Installing a GM HEI Module

Discussion in 'Electrical and Ignition' started by Calipag, Oct 18, 2018.

  1. Calipag

    Calipag FABO Gold Member FABO Gold Member

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    I am trying to clean up the engine harness in our 1970 Dart. It was converted to a Chrysler electronic ignition at some point of its life. Apparently the person who did the conversion only owned yellow wire so every wire is yellow and they did a very poor job at splicing wires and terminating them.
    So, I'm looking to clean all that up while we do our V8 swap. I've read about installing the GM HEI Module and had some questions:
    1) Does installing the GM Module replace the ballast resistor and ECU?
    2) Do you have to replace the stock coil to do this conversion?

    Thank you FABO

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  2. TrailBeast

    TrailBeast Slightly Twisted Member

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    1. Yes it replaces both.
    2. If you use the same coil you still need the ballast resistor to reduce the voltage so it doesn't overheat.

    Better off to do the HEI module and a C, D or E core coil, as they are made to use a full 12v.
    You'll also get the full benefit of the HEI spark, which allows up to an .050 gap on the plugs.

    In a bit here I'll try to post some more info on that for you.

    ADDED:
    One of the cleanest of the HEI coils I have used is this 94-97 Dodge Ram truck coil.
    It runs on a full 12v and does not require a ballast.
    It also put out a spark almost 2x what the old canister type does, and is close to half the size of a canister coil.
    You can either get the pigtail for it, or do what I did and trim the connector section off and solder direct to the terminals.
    These coils work perfectly with the 4 pin or 8 pin HEI modules.
    The 4 pin modules like you normally see used are a bit messy in my opinion, and don't have weatherproof connectors like the 8 pin module.

    The last picture is my own car using the GM HEI coil and 8 pin module with weatherproof connectors.
    I also have the wiring diagrams for all of these combos when you are ready.

    94-97RamCoil.jpg

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    Last edited: Oct 18, 2018
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    • Calipag

      Calipag FABO Gold Member FABO Gold Member

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      Thank you!
       
    • TrailBeast

      TrailBeast Slightly Twisted Member

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      Added the info to my last post.
       
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      • 67Dart273

        67Dart273 Well-Known Member

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        Actually TB I ran my old Mopar coil / no resistor, it worked fine I did that just to see........and it did!!!
         
      • TrailBeast

        TrailBeast Slightly Twisted Member

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        Yea, I have done it too, but it's something I can't recommend to others to do.
        You know how that goes.:D
         
      • 69hemibeep

        69hemibeep Well-Known Member

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        It will for awhile and when the car starts acting like it is vapor locking, it's an over heated coil.
         
      • TrailBeast

        TrailBeast Slightly Twisted Member

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        The HEI module has a different dwell time and is not as hard on the coil, but I still wouldn't trust it 100% without a coil that matches the HEI ohm rating.
         
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        • 69hemibeep

          69hemibeep Well-Known Member

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          I have a CJ5 with a 401 AMC in it and a Davis HEI and love it. It's to bad the top of the distributers are so big for a BB Mopar
           
        • Calipag

          Calipag FABO Gold Member FABO Gold Member

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          @TrailBeast I received your email and will get everything together this weekend and install it. Thanks again for all the help. I'll post pics of my before and after.
           
        • TrailBeast

          TrailBeast Slightly Twisted Member

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          Sounds good.
           
        • Jimacuda

          Jimacuda Well-Known Member

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          I just went with a new distributor that had the module in it already.
          About $50 on EBay...skipwhite or whites speed shop...still available afik.
          2 wires, no ballast, no ecu, nada. $8 spare module, 5 minute swap.
          Working great so far with at least 30 hours run time on it.

          IMG_20180725_175448232.jpg
           
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          • crackedback

            crackedback FABO Gold Member FABO Gold Member

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            Haters to the thread in 3...2...1... LOL
             
          • Jimacuda

            Jimacuda Well-Known Member

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            [​IMG]

            :D
             
          • BillGrissom

            BillGrissom Well-Known Member

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            I am guessing this is because some people got together and decided that the Ningbo "ready-to-run" distributor is unreliable because of ## claimed failures (1?), thus nobody is allowed to use it?

            I bought one for $45 on ebay (Skip White & others). Looks great for the price, but haven't used yet. Pickup looks better than the Mopars (more like GM w/ multiple sense fingers). If you don't like the module they ship with, you could adapt to a GM 8-pin HEI. Re the later, best to use the GM coil and short cable which connects the 2 for easy plug-n-play (85-95 GM V-8 trucks). If scared of junkyards, buy TrailBeast kit.
             
          • 70aarcuda

            70aarcuda Master Hoader of SBM FABO Gold Member

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            Have had one of cheap distributors in my 88 D250 that I converted from TBI to carb....Probably been in there over 3 years now...
             
          • Jimacuda

            Jimacuda Well-Known Member

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          • Calipag

            Calipag FABO Gold Member FABO Gold Member

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            Making progress.

            ign.jpg
             
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