73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: Stewart G Griffin on November 30, 2014, 03:20:59 pm
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i'm trying to figure out what goes underneath the HEI module?
i'm not concerned about what "should" go underneath----i've heard "white thermal compound"/silicone heat sink/dielectric grease etc.
i want to know what GM put underneath there, from the factory. And, if so, what is the part # if available. If not, what is an aftermarket equivalent
If you can determine what GM used, from the factory, and can prove it i will make a "sizeable donation" to the site.
Thank you.
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I don't know but is this fun fact of the day? I like the idea of answering questions to help support the site. I'll be following this to see where it leads.
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It is a thermal conductive silicone grease. It only came with the module so you couldn't get it separately AFAIK from GM so no PN. Aftermarket modules comes with this also. It is also used on CPU's for computers if you need some.
It is NOT dielectric grease, it is heat transfer silicone grease.
You can find this in the service manuals referenced also if you want to look but I just verified and it just calls it special silicone grease. HEI started in 1975.
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"Silicone lubricant" is the term used in both the '79 and '83 service manuals (I'm sure others as well).
(http://i970.photobucket.com/albums/ae188/jaredts/thermalcompound79servicemanual.png) (http://s970.photobucket.com/user/jaredts/media/thermalcompound79servicemanual.png.html)
It is a silicone based thermal compound. You can find some at radio shack.
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Ok, and from also reviewing answers that i posted on other sites it appears that the silicone heat sink, NOT dielectric grease, is the correct thing to use.
i really should make a contribution to the site because i've gotten so much useful info from it.
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I used this on mine. Got it from Amazon:
Arctic Silver 5 Polysynthetic Silver Thermal Compound Paste 3.5g
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From the GM Manual:
91 NOTE: Be sure there is a sufficient amount of silicone grease on the metal face of the module and on the distributor base (where the module seats), when reinstalling the module. The purpose of the silicone grease is to cool the module.
82 MODULE REPLACEMENT
1.Remove distributor cap and rotor.
2.Remove module retaining screws, then lift module upward.
3.Disconnect module electrical connector. Note position of electrical connector prior to disconnecting. Remove module from distributor.
4.Reverse procedure to install. Check to ensure that module electrical connector is installed in proper position. If module is not being replaced, do not wipe grease from module or distributor base. If new module is to be installed, coat module and distributor base with pack of grease supplied with replacement module.
85 1.Disconnect wiring harness connector at side of distributor cap and remove distributor cap.
2.Remove rotor and disconnect wires from module terminals.
3.Remove two mounting screws and remove module, Fig. 13. Two types of H.E.I. wiring harness are used, Fig. 14. The second type is a wiring harness, connector and capacitor which is serviced as an assembly.
4.Reverse procedure to install. Prior to installation, coat bottom of new module with dielectric grease (furnished with new module) to aid in heat transfer into distributor housing. Failure to apply grease will cause excessive heat at module and premature module failure.
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http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Grease-Dielectric-Silicone-High-Performance-Dielectric-Compound-That-Enables-Boots-To-Be-Removed-From-Spark-Plugs-After-Long-Exposure-To-High-Temperatures-Voltages/_/R-BK_7651190_0006382755
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What goes under the HEI module?
a sizeable donation to this site ;D