Swap Mallory with Pertronix FlameThrower HEI III

Discussion in 'Sparky's corner' started by Cutlass, Feb 1, 2020.

  1. ToddsGS

    ToddsGS Founders Club Member

    Not trying to "ruffle any feathers" but a quick Google search on Pertronix should tell you all about there "track record".

    Some work, some don't! They're on version # 3 for a reason . . . .

    We've seen roughly 6 or 7 fail in the last couple years (At the Restoration Shop I work at)

    .
     
  2. Cutlass

    Cutlass Platinum Level Contributor

    No offense taken at all. I very much appreciate all your input. I would not raise any question if I could not live with the potential answers. I do not want to come across as stubborn or ignorant, but in this case I will take my chances. Sending the unit back to US and getting a new one would be easy more than 100 bucks just for shipping, duties and taxes. Lets keep the fingers cross, that my experience will be similar positiv as the ones from Darren and Soren.

    Maybe I am a little to academic sometimes, but I just can't help my curiosity.
    Please chime in with your theories:
    I measured the angle for the mechanical advance at the distributor shaft:
    No bushing approx 26°:
    IMG_0301.JPG IMG_0302.JPG
    Bushing approx 16°:
    IMG_0304.JPG
    There must be a mechanical correlation in between the angle @ the distributor shaft and the corresponding angle at the crankshaft. With 4-stroke engines the distributor shaft runs at the same speed as the camshaft, which is half the speed of the crankshaft. Accordingly the mechanical ratio is 1:2 and "Ralf's theory on:" 1° at the distributor shaft equals 2° at the crankshaft. However this does not make any sense with above values, as it would mean 26°@distributer = 52° @ crank (w/o bushing) and 16°@distributor = 32°@crank (w/ bushing).
    Where do I screw up?

    @ Larry, I am not questioning your advice, just trying to better understand the system.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I'm not really sure how you are measuring angle. That slot looks pretty small to me, typical of a 1112110 distributor. Yes, 1* of distributor rotation = 2* at the crank. When the weights swing out, they change the rotor position making the spark occur earlier (advanced). Try measuring ACTUAL rotor angle change. Maybe bolt on a rotor and move the pin to one side of the slot and then the other. Should be no more than 9*.
     
    Last edited: May 3, 2020
  4. Cutlass

    Cutlass Platinum Level Contributor

    Result of some further investigation:
    Measuring the angle from one end of the slot to the other is not the way to go. Once the weights are installed, they limit rotation in one direction, not the pin within the slot. So here are the new measurements:
    w/o bushing approx 18°
    IMG_0306.JPG
    w/ bushing approx 14°
    IMG_0307.JPG
    Still, the correlation to the crank angle does not make any sense to me.
    Maybe I assemble the distributor and try to measure again.
    Still confused :(
     
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Install the rotor and measure actual rotor angle change.
     
  6. Cutlass

    Cutlass Platinum Level Contributor

    New measurements, to add to the confusion
    IMG_0321.JPG
    w/ bushing 13°
    w/o bushing 22°
    Here you can see what I meant in my previous post, the weights are the stop in one direction:
    IMG_0315.JPG
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Well, one way to see exactly how much you have in the distributor is to install it and run it. Then check it with a light. It isn't out of the question that someone modified the slot. I mean the car is 50 years old. Unless you want to play with it some more.:D:D
     
  8. Cutlass

    Cutlass Platinum Level Contributor

    That is what I will end up doing. Maybe real world data will help me to find answers to my theoretical questions :).
     
  9. Cutlass

    Cutlass Platinum Level Contributor

  10. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

  11. Cutlass

    Cutlass Platinum Level Contributor

    Good:
    The Pertronix unit is installed and is working

    Bad:
    The vacuum canister is no more working. I installed it anyway, as I needed to fixate the base plate for the below measurements
    I ordered a Crane adjustable unit at Summit. Paid 60 bucks just for shipping and if I am lucky will have my hands on it on Tuesday next week.

    Data:
    I installed the "heaviest" weights, which are the ones coming in the Mr. Gasket kit
    No bushing
    no vacuum, canister broken, unplugged and opening at the carb plugged

    First run I did with hard springs and I did set timing to 15° advance @ idle and tightened the distributor
    For the second run I replaced the hard springs with the softest ones (from the Moroso kit)
    At idle I had about 25° of advance
    mechanical advance maxed out with 46° at 3000 rpm

    My conclusions:
    Mechanical advance is way to much (31°), so I will install the bushing. Just not sure if the bushing will be enough to bring down the mechanical to less than 18°
    I will switch to lighter weights, so that advance does not start at idle, will see what springs I will need in that combination.
    Considering, that my measurements have tolerances it looks like there is some correlation in between the approx 18° I measured at the distributor and the approx 31° I measured in the car.

