Premature clutch wear. 1st vs. 2nd gen?

Jo Rhett jorhett at fastlizardracing.com
Mon Aug 12 09:18:30 PDT 2013


Zoran told me not to use the Barnett springs in the 2nd gen clutch unmodified. I can't remember what else he said, but I'd check with him directly if he doesn't speak up here. Sounds like they are not-quite-the-same.

On Aug 12, 2013, at 9:15 AM, Aaron Turner <synfinatic at gmail.com> wrote:
> So I've been trying to diagnose why my clutch slips under hard
> acceleration.  It doesn't slip a lot, just what feels like one revolution
> or so. Happens probably 2-4 times a lap at THill depending on how hard I'm
> on it.
> 
> So long story short, I have a nearly brand new (2 race weekends and about 5
> track days) 1st gen Barnett clutch pack installed in a 2nd gen motor.
> (long story)   Although to be honest, the clutch has been slipping for at
> least half that time (I've had bigger problems to worry about).  I tried
> adding more play in the clutch cable last race round, but that didn't help.
> 
> The clutch seat & seat spring washers from the 2nd gen clutch are NOT
> installed.  4 of the 6 clutch springs were Barnett, the other 2 stock.
> 
> I measured the plates.  The thicker #2 friction plate is on the high side
> of being within spec.  Of the remaining 6 frictions, 4 are in spec (barely)
> and 2 are just out of spec.  All +/- .02mm of spec.
> 
> Steels look good, no bluing/etc.  Pack was installed correctly per 1st gen
> specs.
> 
> So, seems like I probably need a new set of frictions (I couldn't find any
> spec for total clutch pack height, does anyone have any numbers?).  What I
> don't understand is why the clutch wear was so aggressive.  The motor isn't
> making crazy horsepower (less then 80HP) and historically my clutches have
> no problem lasting more then a full race season.
> 
> I know the 1st & 2nd gen SV are *almost* the same... stator, gear position
> sensor and oil cooler being the obvious differences on the bottom end, but
> maybe there is something different with the clutch basket/etc that would
> cause this premature wear?
> 
> Right now, the only idea I have is that the clutch cable was too tight and
> that caused the premature wear.  And by the time I loosened it up it was
> too late.  But honestly, I never felt any difference after adjusting the
> clutch cable.
> 
> Suggestions or ideas?
> 
> Thanks!
> 
> 
> Aaron Turner
> http://synfin.net/         Twitter: @synfinatic
> https://github.com/synfinatic/tcpreplay - Pcap editing and replay tools for
> Unix & Windows
> Those who would give up essential Liberty, to purchase a little temporary
> Safety, deserve neither Liberty nor Safety.
>    -- Benjamin Franklin



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