News

Need a flywheel for my 348 Challenge

Discussion in 'Technical Q&A' started by mdlacroix, Feb 3, 2004.

  1. mdlacroix

    mdlacroix Karting

    Nov 3, 2003
    74
    Greetings all. Just got some bad news regarding my 348. FoD says the flywheel is toast. Specifically, the phenolic blocks inside the flywheel have been overheated and have melted. They tell me it can not be rebuilt and must be replaced at a new part cost of $3200. I am wondering if any of you can be of help in my finding an alternative to replacing with a new one. Danny, from parts, advises me that the proper replacement is a late model (post 1991) single disk version, Ferrari part number 146572. Any help that anyone can provide will be greatly appreciated. Thanks.
     
  2. To remove this ad click here.

  3. rob lay

    rob lay Administrator
    Staff Member Admin Social Subscribed Miami 2018 Owner

    Dec 1, 2000
    50,817
    Southlake, TX
    Full Name:
    Rob Lay
    Hey Mark, unfortunately the 348 isn't covered by Ferrari UK yet, in another 5 years it would of been about 50% off list from them. I would check some of our other sponsors like...

    http://www.sodacoms.com/

    http://stores.andale.com/hgparts

    I would even check with Mike at Norwood Performance as they can call around to all their contacts to find the best price. When I needed a crank pulley they found one at T. Rutlands for $700 less than a new Ferrari price.
     
  4. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,005
    This sounds like one of those dual mass flywheels that my F355 has (also).

    Since this is a challenge car, the dual mass feature might be of less value to you and your driving than simply welding the tow pieces of of the flywheel together and machining off the excess fat--resulting in a lower weight flywheel (and some low-end vibrations).

    If my F355 DMFW eats itself again, I will be doing this to it.
     
  5. ShanB

    ShanB Formula Junior

    Jul 9, 2003
    547
    Tejas/Europe/Desert
    Full Name:
    shanb
    Just a though - like many of these parts, the dual mass flywheel is not actually made by Ferrari. It is a Voith product.

    Just as one can buy some Ferrari AP clutch parts directly from AP Racing distributors, has anyone every tried contacting Voith (or their distributor) directly for info on parts for these flywheels?

    http://www.usa.voithturbo.com/e_vti_welcome.htm
     
  6. mdlacroix

    mdlacroix Karting

    Nov 3, 2003
    74
    Just a short update on my search for a cheaper alternative to a new flywheel for my car.
    So far I have not had any success finding an alternative. I talked at length with the dealer, nice people, but they do not have any other sources, other than Ferrari. I talked with my friends in the aviation maintenance business about having the parts manufactured from scratch. They believe that there is a combination of high cost for the CNC mill and difficulty in exactly replacing the phenolic material, that will result in a higher cost than the replacement part. I am still searching the suppliers and other sources for a used flywheel, but so far no luck.
    Anyone that may know of a used, single disk flywheel, please let me know. Thanks
     
  7. To remove this ad click here.

  8. Caruso360

    Caruso360 Karting

    May 1, 2003
    203
    FoD did the service on my 91 348tb a couple, three years back. In that instance the flywheel was removed and sent out to a machine shop to be turned, similar concept as with the rotors. The machine shop warped the flywheel, which was only discovered after being reinstalled. After start up nasty vibrations were detected at around 1700 RPM. To their credit and the fact that this happened under Dave Helm's watch, a new flywheel was installed at no cost to me. You might want to quiz FoD on what the scenario was. BTW Dave Helms has his own service center up and running in Boulder. His # is 303-938-9000. One more thing, the cost 4 years ago was quoted at $3,500. Good Luck!
     
  9. mdlacroix

    mdlacroix Karting

    Nov 3, 2003
    74
    When you wrote FoD, did you mean Ferrari of Dallas or Ferrari of Denver? I just know that somewhere's in the back of somebody's shop is a FW that the friction surface on was ruined, but the rest of the parts are OK. Thanks for the lead.
     
  10. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    If yours is a race car, I could send you a picture of one of the lightest flywheel clutch assys ever bolted to the back of a 348. This one is from an IMSA race car. Looks to be Tilton at first glance, but is rumored to have come from the factory. If I could email the picture to someone that knows how to post a picture here, I would be happy to snap one tomorrow AM. Having only driven the car once, I can tell you it is far too light for any street use.
    Dave
     
  11. Caruso360

    Caruso360 Karting

    May 1, 2003
    203
    Ferrari of Denver
     
  12. To remove this ad click here.

  13. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,022
    The Brickyard
    Full Name:
    The Bad Guy
    Hey give the guys over at Ferrari Service of Costa Mesa a call. They have two 348 parts cars over there. Ask for Michael. There number is (949) 548-9541.

