right following on from my tapping thread in all motor section on fitting itr late spec camshafts the car started making a loud tapping noise but only on getting walm.

valve clearances were set 5 times (were ALWAYS within spec)
re-built the engine and it still tapped (new bearings/pistons/rings/all pumps etc head apart and no broken springs/good guides/new valves etc etc)

so i dropped the old cams in and it stopped tapping.

so how do i check to see if the cams are a) heavily worn, bent or the valve springs are good?
my mech seems to think as the car got hot the springs changed rates due to the heat and started making a loud/knocking noise.

any ideas?