valve bounce or spring flutter?

everyone knows the noise when the engine is over-revved.

everyone seems to think the noise is the valve springs being too soft to return the valve to the hole smoothly, but a mate says it is actually the noise of the valve springs fluttering, not the valves bouncing. he says that the valves hardly move so it couldn't be that.

i proceeded to inform him of my thoughts about the iq of his anus, but didn't argue the case as he should have more knowledge than i.

what do we all think?

[Edited on 24-3-2005 by theverybigtallman]

As far as I know it's the rocker hitting the valve stem head.

the valve train is unable to follow the camshaft lobes due to too many revs and the springs not strong enough and the whole crappydoodle then sits in mid air getting bashed about by the top of the cam lobe. say you got .4 lift at the cam and it is 1/2 way then its like having 200 thou valve clearance .thats near enough for a not too technicial explanation.