Jim Kelly posted:A warped flywheel can cause driven clutch disc springs to fail. It's always a good idea to surface the flywheel on a clutch job. Long-term slippage can also heat the springs, making them brittle and easier to break. If your flywheel is bad, you'll know before long, launching or not (just kidding about the launch). In my case, cockpit problems were the culprit, but I was a mere callow youth at the time.
The heat checked flywheel can cause the clutch to chatter which will break the springs in the disc. If everything is right you shouldn't have any trouble with a sprung disc. Any one that knows a lot about clutches will tell you there is absolutely no reason to run a solid, unsprung disc on the street. They are harsh, tend to chatter and transmit lots of driveline noise. The same thing goes for a solid disc with no marcel in it. These are for road racing or drag racing only. If you look at the outer edge of the disc, between the two linings you will see a slightly waved plate separating the two halves of the disc. This is the marcel or wave plate that cushions the disc and makes the clutch much smoother.