are you guys referring to the harmonic balancer? That'* what I was thinking it was, but the noise from those usually go away with RPM'*. (usually over 2,000 RPM.)
Maybe I'm an idiot, but isn't the harmonic balancer towards the bottom of the engine, accessory side? (The balance shaft for the engine is under the manifold, but the harmonic balancer isn't..) Like I said.. I might have no idea what I'm talking about though.