    Am I on the right path?
     
  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yes, put a bushing on the pin and report back.
     
  13. Bens99gtp

    Bens99gtp Well-Known Member

    Wish you luck with the brand you have picke . A few years ago I washed my hand of this company......installed 5 different dist in build we did. 2 sbc, 2 bbc, 1 ABC.

    The following year all 5 had issues with the modules......I used both the basic and the one with rev limiter in.......niw I just use a msd and hide the box if needed.....in fact I use the 6520 box lock out the swing and just get past all this moving timing and keep it much more simple
     
    Brett Slater likes this.
  14. Cutlass

    Cutlass Platinum Level Contributor

    Done!

    Bushing alone was not enough to limit mech advance. It came out with 25°, so the bushing reduced the angle by 6°
    So I did some welding & filing to make the slot smaller. I let the bushing installed and now have 14° of mechanical advance. I used the two silver springs from the Moroso kit, along with the weights from Mr. Gasket kit and have no mechanical advance @ idle and mechanical advance is maxed out @ 2800. Total timing is set to 32°.
    I can tell you, I am very efficient now in taking the distributor out and putting it back in :). I guess stuff like this is what helps bonding with your car :).
    Keep your fingers cross, that next week the Crane vac shows up at my doorstep, so that I can finish the whole distributor job.
    Until then I will put in the MSD Super Conductor 8.5mm ignition wire. @ Larry, the little crimp tool, which comes with the kit works pretty good, and I expect it to last until I am done with the nine crimps I need to do.

    @ Ben, I take you by your word. If my unit fails, you did not wish me enough luck :):)
     
  15. Cutlass

    Cutlass Platinum Level Contributor

    After a night of sleep I was wondering, if 14° mech advance is to little. Should I file some more, in order to get closer to 18-20°?
    What would you recommend for setting the vac advance? 8°, so that my total does not exceed 40°?
     
  16. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yes, 18-20* is better. Measure the slot, inquiring minds want to know.:). Low 40's cruise timing is fine. 8-12* of vacuum advance.
     
  17. Cutlass

    Cutlass Platinum Level Contributor

    Will do, that's the least thing I can do in order to give something back to this community.
     
    Last edited: May 10, 2020
  18. Cutlass

    Cutlass Platinum Level Contributor

    Crane kit arrived today. Not bad, considering that I ordered it last week Wednesday. Best thing, that it slipped thru customs, so that I did not have to pay duties and taxes. I have read that it happens sometimes, that customs does not charge anything if goods value is not crazy high. However, this is the first time this is happening to me :)
    It got pretty cold again, so I decided not to fool around with ignition timing, but to install the MSD Super Conductor 8.5mm ignition wire. Installation, including crimping was straight forward and easy. One recommendation, if using the supplied crimping tool, is to use some grease in the inner area of the tool. The crimp comes out much nicer and you do not need as much force for the crimping.
    Looks neat and clean and this time I triple checked that all the plugs are in the right spot at the distributor cap :). Don't wanna embarrass myself a second time :)
    IMG_0326.JPG
    IMG_0324.JPG IMG_0325.JPG
     
  19. Cutlass

    Cutlass Platinum Level Contributor

    I hope I am done. Modified the Crane and set it so, that I have 9° vacuum advance @ 0,7bar (10.3 psi, 22" of mercury) vacuum which I have at about 17001/min
    IMG_0327.JPG IMG_0328.JPG IMG_0329.JPG IMG_0330.JPG
    In regards to the mechanical advance I came to the conclusion, that the width of the slot alone is not the single factor to the amount of mech advance. I got three different set of weights (the ones which came with the distributor, a pair from the Mr. Gasket Kit and a pair from the Moroso Kit). All three gave me different amount of mech advance with the same width of the slot. That said, the position of the pin @ idle is not determined by the slot, but by the weights. Accordingly one should measure the remaining gap in between the pin and the slot, and not the overall width of the slot. In my case I ended up using the weights from Moroso. The overall width is 9,7mm (0.382"), the remaining gap is 2,4mm (0.094") and I get 20° of mechanical advance.
    IMG_0335.JPG
    The total advance I set to 32°, which is all in @ 2900 1/min. At idle I have 12°. Vac advance is 9°, so maximum total is 41°.
    I hope I got everything right, and that my findings make sense.
     
    Last edited: May 23, 2020

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