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Technical Stumbling flathead

Discussion in 'Traditional Hot Rods' started by CSPIDY, May 25, 2024.

  1. chicken
    Joined: Aug 15, 2004
    Posts: 594

    chicken
    Member
    from Kansas

    I think you'd better look in the distributor, specifically at the Pertronics module. The opinion that it will either work or not at all is NOT correct. I raced with a fellow who used them and they would start failing by misfiring at mid/high rpm and get progressively worse.
     
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  2. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    Im looking in to this as well, @FritzFord may have the answer, the engine was fitted with 3 ohm coil so I replaced it with a 3 ohm Flamethrower coil, turns out it’s for a 4 or 6 cylinder engine. The 1.5 ohm Flamethrower is for a v8 engine. I didn’t want to post this because the mods may delete it.
     
  3. j ripper
    Joined: Aug 2, 2006
    Posts: 846

    j ripper
    Member
    from napa ca.

    I’ve said this already; eliminating all that nonsense would be the best move. Just sayin.
     
  4. It is possible - so I'd raise the float level until the fuel is just under 1/2" from the top of the main casting. Given that it started stumbling all of a sudden and the fuel system has not been changed, I doubt this is the issue - but set the float levels correctly anyway.

    It has sounded like a distributor/ignition related issue all along - but it is always good to checkout your fuel system while you're in troubleshooting mode.
     
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  5. FritzFord
    Joined: Jan 24, 2020
    Posts: 41

    FritzFord
    Member
    from Nashville

    Thank you for taking me seriously Cspidy. I’m not making this up, it is directly from Pertronix. They have good customer support if you want to ask them too. They make great modules, but like many other things, they are designed to operate in a specific way. When you set it up as they instruct, they work great.
     
    CSPIDY likes this.
  6. tubman
    Joined: May 16, 2007
    Posts: 7,361

    tubman
    ALLIANCE MEMBER

    This statement is absolute nonsense. It's about electrical load, not the number of cylinders.
     
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  7. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    I spoke to Pertronix tech service, he explained simply as with the 3 ohm it takes a longer time to reach the 40k volts and at higher rpms the discharge voltage is much lower the faster you are spinning the engine.
    Evidently these flamethrower coils are not like the stock coils, I reinstalled my original stock coil and the stumbling is gone.
     
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  8. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    I did adjust the float level in the primary 97 to 1/2 inch down to the top of the fuel level.
    I also found the secondary 97 has a bad power valve, so I ordered 2 rebuild kits for another days work.
     
    Stogy likes this.
  9. Stogy
    Joined: Feb 10, 2007
    Posts: 26,446

    Stogy
    ALLIANCE MEMBER

    Are you running an inline fuel filter...that caused me grief like that 2 times...glue that holds the filter disintegrated and choked the inlets on the carb with chunks of glue...but before that the filter periodically settled over the inlet to the pump and choked the fuel causing the car to start suddenly lose power at speed...

    I read it here to take the filter off drain and shake...mine was like like a rattle...

    Others may have mentioned it but it's a great way of learning about stuff that's for sure...

    20240530_133028.jpg
     
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  10. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    I am running the inline filter that came with the electric fuel pump, through the troubleshooting process I installed my new spare, but obviously there was nothing wrong with the electric pump that was installed.
    Now my new used spare.
    Bottom line line my question has been answered and early in the process, that is priceless

    I appreciate all the commentary, the experience on this site is over the top

    I apologize for the Pertronix mentions, and thanks for permitting them.

    leason time is over
    time to drive
     
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  11. You should still have your distributor "run up" on a machine and reinstall the vacuum brake - such that it is just slightly rubbing on the advance wheel.
     
  12. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    it’s on the list, thanks
     
  13. These flathead distributors are definitely a different kind of creature. But they still look like something that most of us could repair and rebuild at home with some fairly basic tools and a bit of patience.




     
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  14. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    Stogy likes this.
  15. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,717

    ekimneirbo

    I'm more for "If it ain't broke, don't fix it" mentality............:) Since you got it working good, enjoy it.
     
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  16. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    An update of sorts
    The pertronics igniter module bit the dust the other day
    I spoke with pertronics tech service and found out the pertronics igniter modules don’t like metal core plug wires. They give too much EMI
    so
    I have another module coming as well as a used original distributor with points.
    I will be swapping the carbon core wires back in until I get the distributor with points set up.

    I believe this may have been my stumbling problem
     
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  17. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    Well it official
    Don’t use solid core wires with pertronics igniter modules
    The first line in the instructions state this
    Reinstalled the carbon core plug wires with new igniter module
    and
    The engines runs like a banshee
     
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  18. I believe carbon core wires are best/necessary on all electronic ignitions.
    Happy for your banshee.

    Ben
     
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  19. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    I really liked the original style color coded solid core wires with the SS tubes. My goal is to get that look again.
    IMG_2276.jpeg
     
  20. FritzFord
    Joined: Jan 24, 2020
    Posts: 41

    FritzFord
    Member
    from Nashville

    Edit: I guess I’ve been using spiral wound/solid core spark plug wires for years with my pertronix. If I remember correctly from the old Mac’s description, they were rated for electronic ignitions and they have the stock color coded cloth outer insulation. If I ever have to replace them, I’d think about these:
    https://brillman.com/product/1942-1944-8-cyl-ford-car-truck-spark-plug-wire-set/
     
    Last edited: Nov 1, 2024
    CSPIDY and firstinsteele like this.
  21. CSPIDY
    Joined: Nov 15, 2020
    Posts: 699

    CSPIDY
    Member

    Thank you for the lead
    Will definitely consider these, they offer a suppressed option that would be pertronics safe
     
  22. NoSurf
    Joined: Jul 26, 2002
    Posts: 4,582

    NoSurf
    Member

  23. dmar836
    Joined: Oct 23, 2018
    Posts: 379

    dmar836
    Member

    Imagine how it might run if there was an ign advance setup? You still need that even with Pertronix.
    D
     
  24. I would put the original vacuum brake back in the distributor and tighten the screw down until you can feel the leather pad just touch the advance plate. With just a slight bit of drag it will prevent the advance mechanism from flopping around (which make the advance fluctuate as well). With today's gas, you may not need the brake to actually pull advance out - you won't really know that unless you work with the mechanism and see if you're having any detonation issues with it in the initial "just light touch" situation. My guess is that you won't need to tighten it down at all past the initial setting.

    It is still a great idea to have the distributor, coils and wires tested on a distributor machine - one that has the ability to fire the 8 plugs as well. I like to test the whole secondary side of the equation in addition to the primary side.
     
    dmar836 likes this.

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