Designed to drive HEI module plate...

[cudak888]

Was the GM module used?

Yep. That's the one that's in there now. These photos are from the first failure.

-Kurt

 

[Rapid Robert]

You'll have to explain to me what you mean by the "peg"

Some of those modules have a very small locating peg (if it ain't there then no worry). On this non chebby mounting you wouldn't want it if it is there to keep the back from laying flat/haveing solid heat sink contact. & cut it off if it is there.

 

[TrailBeast]

I have a couple of the design to drive brackets, they are really nice.
One thing though, if the hei module ever goes bad, you would have to pull the distributor to change it.
Also if you go with the hei, pentronix sells a sweet module that has a adjustable rev limiter for $70.

The fact that to replace the module is one drawback, and the other is that the 4 pin modules are prone to death from low voltage.
They solved the low voltage problem with the 8 pin module.
Currently Pertronics only sells a unit for points distributors, and nothing for the OE electronic distributor.

Some of those modules have a very small locating peg (if it ain't there then no worry). On this non chebby mounting you wouldn't want it if it is there to keep the back from laying flat/haveing solid heat sink contact. & cut it off if it is there.

Exactly, the 4 and 8 pin modules both have two plastic locating pins on the bottom side that need to be knocked off so the module sits flat on the heatsink.
Been running an 8 pin module for 5-6 years without a single failure of any kind.

 

[67Dart273]

You'll have to explain to me what you mean by the "peg" - it's been a while,

-Kurt

At least some modules have an index peg on the bottom side you have to cut/ file off so the module will sit absolutely flat on the heat sink. This fits in a matching hole in the GM dist. It's quite noticeable, unless it's partially broken off, might hold the module up "just enough" to prevent good heat sink contact

 

[cudak888]

Couple of updates:

1. I seem to remember a peg on one of these units. At any rate, I know I would have cut it off if present.

2. For giggles and curiosity, I tried cranking it over today on a cold start. Started up immediately and fiercely - pretty sure there was enough fuel atomizing in the intake manifold since yesterday to make it wake up that aggressively. Not that it matters.

At any rate, the HEI unit isn't 100% dead.

The coil theories are all starting to add up. I may pull a canister-style coil out of my parts bin and make a couple of pigtails so I can go back and forth between the two coils if I do have a no-ignition situation. One of the fellows at FBBO suggests testing the Ford TFI coil with an oscilloscope.

I'm intrigued at the 8-pin module's low voltage protection. Does it have the same bolt pattern as the "boomerang?"

-Kurt

 

[TrailBeast]

I'm intrigued at the 8-pin module's low voltage protection. Does it have the same bolt pattern as the "boomerang?"

-Kurt

Let me check as I have both here.

As you can see there are two locating pins on the underside, and both the 4 and 8 pin modules have them.
The 8 pin module mounting screw holes are about 1/4 inch wider apart, so the 8 pin will not fit the D2D plate unless it is re drilled and tapped.
That's IF there is enough material there to do it.

 

[sireland67]

The fact that to replace the module is one drawback, and the other is that the 4 pin modules are prone to death from low voltage.
They solved the low voltage problem with the 8 pin module.
Currently Pertronics only sells a unit for points distributors, and nothing for the OE electronic distributor.




Exactly, the 4 and 8 pin modules both have two plastic locating pins on the bottom side that need to be knocked off so the module sits flat on the heatsink.
Been running an 8 pin module for 5-6 years without a single failure of any kind.

View attachment 1715278628

Pentronix does sell a 4 contact hei module with a rev limiter.
I have two of them part# D72000

 

[TrailBeast]

Pentronix does sell a 4 contact hei module with a rev limiter.
I have two of them part# D72000

Yep, I was referring to the OE Mopar electronic distributors.
They don't make a unit with rev limiter that mounts in them.

 

[67Dart273]

have since blown up two HEI modules. Both have been complete failures following otherwise normal operation. Once was within 5 minutes of a cold start while running, the other was about 30 minutes after moving the car from one driveway spot to another on a cold start. South Florida weather ensures that none of this ever takes place at less than 55 degrees Fahrenheit (at worst).

Is it possible you are mounting the modules upside down, thus not contacting the heat sink area of the module?

 

[cudak888]

Is it possible you are mounting the modules upside down, thus not contacting the heat sink area of the module?

100% certain they're mounted the correct way to the plate. I've done enough computer heatsinks and processors not to make that mistake...

That said, I tried cranking it over a few days after this happened. Started immediately up, so the problem is intermittent - and while it may still be the module, I want to run a few tests on the coil. Didn't have time to play with it (or think about it) last weekend, and probably won't this weekend, so it'll have to wait.

Also, I feel a bit bad about hijacking this thread. Might continue this on my build log @ FBBO: '68 Satellite 4-door light refurb...and big fat engine swap. - I'll still post an update when I continue this, just in case anyone is watching.

-Kurt

 

[Rapid Robert]

They solved the low voltage problem with the 8 pin module.
Been running an 8 pin module for 5-6 years without a single failure of any kind.

what is the wiring diagram for an 8 pinner. No worries on the hijack, we are here to further everyones' knowledge anyway we can.

 

[mod5v]

Im thinking low voltage could actually do more damage.. Most 12v systems actually run at 13.5-14v.. A fully charged 12v battery is actually 13.2v ..

 

[gliderider06]

I have been using that plate on my Ramcharger for over 30,000 miles and not a single problem. A BWD module and a MSD epoxy filled coil. Drive it daily to work and never a problem.