    Hey Dave,
    Please get that picture of the IMSA 348 fly wheel up. If you have any more info on it I'm interested. I think Billybob would like some info on it too.
     
  14. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    19,029
    socal
    Dave,

    Email me your picture to fatbillybob@yahoo.com and I'll post it to Fchat.

    Ernie,

    I'll see the machine shop per our 348 FW project Thursday. I am going to try milling off the spider then making a spacer ring the size of the rear bearing. Then I'll weld the inner race of the spacer to the splined shaft. Then I'll weld the out race of the spacer to the cake platter. Thus the splined peice will be one with the FW friction surface. The whole thing needs to be balanced and then we will see how that works. I think we will drop 5 lbs or so off the assembly. If my plan works it will be the quickest and cheapest way to stay 90% OEM and get rid of the grease and all that crap screwing up our clutch systems.
     
  15. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    I will take a picture this AM and send it to you. Thanks, I wouldnt have a clue how to do it. The IMSA car flywheel uses a 3 disc Tilton clutch assy, and a fabricated , deep dished aluminum spacer for the ring gear. Far too lite for a street car, but does it have throttle responce, as the bulk of the weight is packaged in the 7" diameter clutch (near zero moment of inertia). Only way to get it rolling is to get revs up around 5k and start pulsing the clutch. Huge Cosworth cams, so zero torque below 5 k, but you better have it pointed straight when it comes on cam!
    The stock 348 flywheel is a wonderful unit. Without it there is no vibration dampner and harmonic vibrations will pound out the main bearing journals in the block, so you do not want to run without it.
    There was a time when the 348's were a year or 2 old, that there were no flywheels available. Some how Ferrari could get the flywheels for the cars they were building, but not for the parts department! This is when I took the first one apart and rebuilt it, as it needed to be fixed and it was under warranty.
    The design is such that there is only one weak link, and that is where the leak is from. The steel drive hub is press fit to the aluminum housing and then rivited with 6 or 8 large rivits. The aluminum housing expands and contracts a far greater amount than the steel hub and this is where the leak is. Once completely dissambled and cleaned with carb cleaner, I put the assy in an oven and cook the residue out of the area in question. Once completely free of grease I warm the assy withn a propane torch to open the gap as much as it will expand and soak it with wicking locktite. The locktite forms a flexible membrane it the minute space between the hub and the housing. I still service the first car that I did this on, and there has never been a trace of a grease leak after the modification. I also found that putting in an extra 50-70 grams of grease in the 348-355 flywheels gets rid of that "death rattle" you hear when the engine is shut off. Use only the grease supplied from Ferrari. I have tried CV grease and a number of other greases that have the same consistancy, but with marginal results. When the engine is first started you must let it idle for about 15 min. with no revs, as the grease must work its way around to balance things out. One hell of a lot of shaking in the engine until it does and you do not want to rev it durning that period.
    The failure of the flywheel that occured on Caruso 360's car, mentioned above, happened when the friction surface was being remachined at a sublet machine shop. They did not mount it correctly on the mill, and machined it at an angle, resulting in an un-useable friction face. Sorry, their insurance company wanted it back after paying out a claim of that size.
    Dave
     
  16. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    One final thought. John Amette (Boy is he missed! Ferrari's loss, Lambo's gain) when he was with FNA did a good bit of testing using heat sensors in the bell housing on the 355 challange cars. The heat shield the Challange cars ran greatly reduced the temps in the bellhousing resulting in the TOB, slave seals and flywheel lasting much longer. I was able to have our dealership get these shields even when we had no Challange team, as I posed the arguement that they did not enhance performance of a street car, but did enhance the reliability. With this arguement you should be able to have your local dealer order one for you.
    The problem results from the fact that the flywheel sucks the air in from the back, off the muffler, and pushes it out the bottom. The Challange heat shield has 2 small scoups that pick up air from under the car and route it to the back of the bellhousing, feeding in non-heated ambiant air. On the street cars I form small brass screens to these "snorkles" to keep road debris out, and seal the shield to the bell housing with stainless body shop tape. On the street cars (as well as race cars) this greatly increases the life of all the clutch components.
    Dave
     
  17. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    19,029
    socal
    Dave,

    First, the dappened FW is to damp the noise/vibration that messes up the TDC sensor right? The issue with the dual mass FW is not to preserve the main bearings. All parts are internally ballanced so there should be no issue with the need for dual mass to take up driveline shock right? I would expect this to be true if the IMSA unit works because if I am wrong won't the IMSA car just bow up?

