Clutch Wear Calculation - Am I Calculating Right?? | FerrariChat

Clutch Wear Calculation - Am I Calculating Right??

Discussion in '360/430' started by caymangone, Jan 11, 2019.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. caymangone

    caymangone Karting

    Jan 13, 2017
    79
    Missouri
    Full Name:
    Mike
    So after reading every thread I can find pertaining to clutch wear calculations based on diagnostic readouts of "clutch position closed" and "clutch position closed-new", I wanted make sure I'm thinking right. I recently purchased a Launch X431 pro and snapped the following readings:
    Image Unavailable, Please Login
    If I'm calculating right, the percent wear is the difference between the two readings divided by 8.5mm (thickness of new oem clutch) x 100 . In this case, around 37% clutch wear. Is this right? The PPI that was done about 2,600 miles ago showed 33% wear. Car has 19,800 miles on the clock.
     
  2. Ingenere

    Ingenere F1 Veteran
    Owner Silver Subscribed

    Dec 11, 2001
    6,336
    On the Limit
    Full Name:
    Dino
    I just changed the clutch and tried to bring clutch wear to 100% and the X431 pro couldn't do it. Did you try it and was it successful?
     
  3. caymangone

    caymangone Karting

    Jan 13, 2017
    79
    Missouri
    Full Name:
    Mike
    No. I haven't replaced the clutch so I haven't tried to reset the wear. From what I've read on the X431, there's mixed reviews on being able to make changes such as PIS. Can only make whole value changes and not decimal. And some it seemed like even tried that and the X431 wouldn't keep the change. Others may chime in.
     
  4. Ingenere

    Ingenere F1 Veteran
    Owner Silver Subscribed

    Dec 11, 2001
    6,336
    On the Limit
    Full Name:
    Dino
    It worked for PIS.
     
  5. BlacktopRacing

    BlacktopRacing Formula Junior

    Sep 18, 2016
    912
    Pittsburgh
    Full Name:
    Dale
    If I'm reading your post correctly, the clutch was 33% worn at the time of the PPI, and now 2600 miles later, it's showing 37% worn? That sounds about right for taking it easy on the clutch.
     
  6. flash32

    flash32 F1 Veteran

    Aug 22, 2008
    5,561
    Central NJ
    Full Name:
    Dominick
    That is great .. that is the first time I heard the good news.. what version are you running that it works 10.70?



    Sent from my moto x4 using Tapatalk
     
  7. caymangone

    caymangone Karting

    Jan 13, 2017
    79
    Missouri
    Full Name:
    Mike
    Yep. I've done all the tricks in the book for clutch preservation!
     
  8. Flyingbrick242

    Flyingbrick242 Formula Junior
    Silver Subscribed

    Feb 26, 2017
    603
    Northern AZ.
    Sounds correct I came up with 36.82% rounded off to 37%.
    Glad the launch diag tool was useful..!
     
    caymangone likes this.
  9. mike01606

    mike01606 Formula Junior

    Feb 21, 2012
    794
    Cheshire UK
    Full Name:
    Mike M
    #9 mike01606, Jan 12, 2019
    Last edited: Jan 12, 2019
    This is correct by my understanding for a 360. 430 I don’t know.
    I did some searching and head scratching on this and I’ll check the factor later but 8.5 is close enough....
    It should be the travel the release bearing moves for 0.8mm of disc thickness (which is the wear limit). It isn’t the thickness of a new friction disc but coincidentally it is almost the same.
     
    caymangone likes this.
  10. caymangone

    caymangone Karting

    Jan 13, 2017
    79
    Missouri
    Full Name:
    Mike
    Here is a snapshot of what can be seen of the clutch when looking through the inspection port. Looks more wore then 37% to me though. The cut groove in the clutch material is still prevalent but not sure how much more you can go. Someone stated their clutch wore more on the outer edge, following the taper on there flywheel. Image Unavailable, Please Login
     
  11. mike01606

    mike01606 Formula Junior

    Feb 21, 2012
    794
    Cheshire UK
    Full Name:
    Mike M
    Are you sure no one has adjusted the new clutch closed position to fiddle the wear reading?
    20 is high for a 360 and I think there is a spec range in the manual which is lower than 20.
    Mine was tapered when I removed it....I can’t post pics as Tapatalk and the FChat app lock up when I select the pic but I can PM them to you is you PM me an address...


    Sent from my iPhone using Tapatalk
     
    Dave rocks likes this.
  12. caymangone

    caymangone Karting

    Jan 13, 2017
    79
    Missouri
    Full Name:
    Mike
    This is an '07 F430 if that makes a difference. I forgot to mention ealrier.
     
  13. mike01606

    mike01606 Formula Junior

    Feb 21, 2012
    794
    Cheshire UK
    Full Name:
    Mike M
    QUOTE="caymangone, post: 146397696, member: 203853"]This is an '07 F430 if that makes a difference. I forgot to mention earlier.[/QUOTE]

    I think that possibly changes a lot..... you need to find the release bearing movement range between new and worn for a 430. The 8.x mm is the 360 spec. The 430 could be similar but it needs confirming.

    On your picture it appears one side of the plate is thicker. Is that the angle the picture was taken from or is that correct?

    On mine you could barely see the grooves on the edges and virtually nothing was removed near the center....a 360 plate is nominally 8.3 mm new (needs confirming in the WSM). Here’s some pics....you can see the center is barely bedded in.



    Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
     
  14. caymangone

    caymangone Karting

    Jan 13, 2017
    79
    Missouri
    Full Name:
    Mike
    Thanks for the info mike01606! I noticed the difference on thickness of material on either side of the plate as well but it seems to vary, depending on where the clutch rotation landed when I put the car back on the lift as other times there were no perceived differences. It appears your clutch still had quite a bit of meat left on them (7.525 mm on the outer edge, 8.016mm further in if I'm reading it right). Were you having clutch engagement issues that prompted you to swap it out?
     
  15. mike01606

    mike01606 Formula Junior

    Feb 21, 2012
    794
    Cheshire UK
    Full Name:
    Mike M
    I had no problems at all with driving just a whine (that’s the best description I can give) on initial start-up when ambient temps were say <10 DGC.
    I suspected it was a dry release bearing or maybe the crankshaft pilot bearing so pulled the transaxle to change them. I had a new clutch ready to install but as my car drove so well I wanted to disturb as little as possible so put the old one back with a new release bearing. 1st start in Feb and the whine was still there!
    It’s clutch related and I can only think it’s the friction plate kissing the pressure plate/flywheel when the clutch is open making a ‘finger around the rim of wine glass’ type resonance. I’m in the UK and I never hear it between say April and November.
    My current clutch has 23k miles on it...
     
  16. caymangone

    caymangone Karting

    Jan 13, 2017
    79
    Missouri
    Full Name:
    Mike
    Got it! Makes sense. Thanks!
     
  17. epb0

    epb0 Rookie

    Feb 27, 2015
    39
    FRANCE
    Hello,
    I'm don't share your calculation:
    8,5mm, as you show us after, is total thickness, not thickness you can use. If my right, thickness we can use is 5,6mm (Maserati Training information, it should be the same for Ferrari).
    So your clutch wear is ((23,15-20,02)/5,6)*100=55,89%

    You couldn't soustract only 0,8 mm, it's a clutch, not a sheet of paper !
     
  18. epb0

    epb0 Rookie

    Feb 27, 2015
    39
    FRANCE
    #18 epb0, Jan 23, 2020
    Last edited: Jan 23, 2020
  19. mike01606

    mike01606 Formula Junior

    Feb 21, 2012
    794
    Cheshire UK
    Full Name:
    Mike M
    I agree based on the SD printout that 16% agrees with 5.6mm for a 430.

    This isn’t the friction disc thickness you can use, it’s the travel of the release bearing between a new and worn clutch. The disk thickness reduces by much less than this circa 1mm

    The 8.5mm comes from a similar 360 SD printout following the same calculation as yours....I’ve said several times above that the 430 may use different numbers.

    It looks like 100% clutch wear equates to release bearing travel of;
    ~5.6mm for a 430
    ~8.5mm for a 360

    All to be validated of course!
     
    Performify likes this.
  20. epb0

    epb0 Rookie

    Feb 27, 2015
    39
    FRANCE
    It is the same thing. The travel between these 2 positions (new clutch and 100% worn clutch) is thickness we can use.

    I just surprise thickness you can use on 360 is as hight as 8,5mm, and not coherent with others vehicles.
    Where did you find this value for 360 ?
     
  21. mike01606

    mike01606 Formula Junior

    Feb 21, 2012
    794
    Cheshire UK
    Full Name:
    Mike M
    #21 mike01606, Jan 23, 2020
    Last edited: Jan 23, 2020
    By backward calculating the travel distance from the SD % wear and the two clutch closed positions.

    Like I’ve said many times it’s not from any factory training or first hand knowledge and could well be wrong, so user beware!....

    Has anyone an SD printout with the % wear, clutch closed new and CC current they can post?
     
  22. mike01606

    mike01606 Formula Junior

    Feb 21, 2012
    794
    Cheshire UK
    Full Name:
    Mike M
    SD printout for a 360....


    Sent from my iPhone using Tapatalk
     
  23. eric355

    eric355 Formula 3
    Silver Subscribed

    Nov 30, 2005
    1,158
    Toulouse (France)
    Full Name:
    Eric DECOUX
    It's same thing ... but not measured at the same locations.
    The travel of the pressure plate between new clutch and 100% worn clutch, which represents the friction disc thickness reduction, is much lower than the release bearing travel which is measured by the clutch position sensor.
    The arm lever of the diaphragm on the mechanism has a ratio of about 4 (ie. on a 360 , 8.5 mm at release bearing level is about 2 mm at pressure plate level)
     
  24. epb0

    epb0 Rookie

    Feb 27, 2015
    39
    FRANCE
    You're right, there is arm lever ratio to take in account, but there is only one sensor for this measurement.

    Hypothesis:
    Ferrari said thickness at new is 8,3mm and wear is 0,8mm. If we take margin and use only 0,7mm for full worn clutch:
    0,7 x 2 (2 plates) x 4 (lever ratio) = 5,6 mm

    Still this value ;-)

    Eric, do you same some reports with SD or Leonardo on 360 ?
     
  25. eric355

    eric355 Formula 3
    Silver Subscribed

    Nov 30, 2005
    1,158
    Toulouse (France)
    Full Name:
    Eric DECOUX
    I have no experience with Leonardo and SD. At most a comparison of measurements on a CS with my Texa and with a SD (#100% on Texa and #75% on SD !!!!)
    The Texa gives figures more something like 16% of clutch wear per 1mm on thrust bearing position. This would be consistent with a full wear at +6mm.
    With Mike's figures, and from what I have seen on this CS, the SD is more at 12% of clutch wear per 1mm on thrust bearing position (+8.5 mm at full wear)

    From the Texa/SD comparison I thought that the Texa was giving too high clutch wear estimation. Finally, may be not that much ...
     

Share This Page