Coil resistor?

[ledslinger29]

How can I tell if there is a resistor on my positive coil wire?? If there is, where is it and what does it look like?


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[bwyman]

Test the hot wire with ohm meter with the key on. Should measure below 12 volts.

 

[American180]

How can I tell if there is a resistor on my positive coil wire?? If there is, where is it and what does it look like?


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Ford used resistor wire. There is no physical resistor like you might find on a Chrysler. On a side note, the small wire coming from the starter solenoid is meant to supply full battery power while cranking. It is just normal wire.

 

[B RON CO]

Hi, as mentioned, Ford used a resistor wire, and if you have the points and condenser you should measure l
@ 7 volts at the coil. If you have Pertronix ignition you need 12 v at the coil. Good luck

 

[ledslinger29]

That's why I was confused, I have a pertronix ignitor in my distributor. But I'm only getting about 6VDC at the coil.


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[SHX669]

Then you'll have to bypass or replace the resistor wire in the " run circuit " or run a new 12 V supply wire.

 

[Steve83]

There's a thread here maybe a year old in which several pics of the resistor wire under the dash were posted, and someone (maybe Paul) described it. But I think it varied by year, and you have no indication what year your eB or its wiring harness is. Put it into your signature.

This indicates that it runs from C13 (zone B11) to C6 (zone A4):


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[CopperRanger]

So if your running a Pertronix and you have a resistor wire what would happen? Just wondering because I had a Pertronix and it went bad, so I'm back to running points.

 

[ledslinger29]

Sorry fellas, I'm running a 68 w/ a 170.


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[DirtDonk]

If you're still running the stock coil, you still want the lower voltage at the coil. Only the Red wire to the Ignitor needs the 12v feed.
In that case, you continue to use the stock Red w/green wire on the positive of the coil and look for a different source for the Ignitor. They only recommend connecting it to the coil's positive side for convenience, and only if you have 12v there. If not, then you just need the plan-B and a different source.

If you're running an aftermarket coil, then you need to know exactly which part number it is so you can tell if it needs the resistor still, or can run on full power.
A 12v coil will still work on 6-9 volts, but it won't put out to it's full potential.

Paul

 

[DirtDonk]

So if your running a Pertronix and you have a resistor wire what would happen? Just wondering because I had a Pertronix and it went bad, so I'm back to running points.

At the very least it's simply not working to it's full potential, and while it might seem fine, will often as not put out inconsistent spark.
But in those cases you will know it right away by the engine running crappy.

Many here have tried it that way and had it run like crap. Almost as many have run low voltage to the Ignitor had never had a problem. Or at least not initially.

I'm not sure if your low-voltage condition could have caused, or at least accelerated your Ignitor's failure. But I feel that it's indeed possible.
It's the whole volts-vs-amps and heat thing. I don't know if low voltage makes a device like an Ignitor run hotter or not. Someone else with more electrical theory knowledge will need to weigh in on that.

Good luck with the new one though!
I would always make sure the points plate that the Ignitor is mounted to has a good ground connection to the distributor body. And that the distributor body is clean and so is the bore in the engine block that it fits into.
They never mention this anywhere, but I've had electronic ignitions perform poorly because of too much corrosion and/or oil contamination (old burned on and coked oil inside the bore) and even keep them from working at all in one situation.
Simply spinning the distributor back and forth in it's bore on that engine got things working again.

Paul

 

[ledslinger29]

If you're still running the stock coil, you still want the lower voltage at the coil. Only the Red wire to the Ignitor needs the 12v feed.
In that case, you continue to use the stock Red w/green wire on the positive of the coil and look for a different source for the Ignitor. They only recommend connecting it to the coil's positive side for convenience, and only if you have 12v there. If not, then you just need the plan-B and a different source.

If you're running an aftermarket coil, then you need to know exactly which part number it is so you can tell if it needs the resistor still, or can run on full power.
A 12v coil will still work on 6-9 volts, but it won't put out to it's full potential.

Paul

I got the 40511, which is 3 Ohm. Picked it because I read an article by a guy who worked for Pertronix that said you should use a 3 as opposed to 1.5 or .6 on a 6 banger, but then I got the instructions with the coil, which read a little different....


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[DirtDonk]

I see it says you can use it with a 6-cylinder, but it recommends to keep resistor in place.
So you still have the choice as I see it. Yes, you can go with another coil and run 12v by bypassing the resistor wire, or you can keep this one and keep the existing wire and simply find a different source of power or the Ignitor.

This would be done one of several ways. You can find an unused, or under-used 12v wire under the hood to splice into, or run a new wire from the key, or run a relay in the resistor wire to switch 12v to the Ignitor.
In your situation, I would forgo the whole relay thing at least initially and try to find an alternate source.

The Green w/red wire for your original voltage regulator is a commonly used, underhood source for 12v only when the key is in RUN.
If you find one that is usable, but is on when the key is also in the ACC position, you risk burning out the ignition components by sitting there listening to the radio in ACC position and having the ignition hot all that time. So it's more desirable to have your power source on in RUN only.

Paul

 

[ledslinger29]

Thanks for helping with this cornfusion, I'll update when I figure this out, I'll probably bypass the resistor wire and leave it in place for later...

 

[ledslinger29]

Hi, as mentioned, Ford used a resistor wire, and if you have the points and condenser you should measure l

@ 7 volts at the coil. If you have Pertronix ignition you need 12 v at the coil. Good luck

I see it says you can use it with a 6-cylinder, but it recommends to keep resistor in place.
So you still have the choice as I see it. Yes, you can go with another coil and run 12v by bypassing the resistor wire, or you can keep this one and keep the existing wire and simply find a different source of power or the Ignitor.

This would be done one of several ways. You can find an unused, or under-used 12v wire under the hood to splice into, or run a new wire from the key, or run a relay in the resistor wire to switch 12v to the Ignitor.
In your situation, I would forgo the whole relay thing at least initially and try to find an alternate source.

The Green w/red wire for your original voltage regulator is a commonly used, underhood source for 12v only when the key is in RUN.
If you find one that is usable, but is on when the key is also in the ACC position, you risk burning out the ignition components by sitting there listening to the radio in ACC position and having the ignition hot all that time. So it's more desirable to have your power source on in RUN only.

Paul

B Ron Co, I never knew that about the 12V coil for Pertronix, I’ve been running this thing on 6V for 10 years! No wonder it was such a dog!
Paul, I found the old post with the pictures, and used the wiring diagram posted above to figure which wire to pull from the switch, and ran a normal wire directly to the switch, now running on 12V.
I rebuilt the 170 last year, put a mild cam in it, bigger valves, zero decked the block and took .020 off the head to get 9:1 SCR, and an adjustable timing gear, and was honestly very disappointed at how sluggish it still was. Now with the Flamethrower and the 12V, this little thing is a beast (170 beast). I can’t believe how much more power I’ve got, literally laughed while I was driving it tonight. Don’t know how much is the coil and how much is actually applying the right power to the coil, but I’m tickled. Thanks all!


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[DirtDonk]

Thanks for the update. Glad it's running and tickling!

Paul