John T or George

wilson ind

Well-known Member
John T I have 2 or 3 coils in the shop with marking rubbed off. Please give me the oms and other information on how to diagnose voltage. Thanks. Also explain detailed instruction using cheap harbor freight free tester. Also John T as I noticed you are out west, if you will not return by time of Elnora show please let me have your reservation.I called too late to get electric hook-up. Old friend George might get testy if I do not have ac in the fifth wheel.lol George I plan on friday and possibly sat at show depending on weather.
 
Bill, I'm not sure what the ohm reading are for coils. That's more JohnT or JMOR's area of expertize. I think JMOR said you should to have 4 amps in primary, so if you connect 6v to a coil and only show 2 amps, good chance you a 12v coil. On the other hand 6v and 4 amps then good chance it's a 6v coil.

I remember when cars went from 6 to 12v, the 12v coil used a ballast and not the full 12v. Newer 12v coils don't use ballasts, they use all the 12v. So coils without numbers on them could be anyone's guess.

So what voltage do you need a coil for?

Did you ever get the starter I gave you working on the Farmall?

I'll watch the weather and plan accordingly. Be in touch.
 
Little slow this morning, only one cup of coffee.

Ohm's law should apply here, 6v and 4 amps = 1.5 ohms

12v and 4 amps = 3 ohms.

That said, HF meters can't be zeroed. I have many HF meters. I don't trust the ohmmeter for accuracy. I use them more for determining continuity.

However, you may conclude the coils with more resistance are your higher voltage. HF meters are good for measuring current, so I would still recommend doing what I said above.
 
Wilson, I will be at Elnora, Im not going west until its over. Many typical old farm tractor ignition coils have a LV Primary (between little + and - terminals) resistance around:

6 Volt: 1.25 to 2 ohms (many around 1.5)
12 Volt: 2.5 to near 4 ohms (many around 3)

Typically you want to limit the current the points have to switch to 4 amps max which means 1.5 or 3 ohms for 6 or 12 volt coils.

I will find you somewhere at Elnora and you know my Green with yellow Wheels 4 passenger Golf Cart. You and George behave yourselves now.

John T
 

I would not trust that reference .
A coil that is used on 6V or on 12V with a ballast has a primary resistance of approx 1.5ohms.
A coil for use on 12V without a ballast has a primary resistance of approx 3.0ohm.
 
I did get the starter working. put back in trailer and forgot to take a picture. The starter works , however I need to put another belt reduction as its too fast. It turns over faster than the mag impulse trips. Were I to do another I would go with a flexplate on clutch to transmission coupling. Done an f12 that way 50 years ago. Let you know more on show plans later. Coil thing is son bought a 48 chev one ton pick-up 9 foot bed (rather rare) installing 12 volt and ac. Other wise keeping stock. No chev 350 and modifying body, just comfortable old truck
 
John let the poor man have the electric! YOU KNOW HE WOULD DO IT FOR YOU

YOUR FRIEND
BOB
 
Hey, that's my line, no fair using it against me..............Besides, Wilson don't need it, he's a tough old bird lol

Your friend,

John T
 
JohnT, I can behave, but BILL, NO WAY. He was born that way and you can't change an old dog. Too many woman have tired.
 
Bill remember it's a 6 v starter. After shearing off 2 starter drives and chipping a tooth on flywheel, I happily replaced it with a 12v starter I got from YT. Had the same problem with farmall C. They don’t make a 12v starter for it, so I'm using an old 12v lawn mower battery that puts out about 200cca. Slowed it down, not a problem with mag, easy on starter, starts when it's sub zero too.
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(quoted from post at 05:36:22 08/26/15)
I would not trust that reference .
A coil that is used on 6V or on 12V with a ballast has a primary resistance of approx 1.5ohms.
A coil for use on 12V without a ballast has a primary resistance of approx 3.0ohm.

And I am running 12V coil no ballast and a primary resistance of approx. 3.0 ohm.
 
(quoted from post at 05:36:22 08/26/15)
I would not trust that reference .
A coil that is used on 6V or on 12V with a ballast has a primary resistance of approx 1.5ohms.
A coil for use on 12V without a ballast has a primary resistance of approx 3.0ohm.

And I am running 12V coil no ballast and a primary resistance of approx. 3.0 ohm.
 

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