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Old 01-12-2018, 07:32 AM   #1
Bob Bidonde
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Default Original Ignition Coil

I need to know for a technical presentation, what the secondary high voltage of an original ignition coil is.

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Old 01-12-2018, 10:16 AM   #2
katy
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Default Re: Original Ignition Coil

The typical "old" ignition coils put out 5,000 to 6,000 volts, dunno what an original Model A coil puts out.
Maybe someone with an old ignition analyzer scope can supply an actual reading.
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Old 01-12-2018, 10:33 AM   #3
Tom Wesenberg
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Default Re: Original Ignition Coil

My original slant pole coil puts out about 12,000 to 15,000 volts.
Check on Vince's website and he might list the specs. I might be able to find them somewhere, but don't hold your breath.
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Old 01-12-2018, 11:35 AM   #4
Fullraceflathead
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Default Re: Original Ignition Coil

Supposedly the Slant Poles were a little higher voltage around 15,000 volts.
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Old 01-13-2018, 12:04 PM   #5
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Default Re: Original Ignition Coil

Voltage is dependent on rotor air gap, plug air gap, dwell, compression and fuel mixture. A scope will show you how variable it is. Good for others to know. I suspect Bob that you were looking for maximum value. Think of it as a lazy thing; only climbs as high as it needs, to find ground.
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Old 01-14-2018, 08:29 AM   #6
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Default Re: Original Ignition Coil

On an OLD coil, it's a good idea to remove the secondary wire at the coil & crank it over to see if spark is jumping THROUGH the COIL TOWER.
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Old 01-14-2018, 08:44 AM   #7
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Default Re: Original Ignition Coil

Wet your finger and put it in the hole, touch ground with your other hand.

If you just say ouch then it is like 5000 volts.

If you go ouch then say SOB then your close to 10000 volts.

If you say GD, SOB then you are near 15000 volts.

If you say MF GD SOB then your around 30000 volts.

If your repeat 30000 volts several time then you are around 50,000 volts.

At least that is my experience.
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Old 01-14-2018, 09:38 AM   #8
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Default Re: Original Ignition Coil

Something like this?
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Old 01-14-2018, 09:39 AM   #9
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Default Re: Original Ignition Coil

Thought the old rule of thumb was 1K volts for every 1 thousands of an inch on the gap. If that is close then about 35K volts for a 35 thousands gap. Doubt if it is quite that high, but 30K volts would be close
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Old 01-14-2018, 11:30 AM   #10
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Default Re: Original Ignition Coil

Quote:
Originally Posted by Kevin in NJ View Post
Wet your finger and put it in the hole, touch ground with your other hand.

If you just say ouch then it is like 5000 volts.

If you go ouch then say SOB then your close to 10000 volts.

If you say GD, SOB then you are near 15000 volts.

If you say MF GD SOB then your around 30000 volts.

If your repeat 30000 volts several time then you are around 50,000 volts.

At least that is my experience.

Thats a good one and I would say you are right on !!! I got shocked once by my 40.000 volt Flame thrower coil . I have been VERY carefull not to let it happen again . All of the vender replacement coils that I have tested with my jump spark coil tester have failed to jump a 10.000 volt gap . I read somewhere that the original slant pole coils put out around 20.000 volts .
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Old 01-14-2018, 11:41 AM   #11
Purdy Swoft
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Default Re: Original Ignition Coil

I've run the old Mallory Bee Hive coils that have been said to put out 30.000 volts , I could feel a good improvement in performance . The Bee Hive coils are oil filled . By the time that I figured out what I was doing wrong , I had already went through a few of them . Oil filled coils need to be run with the tower pointing upward .
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Old Yesterday, 01:29 AM   #12
Drive Shaft Dave
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Default Re: Original Ignition Coil

Quote:
Originally Posted by Purdy Swoft View Post
I've run the old Mallory Bee Hive coils that have been said to put out 30.000 volts , I could feel a good improvement in performance . The Bee Hive coils are oil filled . By the time that I figured out what I was doing wrong , I had already went through a few of them . Oil filled coils need to be run with the tower pointing upward .
Hey Purdy, glad to see you back on the barn again, Dave.
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Old Yesterday, 03:49 AM   #13
juke joint johnny
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Default Re: Original Ignition Coil

I don't know what the originals put out

But a fellow came round to my house last year in a 29 Canadian Tudor
that he imported a few years ago .

It still had an original Slant Pole Coil on it and it was working fine.

Funny thing is he took it off when I told him "that coil is 86 years old"!!!!
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Old Yesterday, 10:49 AM   #14
Purdy Swoft
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Default Re: Original Ignition Coil

Quote:
Originally Posted by Drive Shaft Dave View Post
Hey Purdy, glad to see you back on the barn again, Dave.
Thanks Dave , I'm happy to be back !!!
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Old Yesterday, 11:06 AM   #15
Purdy Swoft
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Default Re: Original Ignition Coil

Quote:
Originally Posted by juke joint johnny View Post
I don't know what the originals put out

But a fellow came round to my house last year in a 29 Canadian Tudor
that he imported a few years ago .

It still had an original Slant Pole Coil on it and it was working fine.

Funny thing is he took it off when I told him "that coil is 86 years old"!!!!
I've had good luck with the old slant pole coils . I've bought rusty , dented slant pole coils at swap meets for as little as five dollars each . After a good clean up all of the old coils have worked , so far. The service bulletins mention carbon tracks that can extend from the tower up to the metal trube of the coil and short out . I think that the carbon tracks is about all that ever goes wrong . The tracks can usually be scraped off with a pocket knife and all will be good again . The original model A coils are tar filled and sometimes called solid coils . The old guys , way back when use to tell me that coils seldom if ever gave problems .
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