MTFCA Forum

Asking for a friend- if a car is incorrectly connected positive ground- will the starter spin backwards?

No

the starter dont care but everything else does so dont do that. philip

The only thing on a T that is polarity sensitive would be the generator (it can be flashed) and if it has a modern regulator or diode cutout on it. Mechanical cutouts do not care what ground is used.

and the ammeter.

Thanks. I'll pass this info along to a friend who recently bought a car at auction that was incorrectly wired with a positive ground. I've never worked on a T wired Positive ground, so I couldn't give him a good answer.
If anyone has ever been through his situation it would help him if you could list a step-by-step on what to check to get things right.
Thanks.

"and the ammeter." ya true, but it will just read backwards if the wires are not swapped. If it still has a mechanical cutout all you have to do besides the ammeter, is flash the generator after changing the battery leads. Google it.
If it has modern regulator or diode type, it will need to be changed out for negative ground type anyway. No other wires need to be changed.

If it is Friday and the car starts and runs, and the ammeter shows a charge when it is charging, it is fine as-is. You can fart around and spend Saturday afternoon fixing everything to negative ground (and maybe have to spend some money doing it) and on Sunday, you will still have a car that will act exactly like it did on Friday. But it will be correct. If that has value to you, then it has value to you.

I would not be inclined to mess with it until some part of the electrical system needs repairing or replacing and then expend the effort, but I sure wouldn't be inclined to mess with it otherwise...too many other things on a new T that invariably need correcting right away, for safety's sake.

This is not quite related but I inadvertently charged a battery backwards, it was completely dead and the charger did not react and it charged up fully ok, I only got a reaction when I put it back into service. I had to completely discharge the battery using a small light (it took about 5 days) and recharge it the correct way, If you think it can't be done well it can. This did cause me a short period of grief.

David, I did the same thing with an old Cub Cadet...thing actually started, but the amp meter showed a discharge.