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HEI Probs

Discussion in 'The Hokey Ass Message Board' started by daveyboy56, Jul 28, 2010.

  1. daveyboy56
    Joined: Feb 20, 2006
    Posts: 511


    Ok i have a HEI (new with the crate eng) dizzy but in 6000 miles i have gone through 5 ing mods.
    What is going on in there?
  2. Da Tinman
    Joined: Dec 29, 2005
    Posts: 4,226

    Da Tinman

    did you remove the ballast resistor?
  3. Joes50
    Joined: Feb 13, 2003
    Posts: 181


    Hmmm...maybe no dielectric grease between the bottom of the module and the case?
  4. Couple of thoughts. If I remember correctly, the ignition module is mounted on a layer of grease (?..maybe dielectric compound) to protect it from heat. Also wondering about the quality of your modules (Chinese?). I run HEI distributors that I get out of cars at the wrecking yard ... never had a problem (running three cars withem). One other thought (not sure this would cause any problems though) the HEI requires a full twelve volts (if yours is in an old car, did you remove the resistor wire). As I stated earlier, never had a problem withem, but I do carry a complete spare in the trunk of all our cars. Good luck.

    Hit the local wrecker and get a complete GM HEI unit.

    Joined: Jun 15, 2006
    Posts: 3,385


    Good responses above .....


    Is this a GM factory ( delco) unit or off shore unit???
    Repeated module failure is usually due to a heat problem caused by incorrect resistance in the igntion coil. A low resistance coil works the module pretty hard and they over heat and fail.
    I would suggest replacment with a new delco control unit as they have current limiting circuits the aftermarket units usually dont have .
    Assumin this is a chevrolet engine (?) the ignition coil ( yellow and red primary wiring) , the pickup coil ( yellow connector or wire tie) and the module need to be polarity matched for long life....
    Be glad to test the entire unit if needed......
  6. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,027


    I wish I had read that ten years ago when I was fighting a module issue on a Cadillac I owned Bubba. It would have saved me a lot of headaches and replaced modules.
  7. It's not dielectric grease, it's heat transfer, or heatsink grease.
  8. Yepper - it turns a whole bunch of the distributor body into a heat sink for the module. Buy some "Arctic Silver" at a PC parts place and use a thin, even coat.

    One of the things I just did in troubleshooting an ignition problem was to replace a failed module...which originally had dielectric between it and the disti housing.
  9. 325w
    Joined: Feb 18, 2008
    Posts: 5,647


    Low voltage to the mod ?? Wire too small feeding the mod?? Grounds ????? Guy at the electric shop says use at least a 12 ga. wire to feed the HEI. Two cents worth.
  10. IMHO that's a bit of overkill.
  11. I had a few HEI failures over the years, even tho I did everything by the book.
    I got tired of digging them out and putting them back in the distributor while under the hood in somebody's parking lot.

    I moved my control module to the car passenger compartment under the dash so I could replace it easily.

    MAGIC! In the cooler location I haven't had a single failure in over 12 years!

    Here is a picture of my HEI rig in my Studebaker truck- with Radio Shack switch so in the event of a module failure, I could simply flip a switch and keep on driving.
    The great thing is that I haven't had a single failure in over a dozen years, and do not need the spare module.

  12. Now that is "dare-to-be-different"

    You don't have any noise problems?
    Off Topic, but I'm running a megasquirt tbi setup on my jeepster with a buick 340. I had quite a bit of noise problems with the 7 pin wiring stuff.
  13. daveyboy56
    Joined: Feb 20, 2006
    Posts: 511


    Ok it is a new disy from Gm with the crate eng new vortex 330 hp 350cid.
    I have put in 2 stock mod form Gm and 3 or 4 from speedway
    This last time i loaded up the heatsink grease under it . ouesed out

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