Dual Points in One Dist to Pertronix MR-183 | FerrariChat

Dual Points in One Dist to Pertronix MR-183

Discussion in '308/328' started by SMS, Oct 10, 2017.

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  1. SMS

    SMS F1 Veteran

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    #1 SMS, Oct 10, 2017
    Last edited: Oct 10, 2017
    Image Unavailable, Please Login Image Unavailable, Please Login it was time to upgrade my upgrade. I had previously moved both sets of points into my rear distributor for ease of access and timing. Recently while just moving the car around it basically quit running. The spring steel on one of the sets of points broke and grounded the set to the distributor housing.

    So out it all came once and for all and in went the MR-183 Ignitor II with 45,000 V Flamethrower coils. The spark looks like an arc welder strike now. Idle is smoother than ever and it revs nice. Can't wait for the first test drive!
     
  2. Saabguy

    Saabguy Formula 3
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    #2 Saabguy, Oct 10, 2017
    And that arrangement works without the need for the pickups being 180 degrees away from each other?? Do you just change plug wire position in the distributor cap to make it work? Inquiring minds...
     
  3. Fairview

    Fairview Formula 3

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    #3 Fairview, Oct 10, 2017
    Hey Saabguy, Steve Mag. can explain why the pickups are located where they are, but it works.

    When I installed my MR-183 I found that one bank was advanced a few degrees more than the other. I ended up ovaling out the mounting screw holes for one pickup and sliding it just a bit one way or the other. That moved the timing on that pickup and it brought the timing on both banks into synch. Took a bit of experimentation. Jeff
     
  4. SMS

    SMS F1 Veteran

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    #4 SMS, Oct 10, 2017
    135 degrees apart.
     
  5. SMS

    SMS F1 Veteran

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    #5 SMS, Oct 10, 2017
    When I set up the points this way, I put a degree wheel on the shaft and used an ohm meter to know exactly when they opened at the right dwell. That took a lot of circular logic and trial and error until it was all just right. We can assume the new kit has it close but I will check like Jeff did to confirm both banks.
     
  6. SMS

    SMS F1 Veteran

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    #6 SMS, Oct 10, 2017
    No rearranging the plug wires. They stay as the are.
     
  7. SMS

    SMS F1 Veteran

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    #7 SMS, Oct 10, 2017
    Oops. Typo. 45 degrees apart. Or some increment of 45 as the engine fires a different cylinder every 45 degrees of rotation.
     
  8. SMS

    SMS F1 Veteran

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    #8 SMS, Oct 10, 2017
  9. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #9 Steve Magnusson, Oct 10, 2017
    You had that right both times -- they are mounted 135 physical degs apart which causes each to fire their coil every 45 deg of distributor rotation after the other one fires (i.e., they operate as being 45 electrical deg of dist rotation apart). It works because it doesn't have to be the same physical pole of the 4-pole rotor that fires each module in sequence -- mounting the 2nd module at any of the physical positions in the sequence of 45 deg, 135 deg, 225 deg, 315 deg, 405 deg, 495 deg, ...etc. relative to the first module gives the same 45 deg electrical deg operation (but the two modules can't fit without crashing into each other at 45 deg or 315 deg, and 135 and 225 are really similar as 225 = -135).
     
  10. Saabguy

    Saabguy Formula 3
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    #10 Saabguy, Oct 11, 2017
    Got it.
     

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