Hydraulic Clutch Conversion, chime in here....

Discussion in 'U-shift em' started by moleary, May 3, 2015.

  1. moleary

    moleary GOD Bless America

    I have all but given up on the repop clutch parts offered for the BBB, and likely going to convert to a hydraulic set up.

    There are a couple threads already on the subject but they are a bit dated, and appear to be projects that were converting an automatic shift car to manual shift so there are a couple differences for this thread for posting recent experiences. The application is 70-72 Skylark/GS 455 car, Muncie 4 speed, Centerforce dual friction clutch kit CTF-DF148552 converting from conventional manual clutch to hydraulic clutch.

    Please share your experience here.

    I have done some research and have the following preliminary findings:

    There are a few options out there including piecing together seperate components "a la cart" from various sources and fabricating mounting brackets and pedal rod, etc. It appears this approach may be the least direct cost while more labor intensive and time consuming and on the fly engineering. After all that, may still be buggy.

    There appears to be McLeod kit for the clutch $280
    ..and the throwout bearing $375 http://www.summitracing.com/parts/m...cie-m-22/input-spline-quantity-application/26

    There appears to be a "turn key" complete kit from American Powertrain for $580 http://www.summitracing.com/parts/awr-hmgm01101sr

    I am curious about the American Powertrain offering as it cautions GM customers that shimming out the bell housing off the block 0.200" - 0.250" may be required to accomodate the minimum 0.080" air gap between the throwout bearing at rest and the clutch fingers due to the shallow nature of the factory bellhousing. I have not measured what i will have with the Centerforce clutch so not sure if it will be an issue and wondering if the same will be true for the McLeod bearing?

    Last edited: May 22, 2015
  2. knucklebusted

    knucklebusted Well-Known Member

    I have nothing to add but I am interested in the info that may be accumulated.

    The only thing I would ask is what the Chevy guys are doing since they are mechanically identical at this level if you take any engine specifics out of the picture?
  3. sriley531

    sriley531 Buckle up, this could get rough....

    Yep, I'm subscribing to this one too. I've pretty much had it with my z-bar setup. Any and all info those who've done it can add would be greatly appreciated!
  4. BillA

    BillA Well-Known Member

    I went with the American Powertrain unit when I converted my automatic '64 to a TKO600. I also bought a pedal set from them. The McCleod unit was not available at the time but I would give that unit some consideration too. Action on the AP system is perfect. Light pressure on the pedal and engagement is very smooth. I did have to use their .250 CNC cut shim but I'm using a pilot bearing that installs in the torque converter snout as opposed to the stock bushing location, which necessitated shallower depth of the input shaft. Very happy with this setup. I'm also using a Centerforce clutch with a Quicktime scattershield.
  5. 436'd Skylark

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

    My thread I started probably 8 years ago should be around here somewhere. I'm using a wildwood master with a howe bearing. I did have a few hiccups with it though. The howe bearing failed almost immediately. I only got a few weeks out of the original unit. I contacted howe direct and they told me they redesigned the bearing. After some back and forth they sent me a new style bearing for free. Also I bent the clutch pedal. I drive the car very mean and I powershift the hell out of it. Really really mean to it. one day I side stepped the clutch and it slipped badly. I crawled under the dash and the pedal was bent and hitting the bracket not allowing the clutch to engage all the way.

    Other than that its worked flawless. No wear parts really and nothing to grease. Shimming the howe bearing is no big deal. After that all that's needed is 2 braided lines. I would do it again in a heartbeat. I don't think I have more than 300 into the whole deal.
  6. sriley531

    sriley531 Buckle up, this could get rough....

    Well, I'll be reporting back sometime this weekend with results of the american powertrain setup as I just ordered it from summit. I was laying awake in bed last night thinking of the stupid mechanical linkage that's given me grief and decided to sleep on it. Woke up this morning and my mind was made up, time to **** or get off the pot. So its ordered and should be in Wednesday. Time to pull a transmission.....again... :(
  7. moleary

    moleary GOD Bless America

    Good choice, do it now as it wont get any better by itself!

    I down loaded the instructions for the APT kit over the weekend, which is how I learned about the clearance consideration for the T/O bearing.

    What clutch are you running?

    Where did you get your z-bar and clutch fork you are failing with now?

    I wont be back working on the Street Sleeper until the weekend of the 16th.....


  8. sriley531

    sriley531 Buckle up, this could get rough....

