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Thread: Pickup Polarity

  1. #1
    mbaker Guest

    Default Pickup Polarity

    I was told to check the polarity of our distributors, by using jumper wires to switch the magnetic pickup wire orientation, and that the most retarded timing result was correct wiring. Then I was told to either swap the wires in the plug? Or remove and flip over the magnetic pickup? Is all of this correct?

    How much difference will it make in timing, I just want an idea of how much to look for with the light...5-10 15 etc.? Also, which is better swapping the wires, or flipping the pickup?

  2. #2

    Default

    Normally the connections between the MSD distributor and MSD Ignition box will be such that the Black/Orange on the distributor is connected with the Violet wire of the MSD box. The Black/Purple will connect with the Green of the MSD box.

    Changing the connections so that the Black/Orange connects with the Green and Black/Purple connects with the Violet will change the polarity. This may throw the timing off by about 20°.

    With an analog unit (i.e. 6A, 6AL, 7AL, etc) the connection you want is with the most retarded timing. On a Digital unit (i.e. Digital-6 or -7 Plus, etc) the connection you want is with the most advanced timing.
    MSD Tech Support
    915-855-7123

  3. #3
    fourtenposi Guest

    Default

    If the correct polarity is not used, does the system still operate correctly? Or do you have timing issues? I have heard of people having intermittent misses that cleared up once the polarity was corrected. I also have found that I had my crank wheel on backwards. Could either of these issues cause performance issues?

  4. #4
    msdtech19 Guest

    Default

    Dear fourtenposi. Normally the connections between the MSD distributor and MSD Ignition box will be such that the Black/Orange on the distributor is connected with the Violet wire of the MSD box. The Black/Purple will connect with the Green of the MSD box.

    Changing the connections so that the Black/Orange connects with the Green and Black/Purple connects with the Violet will change the polarity. This may throw the timing off by about 20°.

    With an analog unit (i.e. 6A, 6AL, 7AL, etc) the connection you want is with the most retarded timing. On a Digital unit (i.e. Digital-6 or -7 Plus, etc.) the connection you want is with the most advanced timing. Keeping the wires in the correct polarity is the best and only way the vehicle will run perfectly.
    msdtech19
    __________________
    MSD Tech Support
    915-855-7123

  5. #5
    fourtenposi Guest

    Default

    Hello,

    I understand that changing the polarity changes is the timing. As long as you set the timing with the current polarity setting, does it make a differance on how the system performs? Does it do anything weird with the timing at higher rpms with the polarity incorrect?

  6. #6
    msdtech1955 Guest

    Default

    phasing.bmp
    The car would run, but the rotor phasing would be off.

  7. #7

    Default

    I've replaced a MSD 10 with a MSD 6BTM. I have great spark when I jump trigger the coil, but when I hook it back into the pickup wires, it just cranks with no hint of it starting. My mechanic put in a 8366 Distributor, so my question is: Does the MSD 10 have different polarity than the 6BTM? If so, I should flip the wiring to the distributor? Or are there other issues that need attention?

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