New Pertronix III question

Discussion in 'Street/strip 400/430/455' started by rkammer, Jul 22, 2021.

  1. rkammer

    rkammer Gold Level Contributor

    If I convert my points distributor to the Pertronix III I’ll need a full 12 volts to it and the coil. So, is there another place to get ING 12 volts besides replacing the factory resister wire in the bulkhead connector with a solid wire?
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Fuse block.
     
  3. Brett Slater

    Brett Slater Super Moderator Staff Member

    Ray,

    Make sure you keep the points, etc. in your glovebox so you don't get stranded somewhere should that setup crap the bed.

    I ditched mine for the Lectric Limited setup sooner than I thought I would have to after it cooked on me during engine break in.

    20200422_115522.jpg
     
    BuickV8Mike and john.schaefer77 like this.
  4. rkammer

    rkammer Gold Level Contributor

    I know that, Larry. I was hoping there was also an IGN wire under the hood. Is there? I'd rather leave the resistor wire in its original pin location if possible.
     
    Last edited: Jul 22, 2021
  5. rkammer

    rkammer Gold Level Contributor

    I'm probably also gonna go with the Lectric Limited system but wanted to look into the Pertronix III since it has a Rev Limiter which requires 12 volts instead of the factory resistor wire. I also will need IGN 12 volts for the electronic choke mod to my Quadrajet. So, if I go with the Lectric Limited conversion I'll probably use the factory coil connection to trigger a small relay that sends 12 volts to the choke.

    That still doesn't get me a rev limiter so I'll look into the MSD stand alone limiter if it's still available. And, your suggestion on keeping a points unit on hand is well taken.
     
    Brett Slater likes this.
  6. Thumper (aka greatscat)

    Thumper (aka greatscat) Well-Known Member

    Trace the white/gray resistor wire back to the firewall. It may change there and you can connect a non resistor wire there and run it to the coil.
     
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  7. 1973gs

    1973gs Well-Known Member

    Just trace the wire back to the bulkhead connector at the fire wall. Remove the terminal from the connector and from the positive side of the coil. Just tape the original terminals back in the harness and run a new wire from the now empty cavity in the bulkhead. This way it can always be put back to original. IMG_0001.JPG
     
  8. Bigpig455

    Bigpig455 Fastest of the slow....

    I use the III in three vehicles that get raced pretty often, and I like them. The rev limiter is cheap insurance, and I've never had an issue with them in 10 years or better. I run a dedicated 12 volts via a bosch relay direct from the battery, and use the resitor wire for the relay trigger. works well, but you need to install a diode to the alternator in internally regulated cars of the relay backfeeds the alternator/ign switch and you cant shut the car off.

    What I HAVE had issues with is the Pertronix coils. Spend the money and get an MSD blaster 2, tey work well and meet Pertronix spec for low primary resistance.
     
  9. rkammer

    rkammer Gold Level Contributor

    I did that with my last GS and think I still have some of the bulkhead pins left in my parts bin somewhere.
     
  10. Schurkey

    Schurkey Silver Level contributor

    Sure about that? MSD's cheap Chinese coils probably have the same high failure rate as the Pertronix cheap Chinese coils.

    When it was me, I bought a Crane/FAST PS50, which claims to be made in USA as of May 2019. The PS60 is the same thing in chrome.
    https://www.summitracing.com/parts/fst-730-0050




    When wiring an electric choke, remember that you don't want the choke powered when the starter is cranking, or when there's no oil pressure. There's no sense heating the choke coil before the engine starts (long crank times cause the choke to open) and if the engine stalls, the choke blade doesn't need to be open, either.

    Find a power source that's live only when the key is in "Run" position, then route power through a normally-open oil pressure switch, then to the choke heater.
     
  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Ray, some fuse boxes have a terminal for switched 12 volts. In the middle. Just check it with a test light or meter to see if it has power in run and crank. I have my electric trunk release plugged into it. It is labeled BAT and ACC. Just check it in RUN and CRANK.

    If it was me, I'd just do it like in post #7, or as Gary suggested.

    FusePanel.jpg
     
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  12. TrunkMonkey

    TrunkMonkey Well-Known Member

    1 is ignition
    2 is ACC
    Battery above ACC is empty.

    And it is a bit of effort to replace the resistor wire, but I like tidy.

    The fuse block is also to do and a bit easier to do, if that terminal is not powering your George Foreman grill or Jacuzzi pump.

    upload_2021-7-22_9-47-54.png
     
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  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Yeah, IGN, that's the one.:D How'd I miss that?
     
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  14. TrunkMonkey

    TrunkMonkey Well-Known Member

    They are hard to read after all these years. :D
     
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  15. philbquick

    philbquick Founders Club Member

    One of the wires going to the kick down switch has switched 12V (if you have a switch pitch automatic). I put one of these systems in a customers 66 Wildcat GS 401 with the flamethrower coil and it worked well. You'll need to change to 8mm wires. This system also fires the plug more then once per power stroke for more complete fuel burn. It is shipped with the rev limiter set to 5,500 RPM.
     
  16. rkammer

    rkammer Gold Level Contributor

    This is what I plan to do but please explain the use of the diode. My EE experience tells me that when the ignition key is turned off, the resistor wire to the relay coil is an open circuit. And, the relay contacts are also open so there's no current path from the alternator to the ignition coil. So how can the motor be kept from turning off?
     
  17. rkammer

    rkammer Gold Level Contributor

    I should think that, under normal operating conditions the choke heater will take a lot longer to reset the choke blade to off than it will take to start the motor. The last electric choke carb I recall didn't fully reset for several minutes after the motor started.
     
  18. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I've heard of this with MSD box installs.

    MSDRunOn.JPG

    I don't understand why you need a relay at all. Just replace the resistor wire with a 12 gauge wire. What are you gaining with a relay? For high amperage fans, fuel pumps, and such, sure. Not for a Pertronix.
     
  19. 70 GMuscle

    70 GMuscle Plan B

    Go to your local Gm dealer parts department
    Tell them you need connector from
    Tray 1 Bin 2.
    That’s the connector on left above.
    I also run a wire from starter to coil for cranking 12 v
    This is what my 70 required.
     
  20. 70 GMuscle

    70 GMuscle Plan B

    I used crane ignition model in points distributor.
     
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