How Hot should an Ignition Coil Get?

[mjeansonne]

Until a few months ago (2-3) I had the standard coil on my 62 Hawk. I used the resistor wire. I thought I was having coil problems and purchased a Pertronix Flamethrower, 1.5 ohm internal resistor. I bypassed the resistor wire and connected a wire from the ignition switch to the coil as instructed in the Pertronix instructions that came with the coil. I finally switched to a Pertronix Ignitor system to replace the points. Everything worked great!! Then I started having missing problems with the engine. Thinking it was Carb related I started examining the Carb. Saw the PErtronix coil was leaking!! There was a crack completely around the tower, next to the output. (See earlier post entitled: "What the Heck") Wrote PErtronix twice and was told twice that absolutely that a resistor was not necessary!!

Nevertheless, seeing that the coil was getting rather hot (I don't think I could have held it in my hand very long!), I decided to take everyone's advice and add a resistor. I did so and added a 1.5 ohm external resistor, hoping the coil would run cooler. I drove the car a good bit today and when I got home checked to see if the coil was hot. I touched it with my bare hand and it is still getting too hot to hold very long. (Sorry that's the best I can describe how hot is it getting) This is the second PErtronix and I don't want to burn it up too. In fact, I haven't even sent the last coil back to PErtronix for them to replace it!!!

The question is how hot should the coil get?



Laisez le bon temps roulez avec un Studebaker

[41 Frank]

Is it getting hotter than the engine that it is bolted to? It will get at least as hot as the intake manifold,compare and see if there is much difference.

Frank van Doorn
1962 GT Hawk 4 speed
1963 Daytona Conv
1941 Champion R-2 Rod

[rusty65]

Hint:If the ballast resistor is hotter than a mamma-jamma,then it's doing IT'S job.Don't know about the coil temp,cause once my engine gets up to temp,everything's hot under the hood.(yeah, I like 41 Frank's response better too.)

[Bud]

The Pertronix instruction sheet says to leave the resistor in the circuit. The red wire in the Pertronix module must be connected directly to the ignition switch to the ignition terminal not the accessory terminal. If you bypass the pink wire from the ignition switch to the coil, you are putting full battery, generator voltage on the coil and that will cause the coil to overheat. I've had a Pertronix unit in my 62 Hawk for years and wired it per the instruction sheet and it works fine. Bud

[Dick Steinkamp]

quote:Originally posted by Bud

The Pertronix instruction sheet says to leave the resistor in the circuit. The red wire in the Pertronix module must be connected directly to the ignition switch to the ignition terminal not the accessory terminal. If you bypass the pink wire from the ignition switch to the coil, you are putting full battery, generator voltage on the coil and that will cause the coil to overheat. I've had a Pertronix unit in my 62 Hawk for years and wired it per the instruction sheet and it works fine. Bud

That's true if you leave the stock coil in place.

If you are using the FlameThrower coil, it is internally resisted and the instructions tell you to by pass the ballast resistor.

I ran a small block Chevy in my '54 Stude with the Pertronix unit and a FlameThrower coil with no ballast resistor for 35,000 trouble free miles.



Dick Steinkamp
Bellingham, WA

[Bud]

Dick. Bypassing the ballast resistor is correct when using a 3 ohm coil, but when using a 1.5 ohm coil which is what mjeansonne is using, the resistor should remain in the circuit to prevent the coil from receiving to much voltage.. The original Prestolite coil is 1.5 ohms and original the resistance wire is usually around 1.5 to 1.7 ohms.I checked the coils on my Hawk and on my girlfriends Lark with a 259 and stock ignition and they're both hot to the touch after the engines have been running for a while. . Bud

[Dick Steinkamp]

I emailed the Pertronix tech folks and told them that with the Ignitor and 1.5 ohm FlameThrower coil that some say to remove the ballast resistor (or wire around it) and some say leave it in place and hooked up. Here's their response...

Dick,

They are both correct. The FlameThrower coil and Ignitor will work with or
with out a ballast resister. You will not get the full benefit of the
Ignitor and FlameThrower when using the ballast resister. But you will still
get an improvement over your points system with the resister installed.

