To Ballast or not to Ballast?

Discussion in 'Electrical and Ignition' started by Valkman, Sep 15, 2018.

  1. Valkman

    Valkman Well-Known Member

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    I'm getting ready to start up my new engine on a test stand. I have an old stock ecu and harness to test it with. Would it be ok to skip using the ballast resistor for the short period it will take to do this? I'll probably end up using one, but I'm just curious.
     
  2. RustyRatRod

    RustyRatRod Just another dumbass. FABO Gold Member

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    I wouldn't leave it out. They are so cheap and easy to find plus they are part of the system.
     
  3. brian6pac

    brian6pac Well-Known Member

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    depends on if you are running a alternator or just using a battery
     
  4. Valkman

    Valkman Well-Known Member

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    I would be using the battery.
     
  5. brian6pac

    brian6pac Well-Known Member

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    That's the way I do it, just watch the voltage. The ballast just lowers the voltage from 14.5 to 11 or 12 so running it on just a battery the voltage will be 12-11.5 or so, everything will be good.
     
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    • fjr

      fjr Well-Known Member

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      The ballast resistor keeps the coil from overheating due to excess low RPM current. I would use the ballast resistor if you're planning to run the engine for more a few minutes.

      It would be simpler to use an HEI module instead for testing. See HEI Upgrade.
       
    • MOPAROFFICIAL

      MOPAROFFICIAL Well-Known Member

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      It depends on what coil as well, if you have a certain MSD coil ...you don't need to run a ballast at all.
       
    • TrailBeast

      TrailBeast Slightly Twisted Member

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      An internally resisted coil doesn't need a ballast.
      A stock style Mopar canister coil does, or it will get hot.

      For a run stand I would probably opt for a C or E core coil like the newer trucks have.
      It doesn't need a ballast, is small, puts out a great spark, is easy to wire up and isn't oil filled or cooled.

      coil.jpg
       
    • fjr

      fjr Well-Known Member

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      Depending upon the primary winding resistance, the coil may or may not need a ballast resistor. If you're using the coil that is matched with a Mopar ECU and ballast resistor, you will overheat the coil if you run the coil for more than a few minutes without a ballast resistor using a Mopar ECU.

      Coils (like the e-core) that don't require ballast resistors have low primary coil resistance (HEI e-core coils have 0.5 ohms) and are designed for use in CDI ignition systems or variable dwell inductive systems (like HEI). You will burn out a low resistance coil with the fixed dwell Mopar ECU if a ballast resistor is not used.
       
    • 318willrun

      318willrun Stomper 4x4... we kept energizer in business

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      Just curious, have you ever run a coil like the one pictured on a older car? I guess I never thought about putting one of those on. I think getting a coil wire that has two different ends (coil/cap) would be difficult.
       
    • fjr

      fjr Well-Known Member

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      • TrailBeast

        TrailBeast Slightly Twisted Member

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        Yep, last week as a matter of fact.
        You can put any end you want on a coil wire, and that loose wire in this picture is what was for the coil pictured above.
        That coil is a stock Dodge Ram 1500 coil.
        The distributor was running with the coil I posted and this cap and wires pictured, but the distributor has a rotor/cap phasing issue and I didn't want to mess with it at the moment so I pulled it all and went back to my HEI conversion so I could get on with car show day. :D

        dragon fire wires.jpg
         
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        • 318willrun

          318willrun Stomper 4x4... we kept energizer in business

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          what is your thoughts on running that coil (per say, a coil from a 2000 magnum) on a stock Chrysler electronic ignition system (stock distributor, ballast resistor, ECU)?
           
        • TrailBeast

          TrailBeast Slightly Twisted Member

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          They run great with the OE electronic distributor, but you don't use a ballast with these types of coils.
          I have two full different ignitions.
          The one on the car right now is a GM 8 pin HEI module with an advance and total timing modified OE Chrysler magnetic pickup distributor and E core HEI coil.
          (Same as the HEI kits I used to sell here)

          The second is the Ready to Run HEI distributor, a C core coil and 10.2mm Dragon Fire plug wires. (the red ones I posted the pic of above)

          I have also run a E and C core coils both with the stock Mopar ECU with a bypassed ballast without any issue's.
           
          Last edited: Sep 17, 2018
        • 318willrun

          318willrun Stomper 4x4... we kept energizer in business

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          ok, forgive my "re-asking" :D Just so I understand, if I went to this style of coil, I just need to eliminate the ballast resistor, correct?
           
        • TrailBeast

          TrailBeast Slightly Twisted Member

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          Yep, and if you grab one out of a yard get the pigtail with it.
          Also if you do end up with one and want to verify + and - let me know and I can tell you.
          Mine is still out on the car, because I didn't take the time to remove it before the car show Saturday.

          They also run a standard tach by connecting the tach lead to the coil negative wire just like the stock canister coils.

          Gotta go now, but will be back later.
           
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          • famous bob

            famous bob mopar misfit

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            didn`t a clingon ship commander say that !?