355 flywheel rebuilding? | Page 2 | FerrariChat

355 flywheel rebuilding?

Discussion in '348/355' started by Marcelo0131, Jan 21, 2012.

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  1. phrogs

    phrogs F1 Veteran
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    Apr 13, 2004
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    Kzoo Michigan
    #26 phrogs, Mar 1, 2022
    Last edited: Mar 1, 2022
    Never mind, I thought maybe they maybe were back and duh miss read the date of the post.
     
  2. Ferrarium

    Ferrarium F1 Veteran
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  3. Carmellini

    Carmellini Formula 3

    Jul 16, 2019
    1,013
    Which is the correct grease? That link shows lots of different part numbers. Can you tell us which grease you got from MD?
    It would have been great if MD sold their technology to someone like Hill.
     
  4. Ferrarium

    Ferrarium F1 Veteran
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  5. Timmo

    Timmo Formula Junior

    Aug 26, 2017
    705
    Continental Europe
    Apologies for bringing back up an old thread but I have searched through the forums for answers to a question that was apparently not asked yet : when rebuilding an F355 DMF, has anyone managed to source replacement springs? These must soften up over the long term in the same way as springs on a regular clutch disc?
     
  6. Carmellini

    Carmellini Formula 3

    Jul 16, 2019
    1,013
    I don't think spring fatigue would be of concern.
     
    ernie likes this.
  7. Timmo

    Timmo Formula Junior

    Aug 26, 2017
    705
    Continental Europe
    After rebuilding the flywheel on my F355 using the 195g grease pack supplied by superformance (and replacing the clutch, etc) the rattle when turning the engine off is still there.

    There is conflicting information posted on here on the amount of grease that should be used, some saying that adding more than the specified amount in the WSM helped against the rattle whilst others said it made it worse. At this stage it makes sense to me that no matter the amount of grease applied, the flywheel will always rattle if the 4 internal springs have lost their original stiffness, which they should as their function is to replace the springs otherwise normally found on a standard clutch disc.

    Opinions?
     
  8. redwedge

    redwedge Formula Junior

    Sep 30, 2012
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    Steve C
    There are spring manufacturers who will make you some custom springs for reasonable money here in the UK. Not sure where you are based but there must be similar businesses close to you.
     
  9. Timmo

    Timmo Formula Junior

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    #34 Timmo, Oct 6, 2025 at 4:03 AM
    Last edited: Oct 6, 2025 at 4:15 AM
    Yes there are, but I'm frankly stumped that no one on here seems to have ever questioned the replacement of flywheel springs. I'm beginning to have regrets not dumping that DMF malarkey and replace it with a single mass flywheel.
     
  10. redwedge

    redwedge Formula Junior

    Sep 30, 2012
    486
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    Steve C
    I seem to remember Andrew at MD Clutches producing a short run of single mass flywheels and finding improved performance and no loss in drivability. I know he's shut up shop, but might be worth contacting him to find out if he has any old inventory knocking around.
     
  11. Timmo

    Timmo Formula Junior

    Aug 26, 2017
    705
    Continental Europe
    I had a close look at pictures of his SMF and I believe it is made by the same company that supplies Hill Engineering with the reinforced standard flywheel plate. I already asked them for a quote but I'm not really willing to lose the inertia allowed but the heavy-ish standard DMF, as I think the balance between torque and throttle response will be hard to improve for road use.
     
  12. ernie

    ernie Two Time F1 World Champ
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    Nov 19, 2001
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    The Bad Guy
    A couple of months ago I helped a friend rebuild the dual mass flywheel for his single plate clutch 348. While reassembling the flywheel I discovered something that I have never seen discussed. I think I have discovered why the grease in the flywheel gets contaminated with gear oil.

    While the triple seals on the propeller shaft are a key component in helping to keep the gear oil inside the geabox, they still fail over time. As a result gear oil will travel the length of the propeller shaft, due to the centrifugal force of the shaft spinning, and then end up at the input hole for the flywheel. This is my theory of how, and where, the gear oil gets into the flywheel.

    When the flywheel is disassembled you will discover a puck/disc inside the hole where the splines of the propeller shaft fit inside flywheel. The puck is on the backside of the flywheel where the ring nut gets screwed in. That puck is what the set screw, in the middle if the ring nut, presses against when it is tightened down to help lock the ring nut in place.

    Now here is what I discovered.
    The puck has a lip around it so that it can be dropped in place. However, there is nothing sealing it off. It is only be pressed against the metal. So my theory is that over time the gear oil works it’s way past that puck and into the flywheel, contaminating the grease, causing it to liquify, and then work it’s way past the o-rings. (Which is another point of failure).

    So what I did was to put a small amount of sealant (I like Hondabond HT) inside the little ridge/lip of the puck before I dropped it back on the hole. I only put just enough Hondabond around the ridge/lip of the puck so that it would seal, but not so much that it would squish out everywhere when the lock screw was tightened down. I also made sure that both the puck and the hole were completely free of oil/grease before I applied the Hondabond. I used break cleaner to clean the surfaces.

    It has only been a couple of months since I did this. So time will tell if this did or did not work.
     

    Attached Files:

  13. ernie

    ernie Two Time F1 World Champ
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    Nov 19, 2001
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    The other thing is the material of the o-rings.
    Because the o-rings are black rubber I assume they are made from Buna. Buna does not hold up well to oil nor heat. Because of this the o-rings fail over time. This will also lead to the flywheel grease getting past the o-rings, and getting flung all over the place.

    It is my opinon that the o-rings should be made from Viton rubber. Viton holds up very well to oil and heat. You can tell rubber is made from Viton because it typically has a brown color to it.
     

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