My HEI modules fail quickly

April 1, 2008 | By Richard Prince


I have a 1971 Chevy pickup with a 350 cid engine and automatic transmission. I have an HEI ignition in it and the module goes out between 800 and 1000 miles. What do you think would cause this to happen?


The most common cause of premature HEI module failure is excessive heat buildup in the module.

Excessive amperage to the module (caused by, for example, a malfunction in the car’s charging system) will cause it to get hotter.

Another common cause for overheating of the module is failure to apply that special white grease that comes with the new module.

The white grease is particularly efficient at conducting heat, and the purpose of applying it to the module on the side where it mounts is to aid the transfer of heat from the HEI module to the distributor’s body.

But it is important to use only that special heat-conducing grease.

Many other greases, including clear dielectric grease, actually act as heat insulators and thus accelerate failure of the module.