C1 ignition coil
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Heel & Toe
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C1 ignition coil
I have a 1956 corvette. It has a pertronix electronic ignition. The resistor on the firewall is bypassed as required with this ignition set up. I need to replace the coil which has gone bad. Picked up an ac delco coil. U505. It looks like an exact match, 1.5 ohms across the terminals but I am being told it needs to have an internal resistor not external otherwise I would have to re wire the resistor on the firewall. No one seems to be able to tell me if this coil has an internal resistor. Can anyone enlighten me??
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I've never heard of a stock, cylindrical coil with an internal ballast resistor. I seriously doubt there has ever been such a thing.
Resistance is resistance, BTW. The coil itself doesn't care and can't tell if the current limiting resistor is internal or external. If your new Delco coil requires a ballast resistor, rewire the one on the firewall to put it back in the circuit.
Resistance is resistance, BTW. The coil itself doesn't care and can't tell if the current limiting resistor is internal or external. If your new Delco coil requires a ballast resistor, rewire the one on the firewall to put it back in the circuit.
Instructor
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I'm not expert, but I hadn't heard of a coil having an internal resistor in it. That U505 seems to be a stock replacement and universal fit for Chevys which use a ballast resistor in the circuit. What coil did you take off that failed? Pertronix makes one that would work with theIgnitor Electronic Conversion Kit, but can benefit virtually any distributor type inductive systems. # 40011- it is a 1.5 ohm coil too.
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Heel & Toe
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I'm not expert, but I hadn't heard of a coil having an internal resistor in it. That U505 seems to be a stock replacement and universal fit for Chevys which use a ballast resistor in the circuit. What coil did you take off that failed? Pertronix makes one that would work with theIgnitor Electronic Conversion Kit, but can benefit virtually any distributor type inductive systems. # 40011- it is a 1.5 ohm coil too.
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Heath-
From my years of reading the travails of those with Pertronix in their cars I believe I recall that its wiring is often the problem. The little nugget under the cap needs battery current direct from the ignition switch while the coil, from what I understand, will need a ballast resistor in one form or another somewhat matched to the coil impedance. Some of the coils Pertronix sells seem to differ in primary resistance so that a ballast isn't always needed, you will have to ask them.
In 25 years and 9 cars I have never experienced coil failure. Good original coils fail from overheating caused by excessive primary current.
Dan
From my years of reading the travails of those with Pertronix in their cars I believe I recall that its wiring is often the problem. The little nugget under the cap needs battery current direct from the ignition switch while the coil, from what I understand, will need a ballast resistor in one form or another somewhat matched to the coil impedance. Some of the coils Pertronix sells seem to differ in primary resistance so that a ballast isn't always needed, you will have to ask them.
In 25 years and 9 cars I have never experienced coil failure. Good original coils fail from overheating caused by excessive primary current.
Dan
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I used to sell this 12v coil in my store, built in resistor so no external ballast required.
https://www.ebay.com/itm/Standard-Mo...edirect=mobile
https://www.ebay.com/itm/Standard-Mo...edirect=mobile
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I used to sell this 12v coil in my store, built in resistor so no external ballast required.
https://www.ebay.com/itm/Standard-Mo...edirect=mobile
https://www.ebay.com/itm/Standard-Mo...edirect=mobile
Was this coil ever used in an OEM application?
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I have a 1956 corvette. It has a pertronix electronic ignition. The resistor on the firewall is bypassed as required with this ignition set up. I need to replace the coil which has gone bad. Picked up an ac delco coil. U505. It looks like an exact match, 1.5 ohms across the terminals but I am being told it needs to have an internal resistor not external otherwise I would have to re wire the resistor on the firewall. No one seems to be able to tell me if this coil has an internal resistor. Can anyone enlighten me??
I seriously doubt that any stock delco coil would have an internal resistor.
Pertonix specifically states that any 1.5 Ohm coil will do but--from my experience I doubt that as well.
I fought this issue for almost two years---I was going through more coils than tubes of toothpaste. Pertonix was sending me replacement coils and despite countless hours on the phone with their techies, could offer no explanations as to why my coils were going bad so fast.
In the end I decided to agree with Jim Lockwood that electronic ignition on these old cars is "an exotic solution to a non existent problem."
I got rid of all that electronic stuff, put back my original points, coil, ballast resistor and condenser and have never looked back. The car runs like a champ . I dont get towed home any more, my wife likes going out for rides with me again and I have not replaced any ignition parts since.
Thanks Jim!
Eddie
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Regarding coils with internal resistances, electrically the coil primary circuit works the same way as the stock configuration (Jim is correct ). However, there is always power dissipation (ie: heat) when multiple amps are flowing in a circuit. The stock system, with the ballast, divides the heat load amongst the ballast and the coil, whereas the internal resistor coil takes all the wattage/heat. Heat (and the mechanical expansion caused by that heat) is what stresses/damages electrical components.
Not saying that the internal resistor coil is a failure waiting to happen. I'm just saying it's not my first choice when assembling an ignition system.
). However, there is always power dissipation (ie: heat) when multiple amps are flowing in a circuit. The stock system, with the ballast, divides the heat load amongst the ballast and the coil, whereas the internal resistor coil takes all the wattage/heat. Heat (and the mechanical expansion caused by that heat) is what stresses/damages electrical components.Not saying that the internal resistor coil is a failure waiting to happen. I'm just saying it's not my first choice when assembling an ignition system.
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For a coil with internal ballast, how is the resistance packaged? What form does it take.... a lossy pellet, perhaps? Or maybe the resistance of the primary wire itself? Where is it inside the case? What's the trade off.... is there less room for the coil windings?
Expiring minds want to know....
Expiring minds want to know....
Le Mans Master
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For a coil with internal ballast, how is the resistance packaged? What form does it take.... a lossy pellet, perhaps? Or maybe the resistance of the primary wire itself? Where is it inside the case? What's the trade off.... is there less room for the coil windings?
Expiring minds want to know....
Expiring minds want to know....
Dan
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Heel & Toe
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i am left with the 12 volt brown wire from the ignition and the green from the ignition. The green wire was replaced because it was toasted from end to end.
the question is, do i tie these two wires together and connect into positive on coil or eliminate the green. As a side note my wiper motor is connected to the brown also.
I only want to do this once. Running that new green was a lot of contorting in positions my body is not use to!!