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Hot Rods Clutch pressure plate issues

Discussion in 'The Hokey Ass Message Board' started by The_Monster, Jul 24, 2022.

  1. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    Pist-n-broke- I'm baffled too. I have no idea why I'm having such a hard time figuring this out. It should be a slam dunk! Its a Chevy for Christ sake! Not a Nash or Studebaker. This should be as simple as it gets.
    I may purchase a different clutch kit just to see if it IS a defective pressure plate.
     
    Pist-n-Broke likes this.
  2. SS327
    Joined: Sep 11, 2017
    Posts: 1,327

    SS327

    Buy a higher quality clutch kit like Centerforce or RAM and don’t look back.
     
    Nailhead Jason and 427 sleeper like this.
  3. Budget36
    Joined: Nov 29, 2014
    Posts: 9,401

    Budget36
    ALLIANCE MEMBER

    You could mimic depressing the fingers on an arbor press, probably a drill press. I think if you use a hydraulic press you may not feel it.
     
  4. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    I ran the casting numbers on the block
    328575
    68-84 250 L6 - Chevy, Buick, Olds, Pontiac
    I may look for a clutch kit for a 70 olds or a 72 buick.
     
  5. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    SS327- You convinced me. I'm goin onto Summit right now and searching for a CenterForce or RAM clutch kit for this.
     
  6. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 10,255

    Johnny Gee
    Member
    from Downey, Ca

    For what I’ve subjected the clutch in my 56 I should be using a Centerforce but I’m not. It’s a RAM unit that I purchased when PAW (Performance Automotive Warehouse) still had all four stores. I’m still beating on the same clutch to this day.
     
    SS327 and 427 sleeper like this.
  7. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 10,255

    Johnny Gee
    Member
    from Downey, Ca

    ^^^^^ Forgot to mention. It's a "Stock Replacement" unit.
     
    2OLD2FAST likes this.
  8. NoelC
    Joined: Mar 21, 2018
    Posts: 373

    NoelC
    Member

    I'm still on the lazy fence this morning looking over on going out to the garage to get dusty. That said, maybe doing some learning and discovery off the couch will be a goal to strive for?

    Brand new BAD clutch pressure plate - YouTube

    But throwing it out there, if I go out to the garage, unwrap the plastic, flex the fork on the transmission attached to the engine on the stand and it does the same as yours did, does that mean mine's also defective, or does it mean yours is fine...? lol. Misery loves company right?

    I like to think I have a good memory and as I recall, I didn't put much thought into it past getting it cleaned up, the new kit installed and back together. I do recall however I did try the lever action and experienced a similar effect? Maybe not as stark, but similar.
    I had a similar effect in a newer truck at one time as well. That said, it was a work truck and when riding a clutch was called for, it wasn't a broad range between slip and grab. It popped your foot off the pedal.

    When buying a brand new clutch kit, you don't expect to purchase defective. Most of us being on the job learners with enough smarts and back bone to do the job, just figure out a way to do it and get it done.

    Or at least we do until a question arises or we create the question from our curiosity of things.
    Looking back at your original post, I'd like to think you'd be ready to say, "it this", or "this is the reason why it's that".

    It's an expensive enough hobby as it is, but it's more expensive to throw money at parts when uncertain. So... it's either a clutch, a pressure plate, release bearing or it's normal.

    Funny how you hear, it's a stiff clutch, or a soft clutch. Long or short release before it grabs? I'm beginning to wonder if this isn't a case of you thinking there's a problem and us just reinforcing that thought until it is a problem?
     
  9. Assuming that the pressure plate isn't defective . . . I'm sort of running out of ideas for things to check. But how about this ? ? ?

    With the mix of parts, the modified fork, the adapted clutch pedal, the fabricated linkage and a Z-arm set-up that this truck didn't originally have (according to the illustration Johnny Gee posted in the link below) . . .


    https://www.jalopyjournal.com/forum/threads/clutch-pressure-plate-issues.1270066/#post-14557456

    . . . Would it be possible that the clutch pedal travel is now allowing you to push the diaphragm beyond it's normal range of travel? That you're simulating the same condition when moving the fork by hand? That the "oil-canning" you describe is due to the diaphragm spring going "over-center"?

