1952 Ford 8N 12V ground question

I just got a tractor, supposedly it has been converted to 12V. Should it be a positive ground or negative ground?. I know originally they were positive ground. Just wondered if converting to a 12V system changes the grounding from positive to negative?

If you have an alternator, its almost 100% sure that its negative ground. Positive ground alternators are special order but do exist. Motorola had alternators that could be modified in the field to positive ground.. but "common" alternators are mostly negative ground.

(quoted from post at 19:07:28 07/09/18)
If you have an alternator, its almost 100% sure that its negative ground. Positive ground alternators are special order but do exist. Motorola had alternators that could be modified in the field to positive ground.. but "common" alternators are mostly negative ground.

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Not concerned with alternator, but starter and solenoid frying

Starter and solenoid don't care about polarity.

Just be careful not to crank too long, the starter will overheat quickly on 12v.

(quoted from post at 21:50:16 07/09/18)

(quoted from post at 19:07:28 07/09/18)
If you have an alternator, its almost 100% sure that its negative ground. Positive ground alternators are special order but do exist. Motorola had alternators that could be modified in the field to positive ground.. but "common" alternators are mostly negative ground.

Click to expand...

Not concerned with alternator, but starter and solenoid frying

Click to expand...

The starter and solenoid are NOT "polarity sensitive", and the least of your worries.

And they won't heat up any quicker during a reasonable cranking cycle than if they were powered by a pathetic wimpy half-dead 6-Volt battery.

So we've laid another "'ol mechanic wives'" tale to rest!

(quoted from post at 21:04:37 07/09/18)

(quoted from post at 21:50:16 07/09/18)

(quoted from post at 19:07:28 07/09/18)
If you have an alternator, its almost 100% sure that its negative ground. Positive ground alternators are special order but do exist. Motorola had alternators that could be modified in the field to positive ground.. but "common" alternators are mostly negative ground.

Click to expand...

Not concerned with alternator, but starter and solenoid frying

Click to expand...

The starter and solenoid are NOT "polarity sensitive", and the least of your worries.

And they won't heat up any quicker during a reasonable cranking cycle than if they were powered by a pathetic wimpy half-dead 6-Volt battery.

[b:6d99ebd767]So we've laid another "'ol mechanic wives'" tale to rest![/b:6d99ebd767]

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I doubt that very much.

The starter and generator and solenoid can work at EITHER polarity (if genny is properly polarized and a suitable VR) and the starter still turns the same direction at either polarity. If you were to use an alternator Id definitely use Neg ground. An ignition coil (if possible) and ammeter (if so equipped) needs wired to match the polarity you choose.........

John T

but I should run it negative ground correct?

and further I understand the starter and solenoid are not ground specific but what about the battery and coil ?

(reply to post at 14:18:27 07/10/18)

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I'm not clear what you're asking about the battery, but the coil should have the negative going to the points.

Not concerned about the alternator?? Well you should be because if it is hook up backwards for just one second you will let the smoke out of it and then you have to spend around $50 to replace it

(quoted from post at 07:59:34 07/10/18) Not concerned about the alternator?? Well you should be because if it is hook up backwards for just one second you will let the smoke out of it and then you have to spend around $50 to replace it

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Planning on disconnectiong the alternator for now

My Plan is to get the tractor running first as it hasnt been in years.
my plan in order is:
Getting motor to Crank
Getting motor to start
addressing charging system
addressing cooling system
addressing transwission
addressing hydraulics

I'm the third owner of a non-running '52 8N. It has a 10DN Delco alternator with the tiny regulator, making it one wire. It was hooked up POSITIVE ground. I got it running and nothing out of the alternator. I had PM Electric in Hayden, Colorado, check things out, and he said it was indeed set up for positive ground. It had the yellow wire, which is for an idiot light, going directly to the battery side of the solenoid, the black ground wire to the output terminal of the alternator, and nothing else hooked to the output. It would not work wired this way. I disconnected the yellow wire and let it dangle, and ran a wire from the output terminal to the solenoid, and it works well. I've been working on machines and such for over 60 years, and this is the first Delco I've seen positive ground. Don't worry about the starter and solenoid - they work no matter what way you have it set up. If the ammeter reads backward, reverse the wires.

Thanks for this post, thought I was going crazy last night while checking the wiring for my "new to me" tractor. Wanted to test the alternator and everything was coming back negative, very surprised to see that my machine is positive to ground.

I ended up switching my multi-meter to check for resistance to see how all the wires where connected. Definitely had me scratching my head.

Because I know I will eventually screw it up and cross the wires I'm going to get a new alternator and wire it the traditional way with negative to ground. Likely get a whole new wiring harness while I'm at it just for piece of mind. Thanks.

-Tyler