Checking Plug Wires

Discussion in 'PSI Superchargers Tech Questions' started by Flyboy68, Sep 19, 2014.

  1. Flyboy68

    Flyboy68 Member

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    Is there a standard everyone goes by when checking plug wires? We run MSD wires on our promag 44 hemi, and the longest one is 5', and it measures 240 ohms. Should be 200, but is 40 ohms over too much?
     
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    Flyboy68, Sep 19, 2014
  2. Randy G.

    Randy G. Top Alcohol

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    50 ohms per foot is a rule of thumb. 240 ohms for 5' is good.
     
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    Randy G., Sep 19, 2014
  3. Mike Canter

    Mike Canter Top Dragster
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    That is a good check BUT because of the high voltage the biggest problem with plug wires and a ProMag is the insulation breaking down and causing crossfire or shorting the spark to the engine or anything it is touching. If you are an occasional weekend racing you should change your plug wires at least at the start of each season and change your coil wire at least three times a season. For the guys running a full season a minimum of twice a year or three times a year and change the coil wire every 3 or 4 races.
     
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    Mike Canter, Sep 19, 2014
  4. Randy G.

    Randy G. Top Alcohol

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    I changed the plug wires every time I replaced the rods (or as needed after checking them with an ohm meter every few runs). I changed the coil wire every race. You can buy a roll of wire and all the ends and boots off the MSD trailer at the national events.
     
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    Randy G., Sep 19, 2014
  5. Flyboy68

    Flyboy68 Member

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    Mike, sent you a couple emails w/ our grid info. Did you get them?
     
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    Flyboy68, Sep 20, 2014
  6. Blown5402

    Blown5402 Member

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    Ohm good-but still bad!

    We Ohm our wires every race and they can be 40 to 50 ohms per foot, but still breal down completely and have cold cylinders like what has been said, And I know as we had bad cylinders last week, cold most of the run and ohms were good. Changed that wire and all was good? Thanks, Jim
     
    #6
    Blown5402, Sep 20, 2014

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