Clutch - Scew Blown FC

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by TOL, Oct 10, 2009.

  1. Mike Canter

    Mike Canter Top Dragster

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    The Leander Clutch dealer for the USA is Jeff Prock, phone 423.921.9540 (Jimmy Procks brother from John Force Racing)
     
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  2. john348

    john348 Top Alcohol

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    maybe so but i am guessing it is made from the 7000 series alloy
    not one of the other 1000 alloys you found
     
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  3. bryanbrown

    bryanbrown Member

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    http://www.leandersbros.se/Images/press/new2007_04.jpg

    am I seeing this wrong, or is there some potential for the donut to be able to walk around if it was out of balance, or got shocked by hitting the rev limiter or something like that. It doesn't look like any of the stand sticks out over it to keep it in line with the floaters. It's a nice looking piece, but it would suck to have to carry around (and cut) twice as many floaters
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    I think it is more that the floaters shift around just a little and throw the clutch out of balance especially if the slots that go around the stands are worn. With a three disc clutch there is a lot of rotating mass extending far out from the crankshaft. Also, maybe the flywheel flexes some. The other thing I think that happens is that the crankshaft flexes due to rotatinal twist and harmonic resonance. Blower motors do not use harmonic dampers like other cars and you have to ask why not. Once that clutch unit and crankshaft goes into oscillations off their normally centerline then it just keeps on getting worse as the run continues until you tear up the rear main bearing or the clutch actually hits the liner in the can. Like Will said I think these harmonics are worse at some RPMs above 10,000 and again as Will said if that RPM limiter comes on then that crankshaft is going to go crazy because you are shutting off cylinders and the crank twists and un-twists. I believe the Leader clutch use square slots to lock the floaters onto the stands to reduce movement.
     
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  5. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    tracks

    Let me throw another factor in the equation - tracks.

    Since TOL is running a door car, this may not be as bad for him as it would a short wheelbase TAFC.

    Bumpy tracks will play hell on a clutch - namely the flywheel - then the rear main. Manzo told me he has a bad track flywheel and good track flywheel...so he doesn't mess his good flywheel up bouncing around.

    The clutch is catching hell if the motor is freewheeling, then catching, etc.

    Talking with the Leanders Bros., that was one of the main goals of their design was to stop floater movement. They wanted to increase rigidity and improve balance. The clutch is made out of some sort of Swiss aluminum alloy, and is supposed to have some incredible heat dissapation. The clutch is so rigid that when adjusting it, you can't just move one adjuster, you have to back the other two stands off around it.
     
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  6. sean70ss

    sean70ss Member

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    clutch

    How does price compare to aft/crower?

    sean
     
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  7. badbird

    badbird New Member

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    #47
    Last edited: Oct 16, 2009
  8. JustinatAce

    JustinatAce Member

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    A little insight into the floater problem:
    It's not so much that the floaters move, it's the top half of the clutch twisting, boucing and reacting to the forces at work as Will said. If you spun a floater on a balancer, they are close to perfect. The floaters move because the studs move. Think about the fact that the center of 2/3(if not more) of the mass of the clutch is hanging about 4 inches from where it is attached to the crank. Generally speaking, there are 9/16" studs there to support them in an alcohol clutch. So taking the discs out of the equation because they are supported by the input shaft, So we'll say a Ti Crower 10.7 complete assembly weighs 72 lbs loaded, subtract about 20 lbs (liberally) for discs, Thats 52 lbs. of clutch and floaters. So we have approximately 34 lbs. of Titanium and steel are hanging 4 inches from the crank flange supported by nothing but 9/16" studs. When torqued, the assembly gains rigidity from the stands, but the stands can only work as well as the studs will let them. But you have opposing forces working perpendicularly to each other to help keep things straight. The studs and stands are pushing outward, while your plate load is pushing down on the donut, pushing back up on the hat which tries to straighten the studs back out as more and more load gets applied. Something to think about is the fact that the Outer edges of your clutch assembly on a 10.7" are pushing 300 mph at 10,000 RPM's. The further out you go, the faster it gets. Same principles as running a bigger tire vs. a smaller tire. It's harder to pull a 114" than a 110", same holds true with a clutch. Two clutches, identical mass, the smaller will always take less energy to turn. You can accomplish much more energy conservation by making a clutch smaller in diameter than a big clutch lighter. Say you've got a clutch where the O.D. of the structural parts is 12.5" and weighs 72 lbs. Approximate MOI of 2812.5lbs/in^2. Now take the same clutch and make the O.D. of the sturcture 11" = Approx MOI of 2178lbs/in^2. You would have to eliminate 17 lbs(!) off of the 12.5" clutch to achieve the same thing. Reduced MOI = more available to the wheels.

    Why does drilling the floaters help? Essentially, all you're doing is streching the studs before the top half assembly gets a chance to start wobbling the studs, stands and flywheel. By offestting the them, you are stretching them at an equal rate on opposite sides, helping to keep the top half of the clutch in check.

    Leanders has helped the problem by using 7 studs to share the load normally seen by 6 which gives it 17% less load per stud before changing anything else. When you're talking forces in the tons at work, 17% is a pretty significant difference. Whether you have sqaure stands or not, floaters will move as much as the flex in the studs and stands will allow them. We tested a square design vs. a round design on our NASCAR Sprint Cup Car clutches and saw no real advantage other than the contact surface was more consistent on the lugs of the floaters.

    On normal Crower style, the floaters seem loose when cold, but that is done for heat expansion. When that clutch sees 1200-1500 degrees during a pass, everything grows. To give you an idea, I have a customer in a blown pro mod who wanted a tighter bolt circle on some 10.7 floaters so it wouldn't feel so loose. We expanded the total bolt circle by .005", so that's .0025" closer to each stand than the norm. He called me back after testing and said that his pedal didn't work at the end of the run and it was coming down on the motor after the run. The floaters grew into the stands and kept the clutch locked. Clutch cooled down, floaters dropped right out.

    Enough nerd talk for now..
     
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    Last edited: Oct 16, 2009
  9. Mike Canter

    Mike Canter Top Dragster

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    A Leander clutch is $7700 and includes a plate load software and three discs. I think that is pretty close to the price of a 3 disc Crower Ti unit.
     
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  10. j.leanders

    j.leanders New Member

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    I would like to clear something out regarding prices of our clutches, the $8800 that is in our flyer was for customers who bought them directly from Sweden and payed customs and import fees themself.
    We now have a retailer in the US that take care of that.
    The $7700 was for a used unit that we have had for testing.
    Please visit us at booth 2143 at the PRI show in Orlando to have a look at our 11" alcohol clutch a 6 1/8" for Pro stock and also a new model that will be tested in one Pro nitrous car and one NMCA Pro street car before the show.

    For correct prices please contact Jeff Prock at 423-921-9540 http://www.appliednitroustechnology.com/

    Best regards J├Ârgen Leanders
     
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