My 75 L48 had an aftermarket HEI distributor when I got it. Aluminum body with red cap. Pretty generic unbranded.
No numbers. No paperwork, box, or history.

I got the following numbers off the IGN Module,

NB-D1906E M0517

It looks like the standard GM D1906 four pin module will replace this one, if I never need it. The car runs great now. I am looking to keep a quality spare on-hand.

Any ignition module experts who know if this number will cross with the GM D1906?

 

D1906 is the 4 pin GM HEI module.

Lots of other choices

 

Any 4 pin will do, for an emergency backup. Get a "lifetime" from NAPA or Zone. I would always keep one in my HEI cars. They do fail from heat, definitely use heat paste under the module.

 

Brett is referring to:
Heat Sink Compound.

Squeeze tube, white paste. Sometimes hard to find.

 

Good idea.
i see ORielly has a MaterPro 4-pin with a lifetime warranty. Just need to test it before I trust it.

Thanks.

 

Ive been running this stuff for years under my module.

https://www.ebay.com/itm/31110574016...Bk9SR7SBhYKkZA

 

NAPA sells two, a cheapie & their Echlin brand that's U.S. made & comes with a tube of dielectric grease..

 

I think the best way is to go to a junkyard with a lot of old cars in it. Find a original GM module. Pull it and hang onto it.
I still have the factory module out of my original 77 distributor. It's still good.

 

NO. Not dielectric grease. Common error. That is for weather proofing bulbs, connectors etc. It will not work on a module.

Heat Sink Compound

 

Just because they are new doesnt mean they work. Bought a Standard Motor Products from Rock Auto and dead out of the box. Wanted one the next day so bought a Delphi from Amazon . Installed and engine started right up.

IMO only way to know if it works is to install it and see what happens. If it works, leave it in there and keep your old one that you know works as a spare.

 

Die-Electric Grease is not something that really helps do much other than make the spark plug boots come off a bit easier without breaking the wire and protecting rubber. It causes problems when people use it all over in their electrical system as it is NOT conductive.
I use Battery Grease on battery terminals and other important connections. Battery grease IS Conductive and will protect your terminals and posts from oxidizing and or rusting. I also coat the ground connection on my chassis to ensure it remains a good solid connection and with the grease on it there should be virtually no corrosion.

Die-Electric Grease is NOT the correct material to use under the HEI 4 pin module.
HEAT SINK COMPOUND is the RIGHT material to use under the HEI 4 pin module.

First you remove the old module, then clean off the pad on the distributor with an alcohol wipe (or equivalent) to remove old heat sink compound and clean the surface. The trick here is to get a clean mounting surface using the alcohol wipe. Then when the parts are clean you put a minimal (a very thin layer) amount of Heat Sink Compound on the bottom of the 4 pin module and spread it out without touching it. I use a Popsicle stick or single edge razor blade to smooth out and thin the layer of heat sink compound. You do not want too much of the heat sink compound, just enough to make a thin layer on the bottom of the module and then re-install the part.

If you can find a good module that you can keep as a spare I would put it in a vacuum bag, pull the vacuum and seal it. This is probably the best way to preserve the parts.

I use the heat sink compound mentioned by ULTM8Z in his post above. The Arctic Silver "Thermal Compound" is available online at Computer supply stores and for substantially less money. I build PC's and have a stash of Thermal Compound/Heat Sink Compound laying around. A Tube like the one shown on EBAY will last you a long time if you apply it correctly. Just remember, Do Not mix the heat sink compounds in use. Always remove the old material and replace it with fresh heat sink compound.

 

Great information.

Does heat sink compound “age” or evaporate where the module should be removed, cleaned, and fresh compound applied on a preventative basis?

 

I used this product for heat sink compound, seems to work well and is inexpensive:

https://www.mouser.com/ProductDetail...oDGtLh4Q%3D%3D

 

Not so far. I installed a Pertronix module a few years ago and the module I was running before that was also using this Artic Silver. When I removed the old one the material was still essentially like new even after a few years.

 

I did away with the module and wired an MSD 6. Al in it's place . Works very well.

 

I have never seen the Heat Sink Compound dry out and become "ineffective". I am sure it can happen but it takes a long time. I have never seen it suggested to replace the heat sink compound after it is in use for a period of time. I use the Arctic Silver 5 and never had any trouble.

It is the same stuff used on top of the processor between the cooler and the processor in your computer and I have seen them 10 years later as the computer processor stays cool enough to not self destruct.

I only have the module in my 1988 C4's L98, my 1968 has a MSD billet distributor, MSD 6 AL, an MSD Blaster coil, MSD Digital retard box andMSD superconductor spark plug wires. When I test my ignition it sounds more like a welder at the spark plugs. I need this power to light a spark plug when the 12.25-1 Compression ratio is running in my 427. My engine is a L88 Clone using many original parts from a wrecked 1968 L88 Corvette. 560+ hp is fun to use and makes driving very exciting. My local LEO's all know my Corvette and have been very nice. One looked under the hood of my Corvette and he stepped back and said "There is No way we could ever catch this car" to which I responded that I was "smart enough to drive sensibly".

Corvettes are Fun!

 

My next to do. https://www.summitracing.com/parts/msd-6423?seid=srese2

 

I saw somewhere someone is making a multi spark discharge box that goes past 3000 rpm. Not sure how good it actually works but it was interesting. I don't really think multiple sparks above 3000 would make a difference.

 

They don't. It isn't really possible to get multiple sparks when the engine is running that fast. I have a Pro-Billet distributor with an MSD-6 box. It works great but the only real difference in performance is it idles smoother.