Could oil contamination cause clutch drag/bind?

[Al Weyman]

My clutch problem I had yesterday at Thruxton seems to have mysteriously rectified itself. Do you think when I dropped oil out of the rocker covers at the previous race and we are talking a lot (all sealed and bone dry now incidently) and some of that oil found may have its way onto the sintered triple plate Tilton clutch could that then have caused the binding? Then prehaps when I ran it in the race especially holding it on the line in gear as I had to start the engine in gear as the clutch would not disengage that it may have cleaned up the oil contamination.

If not oil contamination has anyone any idea what else could cause this as it was fine when I loaded it on to the trailer but started baulking on the track and gear changing was very bad. By the time I finished the race it seemed to be OK but obviously I don't want to risk it again but it is a bit of a job hauling the box out. I did adjust it for more throw in the interval but it was not an immediate cure and I had to start it in gear to do the race.

[Chris Y]

Personally I've never heard of oil causing bind. It's usually the other way 'round - i.e. oil causing the clutch to slip badly.

However, I'm no expert Others may have a theory..

I presume it's a cable-operated clutch, not a hydraulic system?

[Al Weyman]

Cable? Hydraulic? This is a 70's vintage Camaro we are talking about here, no luxurys like that, just a massive great lever and push rod arrangement :-)

I Know what you are saying but I have had experience with organic material clutches getting oil contaminating then not releasing properly making it very hard to get into gear but don't know about these sintered bronze ones its the fact it appears to have rectified itself that has thrown me somewhat.

[Notso Swift]

I don't know but I guess it would be possible for a layer of fluid to cause a "hydraulic lock" between the plates, but I doubt oil would do that... it is designed to be slippery
When Organic clutches do it it is because the material swells with the oil, brass can't do that, though.

[Al Weyman]

Yes that is how I figured it, I think I will whip the box out and have a look, thanks, before then when I have fixed the brakes I think I will take it for a test day and see what happens. It is probably warped intermediate plates that won't release when it gets hot unless anyone else has any ideas.

[Chris Y]

Originally Posted by Al Weyman

Cable? Hydraulic? This is a 70's vintage Camaro we are talking about here, no luxurys like that, just a massive great lever and push rod arrangement :-)

Yeah, sorry Al, I forgot you drive the caveman-mobile from Wacky Races

I suppose you already tried adjusting the mechanism to give the maximum 'lift' when you had the problem at the race track.. Could there be any 'slop' in the push-rods / linkages (showing my ignorance here) that might not be giving you the correct throw?

[Al Weyman]

Yes there are some adjustments to the throw ratio as well so I did play with that and it was a bit better but I still initially had to start it in gear and hold it in gear on the line, as I say the thing that puzzles me is it seems to be OK now which in someways makes diagnosis even harder if you know what I mean. It would be nice if you could just try these things on the road or a nice disused airfield somewhere instead of risking going to the track for another fruitless expensive mission.