mgs
[Top] [All Lists]

Re: Pos to neg

To: Brian Warmuth <warmuthb@WLSC.WVNET.EDU>, mgs@autox.team.net
Subject: Re: Pos to neg
From: Barney Gaylord <barneymg@ntsource.com>
Date: Fri, 23 Jun 2000 15:16:32 -0500
At 08:28 AM 6/23/2000 -0400, Brian Warmuth wrote:
>.... I would like to convert my MGA from the positive ground to negative
ground .... It has the original fuel pump, however I have a rebuilt one
(converted to operate on negative ground) to install. Since the car has no
"electrical" gauge do you just switch the battery ground, switch the coil
wires, and re-polarize the generator?

For the MGA the answer is, "Yup, that's all".

The original MGA fuel pump had bare contact points or a capacitor (later
cars), and was not polarity sensitive.  Replacement fuel pumps with a diode
are polarity sensitive and would need to have the diode reversed.  The MGA
heater motor is series wound and runs the same direction regardless of
polarity.  I dunno about the wiper motor running backwards, but I never
noticed any difference, and for sure you don't need to touch the wiring
there.  The fuel gauge is also not polarity sensitive (but do be sure the
tank is grounded).

The largest part of the job is turning the batteries (or battery) around
and reconnecting the heavy cables.  The positive post is larger than the
negative post.  For two 6-volt batteries you just reverse the center cable.
 At the (negative) earth side you can buy a new ground cable from your
local cheap parts place for a few bucks.  For the hot cable you can buy a
bolt-on cable end connector, for which I recommend the type with the large
set screw rather than the one with the thin cross bar and two small bolts.

Barney Gaylord
1959 MGA with an attitude
    http://www.ntsource.com/~barneymg


<Prev in Thread] Current Thread [Next in Thread>