After a week long differential rebuild I took it out for a couple quick test drives. Second drive was about 15 miles and I stopped to grab a drink. Came out, car started and made it a couple blocks before it started to misfire. Pulled into another store parking lot. Opened the hood, fuel was in sight bowls, so not fuel problem. Then touched the brand new coil and it almost burnt me. Unbolted off the manifold and hung if off the wiper door actuator. Bought a bag of ice and cooled it down in about 10 minutes. Started up ran fine and drove back 10 or so miles home with no problem. I'm assuming when I stopped for a drink all the heat built up under the hood enough to overheat the coil. My engine runs nice and cool all the time. stays at 180 and goes close to 190 in the heat of the day in heavy traffic in town. Cools back to 180 within a minute of rolling again. Second time now I've broken down in a month. Same issue first time but didn't know it. That time involved a tow truck. Went down a crazy rabbit hole changing and replacing everything. So obviously not mounting the coil back on the intake. I'm running a MSD distributor with a Blaster 2 coil and MSD 8.5 wires. Where are you guys mounting your coils? I read that it can up to 3' but could have issue at higher RPM's depending on your setup. Looking for mounting place ideas.

Thanks

 

I mounted my coil on the firewall next to the wiper motor just to get it away from the engine heat...every little change helps.
Question: Did you replace the OEM 12V wire that exits the fuse block and attaches to the coil System. If you upgraded to a "modern" 12V coil you must put a new non-resistor wire from the fuse box to the coil +Terminal to prevent melting the coil windings.

Also...a coil will get too hot if the ignition key is left in the ON position while you are doing other things to the engine. It wold be better to install an OFF-ON switch under the dash easily reachable. Then you can turn off power to the coil while leaving the key in the ON position while working on other electrical problems.

There also is the problem of defective cols...I bought a Mallory 12V round coil which lasted 2 weeks. The Auot store manager told me Mallory had a batch of coils with defective windings.

Check your coil while it is cold for prper resistance readings....check the coil again after it is hot from the car being driven to see if bad windings might be the problem...it's worth the effort.

 

Maybe its hooked up wrong. I'm running an MSD distributor, MSD 6A ignition box and a blaster coil. Per the wiring chart I used, which was how it was when i got the car except i installed a new wiring harness but hooked it up the same way, it has the yellow wire and I can't quite tell but maybe white with red or black tracers? My camera and eyes are pretty bad. I do see on the chart that the white with tracer colors goes through a fusible link. So that needs to be replaced with a wire straight from the fuse block but leave the yellow? As you can see in the attached picture they are tied together just before feeding the MSD box. Which is the red wire that turns the box on and off. I usually unplug that when doing anything and i need to leave the key on so the ignition is not live. I do have three coils now and I'm pretty sure they are all good. Again been chasing a rabbit down a hole. Your suggestions are greatly appreciated!

 

Get rid of the Blaster coil. Their junk. In a previous thread of yours I mentioned the problems I had with MSD and Accel ignition coils. You won't have those problems with a Delco or Standard Motor Products coil.

 

Here's my post from 2017 regarding the MSD and Acell ignition coils:https://www.corvetteforum.com/forums...ion-coils.html

 

FYI, GM sold millions of cars and trucks between 1958 and 1974 and they all had intake manifold mounted coils and no problems with ignition coils overheating. IMHO, you don't need to reinvent the wheel. As I said earlier, MSD and Acell coils are junk.

 

Wow. This is nuts. I started reading through that post, just want to clarify the wires. The white wire with tracers that attaches with the yellow from the started that turns my MSD box on and off, do I need to eliminate the fusible link? Does my MSD 6A box need that or just a straight wire to the fuse box?

Ordering a new Delco U505 now!

I literally had the thoughts on the side of the road yesterday, I wonder what someone will give me for it! I was having a bad moment!

 

Received a new AC Delco U55 coil. I now have 4 coils. Ran it for about 10 miles and it did not cut out. So.... Maybe that fixed it? I probably need more run time to see for sure to see if it overheats still. I still had this annoying light throttle hesitation it's had for a year though. Found the jets in the carb were way to big. Forgot I installed those last year when I was at my wits end trying to run down the hesitation issue. Swapped those back to stock jets and it's the smoothest its run so far. Of course we have weather here today so not sure I can get it out for some real testing. I also moved my coil off the engine and removed the fusible link. Hoping to do some fine adjustments to the carb and timing today to get it dialed in. Fingers crossed.

Thanks for the suggestions and help so far. Hopefully I can move on to other projects on it that are a little easier. Not sure there are any.

 

So, you are reinventing the wheel.

 

No but until it stabilizes and doesn't leave me stranded with an overheated coil, then I will move it back to the intake and see how it goes. I am a firm believer it has been there and should be. I believe I had a multitude of issues that all came together and left me stranded. Was it a fuel pump issue? New fuel pump, nope. Was it a timing issue? Checked 100 times and changed springs way to much. fix it nope. Was it a over jetted carb? Not really sure but sure helped with light throttle stumble. Was it a overheated cheapo coil? I do know that left me stranded. Iced it down and got back home. Installed a New AC Delco U55 coil. Jury is out if that fixed it or not. I sure hope so. Drove it about another 10 miles today and so far so good. I never found any good information about the original coil wire from the ignition if it was ok to use or not being it has a fusible link. I have a complete MSD setup so that wire is just used to turn the unit on and off not powering the coil. Confused if the white with tracer wire is ok or not with the MSD. Do you have any knowledge you can share on that?
Thanks