1970s HEI eating modules

["Cadillac Kid" Greg Surfas 15364]

Anybody got any idea why an HEI with new modules, cool , and rotor would keep eating modules at just a couple thousand miles?
Greg Surfas

[signart]

Have you changed the coil lately?

[Dave Shepherd]

Usually  occurs when a liberal amount of heat sink compound is not applied to the bottom of the module.  Also poor internal ground connections.

[TJ Hopland]

Is the center button in the cap in the correct way?  Button, washer, then coil?

Any signs of physical interference between the rotor and innards of the cap?  The last new one I bought there was a booger of plastic that hit the rotor and kinda started to make a mess of things. 

How are the wires and plug gap?   Anything that may be causing higher or stray voltages could be wandering around and getting back to the module.

I'm not even sure where I would buy one today if I needed it for something I had to depend on. Maybe DUI?  I kinda fear that this may be one of many products that there is only one place that sort of makes em these days so other than finding a nos or used one we are kinda screwed.  Even 10-15 years ago I was finding the replacements unreliable so I would keep an eye out for those cars when I was at the U pull junkyards for vintage OE ones. 

I have been running them on my small engines like my golf carts and lawn mower.   I have been through 3 modern replacements on the mower over the last 2 years.  Its a twin cylinder that is mostly used for snow plowing in the winter and its mounted to a thick steel bulkhead with lots of grease that barely gets above ambient temp so its not external heat that is killing them.

[signart]

Usually  occurs when a liberal amount of heat sink compound is not applied to the bottom of the module.  Also poor internal ground connections.

Kinda what I was getting at. Make sure the coil ground wire is attached to the coil mounting screw.

[TMoore - NTCLC]

I had a similar problem - had to randomly replace a number of modules - was never getting more than a few thousand miles out of one, and always kept spares in the car.  New cap, coil, rotor, wires, plugs, liberal application of heat-sink paste - made no difference.  Finally, I was on a tour and had module failure without a spare.  Had to buy one from a parts store, and went for the Delco - that module is still in the car and running fine - at least 10 years later.

I had been buying parts from a local wholesaler, and the modules were all off-brand, brown box parts with no manufacturer listed.  Lesson learned - for important (especially electrical) items, go for original equipment when available.

[Bwt]

Glad you have had good luck with the Delco module. One thing I can say. The "Delco" module was not manufactured b Delco like the production, or service parts were for years.  They repackage all of their product line and have for maybe 20 years or more. At least that long with their ignition parts.  Not to say they do not use quality manufacturers. 

[TJ Hopland]

The further you go back the more variety I think there were in a common part like an HEI module.  Certainly 10 years ago there was complete junk around but there still could have been some good stuff at least sitting on the parts store shelves.   If you bought different brands of the same part the parts looked different so were probably being made by different people.   More recently especially today parts for older cars all seem to be identical no matter what name is on the box or what you paid.

[Poncholover]

Modern replacement modules = 
Used genuine GM =  

[Pghcc2006]

Is it the thermal paste perhaps? I use stuff made for CPUs/ gaming computers. Those warm up good  and need a lot of protection lol.