1967 BB 390 hp

[Joey P.]

Hi all, I recently rebuilt my heads and in the process of putting it back together broke a post off my coil. It was a 264 coil and I purchased a new one from Paragon. Received and commenced to finish the project. Got the car up and running but over the last 30 days or so I had what appeared to be what I would call cutting out and could be anywhere in the RPM range. It would immediately pick back up and run well until it cut out again. Thinking I had a good coil I continued to tinker with the car and two weeks ago had it running in the driveway after changing the condenser and thought everything was fine and it just died. I was just going to rule out one part at a time so started with the easiest the condenser. When the car died I still had the shielding off because I was not sure I had solved the issue or not. I happened to feel of the first coil I purchased and it was very hot, so hot I could not just hold on to it. I guess that came as a surprise it was so hot so I let it cool down and then ohm'd the coil. Not having the spec I thought it was good based on the ranges I viewed on YouTube so I continued on with my search. This past Sunday I continued to not have any spark, I removed the breaker points, cleaned them up, put the original condenser back in and reset points. Tried and again no spark. I went to autozone and just purchased a cheap coil to test with since I had not received the second one from Paragon yet. I installed the autozone coil last night, car fired right up!!!! Let it run till the car was about 170 degrees and sounded good, no cutting out at any RPM range and all seemed good but this new cheap coil was also getting very hot, I measured it at 200 degrees before shutting the car off. I know this is long winded but I wanted to provide context so my real question is: What is the normal temp range a coil should be running? If I am too hot what is causing it? Appreciate any and all questions and comments I am about to get.

Regards,
Joey

[Mark F.]

Re: 1967 BB 390 hp

Joey,

Not sure if the coil bracket is the same on a 390 as it is on a 400, but do you have an air gap between the base of the coil and the top of the intake manifold ?

If the metal can of the coil is in contact with manifold metal - it could be acting almost like a heat sink...

[Joey P.]

Re: 1967 BB 390 hp

Hi Mark,

Yes I have a gap. Actually the coil gets hot long before the intake does. Intake yesterday might have been in the 160-175 range and coil was 200+

[Leif A.]

Re: 1967 BB 390 hp

The reproduction coils you're buying from Paragon (or, any other Corvette vendor) are Chinese junk...known to be bad out of the box. Save your $100 plus dollars and buy a coil from NAPA or find an original good 264 coil (David Sokolowski in the Driveline may have one).

[Mark E.]

Re: 1967 BB 390 hp

Good question; I never measured coil temperature. Looking forward to what we learn.

Your story is a reminder to ask "what has changed?" when a new problem occurs.

[Joey P.]

Re: 1967 BB 390 hp

Hi Leif,

Do you or anyone else know what the original 264 coil would ohm out at?

[Joey P.]

Re: 1967 BB 390 hp

Hi Mark,

You are certainly correct and I tried to do just that. When I broke off the terminal on the old coil and put the new one on but prior to getting the car back up and running from the head rebuild I thought maybe I had somehow created a problem during the tear down. I am hoping someone has had a similar issue with the heat if its a problem and will share what they did.

[Leif A.]

Re: 1967 BB 390 hp

Hi Leif,

Do you or anyone else know what the original 264 coil would ohm out at?

From the '67 chassis service manual:

Points coil.
Primary resistance 1.24-1.46 ohm
Secondary 6500-9500 ohm

[Tim G.]

Re: 1967 BB 390 hp

I'm running a 202 coil in my 1967 390 because I can't fine the correct coil, no issues so far. I had an issue with a misfire I couldn't figure out when the car warmed up and a friend told me to bypass the ballast resistor to see if the problem still happened. It was the ballast resistor, I changed it with a GM parts replacement and no more problem. The original 55-year-old resistor was cracked and that was obvious when I got it off the car.

[Joey P.]

David Sokolowski that Leif referred me to and see if he has an original. Fun fun......

[Tim G.]

Re: 1967 BB 390 hp

It does not appear to run hot; I am running through the ballast resistor now.

[Leif A.]

Re: 1967 BB 390 hp

Hi Tim,

Would you happen to know if your 202 coil runs really hot? and I do not know if that is an issue or not and really what I am trying to determine along with what makes them run so hot. I have another Paragon 264 coil that will deliver tomorrow that I will ohm out along with the one I pulled off the car two weeks ago just to see what I find. I will also try to contact David Sokolowski that Leif referred me to and see if he has an original. Fun fun......

Joey,
Underhood temps are well above 200*. I don't think the temperature of your coil is an issue. Made in China is your issue.

[Richard M.]

Re: 1967 BB 390 hp

Joey,

GM Restoration coils, points or TI, as Leif stated, are junk.

200* is not unreasonable.

GM Repro coils can get as high as 250* plus, and short internally and fail after 20 minutes typically. I have 2 263 TI coils that both failed when diagnosing a 67 L71 years ago. Nothing worse than discovering both were ultimately bad.

Rich

The Napa IC12 is a ideal off the shelf coil. It is slightly bigger diameter so you may need to modify the coil bracket.

The replacement you got from Azone will be fine. Keep using it.

Rich

[Mark E.]

Re: 1967 BB 390 hp

My '70 454 has been running with an Accel coil for a few years. Performs fine and it fits the original bracket. But it only comes in yellow or chrome...

[Joey P.]