Not valve noise... it is definitely belt or pulley, or fan related. its really pissin me off, i could fix it in 5 mins if i knew what the hell it was. yes the belts are tightened correctly. the more i listen for it, it almost seems to be coming from the crank pulley but not sure. closest thing i can think of to describe it sounds like a bolt rattling around in a can. not necessarily even a regular pattern, sorta random, like something bouncing around. its the weirdest thing ive ever heard.