Will reversed battery polarity hurt anything?

[Kyzyl]

I have an all original 1936 Coupe that I purchased recently. It started and ran fine during the test drive of 5-7 miles.

Recently I noticed that the battery was installed as a negative ground, however, the wire from the coil to the distributor is on the + side of the coil. So in my mind, the battery was installed backwards, and the previous owner must have forced the battery cables fit.

Yes, the ammeter goes down, instead of up, when it's running, so that's backwards.

The fuel gauge is at the very bottom. I don't know if it's broken, or perhaps responding 'properly' to the reversed polarity of the battery.

The car seems to start and run fine, although it seems to now have a sputter in the mid-range unless there is a load on the engine. Perhaps for setting too long?

I haven't run it much, so I'm not sure if the generator is charging or not, nor have I checked it with a meter.

My question is:
If I change the battery back to + ground, which is how it appears it should be (based on the coil-to-distributor wire), will it hurt anything?

Is there anything else to check before performing this 'smoke test'?

Thanks for your time.

[corvette8n]

https://fordbarn.com/forum/showthrea...rize&showall=1

You may have to polarize the generator after switching back to pos+ ground.

[KiWinUS]

Replace coil

[sugarmaker]

Kyzyl,
Welcome to the Ford Barn! Pictures of your 36 would be great! I am not your electrical guy. But I seem to remember somethinh about the coil wires. But I have slept since then and forgot.
Lot of folks here that can help you on the details for sure.
Regards,
Chris

[V8COOPMAN]

Originally Posted by Kyzyl

My question is:
If I change the battery back to + ground, which is how it appears it should be (based on the coil-to-distributor wire), will it hurt anything?

Is there anything else to check before performing this 'smoke test'?

Thanks for your time.

In a NEG GROUND system, the ignition wire SHOULD go to POS COIL. NEG COIL wire then goes to DISTRIBUTOR.

AMMETER wires need to be REVERSED, or run through the loop from opposite direction.

Coop

[tubman]

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Originally Posted by KiWinUS

Replace coil

I am curious on why you would suggest this.

[KiWinUS]

Originally Posted by tubman

I am curious on why you would suggest this.

Information “Bubba” posted on Barn some time back.

[V8COOPMAN]

Originally Posted by tubman

I am curious on why you would suggest this.

I've heard it said that SOME coils don't take too well to having polarity changed once they have 'MEMORIZED' the flow of things initially.

Coop

.

[pistonbroke]

My brother hooked up my 36 Dodge to neg. ground by accident once and I drove it for a year or so . The two things I remember were the amp gauge was backwards and the heater motor ran in revers making a horrid noise. The battery was under the floor(carpet and pad)so the obvious went undetected and the system maintained 7.5 volts so I as a young man of 27 was puzzled for quite some time. I drove it as a daily driver like this with no other issues .
Tim

[tubman]

Amazing how resilient these old cars were. I wonder how many thousands it would cost you if you hooked the battery up backwards on one of these new cars?

Actually, I would expect there to be a "fail-safe" to prevent major damage. I'll bet it wouldn't run, though.

[koates]

By your description of the ignition system it seems that your coil is a non original can type one and not the original FORD bakelite type that sits on top of the distributor. Providing that there are no modern radio or other neg ground aftermarket equipment fitted to the car then I would just change the battery back to positive ground. The generator should repolarize itself when you start the engine and rev it up a bit and then show a charge on the ammeter. No need to change anything else. Regards, Kevin.

[koates]

V8COOPMAN. I am sorry to inform you that the wiring circuit and components you posted do not relate to an ORIGINAL 1936 Ford V8. I hope this does not confuse the person who asked the original questions. Regards, Kevin.

[V8COOPMAN]

Originally Posted by koates

V8COOPMAN. I am sorry to inform you that the wiring circuit and components you posted do not relate to an ORIGINAL 1936 Ford V8. I hope this does not confuse the person who asked the original questions. Regards, Kevin.

Kevin.... You noted yourself that the coil (as he described it) did not appear to be an original Ford-type coil, even though he thought the car to be ESSENTIALLY original. I agree with your post above that the coil (as HE described) seems to be a POS & NEG post, can-type coil. Hence, what I posted!

Coop

.

[TJ]

Originally Posted by koates

By your description of the ignition system it seems that your coil is a non original can type one and not the original FORD bakelite type that sits on top of the distributor. Providing that there are no modern radio or other neg ground aftermarket equipment fitted to the car then I would just change the battery back to positive ground. The generator should repolarize itself when you start the engine and rev it up a bit and then show a charge on the ammeter. No need to change anything else. Regards, Kevin.

Sounds like the correct answer. I had the same thought that the original coil was not on the car and possibly had the adapter on top of the distributor for that coil. A photo of the setup would confirm it.

[terry]

Kyzyl, is your battery 12v or 6v. Usually if the battery is neg ground the car has been switched to 12v. terry

[bobH]

Me thinks... ya-all are overthinking all this... hook it up either way you want, try it. If it works, done.
If the 36 is still 6V, and if you want it 'stock', then yes, put the battery plus to ground. And if the coil is the type where you can choose polarity, then the plus side of the coil goes to the distributor.
Turn on a big 'draw'... like the headlights. Ammeter should show a discharge (engine off).
Turn the lights off, start the engine, fast idle, ammeter should show a charge.
If you want neg ground, either 6 or 12 V, then another discussion. Do whatever you want.

[Kyzyl]

Thanks everyone for your prompt and thorough replies.

To clarify some questions that some of you had:
- Yes, it's 6v.
- Yes, the existing coil is the 'beer can' type with a + and - pole.
- Currently it is - ground, but I believe it should be + ground based on the reversed ammeter behavior and the + pole of the coil being connected to the distributor.

The consensus seems to be: Switch the battery back to + ground and try it.

I will be out of town for several days, but I'll make the change late next week when I return and let everyone know.

Thanks again for taking the time to help out. Happy New Year everyone.

-Kyzyl