Rick:
Thanks for the suggestions. I have already followed most of your
advice. This Kevlar clutch was new and installed with a new PP last
September after the previous clutch failed at the end of the LRP Vintage
Festival. Since then I raced in two and one half events with seemingly
no issues. The half was a shortened LRP Spring Sprints (VSCCA) when I
broke a lifter. But before that, I was turning some of my best-ever
times at LRP at 1:15.
I seem to be having more clutch trouble with this current 1622 engine,
where previously, I was running a 1500. Maybe the rear bearing
clearances are looser.
I was suspicious of the gearbox seal and the gasket; last time it got a
new seal and carefully glued-in gasket. I'm not getting and noticeable
gearbox fluid loss so I think that's not a contributor to this.
I have not refaced the flywheel; didn't have time to do that last Fall,
but will now. I had not done the thread sealing idea on the bolts; I'll
do that this time. Depending on turnaround, I may install a ceramic
clutch and pp that will be rebuilt from cores. I have less than a
2-week turnaround before my next scheduled event.
Richard Ewald wrote:
> First rule of British clutches (learned many years ago from hard
> experience) if the clutch is slipping, change the pressure plate. I
> don't care if it is supposed to be the world's best PP, it isn't.
> Slipping creates heat, heat weakens pressure plates. ask me how I
> know this. (Hint: Been there, done that, and got the T-shirt that goes
> with it)
> Oil getting past the rear main should be on the wrong side of the
> flywheel. However oil can wick up the threads of the flywheel bolts
> and then get deposited onto the clutch.
> I would have the flywheel machined, and when remounting it, use blue
> locktite, or liquid teflon as a thread sealer for the flywheel bolts.
> Make sure the front seal on the gear box is good.
> Use a new pressure plate. I would also change the disc, but I have no
> experience with kevlar discs so you are on your own there.
> On general principle, I would make sure that the inside of the
> bellhousing was clean so any new leaks would show up.
> Good luck
> Rick
>
> On Sun, May 23, 2010 at 7:53 PM, J. F. Juhas <james.f.juhas@snet.net
> <mailto:james.f.juhas@snet.net>> wrote:
>
> When Roger's engine grenaded at New Jersey, I drove past him but
> just barely. My MGA is struggling with a slipping clutch, and it
> made my last few sessions challenging. This is a kevlar solid (no
> springs) clutch with a competition-grade pressure plate. I think
> oil past the rear scroll seal has contaminated it, even though
> conventional wisdom says that oil from there should get flung away
> from the clutch cover. Has anyone dealt with this? I was able to
> salvage some sessions by spraying brake cleaner up the drain hole
> with the clutch out and spinning on the starter. That and cooling
> off would run okay for about half a race session. Engine is a
> slightly modified 1622 and 4.30:1 rear. My next plan is to go to
> a ceramic clutch material (have a source in NJ) and a PCV system
> to help keep the oil in the engine, although the oil consumption
> does not seem remarkable. Suggestions welcome.
>
> Jim Juhas
> MGA 311
> _______________________________________________
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