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Pos or Neg Ground

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John Moore

John Moore

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The wiring in my Bugeye is a nest of bubba wiring. I'm thinking I'll just buy a new harness from British Wiring and start over again. It appears my BE is currently set up Neg Ground. In the long term I don't plan on running a radio or anything and I was thinking of making it Pos. ground.

I guess I need to decided this somewhat early on, as it will effect my fuel pump and other electrical componet purchases... I guess! The other bad thing is that my dash was also "bubba improved" and rewired. I also have a later 1275 in there, would that effect your choice of set up?

I would appreciate any feedback on if I should set my car up Pos or Neg Ground.... Thoughts?
 
The only thing on a Bugeye that needs to be different for a Neg ground is the generator. All other wireing is the same for both neg and pos.

https://www.starautoelectric.com/Home.htm

Star Auto Electric Company

Instruction on how to polarize a Generator:


In all the years I have been in business, I have heard many versions on how to polarize a generator and voltage regulator. Some versions are correct, others are totally wrong.
Polarization is a procedure which matches the polarity for the generator and the voltage regulator. The majority of the vehicles are manufactured negative ground although some of the older vehicles were manufactured positive ground. The generator has to be set up for either polarity. The generator will charge either way, however the voltage regulator has only one polarity. Whenever the battery is disconnected from the vehicle for any reason the polarization procedure should be performed.
The recommendation on how to polarize a charging system is the following: After the installation of a battery, generator or voltage regulator follow these procedures. The terminals on the voltage regulator are labeled with letters and this is where you will do the polarizing procedure. Both of the components will have battery power so do not start the vehicle or turn on the ignition switch before polarizing them. You will need a small piece of wire fourteen or sixteen gauge with alligator clips on the ends. Find the "B" terminal on the regulator and attach one of the alligator clips, find the "D" terminal and touch the terminal with the other alligator clip. You can touch the terminals a few times and it will produce a soft light spark. Under no circumstances touch the "F" terminal or any other part of the regulator or you could damage the regulator.
For the Lucas voltage regulators that have the teminals labeled A1, A, F, D, E, the polarization procedure is the same however the terminals that will be used are the "D" terminal and either the "A" or "A1" depending on which teminal is used on the vehicle. Either terminal can be used if wires are going to both terminals.
Start the vehicle and you should see the red generator light go off on the instrument panel, you may have to rev the engine up a few RPM, generators have a tendency not to charge at idle speed. If you have a gauge on the instrument panel the gauge will respond accordingly.
Look for more technical information in the future on these page.

Sincerely,
Mike Martinez
 
Hmmmm, thanks guys. I didnt know it was that easy to change back and forth. Maybe I should make it neg ground as that's what I'm more familar with.
 
You also need to reverse the business wires of the petrol gauge, unless you are happy guessing how much fuel you have :smile:

Pertronix ignition or similar comes in completely separate pos-earth or neg-earth versions, so if you have something like that installed, it would have to be replaced if you were switching.

But having done the pos-earth to neg-earth conversion myself on ncbugeye a few months ago, those items and the trick with the dynamo are it.

Finally, don't forget that these are British cars, guys, so we should be using the correct quaint British terminology - it's PETROL, not FUEL or GASOLINE, it's EARTH, not GROUND, and at least for the 50s era of the FROGEYE (Bugeye), it's DYNAMO, not GENERATOR :smile:
 
You guys, fuel gauge does not need to be reversed nor does coil.

My last three Bugeyes have run just fine for years with out any changes other than battery ground and generator polarity.

This is just about a plug and play switch.
 
The fuel gauge does not need to have its wires reversed.

Like Jack said, the coil will work without reversing its connections, it's just less efficient. (For a detailed explanation of why, pop into the Healey forum here and pose the question to Dave Russell. ) For optimum spark on a negative ground car (if you're still running the coil with the SW and CB terminals) move the white ignition switch wire to the coil's CB terminal and the SW terminal goes to the distributor.
 
A local mechanic had a Morris Minor Traveler in his shop for months trying to diagnose the poor-starting/running and had pretty much given up. I stopped in and looked over the engine and pointed out that it was pos ground and the coil wires needed to be reversed.
That done, it started strong and ran well. The coil polarity really matters. The spark from a bass-akwards coil is weak.

Glen Byrns
 
John Moore said:
Hmmmm, thanks guys. I didnt know it was that easy to change back and forth. Maybe I should make it neg ground as that's what I'm more familar with.
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------So is the rest of the world on this side of the pond!---Keoke
 
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