    In a lot of ways this sounds like one of the shortcomings of diaphragm clutches which can occur when shifting at excessively high RPMs. The clutch can momentarily stick in the released position due to high centrifugal forces but will quickly re-engage when the RPM drops below a certain point. And when it does it feels like the transmission is trying to beat its way thru the floor and come up into the cab with you!

    Did you ever check the air gap between the disk and the pressure plate while the clutch pedal was depressed? You may need two people to do this, especially with the engine and trans out of the truck. But you may find that you have the proper clearance (.030" or so?) before you get the pedal, or the fork, to the point where it wants to stick.

    If in fact this turns out to be what's happening, then it's time to re-engineer your clutch linkage for less travel. Or at the very least install some kind of a stop that will limit your clutch pedal travel.
     
    Last edited: Jul 30, 2022
    Budget36 likes this.
  10. Budget36
    Joined: Nov 29, 2014
    Posts: 9,401

    Budget36
    ALLIANCE MEMBER

    Clay mart brings up a good point, when you manually move the lever, does the PP release before the event?
     
  11. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    Johnny Gee-Thanks for that, I hope I'll be able to say that I'll be beating up my clutch soon too! So far, I'm just getting beat up!

    NoelC- If you DO go out and pull that clutch fork back and it oil cans, I would love to hear about THAT! You would only need to cut the plastic at the clutch fork and tape it back up. Curious if it's as hard to pull back as you can see it was for me in the videos

    ClayMart- I wish that was the problem. However, when it was still in the truck and the linkage hooked up, I raised one tire off the ground with a jack. Then, I put it into first and, with the help of my brother, he would try to rotate the tire as I slowly pushed in the clutch pedal. The wheel wouldn't move until it popped.
    We tried it several times and in all the gears (for no real reason, other than to cover all the bases)

    Budget36- When I manually move the lever by hand, I'm not sure when the pressure is released. I wish I had a long input shaft that I could have my brother turn once the pressure if off the clutch disc so we could see everything.

    So, today, I found a parts store that had a different style stock clutch kit. What's interesting is that the throw out bearing had the raised ridge on the surface just like the one I had originally with the other LUK clutch kit.
    Here's pics comparing the new one (Duralast) to the other one (LUK)
    DL01.jpg L01.jpg
    DL02.jpg L02.jpg
    DL03.jpg L03.jpg
    DL04.jpg L04.jpg
    DL05.jpg L05.jpg

    A lot of differences. For instance, look at the 3 outer perimeter flat springs. Duralast has them riveted on the friction plate surface while LUK is riveted on the other side.
    Duralast has several small points under the friction ring while LUK has wide ones.
    Duralast friction ring is solid thickness while LUK is undercut at the inner edge.
    Duralast I.D. of the top cover is smaller than LUK.

    However, after ALL of that, after trying BOTH styles of throw out bearings, checking that the clutch discs where the same thickness... I got the same symptoms... harder than hell, then POP!

    Next thing to do (after I return this clutch kit) is try a different clutch fork.

    Since I don't know which parts are wrong, I'm just going to replace each one, one at a time, and see if I get a different result.
     
  12. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    Thinking............
    The pressure plate diaphragm springs only have so much travel, or pivot. They can only be pressed inward so far. Or to look at it another way, the friction disc on the pressure plate can only be pulled away from the clutch disc so far.

    What it feels like is that I'm starting to press at the last point of the diaphragm spring travel and then it oil cans. I don't think I'm getting the full throw of the springs. Meaning, the full throw of the springs would start off easy and eventually get harder, until it oil canned. I think my travel is starting at the end of the full throw? What could do that???

    Either a thick clutch disc, or the wrong flywheel.

    Since the clutch discs were the same thickness in two different clutch kits, I'm wondering if my flywheel should be stepped down??
    In other words, the mounting surface for the pressure plate is further away from the engine than the clutch disc contact surface?

