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MG MGA - Battery Earth Cable

Can anyone tell me exactly where the battery earth cable goes to on the chassis please?

Colin
Colin Parkinson

Followed by four hours of silence? No one else wants to crawl under the check?

The ground cable attaches to the frame with a bolt and washer(s) and nut at the inboard end of the exhaust hanger bracket which is welded to the underside of the round frame tube.

Years ago I installed a ground breaker battery cut off switch near this point, low on the rear plywood bulkhead with the knob behind the seat. Then the battery ground cable gets connected to the cut-off switch, and the switch is in turn connected to the original chassis ground point with a short bare ground cable, the same part used to ground the engine.
Barney Gaylord

Aah!! That's why I cannot find it. I havnt got the exhaust bracket!!

Thanks (once again) Barney. Sorry about the lightening. But it wont happen again!!!

Colin
Colin Parkinson

You don't need the bolt-on bracket. The ground cable attaches to the frame plate which is welded to the bottom of the round frame tube, next hole inboard from where the exhaust hanger will attach.
Barney Gaylord

Colin, found an old picture. See here:

http://s83.photobucket.com/albums/j307/wbetzel/MGA%201600/Miscellaneous/?action=view¤t=SIMG0143.jpg&refPage=&imgAnch=imgAnch1

Wim Betzel

Hey Wim. Your link doesn't work, but I think I got it sorted:-

http://s83.photobucket.com/albums/j307/wbetzel/MGA%201600/Miscellaneous/?action=view¤t=SIMG0143.jpg

TTFN

Derek Nicholson

Next try:
http://s83.photobucket.com/albums/j307/wbetzel/

Look under MGA 1600 - Miscellaneous
Wim Betzel

Wim's long link works. You just have to piece it together for the complete URL.
Barney Gaylord

Barney wrote "[y]ears ago I installed a ground breaker battery cut off switch near this point, low on the rear plywood bulkhead with the knob behind the seat". I did the same to save the battery when my Coupe is parked. But this does not stop the car being fully operational if the cut off switch turned to "off" whilst the car is running as, presumably, the generator/altenator continues to supply the required electricity. So it seems no good as a safety feature in the event of a crash or for racing.
Joe Gates

This is true. You can disconnect any battery cable while the engine is runing, and the engine will continue to run, as the generator will supply the current to power the ignition. For a "kill" switch to isolate battery from chassis and stop the engine it must also disconnect the ignition circuit from the generator output (or vise versa). You need a multi-pole switch for that application, such as this: http://www.kitcarmag.com/howto/cutoff_switch_install/photo_01.html

I use the ground disconnect primarily for maintenance as an easy way to isolate the battery from the chassis wiring without having to disconnect a battery terminal. This is usually for R&R of the engine or for wiring work. It can also serve as a theft deterent, as long as the thief does not immediately find the battery cut-off switch. If you use a simple two post battery disconnect switch, shut off engine before disconnecting battery. Running an alternator with battery dosconnecte3d could damage the alternator (maybe).
Barney Gaylord

Thanks Barney for your comment and link re the above. Here's another that looks interesting and links to the fuel pump. Seems a nifty option for theft prevention (which is another reason for my cut-off switch).

Joe

http://www.pelicanparts.com/techarticles/Mult_ignition_cutoff/Mult_ignition_cutoff.htm
Joe Gates

This thread was discussed between 04/08/2006 and 07/08/2006

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This thread is from the archive. The Live MG MGA BBS is active now.