s2000 noise
 

Car info:
02 stock motor 46k miles (summer driven)
Oil: amsoil 10w30 sig series (never low)
Mods: intake, exhaust, heat shields

S2000 noise: http://youtu.be/JHjOLvbsJOk

The noise is that slight metallic rattle behind all the typical s2k valvetrain noise.

It can be heard with the windows down inside the car if you listen carefully. Not very loud but obviously an issue to address.
This video was from a while ago but it is the same noise. This is a cold start idle and it does increase with rpm but the noise doesnt get louder. It does seem to get slightly better after warming up. The noise use to only happen every once in a while and I changed the tensioner pulley and sandblasted tct...which I thought helped but as in any car issue the problem just decided not to be there and came back later then went away again. However, now it is constant and slightly louder.
Any opinions? I know its difficult to do over a video but I have taken it to local shops with no luck..they just guess valvetrain noise (it sounds more outside the engine imo)

Try removing the belt and running it.