    The clutch is a center force dual friction. Z-bar is a repop from NPD. Its actually a fairly nice piece it seems, although I did have to put a slight bend in the lower arm to help with alignment to the fork and clear a header tube. The fork is an original. But as I've stated, it hasn't worked right from the beginning, im sick of screwing with it, and I've got 24 days before Norwalk to boot. Time for goofing around is over....
  9. sriley531

    sriley531 Buckle up, this could get rough....

    Well, the kit shipped and Im ready to go. Tick tock tick tock.... [​IMG]
  10. TheSilverBuick

    TheSilverBuick In the Middle of No Where

  11. moleary

    moleary GOD Bless America

    What pilot bushing are you running?
  12. sriley531

    sriley531 Buckle up, this could get rough....

    Just a stock replacement bronze (federal Mogul I think)
  13. moleary

    moleary GOD Bless America

    I suppose you checked the bushing for damage from install? A damaged bushing can cause problems with shiffting...also if the tip of the input shaft that rides in the bushing is greased I have heard causes shift problems.

    It would be nice to know what the cause of the problem is? What was the symptom(s)?
  14. sriley531

    sriley531 Buckle up, this could get rough....

    Yeah, when I installed the bushing the body was still off the chassis so it made access quite easy. I did some light polishing and everything fitted up nice. I really don't think it was the issue (although stranger things have happened). I messed with the geometry on the clutch linkage constantly (despite being very careful with my initial install measurements) and just never could get the right pedal feel. At one point when the pedal was uber heavy, it bent the frame bracket and after that I never could get it right. I ordered a new bracket from cars 3 weeks ago, they just keep telling me "it'll ship when it ships and then you'll know" (I won't be doing any more business with them, their customer service has been consistently lackluster to be honest). With 23 days till Norwalk, I decided enough was enough and I was wanting to do a hydraulic setup eventually anyway. No better time than the present I suppose...
  15. moleary

    moleary GOD Bless America

  16. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    I have one friend that installed their kit on his tri-five with a 409 in it this winter and has been driving the car around over the last month and so far he loves it over the previous mechanical linkage. He is the one that sent me the link and since I currently have the engine/transmission out of the car it has me thinking of doing the conversion. My preference is external slave over internal. What really has my eyes open and paying attention to that link is the fact it says "Buick" right at the top AND even though the pictures at the bottom are of the Chevy piece, they specifically mention that they are picturing the Chevy piece, but the Buick one is of the same style. Which I take as, "We've done the R&D for a piece that actually fits a Buick, not just taken a Chevy piece and say it will fit." They jumped through the extra hoops to create a dedicated page and point out the obvious (use of a chevy picture) to the reader. If I go that route, I will be ordering from them, but this is the limit of my experience with it.

    I've used Moly grease on the nose of the input shaft every time with a stock bushing and never have had an issue with shifting, and Moly grease is pretty sticky, at least when cold. Anything that hangs up the input shaft on the crank though will cause shifting issues. Have you used a dial indicator it ensure the bellhousing is square to the centerline of the crank? I believe +/-0.005" is the tolerance value.
  17. sriley531

    sriley531 Buckle up, this could get rough....

    Yep, the bell housing was indicated in and was in spec per Lakewood's instructions (which was .005", I believe mine was at .004")
  18. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    :TU: Mine was .003" or .004" out and it doesn't have any issues with shifting (when the pressure plate is bolted down all the way :Dou:).
  19. moleary

    moleary GOD Bless America

    From the instructions with the American Powertrain set up:

    IMPORTANT for GM Customers: Your GM bell housing is very shallow. Due to the variances in flywheel and clutch stack-up height you may find that you do not have enough room for the release bearing. If you cannot achieve a minimum of .080 of air gap between the bearing at rest and the clutch fingers, use a small washer or spacer at each of the bolts between the bell housing and the transmission to move the transmission back as much as .200. A turnkey .250 CNC machined aluminum spacer is available for $49 if you prefer.

    With the Centerforce clutch, do you need the shim?

  20. sriley531

    sriley531 Buckle up, this could get rough....

    I read that, I'm going to do the measurements either tonight or tomorrow and see. My results may vary a bit as I'm running a Lakewood scattershield with block plate. I'll be sure to keep the thread updated.

    Speaking of which, ordered the components yesterday and they're out for delivery today. Gotta love summit racing!!

Share This Page