    Second, Joe San Paolo at Concours auto, LaHabra Ca. can do this Tilton modification. I seen it for 308's he has done too. It is very trick. The initial cost is there but once that is done Tilton parts are pennies compared to Ferrari.

    Third, I like to cooling method for the bellhouse. I run a 348 factory challenge type exhaust and testpipes fully hearwrapped for the track and the car runs cooler than just running as a street car. Those cats and big exhaust cans just cook your engine compartment. I like the side benefit of longer lasting bellhouse componants.

    Fourth I don't understand your fix for the grease in the bellhouse FW assembly. The 8 rivets of alluminum to the cake platter rear steel part that connects to the bellhouse via the large lockring is not the problem for oil leaks. The problem is the three crappy designed seals off the input shaft that thurn in the clutch shaft which leak gearbox oil into the FW assembly that wet and thin your grease. I must be misunderstanding what you are saying. Can you clearify? Do you have a fix for this three ring circus?
     
  18. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    The IMSA engine has a finite life span and was built with that in mind. With no source of vibration dampning to cancel out the harmonics, things will break. Every single part that rotates in the IMSA engine has been micro balanced. Racing by nature is a give and take venture and to get more HP, you give up longitivity.
    The greatest amount of dampning is from the viscous grease contained in the FW. This combined with the springs and weights must work or Ferrari would not have done it. Certinally shock loading was also part of the equation.
    All of the 348-355 Challange cars had issues with the gear box breathing and levels. I know that FNA had folks drop the level to slightly below the min mark on the dip stick on the Challange cars, and to the min mark on street cars that were used hard, and increased the heigth of the breathers on the street cars. When everything else is right, the seals seem to hold fine. I have seen square cut o rings below the teflon seals used before. I have seen a number of the FW's that were contaminated with gear oil that leaked, and a number of them with no contamination also leaking.
    I suspect the question here is where is the source of the problem. Are the seals leaking because oil has contaminated the grease in the FW and it is too thin? Might it be a FW that is out of balance? Shaft with a slight twist or bend or slightly undersized? Cant say for sure, just thoughts.
    Dave
     
  19. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    19,029
    socal
    These are Daves IMSA 348 clutch pix
     
  20. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    19,029
    socal
    Thanks for the pix dave. BTW I think the answer is in better three ring seals. I like your idea about running minimum on the dipstick. I did not think that was a good idea while racing but if that is done it will surely help out the seals problem I think. The shafts are probably concentric. I would think at those rpms they would break someting if not concentric. The just undersize is a possibility but well within build tolerances I would think unless the vendors are really lame.
     
  21. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,022
    The Brickyard
    Full Name:
    The Bad Guy
    Nice pix. How about the flywheel?

    On another note, that is a wild paint job.
     
  22. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,005
    I though a bit of history is in order:

    In the 312T era (Lauda, Reggizoni), the Ferrari engine builders discovered that if they used the correctly sized (length and diameter) shaft between the crankshaft and the flywheel (similar to the 348/355) that the tortional vibrations of the engine could be controlled and no real flywheel was needed, only a face for the (multi plate) clutch to hold.

    This shaft takes the brunt of the tortional vibrations not the engine bearings. If you can make this shaft have an antiresonance exactly where the engine has a resonance, then you have set up a harmonic filter that prevents runaway harmonics in the crankshaft.

    "Art and Science of Grand Prix Driving" Niki Lauda circa 1980.
     
  23. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,022
    The Brickyard
    Full Name:
    The Bad Guy
    Nice bit of info Mitch.
     
