clutch/fly wheel | Page 2 | FerrariChat

clutch/fly wheel

Discussion in '348/355' started by Pengster355, Feb 26, 2018.

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  1. 97 Spider

    97 Spider Formula 3
    Rossa Subscribed

    Dec 15, 2012
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    Brian
    Lol, I was reading the last few posts thinking “knock sensor! It’s the KNOCK sensor people” then I read your post and was able to breath a sigh of relief that someone had given the correct answer.
     
  2. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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    #27 johnk..., Mar 1, 2018
    Last edited: Mar 1, 2018
    I'm not buying it. Flywheels with depleted, old grease rattle cold or hot. That is not imbalance, it's a lack of damping. Now if you want to say that when hot the grease settles toward the bottom and therefore causes an imbalance what does it matter if you then try to start the car hot or wait 24 hours and start it cold? How would the grease redistribute itself once it cooled off while just sitting? There are no sensors to check flywheel balance. Plus, the whole loading of the crank in an internal engine is highly imbalanced to start with given 4 combustion pulse per rotation.

    However, I agree with Grant that a 5 .2 car does have knock sensors (2.7s do not). It may be possible that the knock sensor would pick up the sound of the rattle and think it was a knock. But knock sensors don't shut down cylinders. They tell the ECU to retard the timing which could effect starting but I can not see how this would be dependent on hot or cold starts. As I said, rattling flywheels rattle hot or cold.

    But I haven't see a bunch of threads on this and if you have to reach back to 2005 I suspect that was just reaching for straws. One thing I have found about FChat is that people will go to pretty weird extremes to explain things they don't understand. Not saying it can't happen, but it's not you everyday, garden variety type of 355 problem.

    Also, knock sensors are tuned to respond to a specific type of sound representative of a knock. So, the flywheel rattle would have to also fall into that frequency range to trigger the sensor.
     
    Dave rocks likes this.
  3. johnk...

    johnk... F1 World Champ
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    Just a follow up. I did a little snooping around and found a thread on another forum where a guy was having hot start problems. The fur was flying about failing dual mass flywheels being the cause. Ultimately when the dust settled the problem was a leaking fuel pressure regulator and loose clams between the MAFs and the inlet ducts.

    And on yet another forum the hot grease, imbalance issue. But again, once that hot liquid grease settles to the bottom, causing imbalance, how does it end up back where it belongs, uniformly distributed, once things cool off.
     
    Dave rocks likes this.
  4. ahirsh

    ahirsh Karting

    Oct 14, 2015
    78
    Louisiana
    Full Name:
    Aaron
    At no point did I claim to understand it. I think I've made that abundantly clear. What I do know is that it happens, especially with 348s most likely because they are older obviously. I have learned to take everything on this site with a grain of salt, you figure out pretty quickly who knows what they are talking about. In general I do not but that's why I try to learn. If you have about 30 seconds, Andrew Holman mentions the issue starting at the 40 second mark in this video he made about regreasing the flywheel as explains why it's necessary to regrease it. Unfortunately he gives no detail on what exactly raises an error condition or tells the car not to start. I would venture to say he knows more than a lot of folks about the clutch/flywheel assemblies, especially those of us on an internet forum postulating about it.

     
  5. Cauf61

    Cauf61 Formula Junior

    Jul 12, 2016
    557
    Belgium
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    Patrick
    A knock sensor picks up detonation ( at a very specific frequency to de determined per engine !! ) an NOTHING else.
    Position sensors pick up changes in a magnetic field and NOTHING else.

    Nothing on a car that rattles, vibrate, or is in unbalance will influence the sensors/ecu/ignition timing in any way. Hot or cold.
     
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  6. 97 Spider

    97 Spider Formula 3
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    IDK, knock sensors can definitely pickup noises other than detonation and depending on how the computer is programmed to react cause all manner of problems. Back in the days of the 90s LT1 engines people doing bolt on mods and thumping exhaust on their Camaros and Corvettes would run into problems with the knock sensor picking things up and would need to switch to an LT4 knock sensor module in the ECU. Maybe today’s technology is more refined and knock sensors don’t get fooled as easy, but we’re talking about the same 90s technology.
     
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  7. Beetle

    Beetle Formula Junior

    Apr 10, 2013
    776
    I don't particularly care what anyone thinks either. Opinions are like bumper holes everyone's got one. BUT I will say this. Hot start cold start problems I had had are no more after repacking flywheel. And knock sensors pick up lots of things. Does anyone on here have solid FERRARI evidence as to WHAT signals the ECU gives out or what it receives and how the signals are interpreted??? No I believe only Ferrari and Bosch know that. I find this forum great because people can put there opinions and what they have learned from there on experience working on there cars or what there mechanics have found. See I find loose MAF clamps to give a problem with starting crap cos all it will do is give a rough idle but it's something I will look for coz it may have been an issue for someone else. Just because you don't understand or believe it to be a problem don't mean it can't be a problem. Rant over.
     
