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Bugeye-better to have negative or positive ground?

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ichthos

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Hello,
I had asked for help on making my car negative ground. I am trying to keep my car as original as possible, and the more I thought about it, I don't really want to make changes unless it is necessary. How many of you have converted to negative ground? What are the benefits of converting to a negative ground? What are the problems with keeping it positive? My car is dismantled. How do I know if my generator is set up for positive or negative ground? I want to hook up a radio and cigar lighter at some point. Is this possible with a positive groung? I would apprecitate any help you can give me, but I am a beginner at all this.
Thanks, Kevin
 
Our BE is positive ground,c/w the generator and the mechanical tach drive. Never had any problems, but I also am not running a radio.
I shouldn't think the cigarette lighter would be affected by polarity (but don't know for sure). If you do install a radio and choose to mount it on the transmission tunnel, for example, so as to not tamper with the dash (my memory is that the radio 'cut-out' is way off on the passenger's side anyway), then you could isolate it quite solidly so that the positive ground electrical system wouldn't be a problem.
Others with more wisdom?

Doug
 
I run a later Midget center console in my Bugeye, it has a radio (CD player) and a lighter in it so no dash cut out is required.
You might still be able to get a + - grd inverter at Radio Shack but switching a Bugeye to - ground is a 2 minute job and can be switched back just as fast.
Change the ground, switch the coil wires, and flip the generator fields by arcing them across the new hot wire.
Now hook up a radio. Who will know you did this except the person who studies the wires on the coil?
Switching back is the same but disconnect the radio first or you will fry it.
 
My BE remains positive ground and I don't have any problems with it (well, none that aren't also shared with Lucas-powered negative ground cars). I'm currently frustrated by a ground issue with my horn...

I guess going to negative ground would make installing radios and perhaps other accessories more convenient.
 
spritenut said:
I run a later Midget center console in my Bugeye, it has a radio (CD player) and a lighter in it so no dash cut out is required.
You might still be able to get a + - grd inverter at Radio Shack but switching a Bugeye to - ground is a 2 minute job and can be switched back just as fast.
Change the ground, switch the coil wires, and flip the generator fields by arcing them across the new hot wire.
Now hook up a radio. Who will know you did this except the person who studies the wires on the coil?
Switching back is the same but disconnect the radio first or you will fry it.
Click to expand...

Wow, I had no idea it was so easy...Thx for this.
 
The problem, as I see it is this: you decide initially that you want to keep the car positive ground, and start buying pos-ground things for it, like a radio, maybe a Pertronix ignition, and so on. Eventually, you reach the point where you want to install something like an alternator conversion or a more modern radio that's only available in negative ground. Then, you have to replace all the positive-ground stuff you've installed, wasting multo bucks. That's the trap to avoid.

If you're sure you won't go down that road, no problem with keeping it positive ground. However, as soon as you start thinking about adding things like electric fuel pumps, radios, electronic ignition, or similar things that are hard or impossible to find in positive ground, do the switch to negative ground.

To answer your original questions, though, virtually nothing in the car except an electronic tach and radio depends on the ground polarity. That includes the generator, although it's a good idea to "flash" it if you're not sure how it was used previously. Do a search on the internet for negative-ground conversions and that will show how to do that.

Lots of 60s radios can be set up for either positive or negative ground, but it's not simple. Any good electrogeek with the documentation should be able to do this.
 
My Midget is still positive ground. I don't have a radio, and don't want one to drown out the music the car makes.
I have heard that positive ground cars are supposedly more prone to rust in salty/wet areas. I have had both over the years, and they seem to rust the same to me :smirk:.
 
Thanks for all the advice. I will need to think on it a while. The other concern I had was that if my wife were out driving the car somewhere and needed to jump the battery, someone would not hook it up correctly and cause damage. Do those of you who have positive ground have a warning sign in the engine bay?

Kevin
 
Remember to mark that this car is "positive ground" at the battery. Could mimimize some future issues if you have help jumping your car!!!!

ps can't believe you can actually listen to a radio in a BE????
 
Ah, yes, that's VERY important. There is a safety issue here. Most road-service types, who were born after the 60s, will just assume that the car is negative ground and hook up the cables mindlessly. If you are positive ground, be sure there is a reminder tag, and use the RED cable for the ground. This means you'll need a black one to the starter. And, be sure no one tries to jump it when you're not around to warn them.

As for that rust issue, I've never heard a good technical reason why positive ground or negative ground should be superior. I can think of good reasons, however, why the idea would be a myth.
 
Re: Bugeye-better to have negative or positive gro

My label when I converted to a alternator.
 

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Re: Bugeye-better to have negative or positive gro

Thanks again for all your replies. I also own a TR6. I do not have a radio or CD player in it currently because as odd as it sounds, I enjoy the sound of the car itself. I went on a cross country trip last summer and was fine just enjoying the sounds of my car and talking to my wife. I guess one of the issues that Steve brought up is that I don't know what I will want to do later. I have made quick decisions which have cost be dollars later.

My TR6 did come with a cigar lighter, which I use as a power source. I have one last question. I do not know a lot about electronics. I will need a cigar lighter in my Bugeye. If I have a positive ground, and use the cigar lighter for a power source, will there be any problems?

All of you have certainly given me more to ponder. I will not get a chance to get my car put back together and running until summer, so I will have time to think about. Thanks again,

Kevin
 
Re: Bugeye-better to have negative or positive gro

The lighter is like most other things. If all you use it for is a lighter then it doesn't care about polarity. If, however, you ever intend to use it to run a polarity sensitive device, for example, the charger for your cell phone, then it will have to be negative earth.
 
Re: Bugeye-better to have negative or positive gro

If I had one that was positive ground, I would keep it positive ground. The only problem that I have ever run into with positive ground is idiots who cannot understand it. Almost any device can be converted to work with positive ground with a little thought and the vast majority of things it doesn't matter. I should get some GM alternators and make them positive ground and sell them.
 
Re: Bugeye-better to have negative or positive gro

You could reverse the alternator's output by reversing the diodes, but what about the voltage regulator? I've never seen a circuit diagram for these, but I know that automotive voltage-regulator chips exist, and are probably used in them. I doubt very highly that you'll find a version of that chip that works for negative supplies. The alternative is to unground all the electronics, which may or may not be possible, depending on the alternator's design. Modern electronics don't like "floating" grounds, though, and you might find yourself with an oscillating regulator.

In the end, it's simpler just to convert to negative ground. The main reason for retaining positive ground is originality, but if you are adding modern components such as alternators, you've lost the originality, anyway.

My own feeling is, unless you have some good reason for retaining the positive ground configuration, or are in a situation where it just doesn't matter, converting to negative ground is a worthwhile thing to do.
 
Re: Bugeye-better to have negative or positive gro

I just changed my 59 Bugeye from positive to negative ground. Flashed field, changed over coil and (electronic) fuel pump wiring, started up fine, charging OK. Ignition light stayed on after switching off, major current draw from battery (now isolated!). Regulator box is new. Presumably something is stuck on in the regulator. Any ideas?
 
Another vote to leave it POSITIVE (as is mine). Though I have a Pertronix positive ground distributor. No biggie either way.

- Mark (staying positive, just not testing positive)
 
I am being pushed towards negative ground to accommodate a new fuel gauge. Can't find a replacement Mk1 gauge. Existing gauge is not a proper Mk1 so not matched to the new correct sender.
 
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