Is this what the grease is called that goes between the ignition module and the distributor ? I just cleaned mine up (module & dist.) and did not want to put it back together dry.

 

yep, thats it. I need to get some for mine. Not sure if that is the way to spell it or not. lol.

 

Yes, that's how you spell it. Definitely use it - your module depends on it for cooling, and will burn up without it.

You can get it cheap in bulk at Radio Shack or an electronic distributor or maybe even a TV repair shop, as "heat sink compound". Dow-Corning part # 340 or equivalent. You can also use clear dielectric silicone grease, D-C part # 4.

 

Silicone thermal heat sink compound is a little different than plain silicone fluid (dielectric grease). Either will work, but the heat sink compond is just that - a COMPOUND with more than just silicone. Silicone is an inherent dielectric, so it makes a great insulator. It is also a good lubricant, and displaces water well.

The thermal properties of heat sink compound will provide for some of the same electrical insulation properties (which you don't really want/need on an HEI module) but is not an insulator per se. Heat sink compound will provide for better heat transfer, which should be the primary purpose of the layer between the HEI switching module and distributor base plate. Save the pure silicone "grease" for spark plug boots, WeatherPack connector seals, and body weatherstrip seals.

 

I've always used the regular heat sink compound on the module, but was told this by a fellow v6'er, who was told this by a friend of his...

Could it be that the heat sink compound dries up, but dielectric doesn't? The heat of an engine has gotta be higher than the heat any normal electronics would see... right? Even a home amplifier? What does GM specify?

Hay, speaking of audio amplifiers; I've seen some car amps use a special paper between the mosfets and the heat sinks, and they don't use the heat sink grease. Would this be a better substitute for our modules?

 

Heat sink compound contains suspended zinc powder which provides better thermal transfer than standard dielectric grease. The problem with heat sink compound is that it tends to dry out much faster than standard silicone grease. For that reason the auto industry tends to lean towards conventional clear silicone as opposed to the white heat sink compound. Either will work, for underhood applications the regular stuff would be my choice. Hybrid module manufacturers today tend towards using what is called a Sil-pad. It is an impregnated thermal conduction pad that goes between the device and the mounting but you will most likely not be able to find one easily.

 

Thanks for all the info everyone! What comes with the module when you buy a new one? I was going to get a new one but there is nothing wrong with mine, so I just cleaned it up since the dist. is out of the car anyway. I have the regular dielectric so I will probably just use it this time.