In the end it's up to you. If you wanted the car to look original or didn't
really car about maximum performance just leave the resister alone. If you
wanted the best possible performance from the combination you would want to
remove the resister.

If you have any further questions feel free to contact me.
Marvin Grebow Jr.
PerTronix Inc.
Technical Department Ext. 1030
marving@pertronix.com

Dick Steinkamp
Bellingham, WA

[mjeansonne]

Thanks for everyone's input. I rechecked the coil's instructions and yes, it says to remove the resistor. As I indicated in my earlier post, I installed a ballast resistor this weekend, but the coil still seems to be getting hot!!!

I think I am going to try Frank's suggestion, but will use an infared thermometer and see what the coils temperature is in relation to the intake manifold.

Maybe I'm just gun shy!!



Laisez le bon temps roulez avec un Studebaker

[Bud]

I'll bypass the ballast resistor in my Hawk and I'll see what happens. I have an infrared thermometer to check the coil temp before removing the resistor and after removal of the resistor and I'll report what I find. Even with the resistor connected, I'm still getting around 40 kilovolts out of the coil which is a NAPA Echlin high performance coil.

[Dick Steinkamp]

quote:Originally posted by Bud

I'll bypass the ballast resistor in my Hawk and I'll see what happens. I have an infrared thermometer to check the coil temp before removing the resistor and after removal of the resistor and I'll report what I find. Even with the resistor connected, I'm still getting around 40 kilovolts out of the coil which is a NAPA Echlin high performance coil.

The instruction and advice from Pertronix is to remove the resistor ONLY if you are running one of their coils. They instruct you to leave the resistor in place if you are running ANY other coil.



Dick Steinkamp
Bellingham, WA

[Bud]

I had a conversation with the Pertronix tech rep this afternoon and he says do not remove the resistor with any coil but the Pertronix coil as they don't know if the coils from other manufacturers can withstand the added primary voltage. I put a Pertronix coil on the Hawk and checked the firing voltage with my scope and there is about a 5 kv increase in coil output without the resistor in series with the coil. I don't know if that will make much of a difference in engine performance in a stock or slightly modified engine, but maybe in an engine that is run at very high rpm's with high compression. Bud

[BobGlasscock]

Just a technicality for you guys who want more performance and know how to get it. A coil is a transformer built of very small, insulated wire. Higher voltage will heat the wire and can possibly melt the insulation causing the coil to overheat and eventually break down.

'50 Champion, 1 family owner

[Clem64]

FWIW. I experienced the extremely hot coil situation back in the early nineties on my 67' Cougar after installing a Pertronix setup and by going with a direct wired coil as was shown in the instructions from them. Fortunately I discovered it fairly quickly. I mentioned the problem to a fellow old car nut and he told me to go back to the original Ford resistor wire to the coil and it would be ok. I did so and he was correct. While the coil was still quite hot after normal driving it wasn't rippin hot as it was previously. I drove the Cougar for many more years with no coil issues. My Studebakers have the Pertronix Ignitor and Flame Thrower coil setup and utilize the factory resistance wire and seem to be quite happy.

Dean Croft
Roseburg,OR

CLEM DESEE

[mjeansonne]

I can't seem to find anyone with an infrared thermometer... nor do any of the local parts houses loan them out.

I am still experiencing an extremely (I think) hot hot coil!! I am at my wits end. Even though PErtronix says that I don't need one (it has a 1.5 ohm internal resistor), I placed a 1.5 ohm ballast in the circuit, but it hasn't helped. In fact, it gets hot too (I know that's normal, but not that hot).

What can be the problem? Again, I ask the question... How hot does a coil get!!!???



Laisez le bon temps roulez avec un Studebaker

[WCP]

Very hot! The Flamethrower coil on my Avanti got hot enough to melt or soften high density polyethylene wire loom jacketing that was lying across the coil. The coil in an Avanti is housed in an emission box that makes the problem worse. I installed a piece of 90 degree rad hose under the intake manifold to deflect some fan air up into the box for some cooling. Don't know if it helps but I have over 11000 km on that coil with no problem. However, just in case, I carry a spare Flamethrower in the trunk. Peace of mind. I don't think you should have a problem with your Hawk. Just make sure no plastic or rubber (or skin) touches the coil jacket.