8 pin Hei problem

Discussion in 'Electrical and Ignition' started by 7dart0, Jun 9, 2018.

  1. 7dart0

    7dart0 Well-Known Member

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    I have my coil and 8 pin module mounted to the right of the master cylinder. I bought the kit from classic HEI about 3 years ago. Do you think its to hot of a spot because of engine and header heat?

    I ask because it burnt up yesterday and I had to get a tow home. I went to advance auto bought a new one and it started right up.

    Tom
     
  2. wish4hemi

    wish4hemi Well-Known Member

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    Did the kit come with a heat sink? Regardless of where you put the module, it needs a good heat sink.
     
  3. 7dart0

    7dart0 Well-Known Member

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    Yes it came with a small piece of aluminum a little bigger then the module itself.
     
  4. 67Dart273

    67Dart273 Well-Known Member

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    You say to the "right of" You mean outboard of (actually left) or inboard......towards the center of the car

    If it's outboard of the master, I doubt you will find a cooler place in the bay

    I had my 4 pin mounted above my dist. on the firewall and it "lived."

    Actually I used the firewall as a heat sink as an experiment.

    Stuff does fail occasionally
     
    • Agree Agree x 1
    • 7dart0

      7dart0 Well-Known Member

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      No it's toward the fender so outboard. I know things fail I was just curious if that spot was ok or if I should extend the wires and run it up under the battery tray.

      Also is there any benefit from getting an aftermarket module like flame thrower, dyna mod, accel?
       
    • 67Dart273

      67Dart273 Well-Known Member

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      Unless you are running a 600hp monster I doubt it. Lots of us run HEI modules and they work pretty well. No idea at this point what might have caused the failure. Make sure the ground terminal is well connected, that it's mounted properly "flat" to the heat sink and that the charging system/ voltage is not going nuts.

      It might also be that some coils (or a failing coil) is hard on the unit

      HERE IS ONE THING FOR SURE: (that will kill modules) Something which allows secondary voltage to "shoot up" IE climb. Something which added a great deal of resistance or gap in the secondary circuit, such as a bad coil or plug wire, broken plug, or running it with a wire disconnected, or a rotor contact broken / bent
       
    • TrailBeast

      TrailBeast Slightly Twisted Member

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      It should be fine there, and is where mine has been for 5+ years. (in AZ):D
      Sorry it went out on you.

      I personally have not seen nor heard of one bit of difference in performance or reliability between the OE module and aftermarket more costly ECU's with someone's sticker on them.
       
    • BigBlockMopar

      BigBlockMopar BigBlockMember

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      Prolonged idling is what usually can kill an ignition module.
      Long ignition dwell times at idle, engine heat and hardly no engine bay air circulation warm up the module quickly.
      I've had a 4-pin module fail which was mounted on the pass.side inner fender with a cooling block. It bailed after sitting in heavy highway traffic for a while. Just when we could speed up again, it failed some 5-10 seconds later.
      Also had a ign. module in an '88 European GM-car years back. Same deal... Long 15-20 minute traffic jam, get moving again, engine dies never to run again. Another toasted module.
      They need better cooling.
       
    • TrailBeast

      TrailBeast Slightly Twisted Member

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      There would be a lot of dead GM's in Arizona if that were anything but a coincidence.:D
       
    • BigBlockMopar

      BigBlockMopar BigBlockMember

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      Dry heat is different :D
       
    • 67Dart273

      67Dart273 Well-Known Member

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      I'm gonna need better proof that this LOL. Hundreds of thousands of those have lived IN DISTRIBUTORS right at the top of the engine in every GM V8 made from ?? to ?? I've torn some of those down that obviously had the original module
       
    • BigBlockMopar

      BigBlockMopar BigBlockMember

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      Having been stranded on the side of the road twice by these pos's, I have had my share of proof more than I wanted ;)
      Most likely some aging of the electronic or wiring would have contributed to the misery, but I don't care. :)
       
    • RustyRatRod

      RustyRatRod Just another dumbass. Technical Editor

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      I plan on mounting the unit on the inside of the firewall, or the inside kick panel on my rat truck. I agree though, that literally millions of these HEI modules have suffered a less than stellar life and kept right on going. I think 1974 was their first year so that's a lot of HEI modules.
       
    • 1994redram

      1994redram FABO Gold Member FABO Gold Member

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      I bought a bracket that bolts to the bottom of the mopar distributor and the module mounts to it. It's been mid 90 degree temps here and no amount of idling or cruising has killed mine. I'm still happy with it, it's hidden out of the way and no more clutter on the firewall.

      Mopar HEI Conversion
       
    • 67Dart273

      67Dart273 Well-Known Member

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      ^^ Seen those and a "cool" idea, but do they fit 8 pin? ^^
       
    • TrailBeast

      TrailBeast Slightly Twisted Member

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      Mounting holes in the 4 pin module are closer together by about 3/16.
       
    • BillGrissom

      BillGrissom Well-Known Member

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      I am sure TrailBeast instructions covered it, but insure the pickup wires from distributor to HEI module are twisted together tightly and route far away from any coil wires. If not, the module can be self-trigged by the HV sparks, which could quickly overheat it. In GM, the pickup wires are very short since both are inside the distributor.
       
    • 7dart0

      7dart0 Well-Known Member

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      I will try that. I know mine are not twisted at all.