Oliver 77

We got the Ollie home today. I noticed that Dave put a 12 volt battery in it ,but it has an old generator. I assumed that means 6 volt? How can I tell? Also will neg, positive ground have caused any issues? He never got it to start, but it spins over. Rain came in and I didn't get to explore farther....

Forgot video.....
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Did I miss something? Did you get another tractor? Is the 77 yours? Great video!!!

Yep. Our friend Dave bought it when we got the MM and they have sold the farm here and moving to Idaho. So he sold me the 77. 2 tractors in 2 days! And my wife said we need to build a new tractor shed!!

That's a good looking Oliver! Nice buy!

So that makes 6? I had a 77 gas nf and a super 88 diesel wf when I was in high school. Would love to have the super 88 diesel back. I have always been a Oliver fan.

Yep 6. Did you see the pictures yesterday of the Allis B? Oliver 77 was my bucket list tractor. Does this mean I can stop buying.........man I hope not!!

Yes I saw the B yesterday. No don't stop buying old tractors! Can never have too many!

The gas tractors were 6V positive ground from the factory, but the diesels were 12V positive ground, so back in the day before Delco 10SI conversions they'd put a generator off a diesel to convert to 12V. That would be my preference as well so it would keep it looking "original".

Haven't looked too close, will the generator have a tag indicating if it's 6 or 12 volt? Either way it's positive ground? Will I need to polarize the generator if battery is hooked up negative ground? Spark is getting to distributor but not getting to plugs. That I can figure out.

Nice looking Oliver!
Someone will correct me if I'm wrong, but I believe on a Delco generator the 6 volt ones have a black tag and the 12 volt ones were/are red.
As far as the ground, whichever terminal on the coil is connected to the distributor is what the ground is--i.e. + side to distributor, positive ground.

Thanks. Hope this rain blows out
tonight and I can get a better
look tomorrow.

Need to make yourself a push/pull pole if you're going to fool with non running tractors

Nice! Is that original paint?

As for the electrical system, it was probably 6v positive ground. Just about all the gas tractors that era were. Do some investigative work, look at the electrical components, like the generator, regulator, coil (and resistor if equipped), light bulbs, anything that might have a voltage or part number on it. Google the part number, see what the voltage is.

If it has a resistor ahead of a 6v coil, good bet it has been converted to 12v.

To check the charging system you'll need to get it running first. You can start it up on 12v if that's the battery you have available. I would connect it positive ground. Then before starting it, polarize the generator. Easy, just run a jumper wire from the negative battery post and spark it to the A terminal of the generator. Just spark it, don't leave it connected.

Have your volt meter ready, connected across the battery. Get it started and revved up to charging range, see what the voltage reads. If it reads around 13-14v, it is charging and has been converted to 12v.

If the reading is low, around 12v, it is not charging. Try removing one battery cable (safe to do with a generator only), keeping the volt meter connected to the cable. If it keeps running, and the voltage drops to around 7-8v, it is set up for 6 volt.

If the voltage immediately drops to zero as soon as the battery is disconnected, something is wrong with the charging system and it will need further diagnosis. If you are trying to keep it original, try to save all the original components. They are much higher quality than new aftermarket. If there is a good starter/generator shop near by, they can be a valuable asset.

Thanks for the information on the charging system. Hope to have time to tinker with it tomorrow. Oh the paint......it's got horrible brush strokes all over it. Yikes!!!!

Just look at the generator housing. On a Delco,a six volt will be the same diameter the entire length of it. If it's a 12,it will be smaller at the rear around the brushes. I'd need a closer picture,but from what I can see,it looks like a 6.

Here ya go! Couple pictures





The old guy Dave bought it from said the starter was rebuilt and he had put tape around it to keep dirt daubers out. It works.

6 volt. Straight case,black tag. The starter's a 6 too,but that'll work just as well with a 12 volt battery.

It's easy enough to change those to 12 volt generator systems. All the diesels and the gassers from 1957 on were 12. The generator and regulator will bolt right on and the wiring is the same. Just change the coil and lights. I've changed my 66 and 77 with 12 volt generators. You'll have a devil of a time getting an alternator mounted up in far enough to get the side cover closed without bending it,although "old" claims to have done it.

Pull a bulb out of one of the lights and write down the bulb number. From there you can look up if the bulb number is for 6 volts or 12 volts.

If those are the original lights,and they look like they are,the bulbs are almost certainly 6 volt. They had an odd flange on them and were the only ones that fit those sockets. I believe Korves Oliver has 12 volt bulbs for them now,but until very recently,you couldn't get a 12 for them.

Grandpa Love, I had my 6 volt generator rebuilt for 12 volt at local shop for less than 100 bucks. I had the receipt kicking around with part numbers and now I can't find it. On my 77 that's 6 volt I still use a 12 volt battery. I tried keeping it original with a new 6 volt battery but battery crapped out. Starts great with 12 volts and can buy new 12 volt at Walley world for 50 bucks. Fire up my HG crawler with an old 12 volt as well. I should of returned that 6 volt to tractor supply.

So as long as I don't hook up lights 12 volt battery will run it ok? No changes?

An Allis Chalmers D19 will have the generator you need 12 Volt,positive ground.