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Old 06-13-2013, 04:49 PM   #1
Doot
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Default Coil... Labeled: "dist" is that the plus side?

I have the wiring diagram right in front of me, but I want to know which side of the coil is plus & minus? It only says on one side "dist"! Is the "dist" side plus or minus? Thank you!

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Old 06-13-2013, 05:13 PM   #2
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Default Re: Coil... Labeled: "dist" is that the plus side?

Dist will be the negative post. It assumes a modern negative ground system.

Is your car positive ground or negative ground?
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Old 06-13-2013, 05:15 PM   #3
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Default Re: Coil... Labeled: "dist" is that the plus side?

The positive battery cable from battery is on the frame...
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Old 06-13-2013, 06:14 PM   #4
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Default Re: Coil... Labeled: "dist" is that the plus side?

Here is a link Tom posted on determining correct coil polarity.
http://www.chicagolandmgclub.com/tec...neral/574.html

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Old 06-13-2013, 06:31 PM   #5
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Default Re: Coil... Labeled: "dist" is that the plus side?

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Here is a link Tom posted on determining correct coil polarity.
http://www.chicagolandmgclub.com/tec...neral/574.html

Bob
Okay!!! That was a little vague, but nonetheless helpful!!! I was hoping for a more direct answer!
A coil has a positive and negative post regardless if they labeled "dist" or not! I know your link suggested that from the factory they might not know which side is which, but I have to disagree! There is no way Henry Ford would not have distinguished the polarity of his coils for the common man back in the day!!! My car is All original and I can't find the literature for polarity directly from the factory..... It's not a matter of a running/car issue, I just want to KNOW for myself!
I appreciate the info you have given me thus far, and want you to know you are helping!!! Thank you!
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Old 06-13-2013, 07:12 PM   #6
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Default Re: Coil... Labeled: "dist" is that the plus side?

On a stock Model A Ford, the "dist" is the positive (ground) side. When the distributor points close, they ground . The black wire (coming from the junction box) is the negative (power ) wire and goes on the "batt" side of the coil. It is that simple.
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Old 06-13-2013, 07:29 PM   #7
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Default Re: Coil... Labeled: "dist" is that the plus side?

There are so many different coils and you cannot tell by looking at them if they were made for + or - ground, it can get very confusing. The best and easiest way is to get a polarity tester. I think all the parts venders sell them. Very simple and takes the guess work out.
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Old 06-13-2013, 07:39 PM   #8
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Default Re: Coil... Labeled: "dist" is that the plus side?

Any coil that is marked DIST and BAT is totally meaningless, unless you know the specific car that coil was made for and which battery post was ground on that car.

I wish all coils simply had a + and - marking, then there would be no guesswork, as the battery ground should be that same as the marking that goes to the points. Positive battery ground means + on the coil goes to the points.
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Old 06-13-2013, 07:58 PM   #9
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Default Re: Coil... Labeled: "dist" is that the plus side?

Okay to all participants! I will do the necessary tests you mentioned and go from there! Thank you! I will keep you posted!!! Thank you
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Old 06-13-2013, 08:09 PM   #10
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Default Re: Coil... Labeled: "dist" is that the plus side?

Quote:
Originally Posted by SteveB31 View Post
On a stock Model A Ford, the "dist" is the positive (ground) side. When the distributor points close, they ground . The black wire (coming from the junction box) is the negative (power ) wire and goes on the "batt" side of the coil. It is that simple.
Here's the diagram I am using... Just wasn't sure which terminal to use off the coil... I think you nailed it!
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Old 06-13-2013, 08:18 PM   #11
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Default Re: Coil... Labeled: "dist" is that the plus side?

Quote:
Originally Posted by SteveB31 View Post
On a stock Model A Ford, the "dist" is the positive (ground) side. When the distributor points close, they ground . The black wire (coming from the junction box) is the negative (power ) wire and goes on the "batt" side of the coil. It is that simple.

Hopefully this pic came out straight up and down?
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Old 06-14-2013, 01:59 AM   #12
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Default Re: Coil... Labeled: "dist" is that the plus side?

Okay... Forget about this thread.... Got that question fixed... Went through wiring diagram and all wires are now correct!.

See new thread...
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Old 06-14-2013, 03:47 AM   #13
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Default Re: Coil... Labeled: "dist" is that the plus side?

Doot, If a coil is marked "Dist" Then that side is wired to the distributor. The other side goes to the feed or ignition switch. The coil can be used in a negative to earth or a positive to earth system. The coil is not polarity sensitive. It is the way it is wired inside, that decides which side is the "Breaker" side or "feed" side.
I have posted, hopefully to help others following this thread.
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Old 06-14-2013, 04:21 AM   #14
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Default Re: Coil... Labeled: "dist" is that the plus side?

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Originally Posted by Bluebell View Post
If a coil is marked "Dist" Then that side is wired to the distributor. I have posted, hopefully to help others following this thread.
. Yeah that's right if it's the correct coil and if the polarity of the car ground hasn't been changed. As others have pointed out the only way to be sure is to follow the guidance they've given. ( er, to be honest though on the A I found that an incorrectly wired coil still works OK!)
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Old 06-14-2013, 04:58 AM   #15
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Default Re: Coil... Labeled: "dist" is that the plus side?

Yes, as John said, the car will start just fine either way the coil is wired. When the polarity makes a difference is when you need every bit of the available spark, such as running a higher compression head and flooring the throttle, then the spark plugs fire easier if the hot center electrode is NEGATIVE, as explained in the excellent short read by the Chicagoland MG club. It's well worth reading.

As I said earlier, the DIST label is meaningless unless you are using the coil on the car it was labelled for. Almost every Model A I see has a replacement coil, rather than the original coil with it's spot welded mounting bracket. That how I've been able to find so many good original coils at swap meets.
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