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GM HEI problem

Discussion in 'The Hokey Ass Message Board' started by rdemilt, Oct 16, 2011.

  1. rdemilt
    Joined: Jan 12, 2009
    Posts: 135

    from so florida

    I have 80's era stock oldsmobile motor with HEI in a 1955 truck and have had issues 3 or 4 times in the last 15 K miles where I'll park the truck and it will fail to restart, hot or cold. I found that each time this occures there will be some kind of black sooty film on top of the rotor tab and center contact of the rotor. It is very faint and easily wipes away with my finger and off I go again for several thousand miles. I thought the plastic may have been deteriating so both cap and rotor were replaced with echlin parts from NAPA but the problem still occures. It looks to be just carbon from the sparking under the cap eventually causing ignition failure,
    but why ?????

    The truck runs very smooth and is driven most days, it has good plugs and wires too. any ideas are appreciated.

  2. Dielectric grease in that spot will help.
    Joined: Jun 15, 2006
    Posts: 3,385


    A couple things from the old days of GM HEI service.
    Take the cap and cover off for a little inspection, the coil can be removed and make sure the coil lead wires are NOT red and yellow ( red and yellow are chevrolet) yours should have a white lead wire indiacating Olds pontiac. These coils are wound in correct polarity to work with correct pick up coil etc.
    Remove the splash washer with carbon button in it and coat washer with dielectric and reassemable......
  4. HEIs make the metal dust from arcing through the advance weight posts. remove the weights and look at the base of the post, it will look like a clean saw cut at the base.
    dielectric grease will help.

  5. spiderdeville
    Joined: Jun 30, 2007
    Posts: 1,134

    from BOGOTA,NJ

    module getting ready to go or pickup coil acting up
  6. rdemilt
    Joined: Jan 12, 2009
    Posts: 135

    from so florida

    Thank you for all your advice and good ideas. I will be looking into some of the recomendations this week.

  7. 1950ChevySuburban
    Joined: Dec 20, 2006
    Posts: 6,188

    Member Emeritus
    from Tucson AZ

    Make sure the little metal ground strap is in there. I've seen them forgotten.
  8. baker53
    Joined: Jan 17, 2003
    Posts: 340


    Also, make sure the spring is in place between the coil base and the carbon button.

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