Positive Earth?

[Rineheitzgabot]

I know I have read about his subject on this forum before, but I truly can't find any threads, so I am starting this one.

I want to install some accessories and am not sure if I am grounded positively or negatively. What is the easiest, most accurate way of checking it. PO's have made several mods to this truck, and I suspect that polarity has been reversed, but not certain.

Additionally, if I find that I need to convert to negative, does anyone have any links that I can go to for a step-by-step?

As always your help is appreciated.

[LaneRover]

Does the positive battery cable go to the 'ground' of the vehicle and does the negative battery cable go to the starter relay? If so then you are positive ground. If not then and you are not sure that it is negative ground then get the 'changeover' instructions (from the web somewhere I am sure) and see if the work has been done or if someone just changed the battery cables without doing the work.

If you have an alternator and not a generator then it is negative ground.

I think that Rovers North has the instructions to go from positive to negative ground somewhere.

[thixon]

Yeah...what Lanerover said.

I think TerriAnne's web site also has an article on switching over to negative earth (it aint hard, you could figure it out on your own.).

[Rineheitzgabot]

My positive cable goes to the solenoid, while the negative cable goes to the frame. The way I took your post, this is not an absolute way of determing whether it is negative ground or not. :confused:

[Eric W S]

My positive cable goes to the solenoid, while the negative cable goes to the frame. The way I took your post, this is not an absolute way of determing whether it is negative ground or not. :confused:

Are you running anything that would require negative earth such as a modern radio or winch? That'll give you a clue right away.

[Rineheitzgabot]

Eric,

I am not running any modern accessories, currently.

[JSBriggs]

My positive cable goes to the solenoid, while the negative cable goes to the frame. The way I took your post, this is not an absolute way of determing whether it is negative ground or not. :confused:

You have negative ground (earth). The absolute way of determining ground is to see what battery terminal is connected directly to the frame.

The only way this is even slightly ambigious is if the preveous owner did some sort of partial conversion.

Does anyone know what year the factory switched from positive to negative?

-Jeff

[LaneRover]

You have negative ground (earth). The absolute way of determining ground is to see what battery terminal is connected directly to the frame.

The only way this is even slightly ambigious is if the previous owner did some sort of partial conversion.

-Jeff

Exactly!

[Rineheitzgabot]

You have negative ground (earth). The absolute way of determining ground is to see what battery terminal is connected directly to the frame.

The only way this is even slightly ambigious is if the preveous owner did some sort of partial conversion.

Does anyone know what year the factory switched from positive to negative?

-Jeff


Alright. Cool.

I still have the generator and I want to do the alternator conversion to it, eventually, as well, and I want to get this all squared-away before I move forward with any electrics-stuff.

Thanks for all of your help.

[LaneRover]

FYI, just came across this one.

According to the RN website the change from positive to negative ground happened in 1967 and that trucks that ORIGINALLY were positive ground have independent wiper motors and an amp gauge in the instrument cluster.

[Rineheitzgabot]

I figured this out earlier, back in Dec. when I started this thread, but since us guys are "all in this together", as Red Gren would say, I thought I would share with you something I discovered this past weekend; The text that is written on a small placard, just forward of my radiator. It says:

"Negative Ground"

Hmm.

Hey, Iv'e got three kids, alright?!! My IQ has dropped about 15% since I had the third one.

[scott]

badvibes runs in a 64 iia swb (when it's running). he had to do the neg earth to pos earth conversion. why would a pre 67 be a neg earth?

[superstator]

badvibes runs in a 64 iia swb (when it's running). he had to do the neg earth to pos earth conversion. why would a pre 67 be a neg earth?

That has to be a misunderstanding. Only reason to go from neg earth to pos earth would be to take a previously converted vehicle back to factory spec as part of a really meticulous restoration.

[scott]

That has to be a misunderstanding. Only reason to go from neg earth to pos earth would be to take a previously converted vehicle back to factory spec as part of a really meticulous restoration.

you're right, i got that backasswards. he converted his 64 from a pos earth to a neg. sorry. but again why would a 64 be a pos earth?

[superstator]

I've heard that in the dark days of the automotive industry there was a theory that positive ground was somehow safer or more efficient. Whatever the original reason, they eventually decided that making their chassis into giant anodes and then driving them around on salty roads was a bad idea, and the whole industry slowly switched to negative earth. Most American makes did it around the 50's, and the brits did it in the 60's. In Rovers case, they switched over when the '67 nada 109's came out, and followed on with the rest of the models in '68. I think a few makes even made it into the '70s with positive earth (MG?) before succuming to peer pressure.

I don't know if it was a factory thing or a previous owner thing, but my MG was negative earth but with the wires color coded backwards. Red was negative and ran to the frame, black was positive and ran to the starter. I melted a good pair of jumper cables by not thinking or taking the time to actually look at the terminals. I have learned to always check twice on anything made in the UK.