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Hot Rods Who's running external clutch slaves

Discussion in 'The Hokey Ass Message Board' started by model A hooligan, Apr 28, 2018.

  1. The most volume of fluid that can be pushed with the shortest stroke.
  2. Well both are the same bore.. like I said I'm going to get a 1" the only difference is the wilwood has a longer stroke than a tilton. The body of the tilton is a bit shorter

    I take it as the both pump the same except the longer one can pump farther than my pedal can move.
  3. Per every 1/16" of stroke both will transfer the same volume of fluid. When the short one stops's the larger one will continue to give more fluid the the slave. So, will your pedal assembly allow the longer stroke master to discharge completely to give you maximum slave travel your looking for?
  4. A 3/4" bore master has a cylinder area of 0.45 square inches
    A 1" bore master has a cylinder ares of 0.79

    That's approximately 80% increase in size.
    The 1" master will deliver 80% more volume for the same stroke, your slave will move 80% more than it does now, and the pedal effort will be 80% higher.

    Is it enough throw? Is it no much effort? Not sure because the ratio of the modified fork isn't here and the distance the throw out bearing needs to move isn't here either.
  5. Lol :) Didn't I say math couldn't answer all question where things are beyond one's control.

  6. Well this is my thought, the pedal before I could push it with my hand,and not even using that much strength. My foot is much stronger (I've had cars with hard clutches before) I feel that I would actually like the pedal being much firmer and the increased movement is what I need so I don't really see a downside. I've got a 1" wilwood high capacity on order. Should be here before friday
    Johnny Gee likes this.
  7. Feynman was great
    Johnny Gee likes this.
  8. Well guys, got the 1" master on and bled. Clutch works finally. Takes about 700 lbs of force to move it...

    Getting tired of this problem.
  9. Nice! :cool: See, post #90 didn't hurt that bad after all :)
  10. Me too, what else can I do.
  11. ^^^^^ In french "je t'ai dit"
  12. I'm guessing I should of went with a 7/8 master. I just figured with pedal travel I needed the bigger bore.

    My thoughts are, maybe my clutch lines that had a curve up (I removed them) was not letting my 3/4 master bleed fully.

    Maybe adding a longer bolt with a spacer off the fork to get more leverage to see if it helps and add on more fork if it does.

    Try my old 3/4 with the straighter lines and bleed the hell out of it. Seems like this one was acting the same till I took the slave off and let it move freely while bleeding
  13. I can't see post numbers on my phone
  14. Your answer to the suggestion of using a larger bore master was "Master cylinders are not exactly cheap for these."
  15. Gotcha, yeah but now it's actually so hard to push I cannot drive it. I've had hard clutches but this is CRAZY. It feels like pushing 4 clutches with one foot. Boy does the slave cylinder move though.

    I don't know if maybe I just still had air in it before or what. It felt like this one was doing the same thing till I took it off and all of a sudden it got more air out (it was streaming straight fluid before I moved it) and then the pedal instantly got hard. Maybe I gave up too early on bleeding the old one. I'm contemplating switching back and seeing if it will work
    Johnny Gee likes this.
  16. You guessed best you could and figure the best with what you knew with great intentions, but it's NFG.

    One more time ,,,,
    if you don't want to follow this I get it, but I'll laugh at you and wipe a bugar on the back of your neck.

    Step 1. Find out exactly how far the clutch fingers need to move in.
    That will be the same measurement the throw out bearing needs to move.
    Don't do one more fucking thing until you know that, don't spend any more money, don't monkey around bleeding, don't waist 1 more second until that's done. Don't get laid don't collect $200.00 don't do anything else. While your at it find out the release pressure too.

    Step 2. Measure the clutch fork. You need 2 numbers - slave hook up to pivot and pivot to forks fingers.

    With those 2 bits of info you can know ( not guess not figure not trial and error not NFG) by calculation the stroke needed out of the master to get the clutch to release. You will also know the force needed at the Slave to do it.

    Step 3. Find out exactly how much pedal travel you have and exactly the pedal ratio.

    Now you can begin to calculate the size master needed and the force your leg must produce to get the job done. If the force is too great you need a better ratio at the pedal or the fork.

    100% of this can be done- could have been done without all this fucking around and wearing yourself out over this problem.
  17. And now we know some of this
  18. "If one is good (7/8") two must be better (1")" :)
  19. You are telling me to find the answers to what I can not.

    I do not know how the hell to measure at the bearing how far it moves. Not like I can stick measuring devices in the fork hole.
  20. A 7/8" bore master cylinder has an area of 0.60
    The 1" bore is area is 0.79. But let's just go out on a limb and say 0.80
    That's a 34% difference.
    Then just put the rest of my other post down here.

    That information should come from the clutch manufacture.
    It should be published in their technical info for the product.
    If it's not published the manufacture will have it in their files.
    You really can't set up an after market clutch or design a release system without knowing how far the thing needs to move. EVERY ONE OF THEM IS DIFFERENT, that tidbit of info was also in the link I gave you earlier.
  21. I was thinking of making a spacer to lengthen the fork and the mounting at the trans to see how that works. Maybe a little more leverage will do it. Just figured to mount it as close as the manufacturer said.

    Sure does seem like this one was acting just like the smaller one till I removed it to bleed it by pulling it with my hand instead of it trying to pull the clutch
  22. Is your clutch within that generally kinda sorta about 0.550 of travel at the fingers??
    I don't know but you still need to find out.

  23. I couldn't tell ya honestly. But it is a standard gm 10.5 clutch like the one pictured. I've looked online and found no info so I'll have to call LUK or something and see. I would say that's probably accurate though.

    I like that graph posted about pressure vs lbs of force needed. I'm going to go back and study this right now. Cool link,thank you for that
  24. My 1st round with my hydraulic clutch produced a pedal that took 2 people to push. In my case it was pure leverage. I had moved the pivot point south on the arm by 2.38" from stock. I just looked at the CAD drawing for my mounting plate. Once I got it higher on the arm it worked easily.

    But you have the CNC pedal that mounts to the floor, guess you are stuck with whatever ratio that comes built into it.
  25. Doesn't mount to the floor. There's even a picture in here posted of it hanging under the dash.but I can't make it longer at the bottom because the pedal will be too close to the floor. And if I welded in a tab on top the pushrod that goes into the MC would be coming in at a angle.
  26. It's a no cost try worth trying. I didn't like the idea of a short fork to start with as per manufacturer request some many post's back for the very reason happening now. I know I've busted your balls a lot on this but that's only because you asked if I had been following along is a spite full way because I made a joke that 31 Vicky liked. Moving along. Trial and error is nothing more than an experiment which is what science is. Keep playing with it your own way. Your the boss on this. Soon enough you'll have it all under control.

  27. I'm thinking of getting a longer bolt and trying to put washer to space out the slave as a 'mock up' longer fork to see if it does anything
  28. Love it love love it Johnny!!!

    Then there this asshole,
    Yet Both are equally true.
  29. I thought memes was a 'Facebook thing' guess I am not hip.

    My fork is about 1 1/4 shorter than stock. Would that make up for 27,000 lbs of pedal force needed? I don't have the part I cut off but could find a way to lengthen it

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