings rather than a perminant
magnet type field. Horns and turn signals work with either polarity.
TTUL8r, Kirk Cowen
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