Positive or negative ground question

[8NHENRY]

I know this may seem like a stupid question. I bought a super 88 Oliver, which has a generator on it and it has no battery in it. I am pretty certain it is a 12 V system but how can I tell if it’s positive or negative ground? The original owner has passed away and there’s nobody around to ask that knows the tractor. Thank you in advance.

 

[rustred]

Those are 6 volt systems. Should be pos. Ground. Talking gas here. Look at the cable end going to ground that should tell the story , as I said should unless it’s been messed with. Diesel’s are 12 volt.

 

[Janicholson]

Delco generators have a oval ID plate with # s stamped in. run that number and see what uou get. Jim

 

[wore out]

Delco generators have a oval ID plate with # s stamped in. run that number and see what uou get. Jim

Also, as to 6 or 12, if a Delco generator, 6 Volt units had black printing on the tag, 12 Volt units had red printing on the tag.

As to ground polarity, the voltage regulator (if it has one) MAY be marked (POS) or (NEG), indicating that it was designed for and will have the longest contact life when operated at that ground polarity.

 

[docmirror]

Both 6 and 12 V battery plus and minus terminals are slightly different diameter. The pos battery is slightly larger dia than the neg. Try to connect the ground cable first. If it's loose on the terminal, try it on the pos side, and then take that off and test the other cable. Usually, it will only go one way. Try the cables one at a time.

 

[Rich'sToys]

If it's a gas tractor you can check the wire from the distributor to the coil and see which terminal it is connected to.

 

[paul]

Is it a gas or diesel? If gas it should be a 6 volt system from the factory, positive ground.

12 volt generators were rather uncommon, but there was a period in there they were used on some diesels, before alternators took over. I’m not exactly sure if Oliver has 12v generators on their early diesel stuff.

Paul

 

[Tramway Guy]

Is it a gas or diesel? If gas it should be a 6 volt system from the factory, positive ground.

12 volt generators were rather uncommon, but there was a period in there they were used on some diesels, before alternators took over. I’m not exactly sure if Oliver has 12v generators on their early diesel stuff.

Paul

All of the Oliver Diesel tractors were 12 Volt, from 66’s to 2255’s. With generators, they were positive ground; with alternators they were negative ground.

 

[used red MN]

If it's a gas tractor you can check the wire from the distributor to the coil and see which terminal it is connected to.

This is what I would go by, if the wire from the distributor is on the negative terminal of the coil then it was set up for negative ground. If the distributor wire connects to the positive terminal on the coil it is positive ground. Then look at the coil to see what voltage it says it is. If it says 12 volt no external resistor required the system was 12 volt. If it says 12 volt external resistor required it is a 6 volt coil or it will be marked 6 volt. Whether the generator is set up for 12 volts will require more investigation of it and the voltage regulator.

 

[8NHENRY]

Thanks for all of the replys, this will help allot. This is a 1958 Super 88 and from what I find they call that the Improved S88 which came with 12 volt set up. But I am still verifying that before I hook the battery up. Thanks once again.

 

[560Dennis]

Did a search ,was include in previous post

 

[BarnyardEngineering]

The posts on most batteries are slightly different sizes between positive and negative. It's likely that the clamps are still molded to whatever post they were on last, so when you go to put the new battery in, pay attention. If the clamp don't fit, it probably wasn't on that post before.

 

[2SteveWI]

I know this may seem like a stupid question. I bought a super 88 Oliver, which has a generator on it and it has no battery in it. I am pretty certain it is a 12 V system but how can I tell if it’s positive or negative ground? The original owner has passed away and there’s nobody around to ask that knows the tractor. Thank you in advance.

Have an Improved super 88D that I recently purchased. it is 12 volt neg. ground. This has the generator with power steering pump attached. The generator charges. Ammeter goes in right direction when running. Have a green wheels super 77 gas that was originally 6 volt positive ground. Upgraded that to 12 volt pos. ground generator. works great. Steve.

 

[rrlund]

Those are 6 volt systems. Should be pos. Ground. Talking gas here. Look at the cable end going to ground that should tell the story , as I said should unless it’s been messed with. Diesel’s are 12 volt.

His is 12v. It's a 1957 Improved Super. 57 was when they switched to 12v on the gas tractors. If it's original, it's positive ground. Oliver used positive ground until they switched to using alternators.

 

[8NHENRY]

Thanks for everyone help. It’s a 12 volt generator and positive ground. Tried to get it going but the points are fried