[Cobra 29]

Jim, I believe that your slave / clutch arm tip travel is very close to the movement you need to completely disengage your clutch and when the parts are warm / hot they expand enough to remove this clearance that you have when the parts are cold. I believe this has happened on my car because I was continually on the "edge" of having enough travel to completely disengage my clutch until I fitted a larger master cylinder that increased my slave cylinder travel beyond just enough movement.

With your engine running and the clutch pedal fully depressed can you shift into reverse without any grinding of the transmission gears? How does this work when everything is cold and when everything is at operating temps?

Shifting into reverse from a stop and shifting into 5th while running when I did not have enough slave / clutch arm travel to completely disengage clutch always resulted in some gear grinding.

I also believe that as the clutch disks wears, we need to re-adjust the clutch arm to slave nut to maintain enough travel to completely disengage the clutch when the pedal is depressed and to have the least / no pressure on the throw-out bearing at rest (clutch pedal fully out / back).