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Dyna coils

Discussion in 'Loop & Tonti' started by jr1967, May 18, 2020.

  1. jr1967

    jr1967 Cruisin' Guzzisti

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    Quick question; I found in an article about some unknown dual output coils that you can run them as single output coil by grounding one output to ground. Leaving that output not grounded supposedly gives you no spark on the other lead.
    Would that also apply to Dyna coils? I just don't know how they are build inside.
    Reason I ask is that I am planning on swapping a single plug engine for a dual plug engine in the near future both with dyna III ignitions.
    Thanks for any input
    JR
     
  2. Kevin.NZ

    Kevin.NZ Cruisin' Guzzisti

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    with dual output coils, when they spark, one end is positive and the other negative , thats why on my Breva one of the outputs is marked in red paint and goes to the outer plug
     
  3. jr1967

    jr1967 Cruisin' Guzzisti

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    Hello Kevin, that's interesting; I didn't know that could be the case....
    But on the dual output Dyna coils that I have, the outputs are identical, I have not seen any instructions that it matters on which plug they go, since they are also used on 4 cylinder bikes with a wasted spark ignition(like KZ900, CB750 etc). So my question still remains; can I just ground one lead if I want to feed only one spark plug or can I plug in only one lead without the possibility of frying the ignition module?
    Cheers
     
  4. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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    As far as I have been taught, running power across any lead from a high energy ignition coil, that does not have a ground back to the block, will irreparably damage or destroy the coil itself. Always.

    So, I would use an appropriate single or dual plug ignition coil as the configuration requires.

    Personally, I would not just ground one lead out as you have suggested. Seems very sketchy at best.
     
    john zibell likes this.
  5. V700Steve

    V700Steve High Miler GT di Razza Pura

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    If you have dual out put coils and you only want to use them as singles you put a cap over the one not used till a later date. The power goes nowhere w/o a HT wire plugged in.
     
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  6. jr1967

    jr1967 Cruisin' Guzzisti

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    Ok thanks, I am just hoping to not repeat frying my ignition like I did with a car that I cranked over with the distributor cap removed(to align the rotor with the hole in the shaft)
    A german site showed a picture of their dual coil with a ground lug crimped on one of the leads for single plug use. That got me wondering....
    I can try to find their website to show the doubters :)
    I am just at work now...
     
  7. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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    abusus non tollit usum
     
  8. jr1967

    jr1967 Cruisin' Guzzisti

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    My 6 months of Latin didn't really cover that but thankfully google does :)
     
    Last edited: May 19, 2020
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  9. jr1967

    jr1967 Cruisin' Guzzisti

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  10. jr1967

    jr1967 Cruisin' Guzzisti

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    I can of course get in touch with Dynatec to find out what they suggest. I'll post it here once I have an answer so we can all learn something. Perhaps the best answer is "don't do it" :)
     
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  11. jr1967

    jr1967 Cruisin' Guzzisti

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    Well hats off for Larry Nelson at Dynatec for an almost immediate response!

    Larry Nelson (Dynatek)

    May 19, 2020, 1:17:20 PM PDT

    Hello JR.
    Thank you for contacting is regarding coils with your Dyna D37-1 ignition.
    While you could do as you describe, it actually overloads the coils and likely the Dyna III module as well. In addition, if one oif the grounding lugs were to fail, you will destroy the Dyna III module and/or coils.
    We will have to let you decide what to do, but we really would recommend the DC10-1 coil set having the correct 5.0 ohm primary rating and one spark plug output per coil.
    If you need any further assistance, please let us know.
    Thank you.
    Larry Nelson
    Technical Support
    Dynatek

    So, everyone that responded, thanks for the input. I am a little wiser :)
     
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  12. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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    Thank you for confirming what I had been taught. It’s good to be validated.

    Also, it’s good for you to know from the horse’s mouth!
     
    Last edited: May 19, 2020
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  13. Andrew Stewart

    Andrew Stewart Just got it firing!

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    L
    I do not know about Dyna coils but I can certainly agree with this post from my personal experience with my Cal. Vin. I recently, through my own ignorance, ran it for about 4 miles on only the 2 outer plugs. Having kindly been given advice on here I put it back together and have now covered over 180 miles and it's running fine. I don't know if I've shortened the coils lifespan, but I can say at the moment they are performing as they should.
    AS
     
  14. jr1967

    jr1967 Cruisin' Guzzisti

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    Some other info that I gathered is that the Dyna ignition is actually designed to run fine with the stock old school coils as well. Since they are in the 3 Ohm range, the conclusion is that the way the Dyna coils are build create the issue with heat build up, hence the recommendation for 5 Ohm coils.
    So I'll run the Cali with the stock coils until I am ready for the swap with the twin spark engine. I the mean while I'll try to source some affordable 5 Ohm dual outlet coils.
     
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  15. Moto-Uno

    Moto-Uno Cruisin' Guzzisti

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    I'm not so sure this is completely understood , lower resistance coils (3 ohm) draw more current than high resistance (5 ohm)
    coils . That current draw (amps) has to pass through the dyna ignition unit . If you ask them they always suggest , if possible ,
    to use the 5 ohm coils , less current = less heat . Less heat improves it's chances of a longer life ( 5 years +) . The lower resistance
    (3ohm) coils also pass more current through the ignition points , longer potential life with the 5 ohm coils .
    With most coils when the secondary coil collapses (points open) the spark energy wants to complete the circuit to ground , if
    that's prevented ( plug lead falls off , for instance ) the spark looks for a path to ground , and that's frequently through the coils
    internal wiring . With time that path gets easier than jumping the plug gap and you end up with a failed coil . Peter
     
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