Burning hei coils

[Ricko1966]

Have you checked charging voltage . Put a volt meter on it spin it up see if you are over charging. Also check for A C voltage indicating a bad diode.

 

[Bronze Knight]

Isn't there a thing where if the Tach signal wire gets grounded it'll burn the coil out? May be worth checking the whole run of the Tach signal wire, or at least both ends.

 

[Toad455]

Hi guys new to the group, I’m having a problem with hei coils burning up after upping my cr with smaller chamber heads (not saying that’s the cause it just started giving me this issue after the head swap) I’m not sure what the issue is I’m kind of stumped any help would be great not sure if I may need to add more grounds or what.

I accidentally left this ground strap off once on a Firebird years ago and got the same coil burning problem, didn't take long. I'll try to attach pics. One end of this ground strap goes down and becomes one of the three tabs that the wire connector plugs into. As I remember this strap goes Under the coil, (you can barely see the strap on pic at far right). Pic in the center shows a wire instead of the ground strap, I personally haven't seen one like this but looks like two designs to achieve the same thing.

 

[59840Surfer]

Did you check the available voltage at the power coming into the HEI coil?

If you have a dropping resistor or the factory resistive primary wire in the circuit, the coil can die while it's sucking wind (low voltage) by pulling higher amps --- and that'll burn out the HEI coil quickly!

Amps generate heat. Higher than normal Amps generated higher than normal heat.

I ran a dyno shop and found this problem a lot!

I also learned to hate Champion plugs 'cause, after a run on the dyno, the Champions were drawing 18KV at idle; if you snapped the throttle, the KVs went 'away above the coil's max output.

 

[DQUK]

Like a few other guys have commented, check your engine earths. Had a similar issue on a 65 Nova I had. Swapped engine plates to poly bushes and after 50 or so miles car started to back fire then cut out and wouldn’t start again. Ran a brand new earth strap across front of engine attached to both heads and block then to chassis and issue sorted. Must of gone through about 4 coils beforehand though!