  24. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    Mitch,
    Very good point, I will have to read that book. My studies (books only, as I do not have any hands on to prove a point) to date tend to agree with that conclusion as well, but the only practical application has been in F1 where the rev range is so small. In the street / race car where the rev range is so broad this has yet to be accomplished. The 355 Challange engines had a nasty habbit of pounding out the main journals requiring a re-ream fairly often. The 348's had a much better track record in this area. These stats came from an individual very closely connected to the factory, whom I believe without question. I personally have had no hands on experiance with this point as my dealership was not involved in the Challange series. I have not yet found a street motor that had the main journals beat out in either model, and I have built a good fair amount of those.
    Point well made.
    Dave
     
  25. rexrcr

    rexrcr Formula 3

    Nov 27, 2002
    1,572
    Kalamazoo, MI
    Full Name:
    Rob Schermerhorn
    Good thread.

    Torsional damping of the 348 flywheel is a good thing, don't eliminate it. I agree with Dave here. Horses for courses: no flywheel/harmonic damping on race engines for teams with huge budgets is great. However, don't emulate the pro's here if you value component longevity. You'll pound more than just crank bearings, the trans gets beat up too.

    Adding more than the original amount of flywheel grease is covered in a TSB. Increase to 230 grams, approx 262 ml. Improves damping characteristics. Leaks of gear oil past triple seal is the culprit. Combines with grease (normally white) reducing viscosity and turning it to gray sticky mess which gets ejected past OD o-ring.

    I feel your pain regarding maintenance issues and desiring a better way. However, as in all of engineering, compromises must be made, and IMO, maintaining this system is better than designing a new one, for this application.

    Regarding the clutch/flywheel housing air ducts, remember, part of the modification, and one key in why it works so well, is installing large holes radially in the aluminum housing to vent the air now ducted in. There is a Challenge TSB on this. Couldn't hurt on a 348.

    Back on topic, I agree that perhaps the best solution for mdlacroix is cannibalizing an old flywheel that's warped, but has usable plastic components.


    Best regards,

    Rob Schermerhorn
     
  26. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,005
    This could be pointing towards a different reason/rational: In a F355 challenge DMFlywheel, after a few laps, the grease will be getting hot (as in real hot). This can change the damping characteristics and move the nulling point (RPM range) away from the target RPM range (crankshaft resonance) such that the DMFW is no longer absorbing/preventing the Crankshaft vibrations it is supposed to absorb/prevent.

    Since street cars are not driven this hard this long very often they seldom encounter the issue.

    Food for thought!?!

    Side point: The LT1 Vette engine used a single frequency harmonic balancer. But when the extra revs (6000 became 6500) became available for the LT4 engine, the harmonic balancer was altered to balance two different harmonics. Perhaps this is the issue with wide RPM band of good TQ--there are multiple resonances that much be controlled or heavy bearing loads will exist.

    This may indicate that the F348 engine did not encounter the RPM band where its crank went into its second (or third or forth) resonance point (above redline).
     
  27. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    19,029
    socal
    Well, first I'd like to say that all these car 360 challenge included are street cars. That is where the first set of Ferrari compromises take place. The 360C may be closer to a racecar but is still very far removed. 333SP o.k. different class. That said I think this is all horsehockey with vibrations second order harmonics etc.. I don't discount the great Fchat sources and their abilities to understand the physics. But I don't beleive those are the issues in this case. The only thing I can remember from my high school physics is that second order is not first order and way less significant unless you are trying to balance a pyramid set of wine goblets on your Lexus hood. I do not believe tha Ferrari put DMFW's in the 348/355 to increase longevity. If they were interested in longevity they would not have dumb A wiring that looks like luigi puked up his spagetti dinner. Nor would they make those dumb 3 seals, Nor would they make those wonderful exhaust ecu's they way they make them. So Here is what I believe and I have absolutely nothing to back it up. 1) other manufacturers use DMFW to reduce harmonics that they do not want street drivers to feel. They don't want owners to think their cars suck and complain to them. 2) manufactureres never spend any money they do not think will return them dividends. 3) porsches the closest things in the street world to Ferraris use DMFW that are routinely replaced in the aftermarket with zero problems with harmonic destructions. The old toyota supra was a torque and horsepower monster with up to 500 aftermarket horsepower. Their DMFW were routinely removed for solid FWs. 4) in the case of the 348 it is possible to mess up the TDC sensors due to aberant vibrations (the system barely works the way it is) 5) due to the fact that the DMFW is moving in the driven direction I do not understand how it could absorb any harmonics. It would absorb harmonics if the parts inside could rock fore and aft. It cannot rock fore and aft once in motion and under load. The parts slop into a basically locked position under load. The harmonics would still be there and the DMFW can't do anything about it. 6) The most vibrations come during starting. Things are not yet settled into a driven direction. This is where the vibrations can be most absorbed and minimized aberant noise to the TDC sensors. This is eveidenced by failure to hot start when the grease gets thin. 7) The voight DMFW was never designed to disguise a bad system that would rip itself apart. It was designed to absorb driveline shock and improve drivebility. Parts must be internally balanced for longevity you can't cheat physics. Yes the 348 is better from a street perspective with the DMFW just like it is with an interior and those 45lb seats to reduce 2nd order harmonics. Well I run with no interior and 10lb carbon seats. Guess what no problems. 8)Many cars are also run with almost no mantenance to the DMFW. They shutter and rattle and the DMFW is basically non-functional. Those cars do not have a higher percentage of engine damage.

