PST Carbon Fibre Tailshaft Failure

Discussion in 'Z32 Technical' started by rob260, Oct 4, 2010.

  1. rob260

    rob260 Moderator Staff Member

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    So it seems I was too quick to reccomend PST tailshafts as mine has unforunately failed.

    The carbon and ally tubes have separated, giving all the symptoms of a failed clutch. There is no visible breakage but there is a very loud screech/vibration that resonates through the bellhousing when the clutch is engaged under load.

    I can only conclude that sustained heat has caused the resins used in the bonding process to melt. There does seem to be some residue on the shaft.

    The slippage described is actually visible, I will try and get a video up in the next couple of days.

    Unfortunately for me this leaves the car decomissioned on a trip to QLD while I wait for a new one piece to get made up. I have emailed PST to see what they have to say.

    So yeah, as far as I'm concerned PST can no longer be considered the "good" c/f option. I would only consider chrome molly or steel for a replacement.
     
  2. ezzupturbo

    ezzupturbo JDMAutomotive

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    carbon and aly have different expansion rates so its only a matter of time before they fail. my ol girls rx8 failed after 2.5 years. i would go for a molly replacement. i think they are smaller diameter to so lesser rotating mass :)
     
  3. BLACK BEAST

    BLACK BEAST SLICKTOP TT R-SPEC

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    Damn it


    that sucks

    like to see what Mark's response is from on this .
     
  4. ezzupturbo

    ezzupturbo JDMAutomotive

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    there is a galvanic corrosion tendency where carbon components actually eat aluminum
     
  5. BLACK BEAST

    BLACK BEAST SLICKTOP TT R-SPEC

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    why wouldn't they use steel instead of Ally ?
     
  6. ezzupturbo

    ezzupturbo JDMAutomotive

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    steel is even worse with heat expansion rates
     
  7. ezzupturbo

    ezzupturbo JDMAutomotive

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    personally i think small diameter molly shaft is the way to go
     
  8. Nigel300

    Nigel300 New Member

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    Hey Rob when you get your new steel or C/R shaft made up, maybe you can ask UAS if they want to make some sort catch loop for these one piece tailshafts as a safety measure? I'll be in for a group buy.
     
  9. Tektrader

    Tektrader Z32 Hoe, service me baby

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    There is alreadya bent sheet steel cross bar under the drive shaft from Stock.

    Dont know if its big enough but it is there.
     
  10. Nigel300

    Nigel300 New Member

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  11. UNIQUE ZED

    UNIQUE ZED Zed Racing World

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    No good

    Might need to look at heat shields or other reason, or maybe no reason why it failed.
     
  12. rob260

    rob260 Moderator Staff Member

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    Definately heat related and failure occured at the gearbox end of the shaft. That said if it was fit for purpose you would think it should hande the heat. My dumps are HPC coated and the factory heat shield is in place.

    Maybe heat wrap would have helped but it's a bit of a bandaid fix.

    I emailed PST on Monday night our time but no response yet.
     
  13. BLACK BEAST

    BLACK BEAST SLICKTOP TT R-SPEC

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    Hey Rob

    your exhaust runs closer to the tailshaft than mine

    You have the custom exhaust that runs in the tunnel close to the box and shaft?
    Could this be the problem?
     
  14. rob260

    rob260 Moderator Staff Member

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    Yeah maybe but the dumps/cats are well forward of the tailshaft. The x pipe sits under the rear of the gearbox so it's not like the shaft is exposed to all of the seriously hot stuff...

    [​IMG]
    [​IMG]
    [​IMG]


    I think it is the ten hour drive (Syd to Brisbane) that did it, but not like it was under sustained boosting or anything. It would get hotter with a few hard laps I am sure. Got a steel one piece in there now and no issues for the drive home. I had a quick chat to my neighbour tonight who is an aircraft engineer and he was very surprised that they would bond c/f to alloy without using pins or something solid to secure it. I'm not sure what the PST process is, still have the shaft so I will have a better look in the morning. But yeah he did mention that without a fastening system it wouldn't last...

    I'm hoping PST get back to me, I sent a pretty straightforward email explaining what had happened and will they fix or repair it if I return it to them.
     
  15. BLACK BEAST

    BLACK BEAST SLICKTOP TT R-SPEC

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    it looks like the xpipe is right under shaft where its bonded to the ally ?

    heat rises so will probably get hotter than you think..
     
  16. WazTTed

    WazTTed Grease Monkey

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    i would be asking for a full refund. no way i would run another CF shaft after seeing what has happened.
    im more than happy with my 1piece steel unit
     
  17. a2zed

    a2zed Guest

    Your centre muffler is very close to the front, maybe move it back to get a little more airflow over it. Would be alot of heat build up at the muffler there.
     
  18. rob260

    rob260 Moderator Staff Member

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    Understand what you are saying re heat and also comments from black beast. Really though I shouldn't have to compromise my exhaust setup if the tailshaft was up to the job....
     
  19. a2zed

    a2zed Guest

    I guess it might be a draw back of a carbon shaft. Be interesting to hear what PST have to say about it.
     
  20. BLACK BEAST

    BLACK BEAST SLICKTOP TT R-SPEC

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    I remember Mark from PST telling me heat isnt good ..

    Do you have his new email contact?
     

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