clutch hardness

out of interest what spec are clutches heat treated to, what level of hardness does it have to meet in order to meet SFI spec

 

Clutches usually aren't heat treated if made from Aluminum or Titanium, since they are normally made from billet blocks. Now the individual components, such as pins and levers are usually made from a tooling steel like M4, and some even make them out of Titanium. The steel parts are usually an RC of 50 or better.

As for being out of SFI spec, all I can tell you is that once the hardness breaches what the material was originally certified at, you may look to have it annealed back to it's certified hardness. I know of some issues in the past with Aluminum flywheels in blown alcohol getting brittle after a few seasons and making a big mess in the can!