    I'm gonna research that one. Maybe I have the wrong flywheel?
     
  13. NoelC
    Joined: Mar 21, 2018
    Posts: 373

    NoelC
    Member

    Seems I took your advice, the "if I do part".
    Mine to. I'd say it offers some oil can effect. Maybe not as bad, but that's because it's subjective. You look stronger but it did take some effort and I managed to pull it back.

    As well I took a video. Send me a PM and I send it to you from my computer, you can decide if it's worth posting for everyone else's enjoyment if you wish.

    A third hand wouldn't have hurt but you could clearly make out fork movement, and the sound of my straining and something moving.
     
    Last edited: Jul 30, 2022
  14. Fordors
    Joined: Sep 22, 2016
    Posts: 4,393

    Fordors
    Member

    To check a clutch disc either clamp it in a vise or you can use a c-clamp but you only want to clamp it enough to flatten the marcel. The marcel is kind of a wavy spring steel shim that cushions the friction surfaces so engagement is not too harsh. When clamped you should have a measurement around .310-.320. As far as your flywheel goes if it was ground too much when manufactured the springs on the disc might contact the flywheel bolts, otherwise I think it should by fine.
     
  15. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    Progress! Not a solution yet, however, progress.

    I called up the transmission shop that I purchased the rebuilt Saginaw 4 speed from and explained to him my problems. He was baffled just like all of you guys.
    Then he asked me, which clutch kits did I purchase. I told him that I first purchased the LUK and then purchased a DuraLast.
    He said, "LUK is a good company, those are the clutch kits that I use and sell here at the shop." He said he wasn't familiar with the duralast. And then he asks me what was the clutch kit part number that I ordered. I said pulling from memory I believe it was 110-4008.
    He said that's not the clutch kid that he uses with chevrolet. He uses LUK 04-021. I said that's a stock clutch kit for stock applications and stock horsepower? He said absolutely! He said he uses them on all of his classic Chevrolets that come into the shop. I said does it matter if it's an inline 6 or a v8? He said it makes no difference and he's never had someone return.
    He told me to pull off my entire clutch kit and bring my bellhousing and clutch fork and everything to him tomorrow after work. He wants to see what my clutch kit looks like. He said that he has the clutch kits that he was talking about right there in the shop and that he will set me up.
    So after our phone call, I typed that part number in google and it pulled up Summit. Heres what it looks like.
    Screenshot_20220801-103920.png
    Notice anything different between the diaphragm springs on this pressure plate and the one that I have?
    Screenshot_20220801-080015.png
    TOTALLY different!!!
    So while I was on that page in Summit, I scrolled through the list of applications that this clutch kit would fit on. I wrote down 1968 nova, 1965 Bel Air, 1970 Impala. All V8's. NO inline 6 applications!
    Then I went to RockAuto to see if I could find the same clutch for all of those different years just to do a cross reference.
    All of them offered the same clutch kit with the same part number
    Screenshot_20220801-105542.png
    I'm very, very excited to try this new clutch kit because it is completely different from everything that I have been trying so far and is recommended by a transmission guru who has been using this company and this clutch kit for years with no complaints.
    I will bring him all of my components tomorrow and purchase a brand new setup.

    Now, knock on wood, if this new clutch kit works, will I ever fully understand why this clutch kit did not work?
    It makes no sense to me and hopefully when this guy sees my components he will have an answer.
    You know I'm going to update you regardless so, fingers crossed and tomorrow can't come soon enough!
     

    Attached Files:

    Last edited: Aug 1, 2022
    warbird1, Johnny Gee and ClayMart like this.
  16. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 10,255

    Johnny Gee
    Member
    from Downey, Ca

    Just for shits and giggles take the flywheel as well.
     
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  17. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    Johnny Gee- not a bad idea, Ill take you up on it!
     
