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Is this Testarossa Clutch Intermediate Plate messed up?

Discussion in 'Technical Q&A' started by Veedub00, Mar 9, 2019.

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  1. Veedub00

    Veedub00 F1 Rookie
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    Are these leaf springs supposed to be flat? All three of mine are crooked like this. Should I flatten them somehow?

    My clutch went out last year. Put in a clutchmasters rebuild. I have been messing with the spacers since. Too tight, too loose. Adjusted the clutch pedal. Doesn't go in gear from a stand still. Put in spacers, then it slips a bit. I just pulled it again and was wondering about these leaf springs. any help would be appreciated. Image Unavailable, Please Login Image Unavailable, Please Login
     
  2. Motob

    Motob Formula 3
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    Those springs look perfect. They are bent from the factory, as this is what pushes the intermediate plate away from the flywheel when the clutch is disengaged, so the front clutch disc doesn't drag. Do not straighten them. It is important to get the spacing of the assembly correct (with the spacers on the correct side of those leaf springs) in order to keep the clutch from dragging, causing the gearbox to grind when going into reverse from neutral.
    I have had brand new TR clutches from AP Lockheed have a dragging issue.
     
  3. tbakowsky

    tbakowsky F1 World Champ
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    Looks like you have re-lined the discs in kevlar or what ever. My suspicion is, the discs are too thick. I have seen this countless times before. The other thing I noticed, is the fact your secondary disc appears to be doing nothing. There doesn't appear to be any wear markes on it vs the primary.
     
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  4. Rifledriver

    Rifledriver Two Time F1 World Champ

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    #4 Rifledriver, Mar 10, 2019
    Last edited: Mar 10, 2019
    I agree with Tom. I have yet to find a clutch rebuilder who used or had available to him the correct thickness lining face material. By the time you have 2 discs a little too thick the geometry of the pressure plate can't handle it. Never seen one work correctly. All the specs are in the shop manual.
    If the shim size does not get the static angle of the clutch fingers correct and still release fully in the standard stroke of the TO bearing it wont work correctly no matter what you fudge. The amount of compression of the discs from static to fully compressed is equally important.

    Not seeing any balance marks on any of those parts either.

    And a kevlar clutch in a TR is just begging to break transmission parts. I got a big pile of them here as a result of a kevlar clutch.

    By a clutch that will work. Ferrari has plenty of them. Throw that junk away.
     
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  5. Veedub00

    Veedub00 F1 Rookie
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    Thanks for the information guys. I really appreciate it.

    The discs are supposed to be 8.2mm right? I measured slightly over at 8.28mm. Is that extra .16 mm messing it up? I'll measure the rest when I get home tonight.
     
  6. Rifledriver

    Rifledriver Two Time F1 World Champ

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    8.28 compressed or free? And what is it the other way?

    8.28 isn't 8.2 and there is no room for variance in those clutches. Mac Tilton was a good friend and he always considered that clutch design to be a joke. He was right.
    Stick to the original specs or you will have trouble with it.

    And by original specs I mean the facing material too. I have no idea why you would change. I have seen those clutches go 80,000+ miles. Kevlar is a bad choice.
     
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  7. MerlinTech

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    There is a formula to measure set up height on this clutch. The last one I did I had to machine the parts to fit. tried two clutches and both were the same so I just machined away what I didn't need and bam, just right. I made a spread sheet to plug in the numbers and it let me know what I needed. The pictures show the WSM set up height specs.
     

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  8. Veedub00

    Veedub00 F1 Rookie
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    what did you machine away? friction material?
     
  9. MerlinTech

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    No, I machined the aluminum spacer.
    Most clutch re-line shops want the complete system. From the flywheel out so they can calculate the set up and it is then a bolt on.
    You can always ship it to me and I'll set it up for you. You might need to add not subtract. You may need new washers of a different thickness. It is not a one size fits all deal.
    Call me if you need to 770-845-8335
     
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  10. ago car nut

    ago car nut F1 Rookie
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    If you drive correctly!
     
  11. Veedub00

    Veedub00 F1 Rookie
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    My spacer needs to be -0.98 mm.
     
  12. MerlinTech

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    So the distance ring needs to be thinner? Is that what I am seeing here? If the spacer number is negative then something else has to change.
    You need to have the distance ring machined, be aware it is stepped and both levels have to be machined the same. You need to get someone that TRUELY understands what they are machining before you end up needing a new distance ring. This is what I had to machine to get it right. But the amount changes with each one.
     
