Noise From Timing Cover Area

[the stink]

My engine is a RB25DET in a 96 R33 S2. I first noticed it was making a noise near the timing cover about 5000kms ago but recently after changing the timing belt it appears to have got a lot worse.

The noise is worst when the engine is cold and fast idling at around 1000RPM, over 1500 RPM it disappears completely and once the engine warms up and the idle revs drop it quietens down a lot too. The noise is a strange sort of rattling like something is loose.

I have done a search and found a post which describes a similar noise and someone suggested it might be failing timing belt idler or tensioner bearings, and while the noise does sort of match with this, when i changed the timing belt i checked these bearings and they didn't feel at all loose.

I was thinking it may be something to do with the VCT solenoid on the intake cam pulley but i don't know enough about whats inside to say if this is possible. I did read the cam timing solenoid switches on at 1200 and off at 5000 rpm which may have some significance.

Anyone have any possible explanations?