    Since I have not yet made a solid FW my current conclusions are that a solid FW will be fine. I actually ran with a homemade pinned FW that was not balalced (I did not have the tools) and it worked. There were some issues and that experiance leand me to believe a bell built solid FW will work without issues. Concours Auto ran a 348racecar with a Tilton unit similar to Dave's IMSA pics and the Tilton FW set-up was not the limiting factor in the longevity of the car. There is a long way between Dave's IMSA pics and a solid FW of stock size and proportion and many layers of reliability in there too. With a solid FW You may have more vibrations as you transition a specifc RPM than may be damped by the DMFW. People dump clutches and there is huge driveline shock from those actions that can be taken up by the DMFW. I do not think there is as much shock to the system by going from a 3rd gear redline to 4th gear shift than a off the line clutch dump burn out. I would think those are the kinds of issues Ferrari want to cure. FWIW, those are my thoughts. I'll report more when I make my solid FW or cure that stupid three ring circus of seals.
     
  28. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    7,005
    Disagree about horsehockey (see below) Agreed about complaints.

    If you note the third response in this thread, this is what will happen on my car if the DMFW goes south again. However, I understand the vibration issues (hint when my DMWF went, I had plenty of miles to listen to the new vibration patterns) and am willing to live with it, however some Ferrari clientell would not.

    So, its not Horse Hockey! is it?

    [QUTOE] 5) due to the fact that the DMFW is moving in the driven direction I do not understand how it could absorb any harmonics. It would absorb harmonics if the parts inside could rock fore and aft. It cannot rock fore and aft once in motion and under load. The parts slop into a basically locked position under load. The harmonics would still be there and the DMFW can't do anything about it.[/QUOTE]

    Wrong. Durring a single rotation of the crankshaft, the crank accelerates 4 times with strong pulses from the combustion process. In addition, there are 4 weak negative pulses assocated with the compression cycle. Since these events are happening more often than a single cycle, they occur at HARMONICS to that cycle (*2, *3, *4, *3/2, *4/3, .....).

    So, during a single rotation, and while continuing at the same long term RPM, the crankshaft accelrates and decelerates 4 times. This IS vibration. However, it is only felt when the vibrations hit a resonance with the crankshaft where the small vibration can be magnified like a bell magnifies
    the sound of the hammer striking it.

    Flywheels (and harmonic balancers) absorb most of this vibration.

    The largest vibrations occur when the clutch is suddenly released and
    the RPMs of the engine are suddenly moved a large numbe of RPMs. The large movement in RPMs imarts a broad spectrum of harmonic energy into the crankshaft. If the spectrum hits one or more resonances, they will vibrate just like a bell.

    Direction has nothing to do with it. Events happening at regular intervals more often than a single revolution have to do with it.

    How often are these cars put on a race track and given a good run?

    Yes, you are finally back on track. and if you read my first post, when/if my DMFW takes another hike, it will become pinned and milled down to a SMFW.

    Note race cars only use about the upper 1/2 of the rev band, this simplifies
    the harmonic balancing issue compared to a road car that has a 88% rev band (1000 through 8500 is a 7500 rev band::7500 compared to 8500 is 88%. Also note, race car drivers don't complain about vibration unless the vibration prevents the engine from delivering power, road drivers have different desires.

    Summary and recap:

    DMFW can absorb vibrations that SMFW cannot
    DMFW can be converted back into a SMFW without excessive risk
    The risk is not zero with respect to bearing loads
    Some drivers will not like the vibrations of a SMFW
     

Share This Page