Conical flywheel surface – what to do? | FerrariChat

Conical flywheel surface – what to do?

Discussion in 'Technical Q&A' started by Lars Ljungstrom, Apr 28, 2020.

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  1. Lars Ljungstrom

    Lars Ljungstrom Karting

    Sep 20, 2016
    64
    Gothenburg, Sweden
    Full Name:
    Lars Ljungström
    Hi friends,
    Anybody who knows what to do if the flywheel contact surface against the clutch has become very slightly conical (more worn towards the centre), instead of spending a fortune on a new dual mass flywheel (mine has recently been restored inside by a workshop). My car is an early 348 with a twin plate clutch.
    Thanks in advance for any tips,
    Lars :)
     
  2. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    12,661
    San Carlos, CA
    Full Name:
    Mitchell Le
    Upgrade to a single mass flywheel, if you gonna get another one.
     
    tbakowsky likes this.
  3. Lars Ljungstrom

    Lars Ljungstrom Karting

    Sep 20, 2016
    64
    Gothenburg, Sweden
    Full Name:
    Lars Ljungström
    Hi and thanks for your reply!
    IF I´ll have to get another one, I´ll consider this. But I´d like to continue to keep my car original and I guess Ferrari had a reason for fitting a dual-mass flywheel. I´m terrified just to think about if a solid flywheel could do any harm to the gearbox...
    Thanks,
    Lars:)
     
  4. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    12,661
    San Carlos, CA
    Full Name:
    Mitchell Le
    They also have a reason to move away from the dual mass flywheel to a single mas flywheel in all later designs of the 348 and the 355.
     
  5. Lars Ljungstrom

    Lars Ljungstrom Karting

    Sep 20, 2016
    64
    Gothenburg, Sweden
    Full Name:
    Lars Ljungström
    Yes, but I don´t know if axles, gearbox internals etc in the 348 and 355 are adapted to a dual mass flywheel.
     
  6. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,114
    Georgia
    Full Name:
    Wade Williams
    It is not the transmission that will suffer. On 348/355 engines the front hub for accessory belts is solid. The flywheel is the harmonic damper for the engine. The splined shaft connects the flywheel directly to the crank. This prevents harmonics from causing all kind of issues in the valve train & timing gears (in the font case).
    Also, the flywheel surface has always had a slight bevel. This was taught in tech school way back when. I had a shortened straight edge to check flywheels when replacing clutches early on to verify. I have also had F1 355 flywheels resurfaced and the initial bite when pulling away was a bit more harsh feeling. If the flywheel has no smearing from heat or slippage, just put a new clutch in it and go. Smooth is the desired surface. Heat checking in my experience has never been an issue with 348/355 flywheels, as long as the surface is smooth.
    Now go drive the hell out of it.
     
    Wade and brian.s like this.
  7. Lars Ljungstrom

    Lars Ljungstrom Karting

    Sep 20, 2016
    64
    Gothenburg, Sweden
    Full Name:
    Lars Ljungström
    Thanks for interesting input!
    I wonder how you had the 355 flywheel resurfaced – how is that made?
    Would it be possible to replace the contact surface? I heard something about having a new piece manufactured and then rivet it to the flywheel (maybe I misunderstood it).
    Thanks in advance,
    Lars:)
     
  8. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,114
    Georgia
    Full Name:
    Wade Williams
    You can do that with the friction disc and some flywheels but not 355. The flywheel can be pressed out of the housing and set up in a flywheel grinder machine and resurfaced just like any other flywheel. We had a guy (The Clutch Man) that had the machine in a truck and would do it in our parking lot.
     
  9. POLO35

    POLO35 Formula Junior

    Feb 21, 2005
    712
    Treasure Coast Florida
    Full Name:
    MATT
    Personally I would just install 2 new clutch discs and see how it performs. See how it feels, if it skips or not. Overtime the new discs will "wear" into the surface of the flywheel face. I bought my disks from Ferparts in California but they're available at pretty much any Ferrari parts supplier. I paid 250 per disk
     
  10. DoubleD33

    DoubleD33 F1 Rookie
    Rossa Subscribed

    May 2, 2012
    2,732
    Pasadena, CA / Oahu, HI
    Full Name:
    Dan D
    I thought the flywheel had a bevel but was not sure and did not want to comment. Do most all F cars that have this bevel?
     
  11. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
    1,114
    Georgia
    Full Name:
    Wade Williams
    I haven't measured a lot of them, I remember checking a 360 and it was not flat. I know 308/328 is flat. I am pretty sure it started with 348.
     
    DoubleD33 likes this.
  12. POLO35

    POLO35 Formula Junior

    Feb 21, 2005
    712
    Treasure Coast Florida
    Full Name:
    MATT
    Just throwing this out there I've become a bit of an expert on the 348 clutch. The Tolerance on that clutch is extremely tight as the plates where the pedal becomes increasingly more difficult to push. It all has to do with the geometry of the throwout bearing and the flip over point of the pressure plate. If you were to resurface the flywhe the slightest bit it will make the pedal effort harder. I actually run my 348 with the clutch shims removed which again alter sthe flip over point and makes the pedal effort easier.
     

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