  18. NoelC
    Joined: Mar 21, 2018
    Posts: 373

    NoelC
    Member

    Looking at those pressure plates I think you could make another action video.
    Show what height the fingers are in comparison to each other and if they are the same?
    Force / pressure that it takes them to lift the clutch disc.
    Depth of movement to lift the disc.

    I was thinking however, in the name of science and under the category of learning, you have two bell housings, they're not exactly rare...maybe cut one up with a big inspection hole on top to see what's going on when you push the lever.
    Yup, some day's I'm full of bright ideas.

    Clutch Fork Action - YouTube

    This is for those that read and were left hanging on the video I said I'd take. Well, I'm on YouTube now baby.
     
  19. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,942

    ekimneirbo
    Member
    from Brooks Ky

    I certainly give you credit for having so much perseverence.........;)
     
  20. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    NoelC- I would definitely be bringing all of the clutch parts that I currently have home with me after I purchased the new clutch kit setup. I will for sure be making a video and letting folks see the comparison if there is any. I hope to God there's some positive comparisons! Hahaha
    My other bell housing does have a viewport that was done by someone with multiple drill holes. It was covered up but I can easily take the cover off and clean the hole up a little bit so that I can see what's going on. That's only if I don't get some really nice smooth movement out of this one. If I don't get smooth movements out of this one I may just ride motorcycles from this point forward, lol!

    Ekimneirbo- thanks man! I really don't have much choice. I want to drive my 48 so badly and would like to get it finished before the end of the year. Let's hope it all works out
     
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  21. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    I've got all the parts in the back of my car! I'll be heading to his place in 2.5 hours when I get off work.
    One thing I noticed when wiping the grease off of the original throw out bearing. My clutch fork marred up the edge of this thing really bad! That shows just how much pressure I was exerting on this part to disengage the clutch!
    Crazy!
    IMG_20220801_185559763.jpg
    IMG_20220801_185721788.jpg
    IMG_20220801_185438223.jpg
    I'll post again once I get home, hopefully with some good news and new parts
     
    Johnny Gee and Budget36 like this.
  22. I've seen several sites that list this flat, cast iron fork for '60 to '72 Chevy truck applications. Not sure how it works with earlier models than that. At least there's one picture that you might get some dimensions from.

    https://4speedconversions-com.3dcartstores.com/3765372.html.

    Something looks suspicious with the fit of the fork to the pivot ball in these two pics posted earlier. Or was this explained already?

    007.jpg

    009.jpg
     
  23. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    ClayMart- yeah those pictures were taken the minute the transmission was pulled away from the bell housing the first time. Either got misaligned or knocked around during the engine removal process. I'm going to be heading to the transmission guy in about a half hour so I'll let you all know what he says after I get back home
     
  24. The_Monster
    Joined: Sep 8, 2003
    Posts: 1,805

    The_Monster
    Member

    UPDATES!!!!

    I went to my transmission guy after work today. He looked over my clutch kit that I brought to show him. He noticed a few things wrong right off the bat.
    First off, big thanks to Johnny Gee for suggesting that I also take my flywheel. That was the first thing that peaked his interest. He said that flywheel is so lightweight that it could only be used for late model Chevrolets. Then he showed me the flywheel that I SHOULD be using for this era of drivetrain, regardless of inline 6 or v8. It's like 30 lb difference!
    IMG_20220802_172958349.jpg
    IMG_20220802_173022901.jpg
    Next, he noticed my pressure plate was drastically wrong. He has never seen that pressure plate before and said that it also must be for a very late model. He pulls the clutch kit that he uses for all classic Chevrolet, regardless of inline 6 or V8. Here they are in comparison to each other.
    IMG_20220802_174722804.jpg
    IMG_20220802_174730755.jpg
    IMG_20220802_174736361.jpg
    IMG_20220802_174747154.jpg
    IMG_20220802_174933394.jpg
    IMG_20220802_174937846.jpg
    IMG_20220802_174943152.jpg
    IMG_20220802_174952711.jpg

