Burning hei coils

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

SleeperC1083

Junior Member
Joined
Jul 17, 2024
Posts
6
Reaction score
3
Location
joliet illinois
First Name
jesse
Truck Year
1983
Truck Model
c10
Engine Size
355,forged rotating assy, gm performance aluminum heads
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.
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
11,250
Reaction score
17,174
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
I'm leaning towards a grounding issue. Hopefully others chime in.
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
11,250
Reaction score
17,174
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
Did you reinstall the ground strap from the back of the head to the firewall?
 

SleeperC1083

Junior Member
Joined
Jul 17, 2024
Posts
6
Reaction score
3
Location
joliet illinois
First Name
jesse
Truck Year
1983
Truck Model
c10
Engine Size
355,forged rotating assy, gm performance aluminum heads
Yea I’ve got the one from the head to the firewall, it’s just odd the way it acts because I could do a hellacious burnout and then a minute later I’ll be going down the road and it’ll just die (that’s what happened the first time it burnt out) and I’ll throw a new coil in it and it’ll be good for a couple hundred miles and do the same thing again so maybe it’s over powering should I put a 6al setup on it since it does have high compression?
 

Rustisbest

Full Access Member
Joined
Jul 20, 2021
Posts
182
Reaction score
456
Location
Athens, TN
First Name
Matt
Truck Year
1979
Truck Model
C10
Engine Size
377
Make sure your putting stuff on in the right order.
Carbon brush/button first, then the insulating washer, then the coil.
There's a ground strap that goes under the coil at one of the hold down screws too. Seen em missing before.
 

SleeperC1083

Junior Member
Joined
Jul 17, 2024
Posts
6
Reaction score
3
Location
joliet illinois
First Name
jesse
Truck Year
1983
Truck Model
c10
Engine Size
355,forged rotating assy, gm performance aluminum heads
Everything’s in the right order with dielectric grease etc I honestly think it’s the truck side of things because my power windows and turn signals were acting goofy, I plan on gutting it to be a street/strip truck so im most likely gonna go through the wiring on it and replace most of it. If anyone has a complete wiring diagram or hack on how to turn a Silverado into a strippo work truck that shows which wires to get rid of like a/c and cruise control that would be great.
 

DoubleDingo

Full Access Member
Joined
Jul 3, 2012
Posts
11,250
Reaction score
17,174
Location
Right where I am
First Name
Bagoomba
Truck Year
1981
Truck Model
81-C20 Silverado Camper Special-TH400-4.10s
Engine Size
Carb'ed Vortec 350
I may be wrong, but I don't think the electrical system output is dictated by horsepower or torque
 

SleeperC1083

Junior Member
Joined
Jul 17, 2024
Posts
6
Reaction score
3
Location
joliet illinois
First Name
jesse
Truck Year
1983
Truck Model
c10
Engine Size
355,forged rotating assy, gm performance aluminum heads
I don’t think so either but my mind works goofy sometimes and for some reason I’m thinking the spark plugs are drawing a **** ton of spark and over working the coil
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,446
Reaction score
8,679
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Your HEI coil should have 2 grounds,as pictured. The distributor body grounds through the distributor clamp through the block and you should have the engine block grounded either directly to the battery or frame. If you only have the 1 ground under the cap they burn up in short order. Make sure your distributor hold down is tight.what gap are you running on your plugs?
 

Attachments

  • Screenshot_2024-07-17_214400.jpg
    Screenshot_2024-07-17_214400.jpg
    103 KB · Views: 46

SleeperC1083

Junior Member
Joined
Jul 17, 2024
Posts
6
Reaction score
3
Location
joliet illinois
First Name
jesse
Truck Year
1983
Truck Model
c10
Engine Size
355,forged rotating assy, gm performance aluminum heads
Thank you for the diagram I do not have that second ground strap it never had it to begin with even when it had the original 305 in it, it always had the one that connects to the coil that you screw down when you put the coil on , I will be sure to add that second one that goes to the ignition module wires. Also I have them gapped at .040. It’s a 355 with flattop pistons and 58cc aluminum heads
 

SleeperC1083

Junior Member
Joined
Jul 17, 2024
Posts
6
Reaction score
3
Location
joliet illinois
First Name
jesse
Truck Year
1983
Truck Model
c10
Engine Size
355,forged rotating assy, gm performance aluminum heads
Also I’ve done 2 other head swaps with this same motor and have never ran into this issue
 

squaredeal91

Full Access Member
Joined
Mar 10, 2023
Posts
2,534
Reaction score
4,579
Location
Cave junction Oregon
First Name
Greg bush
Truck Year
1991 SB
Truck Model
K30
Engine Size
5.9 Cummins 12 valve
Yea I’ve got the one from the head to the firewall, it’s just odd the way it acts because I could do a hellacious burnout and then a minute later I’ll be going down the road and it’ll just die (that’s what happened the first time it burnt out) and I’ll throw a new coil in it and it’ll be good for a couple hundred miles and do the same thing again so maybe it’s over powering should I put a 6al setup on it since it does have high compression?
Someone I used to know had same issue with hei distributor. Never figured it out. Blamed grounds at first. Hope this gets figured out. What about the alternator possibly killing it?
 

RanchWelder

Full Access Member
Joined
Jan 14, 2023
Posts
798
Reaction score
1,144
Location
Earth
First Name
--------
Truck Year
87
Truck Model
Blazer
Engine Size
355ci
Aftermarket coils, distributors, or HIE modules or distributors and coils or weatherpack connectors, that do not say ACDelco or Delphi or OEM fail at an alarmimg rate?

Why?

It just makes me crazy?

OEM or fail? Say it isn't so...

Guess who makes them all?

Your General!

It's a scam!

Buy the best or go home with sand in your shorts!
 

TotalyHucked

Full Access Member
Joined
Feb 24, 2020
Posts
3,671
Reaction score
11,854
Location
Auburn, Georgia
First Name
Zach
Truck Year
1985
Truck Model
Sierra 1500
Engine Size
5.3
First off, what brand coils are you running? If they're MSD, throw them in the garbage.
 

Latest posts

Forum statistics

Threads
44,157
Posts
950,585
Members
36,271
Latest member
jstewart7501
Top