Should An Ignition Coil Be Grounded?

Lanse · Sep 29, 2017

Title is the question, does anyone actually know if a standard 12 volt negative ground system's coil should be grounded to anything, anywhere? If so, where. Thank you.

Pete_5959 · Sep 29, 2017

No.

r/

Pete

denglish · Sep 29, 2017

(quoted from post at 13:11:12 09/29/17) Title is the question, does anyone actually know if a standard 12 volt negative ground system's coil should be grounded to anything, anywhere? If so, where. Thank you.

The coil's primary side gets grounded very time the points close. The secondary side is always an open circuit, due to the spark plug gap. The secondary side is momentarily "closed" when the spark jumps the gap. Other than those two events, you don't want either the primary or secondary to be grounded. In fact some old engines use the grounding of the secondary as an engine kills switch.

John T · Sep 29, 2017

If you're talking about the can/case itself, NO it does not need to be grounded to the tractor frame itself, or at least that's how its been on EVERY old farm tractor I've (farmer and used tractor dealer) seen..........

The Coils LV Primary winding is connected between the small + and - terminals (have seen them labeled BAT and DIST) and the low side (+ or - depends if its a POS or NEG grounded tractor) is what gets grounded via a closed set of points.

John T

James Howell · Sep 29, 2017

Does the tractor have an alternator or generator?

coshoo · Sep 29, 2017

Do you mean should the case be grounded? Every one I've seen is mounted in a metal bracket that is bolted to the engine, so it's already grounded just by mounting it.

Bob Bancroft · Sep 29, 2017

I once had an "epoxy" coil on a tractor. Kind of hard to ground that! The tractor started acting up. After tuning it up, I noticed a crack right down the side of the coil. I wished I had seen it before. I don't know if they are still sold. That was my first, and last epoxy coil.

buickanddeere · Sep 29, 2017

There is not ground on a tractor such as there is in your home electrical panel.
Most mobile DC machines do use chassis return which somehow has been miss named as ground.
The ignition coils in a JD diesel "float" compared to the coil on a JD 70 gasser.

JMOR · Sep 29, 2017

(quoted from post at 17:16:25 09/29/17)
There is not ground on a tractor such as there is in your home electrical panel.
Most mobile DC machines do use chassis return which somehow has been miss named as ground.
The ignition coils in a JD diesel "float" compared to the coil on a JD 70 gasser.

unny

Should An Ignition Coil Be Grounded?

Lanse

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Pete_5959

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denglish

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John T

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James Howell

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coshoo

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Bob Bancroft

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buickanddeere

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JMOR

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