    Earlier, I ran the casting numbers on the block
    328575
    68-84 250 L6 - Chevy, Buick, Olds, Pontiac.
    Since my first car was a 1972 Nova with an inline 6, I conducted all of my research for clutch kit parts based on that.
    That is the reason I made it apparent with the blue tape information that you will get drastically different results if you look for a clutch kit for an inline 6 versus a clutch kit for a V8 within 1965-75.
    My man was cool enough to put the flywheel on the machine and deck the surface for me
    IMG_20220802_160946899.jpg

    I could not wait to bolt everything together and try it out!!
    IMG_20220802_182416879.jpg
    IMG_20220802_182951430.jpg
    IMG_20220802_183752614.jpg

    I am VERY happy to report that my clutch fork pulls back MUCH easier now and does not have ANY oil can or popping issues! I put the transmission into gear and had my brother twist the output shaft as I pulled the clutch fork back. The output shaft was free within about a 1/2" of travel!

    I call this a success!

    To wrap up this long thread, if there is anyone out there trying to purchase a new clutch kit for a classic inline 6 Chevrolet, look for a clutch kit for a V8 instead. For some reason, Summit racing, O'Reilly's Auto parts, RockAuto and others have substituted the correct clutch pack for a much later era with the inline 6 application.
    I hope this thread will help someone in the future. Thank you all so very much for all of your ideas, suggestions, comments and helpful advice! I've been away from this forum for many, many years. This experience has rejuvenated my love for this forum.
    Cheers!
     
    Last edited: Aug 2, 2022
    warbird1, jaracer, NoelC and 6 others like this.
  25. Wanderlust
    Joined: Oct 27, 2019
    Posts: 574

    Wanderlust

    They’re probably all accessing the same parts program which obviously is incorrect, ran into a similar situation trying to source a distributor for my y block.
     
  26. NoelC
    Joined: Mar 21, 2018
    Posts: 373

    NoelC
    Member

    While happy for your resolution, I'm disappointed by the final answers. That's right...the final answers.
    Maybe it just me but I'm not hearing about a smoking gun, the evidence to prove a crime was committed? I'm hearing newer model excuses not a solid case for guilty as charged.
    That's ok. Because I'm inclined to think defective pressure plate. I watched a You Tube video, lol, very much a possibility. I'd be inclined to take it apart to fix it real good and find out if it was broken inside,
    but that's me.
    Maybe you could flip it over like a turtle on it's back and with a couple of clamps on a solid table top mimic to accomplish an action and maybe notice a binding take place?
    Or as you have called it a day on it, lets just call it done.
    Well done ol chap!
     
    ClayMart likes this.
  27. Sounds like the short answer is, you got the wrong parts package. You ordered what you thought you needed, and the parts house did some kind of numbers change to make One Package cover more years than they should have. This is common when not having a total package to start with and a bunch of loose parts laying around that all look common and "SHOULD" work together. It's the small things that screw you up.
     
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  28. Fordors
    Joined: Sep 22, 2016
    Posts: 4,393

    Fordors
    Member

    Something in the parts you had initially had to be wrong, did you ever verify the compressed disc thickness? If it was too thick it would pull the diaphragm fingers too low when bolted to the flywheel and while I don’t know for sure I suspect that could result in the “oil canning” you described.
    Oddly the mechanic had never seen the pressure plate you brought to him and he stated he uses the 04-021 clutch for both 6 and 8 cylinder vehicles when he changes a clutch. If he removed a flat finger pp on a GM six cylinder how is it he’s never seen one?
    Other than knowing your clutch now works there’s been no answer as to what was wrong.
     
  29. [​IMG]
    I think what the mechanic was referring to is the major difference in the housing and finger placement between the 2.
     
  30. Wish i had seen this a week ago, had the same deal a few years back with the clutch for my 64 Buick (383 small chevy and 5 speed) I had to adjust the clutch linkage all the way out to make it be able to even touch the pressure plate. Took me a week and 5 or six times in and out to figure out the pressure plate was wrong. it Was a Luk, it just had the wrong fingers on it. I ordered up Ram clutch and immediately noticed the taller fingers. no problems after that.
     

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