After having some weird clutch engagement issues, I finally took the transmission off to see what was happening in there.

A piece of the clutch disc had come off and was getting wedged between the pressure plate and bell housing. Bell housing seen better days.



But, the weird part is what was happening to the clutch disc:



The springs were actually migrating outward, munching through the hub. Eventually this segment broke off after the spring cut through enough of it. Every spring was doing the same thing.
This segment was just about to go:



Any ideas what could have caused this? Poor quality clutch disc? (Old CM FX300) Bell housing bolt not torqued correctly?

I'm fairly certain my clutch engagement issues were stemming from the sprung hub not operating like it should, likely getting hung up sometimes. Thing probably was about to grenade entirely.

 

Catastrophic failure

How many miles on it?

How many launches on it (just curious if the clutch saw some extreme duty?)

 

Clutch had about 60k miles on it. Only a handful of street launches over the years, I was not doing quarter miles. It was my DD for about 6 years with that clutch until I got a different daily.
Big reason I started looking for a different daily was because it was becoming such a chore to drive with the clutch engagement point changing after I opened the throttle to any degree.

I would love to know what happened, so I'm going to continue to search around, since clutchmasters made this disc for other cars. But at this point I think you're right, it was a part failure. Just never seen one fail in quite this way.

 

No weird sounds or vibrations happening? Just the varying engagement point?

 

There were two different personalities to it. If I drove the car without getting on it much, like during a commute in traffic, it felt quite normal. No vibrations, sounds or strangeness with the pedal throw.
However, if I did give it the beans, suddenly the clutch pedal would get very loose and could feel heavy vibration through the pedal. Clutch engagement would occur maybe 1cm from the floor. A few pumps of the pedal and it went away though, returned to normal.

After seeing the disc, I'm thinking that when getting on boost, it torqued the sprung hub far enough that the springs got hung up in some way. Pumping the pedal while it was hung up may have been grinding the springs into the hub.

There was no transmission input shaft spline damage, and the clutch hub splines don't have any visible damage either.

 

I replaced the OEM clutch with another OEM. I then drove about 20K and then decided (about two years ago) to swap out the transmission (due to a manufacturing defect in the transmission). Any time the transmission is out I use it as an excuse to freshen up the clutch. One of the springs in the old disc was compressed and about to fall out. This with no launches and no hard driving at all. So, I'm guessing some maker of clutch springs made some bad ones and they got used in both your clutch and mine.

 

Bizarre. So it was a similar situation where the clutch disc was slowly acquiring more gremlins over time that likely would have ended similar to mine if it had been driven longer. I would have liked to check the clutch disc earlier but thinking about the effort to remove the transmission sent me packin every time I thought about it, until a couple weeks ago.

I think I'm going to conclude it was a manufacturing defect in the hub and springs and move on.

After seeing this video, I'm more certain the failure was a manufacturing issue (@1:14):


It's an S2000 clutch but same exact clutch manufacturer and same model number as mine. I remember mine rattling like that when it was new. I remarked on the rattle before the clutch was installed but didn't know enough at the time to know that much play was bad news.

 

The best style of clutch I've ever seen is like the Ogura single/twin plate
Not sure if they make one for your transmission

The floater disc makes a special kind of noise when you depress the clutch pedal.
They are extremely reliable, hold a lot of power and often exceed 60k service life in daily drivers

 

I think you are right on track with the defect theory. That just sounds like bad luck and a failed disk. On the bright side, once a new one is in, you are golden! Bummer when a part fails, though. I had an Exedy clutch take a dump on me, once. One of the springs came out and logged itself in the pressure plate. It rendered the car useless. Oh, the mess it started...

 

Perhaps easier to ask what that DIDNT destroy... did that bollocks up the mains or thrust bearings at all?

I'm taking the engine apart and having a shop look at it just to make sure. Seemed like a good idea, since I've gone through the effort of removing the transmission already, and I would like to keep the car running as long as I can manage. Love these things

 

Engine was fine. I couldn't release the TOB, so.had to.remove the PP, bolt by bolt, through the inspection cover. Finally I could pull the trans.
I then had to cut every single tooth out of the pressure plate to get the TOB off, then the PP out of the trans. Took a whole day.

 

E 6, destroyed two clutches . replaced now with Exedy twin plate, rattles a bit but so far so good.