  13. Veedub00

    Veedub00 F1 Rookie
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    I am going to remeasure "C" later tonight.
     
  14. MerlinTech

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    You didn't measure "C" when you did the calculation? "C" is not something that you can change.
     
  15. tbakowsky

    tbakowsky F1 World Champ
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    If I could make a suggestion. Instead of going through all of this and wasting a lot of time and effort, why not just purchase the clutch kit from AP racing, install and be done? The kits are available from all the usual suppliers, and sometimes can be had for a much more reasonable price from the UK suppliers, even when factoring in shipping and exchange rates.
     
  16. MerlinTech

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    The last two AP kits I purchased did not come with the distance ring and I had to machine everything to fit.
     
  17. tbakowsky

    tbakowsky F1 World Champ
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    I can honestly say I have never had an issue with the AP clutches. Maybe I have just been lucky.
     
  18. Steve Magnusson

    Steve Magnusson F1 World Champ
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    One thing that I'll fault F for doing is not giving the nominal values for those dimensions -- for example, knowing the nominal value for A and B (even though they will vary due to tolerances) would be very useful IMO to check if anything has been significantly modified. Same for flywheel thickness -- they often give a "wear limit", but not the nominal thickness of a new flywheel. After time travel gets invented, someone should go back and tell them to include those ;).
     
  19. MerlinTech

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    In reality, I don't think they had any idea what the values would be. I would think Steve has forgotten more than Ferrari knew when they built these cars.
     
  20. Rifledriver

    Rifledriver Two Time F1 World Champ

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    #20 Rifledriver, Mar 13, 2019
    Last edited: Mar 13, 2019
    Thickness of the flywheel has never been an issue until they get so thin warpage becomes an issue. With double discs and an interest in keeping clutch pedal effort in a range they wanted (that was the reason for the double disc to start with) length of stroke is an issue. The master capacity will only move the bearing so far before the pedal hits the floor and if either the clutch set up is incorrect or the leaf springs between disc facings are not right it will not fully release with the usual outcome. Additionally due to the geometry of the pressure plate if the fingers are too convex the travel ratio prevents full release at full stroke, possible slipping and possible exceeding reward travel limits of the TO bearing. If the fingers are too flat, at full travel and high RPM centrifugal force prevents a re-engagement when the pedal is released.

    Since 1985 with all the TR clutches I have installed I only had trouble with one of the AP TR clutches.It was out of balance. I have taken issue with the as delivered shim set up and changed a few but that is it. I suspect if parts were found to be missing they were robbed from the package at some point in the supply line.

    As for changing material the original stuff lasts a very long time. It has a huge facing area. I have no concern about ours. In my lifetime I'll never replace it but due to the grabby-ness or abruptness of the kevlar clutches I have seen installed they had a very high rate of gearboxs with big expensive broken parts. Here in the shop I have a broken diff and the second broken mainshaft and a couple of broken gears from a 512 TR whose owner insists he keep his kevlar clutch. He is up to about $30000 in transaxle repairs.
     
  21. brian.s

    brian.s F1 Rookie
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    Better still, the hybrid disc! Part normal and part kevlar, nothing wrong with that concept.............
     
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  22. tbakowsky

    tbakowsky F1 World Champ
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    Oh my! I had a customer insist on installing such a mixture in his Murci e-gear. I warned him 2 ways from Sunday it will not work properly. He insisted,he supplied the part so I did the deed. It drove awful, I mean the car would buck and lurch so badly is was undrivable. He paid the bill, I handed him his keys and told him to have fun.

    He did a u-turn midway out of the parking lot, threw me the keys, and told me to call him when it was done. I made some good scratch on that one. They are good for at least one thing..
     
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  23. Rifledriver

    Rifledriver Two Time F1 World Champ

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    Well yea, in an Egear and F1 thats the case. I had a client with a CS who wanted kevlar. I told him I'd be happy to do it and I'd charge him full tilt next week to do it again with a stock clutch. He decided to be smart.
     
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  24. Motob

    Motob Formula 3
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    As I said before. I had trouble with a brand new AP TR clutch dragging from improper shim setup. As I remember it even had notes from AP on or in the box on the shimming setup that they had calculated. They are the OEM manufacturer, you would think that they could get it right the first time.
     
  25. Rifledriver

    Rifledriver Two Time F1 World Champ

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    The calculated shim size is right on it. AP has never been a great company in my opinion but its what we got. Their design theft and patent infringement made Mac Tilton a rich man though. I think Valeo makes better clutches.
     

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