Dynaflow high accumulator actuator?

Discussion in 'The "Juice Box"' started by Craig Holmes, Aug 18, 2020.

  1. Craig Holmes

    Craig Holmes Member

    Anyone ever engage the switch pitch with a solonoid On a Dynaflow? I was thinking about replacing the carb actuated rod with a 12v solonoid and wiring it to brake pedal/ kick down switch/ toggle switch. Not sure if operating like this would heat up the transmission and cause damage. I mainly like the idea of engaging high stall with the brake on. Would be easier on engaging forward or reverse. Thoughts? Experience?

    thanks,
    Craig
     
  2. suntreemcanic

    suntreemcanic Well-Known Member

    Are you talking about a Turbo 400 rater than a Dynaflow?
     
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  3. LARRY70GS

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

    Not sure if that is feasible, but I am sure it would super heat the fluid for sure. It might also make the car response lazy from a stop and at low speed, like a "too loose" converter. Even the later switch pitch only actuated hi stall above 60% throttle. Off idle was low stall. In Drag racing, it is advantageous to engage hi stall for the first 60' or until the 1-2 shift. For regular street driving moving from a stopped position, you want low stall. I actually experienced that when I swapped in the smaller 12" converter in my switch pitch. The timer box I was using had a brake switch timer that controlled the high to low stall, and it was not adjustable below 3 seconds. I found that taking off in hi stall made the car lazy as the converter was too loose in that situation. I had the timer box modified so that hi to low stall occurred immediately upon brake release. There was a separate vacuum switch on the timer box that would put the converter back into hi stall below 5" of vacuum. That turned out to be the best way of controlling the stator angle change, just as Buick had designed it to operate
     
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  4. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Isn't the whole trans a constant variable pitch? Wouldn't it be nearly undriveable if it was rigged wide open?
     
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  5. Craig Holmes

    Craig Holmes Member

    Its not constantly variable. The TC has a primary pitch with a ratio of 1.9 and a secondary (activated via a mechanical rod on the stator) of 3.4. Each TC phase will be variable throughout its operation until I'm guessing about 90-95% lockup. If I ran it off a solenoid the full throttle behavior would be the exact same as it would operate the solenoid via a switch on the car (like the 400). The only advantage would be it would be in the 3.4 (high stall) mode when the brake is applied. This would allow for a higher idle speed, and a smoother engagement form P>>D and P>>R.. I doubt I would run to a toggle switch for "Race Mode". I think that would heat the fluid and destroy the transmission.
     
  6. Craig Holmes

    Craig Holmes Member

    Doesnt the 65-66 switch pitch run high stall with the brake on? This would be the only reason I would want to try to mod the Dyna to a solenoid. To get a better, slightly faster idle and smoother engagement into gear. Not exactly sure how it would behave just off idle as it would swithc to low stall when I release the brake and start to accelerate. Could be funky.
     
  7. Craig Holmes

    Craig Holmes Member

    No, Dynaflow. Talking about controlling the switch pitch convertor of the Dyna with asolonoid instead of throttle-rod to be more like a 400. The only thing Im not sure of is if the 400 runs high stall with brake applied. I see potential advantage this way as it would make idle quality better and engagment into gear smoother. Dyna is kinda harsh going into reverse and I heard it breaks easily.

    I thought about swapping to a 400 (actually have a 64 400 on my garage floor). But my Dyna operates perfectly and doesnt leak a drop. It also is easy on the Nailhead with 140k. I doubt its ever been over 3500 rpm in its entire life. With a 400 or 700R4, etc. I can see getting frisky and hitting 4500-5k at times. I doubt my motor would like that at this point.
     
  8. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    My 66 switch pitch is in high stall at idle. It's unrelated to the brake pedal switch though. It's a a another stage in the kickdown/converter switch, if that makes sense.
     
  9. LARRY70GS

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

    Yes, high stall at idle. Then low stall immediately off idle, then back to high stall above 60% throttle. When I ran the switch pitch, that is the way it was controlled by the timer box. It worked great. Not sure about the Dynaflow.

    This is the idle switch,
    Switchpitch2.jpg
    This switch controls the switch back to high stall above 60% throttle and the kick down at full throttle,
    Switchpitch1.jpg
     
    Last edited: Aug 25, 2020
  10. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    The adjustment is crucial. The converter dropping to low stall while accelerating from a light can feel like a bad off idle stumble if too tight or feel like a slipping trans if too loose. With a cable throttle it might be better, but the mechanical linkage on the olds made it a real pain especially in cold weather. I surmise thats part of the reason the switch pitch was discontinued. It has a much different feel over a normal converter that may have turned buyers off.
     
  11. LARRY70GS

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

    I thought it was the bean counters:D coupled with the doctors and lawyers not being able to appeciate the difference.
     
  12. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    They ruin everything!

    In a high horse midsize car with decent gearing what I described might not be as noticeable. The olds is 4k lbs, has 2.78 gears and a 280 horse small block....
     
  13. Craig Holmes

    Craig Holmes Member

    Great Info!! Thanks a bunch. Definitely gives me some context.
     
  14. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    Here's the switch on my Olds, Larry. All in one clock switch. Forgive the crappy unrestored engine bay.
     

    Attached Files:

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  15. LARRY70GS

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

    Yeah, that is different. Never saw that. Olds did it differently. Thx.
     
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  16. d2_willys

    d2_willys Well-Known Member

    On a Dynaflow, one must remember that the torque converter is not the same as most 3 member converters. At rest, the converter is set to use the FIRST turbine for pulling away from a stop, then the SECOND turbine eventually comes into play when vehicle load eases up. Changing the stator pitch at idle may or may not work well with the design of the torque converter. In the stock mode, the variable pitch stator changes only at WOT.

    You could try it by removing the link at the carb and attach the link to keep the stator in the high angle. But, for safety's sake, I would also attach a transmission fluid temp gauge to see if the fluid starts to rise at idle. If it does, the smallish fluid cooler on the transmission might have a hard time keeping the fluid from boiling, and the engine may even heat up from the radiator trans cooler heating up too.
     
  17. 69hellcat

    69hellcat Well-Known Member

    I have a old Kenne Bell news that states when Pops ran the 61 Invicta they used the heater blower control cable to control the stator on the Dynaflow. I tried it on my 62 cat making a bracket to hold the cable after taking it off the heater switch. In low range it will brake stall to 3800 rpm. In my testing on the street shut the stator down to low stall as soon as you launch. I just dont think Buick intended full throttle shifts from low range to drive. Pretty brutal will bark the tires everytime when shifting. Seems to build mph better with the stator shut down after launch. Iam sure a selinoid could be used to control the stator too. Pop Kennedy also ran a triple turbine flight pitch Dynaflow on the red 59 Invicta many wins with that car back on the day.
     

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