[Mgs] More NJVGP news: clutch advice needed

[J. F. Juhas]

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 at snet.net 
> <mailto:james.f.juhas at 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
>     _______________________________________________