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clutch replacement intervals?

Discussion in 'Technical Q&A' started by Island Time, Mar 30, 2005.

  1. Island Time

    Island Time F1 Veteran
    Silver Subscribed

    Dec 18, 2004
    7,025
    East TN
    Full Name:
    David
    I'm looking at the 3x8 series as my first F-car. Two I've seen had to have new clutches installed, one at 7k mi, and one at 15k miles. I guess one wouldn't expect to see 150k mi. clutches in such high-performance cars (like in a pick-up), but this is rediculous (scary really). What's the deal? Sounds like more of a design flaw? What's your-all's experiences with clutch replacement intervals? (Sounds like to expect to replace the clutch no matter when it was last replaced!) As to cost...I guess if you have to ask..

    Any help?
    Thank ya much...
    Dave Cate
     
  2. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,149
    way north california
    Full Name:
    chris morse
    Dave,

    The po had Midway industries, (manufacturers of Centerforce clutches), in arizona rebuild the clutch on my 77 GTB, due to an oil leakl.

    Recently, one of the "dual Friction" pucks came off and stacked up on another puck, making the clutch inoperative.

    I talked to Dennis McCann at all ferrari parts, Nick at Forza and James at Norwood. The least expensive "stock unit was $485 from McCann. All three sources had a carbon/kevlar upgrade starting at an upcharge of about $100.

    After a couple of trys, i got through to KC, an engineer at Midway. We discussed clutches at some length and he agreed to look at my clutch. He stated that a bonding failure was extreamly rare. They do not sell clutches for the Ferrari, but do custom rebuilds for high performance applications in addition to manufacturing the centerforce units.

    I mentioned that i had heard many complaints of short clutch life on the 308 and asked him if the 308 clutch was too light for the car, either in diameter, clamping pressure or construction. His comment was that the old clutches had adequate surface area and clamping pressure but that the old material lacked durability compared to todays materials.

    They are rebuilding my disc with full rivited carbon/kevlar face and reassembling my pressure plate to yield 10-15% more clamping pressure.

    Even after approximately 7 years of "use", they are giving me a deal on the rebuild - approximately $200. Nice people.

    More info when it gets back and on the car.

    hth,
    chris
     
  3. matteo

    matteo F1 World Champ

    Aug 1, 2002
    13,748
    On a plane somewhere
    Full Name:
    Heir Butt
    I put 27K on my 78's clutch. I sold it before it needed to be changed. My 83 has 5k on it now.

    Clutch life depends on how your drive. If you drive like every light is a race then you will burn it up quick. I drive my car 90% like my daily driver.
     
  4. wise3

    wise3 Formula Junior

    Oct 10, 2004
    369
    FL
    Full Name:
    Ward Orndoff
    Like Matteo says, it depends on your driving routine. I got 40K on my first 308 clutch (the first 10K of that was by previous owners). Next one disbonded after 2 months. Put in a V12 clutch, and that one lasted 60K. My driving is 95% daily, 5% track. But I don't speed shift or power shift.
     
  5. chrismorse

    chrismorse Formula 3

    Feb 16, 2004
    2,149
    way north california
    Full Name:
    chris morse
    Clearly the major determinant of clutch life is the operator:

    High rpm, full power, drag race starts are the worst.

    Constant major slippage and relatively high rpm just to get the car going is another major no-no. God, I just cringe when some people drive my vehicles.

    Another favorite to be avoided, (by my engineer dad no less, is the holding of the car on a slight slope at a stop with the clutch slippping), what can i say?

    My best buddy, a berserker autox, hillclimb and scca racer and truck driver taught me long ago that the way to make a cluutch last is to get the car moving, get the clutch all the way out and THEN blast the loud pedal.

    Tougher carbon/kevlar will also help.

    hth,
    chris

    p.s. wish i could do the multiplate low mass unit like sloan. budgets - damn.
     
  6. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    16,688
    USA
    Full Name:
    Hugh G. Rection
    Too many variables to say. For example:

    1) Cars are driven little, sit a lot...who knows what some uncertain storage conditions may do to clutch life.

    2) Cars can be driven a lot harder than your average Honda or Toyota.

    3) Parts may be not of the best quality.

    4) Most Ferrari owners (that I know) baby their cars, though they may drive "spiritedly"; yet they can still have short clutch life.

    But I have to admit that in general, Ferrari clutches do not last as long as your average Toyota. Even with good drivers, that don't abuse their cars, and KNOW how to drive a manual trans car. While there are exceptions, it seems most Ferrari clutches seem to only last 20k to 40k miles.
     
  7. Mule

    Mule F1 Rookie
    Rossa Subscribed Owner

    Jun 25, 2003
    3,452
    Alaska
    Full Name:
    Mule
    As said, definitley the operator. I just changed mine at 49K miles (first time) and it had a good bit left, but I did it preventatively since I am moving to Alaska.
     
  8. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
    Rossa Subscribed Owner

    May 4, 2001
    28,826
    Birmingham, AL
    Full Name:
    Tommy
    7k and 15K are WAY too short of a life span for a clutch in a 308, period. You can make them last almost forever if you drive correctly. My car had 57,000 miles when I bought it and I could find no mention of a clutch replacement in the history. That's not to say it didn't have one. The previous owner had the car for 4 or 5 years and had not replaced it during his ownership. It now has 93,000 miles on it and I have tracked the car AT LEAST 5 times a year since I bought it in 1997. A typical track day is around 100-125 miles of H-A-R-D driving. I mean hard enough that I used to peg the oil temp on each session until I installed a fan on the cooler and stopped shifting at 7700 in the first three gears during every session (save the posts on this please, there is nothing wrong with my car. The problem disappeared when I stopped driving it like I stole it out there in an Alabama summer).
    Anyway my clutch is still fine. I shift properly, I do not spin the tires at a red light and most importantly: I NEVER use the clutch instead of the brake on a hill waiting for a light or whatever. At stoplights, it's in N with my foot off the clutch - saves on the throw out bearing. If you treat it right you will probably sell the car before you need to replace it, I promise.
     
  9. Verell

    Verell F1 Veteran
    Owner Consultant

    May 5, 2001
    6,967
    Groton, MA
    Full Name:
    Verell Boaen
    A major cause of premature 3x8 clutch failure is lack of regular adjustment of the clutch linkage, or improper adjustment. Especially with 328s & 308s with the newer style linkage that came out about '81 & has been retrofitted into many cars.

    Unfortunately, the design of the 3x8 clutch is that as it wears, pressure on it is reduced. Adjusting the clutch linkage (NOT the cable) every few thousand miles restores the pressure. If you don't adjust the clutch, pressure will be continue to be reduced to the point that the clutch starts slipping slightly under load. Wear accelerates rapidly from that point. Lack of adjustment is what frequently takes out clutches in 10K-15K miles.


    Actually, on the 328s & the 308s with the updated clutch linkage, the throwout bearing is always in contact with the pressure plate & spinning with it, so in or out isn't a big wear difference factor. The earlier carb'd cars with the old style linkage had a non-contact throwout bearing, that only spun when the clutch pedal was down.
     

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