[chevyrestore]

Hey guys. Ive got a 1980 454 motor in a 59 chevy truck.

My problem is ive got an aftermarket HEI setup (procomp distributor with MSD blaster coil) (the square coil not the cylinder). When the motor gets hot and its hot outside the truck starts to misfire, then when its cool out it works fine. I replaced the coil once and that fixed it but now that its hot outside again its happening again.

Could this be a wiring concern or a physical outside air temperature too close to the coil causing the problem? I have a EZ wiring harness installed in the truck and no ballast resistor on the setup.

Not sure if I need to go one step farther and drill the firewall and mount the coin in the cab or if I need to be fixing wiring.

Any help is appreciated, thanks everyone

[timothale]

Usually coil overheating is caused by running the wrong coil , one that requires a ballast on Bat voltage, did they give you the correct coil?

[chevyrestore]

I got the distributor straight from procomp and the coil from kragen. What should I do?

[oldbogie]

Originally Posted by chevyrestore

Hey guys. Ive got a 1980 454 motor in a 59 chevy truck.

My problem is ive got an aftermarket HEI setup (procomp distributor with MSD blaster coil) (the square coil not the cylinder). When the motor gets hot and its hot outside the truck starts to misfire, then when its cool out it works fine. I replaced the coil once and that fixed it but now that its hot outside again its happening again.

Could this be a wiring concern or a physical outside air temperature too close to the coil causing the problem? I have a EZ wiring harness installed in the truck and no ballast resistor on the setup.

Not sure if I need to go one step farther and drill the firewall and mount the coin in the cab or if I need to be fixing wiring.

Any help is appreciated, thanks everyone

Given that ProCom sells about a half dozen different models of this thing, the question has to arise as to what is the part number?

ProComp in the past has had a lot of problems with the electronics and electrical parts. I don't use the stuff but know several people that do. I'd go back over the instructions to discover what the connection voltages should be then check them out. If the coil or the electronics are under volt and in the case of the coil overvolt they/it will run hot.

Bogie

[cdminter59]

Which model of Pro-comp distributor do you have? Has the wiring from the truck been upgraded? Are you using the Blaster SS coil MSD-8207? If so the primary resistance is not enough. You should be using a Blaster High Vibration MSD-8222 or any of the Blaster 2 coils that have a primary resistance of 0.700. The MSD-8222 is epoxy filled like the one you have. The Blaster 2 coils are oil filled.

[chevyrestore]

It's the procomp pc7000 small cap and the msd 8207. Is there a way to get the 8207 to work or do I need to get the other msd coil? Thanks for the awesome info so far

[cdminter59]

See my post #5. The primary resistance is too low on your coil. The MSD-8222 is the coil you should have. Pro-comp recommends 0.5 to 1.0 primary resistance. Also does your ignition switch wire going to the coil have +12 volts all the time. Older chevys had a resistor wire from the switch to the coil. After starting the volts are reduced to 8-9. If this is your case run a new +12 volt wire from the switch to the coil. Here is the wiring diagram for the 7000 series. http://www.store.procompelectronics....PC7000INST.jpg

[chevyrestore]

thanks, I ordered the coil (should have it this weekend) and ill check the voltages tomorrow. Ill let you guys know how it turns out

[chevyrestore]

the coil is getting 12-13.6 volts depending on how hard the alternator is working...is that fine or does it need to be 12 all the time? Got the new coil all wired up but need to fine a new coil wire to distributor tonight or tomorrow to get it finished up.

[AutoGear]

The only thing I will add is get this fixed ASAP; and you may want to keep the battery disconnected until you do. When I was a kid, one of the local hotrodders had a pretty rough looking 71 camaro with an equally dogged 454 from some truck in it. He added a SUNROOF, grant steering wheel, and a few other pieces of junk AND an Accel SUPERCOIL. If you've never seen one, these things are like the size of a windshield wiper motor. He wired it in incorrectly and it boiled over one night under his dash. The amount of boiling hell this thing unleashed all over his interior....impressive to say the least.

[timothale]

In the 60"s I was driving a 10 wheeler farm truck and the under hood wiring shorted out on a year old truck, I hot wired it 12 V to the coil to get back to the farm, I got there and about 2 min later the coil exploded, Oil and fine wire everywhere.

[chevyrestore]

Hey I got the coil you guys recommended installed and it has the proper voltage, same misfire though.

Its weird, sometimes when I rev it up quickly (like a hard acceleration) its fine, nice and smooth all the way up with tons of power.

Then other times it pops out of the tailpipe and has a noticeable loss of power while thats happening. Completely random when it happens, might run good once, then 3 seconds later on the next acceleration it misfires, could do that a few times or run good again the next time.

I uploaded a .zip file on here of an mp3 I made with the popping sound if it helps anyone to figure out. I am at a loss on this one. Nothing seems to be able to fix it.

Heres what I have done:
rebuilt carb (edelbrock 750cfm manual choke)
new intake manifold gaskets
new spark plugs (acdelco r45ts if I remember correctly)
new MSD blaster MSD-8222
new spark plug wires

I did each of those 1 at a time to see if that fixed it or not and none of it did.

[chevyrestore]

I noticed a mechanical type ticking noise from the motor today while it was misfiring, im thinking valve lash/ possible bad lifter now.

If it ends up needing a lifter will it damage the cam to put a new lifter and pushrod on whatever cylinder is making the noise or what should I do considering I am using the same camshaft?
I did just replace the intake gasket, is there any possible way to replace the lifter without removing the intake manifold?

[va4cqd]

you're asking for trouble just replacing one lifter

[chevyrestore]

what happens if you replace just the 1 lifter?