HEI module

During the course of building my daughter's car, I have had the worst luck with the ignition modules crapping out on me. I started with a known good distributor that I had bought new at O'reilly's. It had been used in a daily driver for a little over a year, then unused for a year (wreck) until I pluck it out for use on the 74.

This time it lasted for initial tuning and a drive across town to an exhaust shop, and died in their lot. Got a new module from O'Reilly's (BWD brand) CBE4. It had a clear heat transfer compound provided with it. I used some of this along with re-using the original white compound that I was used to seeing. It worked, got the car finished and tuned some more, then took it the next weekend on a road trip to a neighboring town that was about 50 miles away. On the way back, it died on the highway (near some driveways luckily). It started again after cooling down, so I got to the nearest air-conditioned place and let it set for a couple hours before finishing the trip home.

The next day I got it warrantied for a new one, this time a CBE4P. This time I cleaned all the heat transfer compound off the distributor and used the clear stuff that BWD supplied. It lasted all of 10 seconds. Warrantied again and got another CBE4P except I insisted on getting the white heat transfer compound before I left. This happened just under a year ago on 8/29-8/30. This one lasted until 7/31 when my wife and daughter got stranded at a Chinese restaurant. Just happened to be across the street from-yep- O'Reilly's. So I go there and get the only one they have in stock, a CBE4. They still supply the clear stuff with the module, but I don't use it.

Got it running, but I'm questioning the reliability of the Borg-Warner brand. I researched as much as I could at the time and the BWD was supposed to be one of the good ones. I guess time will tell on this one. I am hoping that I really only got one faulty one and the others were due to ineffective heat transfer compound (the clear stuff).

Have you checked the voltage output of your alternator at idle? I think 13.8V is the target but if it's way high like around 15V maybe the internal regulator is bad and thus the high voltage is burning up the modules? Just a thought and real quick to check

Voltage is fine.

Hey. How well is the block grounded? All electrical systems start with this foundation. Do the modules get hot and smell funny or do they just open up and quit working?

Just a side note on O'rilleys electrical parts. I was there on Tuesday to buy a Heater blower resistor for a 98 Cutlass I am flipping. I brought my original GM one in for reference. The $18 MasterPro they brought out to me had a longer circuit board than the original, so they brought out the $26 BWD not only was it the same length as the MasterPro it was the same part, same number, same font on the numbers. it was the same part. They then brought out one more of each to see if they had been somehow switched it the boxes... Nope all the same part. although the BWD box had way nicer graphic's. Check this out before spending more on the BWD brand. The cheaper one fit and worked fine.

Did the 74 have points originally? Are you still running the resistor wire for the point system? Too low voltage will fry the modules as well. HEI needs full voltage. Points ran on about 8V.

The harnesses forward of the bulkhead are brand new. The engine harness was built to run an HEI. The car has no electrical problems except for the rheostat in the light switch. Sometimes the dash lights go dark and the switch needs to be jiggled to turn them on again.

I did run a ground strap from the body to the engine recently because the volt gauge was giving me erratic readings. Now it is rock solid.

Now that I typed this out I wonder if the low voltage reading on the gauge would have been in effect at the distributor also? It is an aftermarket gauge that is tapped into the fuse box at an unused, switched power port.

flakey coil? Do you have another one to compare side by side ohms readings?

I have at least two other coils, but I need to get another meter before I can do any readings. I really suspect the lack of a ground strap from the body to the engine caused it to fail.If the coil supply wire was fluctuating in voltage like the gauge was, then it could have damaged it a bit at a time.