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MG Midget and Sprite Technical - POS or NEG Ground????

I just purchased a 1971(?) midget, has not ran for several years and has no battery......only one cable left and is black in color......... how can I find out if car is neg or pos ground?????
A Marrett

If it has an alternator, it is negative earth. OTOH, the changeover to negative earth was in 1967, so, unless a DPO did a nasty on you, you are negative earth.
David "fairly negative" Lieb
David Lieb

71 should have a dyno for USA spec...the alt came in 72....But yes it is a negitive ground


Prop...DAVID!!! Your Grounded for being negitive ...Prop
Prop

Aren't the battery terminals in the US the same as the UK? If so, the terminals are different sizes so the battery should only fit round one way.

Also, look at the terminals on the coil (if still connected) where the one going to the distributor will possibly be marked with a plus or neg symbol which indicates......

(Can someone fill in? I was on the booze last night and am not thinking straight yet.)
rob multi-sheds thomas

Look at the rev counter. Usually marked positive or negative earth.
f pollock

Ahh... don't be fooled by the tacho.. I've just converted my '67 sprite to neg earth and the tacho is easily modified.
N Broadbent

Hi Rob

Coil terminals used to have CB (contact breaker) and SW (ign switch); when there was only positive earth around, this was fine.

IIRC coils these days do indeed have +ve and -ve terminals... so that whether +/- earth, the spark always goes the right way (electrons from centre electrode to earth rod).

A
Anthony Cutler

Thanx, no terminals for battery left either, has generator, but is 71 and since change to Neg earth was in 67 I will go with neg ground. Thanks
A Marrett

I love photos of assumptions

Prop


Prop

Prop,
Your photochop skills need some polishing.

Re-read your Horler. Alternators started in the US cars in 8/71.
David "US RWA=+gnd" Lieb
David Lieb

Battery terminals are not the same size. If the remaining cable is connected to the solenoid or the firewall, you should be able to tell whether it fits a + or - terminal of a battery.
David "Still inconclusive..." Lieb
David Lieb

This thread was discussed between 11/11/2009 and 12/11/2009

MG Midget and Sprite Technical index

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