  8. Beetle

    Beetle Formula Junior

    Apr 10, 2013
    776
    You have proof from Ferrari and Bosch to prove this. Please elaborate
     
  9. taz355

    taz355 F1 Veteran
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    If your talking too Brian he doesnt need proof, he did not say Ferraris def react that way he did state the problem he has encountered.
    I believe he said they could be similar rather than previously someone said they would never do that.
     
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  10. Beetle

    Beetle Formula Junior

    Apr 10, 2013
    776
    Totally the opposite I agree with Brian's comments 100%. Some of the others I disagree with. Sometimes on here people tend to agree or disagree but there always right and that's fine. My comments are from my own experience and what has worked for me. In saying that there are only a few on here and especially the Australian section that think their right and everyone else is wrong. All I'm asking is show me the evidence from Bosch or Ferrari on what some sensors pickup or don't otherwise as I stated it's just an opinion
     
  11. matfo

    matfo Rookie

    Aug 1, 2013
    39
    Sweden
    The clutch had started to slip on my Mondial T -92 when i bought it so I knew it needed to be replaced before purchasing the car. It has about 80000km on the clock so it's also time for a service.

    However, when my mechanic disassembled the clutch he saw that the flywheel was very worn so that needs to be replaced (see attached picture). In fact, he said that this was probably the worst worn flywheel he had seen on a Mondial/348. :( Since it seems to have some hot spots we don't think it's possible to machine the surface on this one.

    Any suggestions on where to find a replacement flywheel for reasonable price?

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  12. Beetle

    Beetle Formula Junior

    Apr 10, 2013
    776
    There are some pretty good diamond cutting flywheel machines around nowadays. Take it to a good machine shop before you buy another one and let them assess it they look at some pretty bad flywheels pre machining them, they will know if it can be done
     
  13. matfo

    matfo Rookie

    Aug 1, 2013
    39
    Sweden
    Ok, I thought the problem was that the hot spots would stay even after the surface is machined, causing problems eventually?
    Because I don't think the actual machining is a problem when using the right tools, as you said.
     
  14. Beetle

    Beetle Formula Junior

    Apr 10, 2013
    776
    That's cast iron unfortunately
     
  15. matfo

    matfo Rookie

    Aug 1, 2013
    39
    Sweden
    Now I lost you, what do you mean?
     
  16. johnk...

    johnk... F1 World Champ
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    Hot spots = no good.

    But you know what? If you want to do a 1/2ass job just throw a new clutch disk in there. If you drive normally you would never know the difference. :rolleyes:
     
  17. matfo

    matfo Rookie

    Aug 1, 2013
    39
    Sweden
    Yes, that's what I thought. I.e that the hot spots could be a problem even it the surface was machined. It was the cast iron comment I didn't understand.
    For me, putting it straight back isn't an option, I want it to be proper done but I'm interested of finding a solution for that at a reasonable price. :D
    Any ideas? :rolleyes:
     
  18. Beetle

    Beetle Formula Junior

    Apr 10, 2013
    776
    MD clutches new flywheel there in the UK or new unit from Ferrari super expensive the 2nd option. I will say though I have had cast iron flywheels re machined and you can see the hot spots but they haven't been a problem in a daily driver. I have not tried in a Ferrari? I'm sure someone with more knowledge will chime in
     
  19. johnk...

    johnk... F1 World Champ
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    Agree with Paul. Let a reputable shop look at it. I don't see any bluing, like this, so it might not be that bad. Yours just looks beat up.

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  20. matfo

    matfo Rookie

    Aug 1, 2013
    39
    Sweden
    Here are a close up, and I'm worried that there are blue spots, look in the outer area at "six o'clock" for instance. :eek:
    So far MD clutches is the only reasonable alternative I have found so that could be the solution. :)
    Have I understood it correctly that the new flywheels they are offering are solid? If so, I guess the friction plate should be sprung instead!? Or do you still have the springs and grease etc with the new flywheel? I realize MD could answer this but I haven't been in contact with them yet. I also need to check with my mechanic regarding options.
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  21. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    The flywheel comes apart from the whole assembly and therefore you just keep the spings and balancer with grease from the stock unit.
     
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  22. taz355

    taz355 F1 Veteran
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    Feb 18, 2008
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    Normally is a relative term. Ha ha
     
  23. johnk...

    johnk... F1 World Champ
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    Ok Grant, If you drive like me. ;)
     
  24. Pengster355

    Pengster355 Formula Junior

    Mar 9, 2006
    269
    Singapore

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