A little background of what I've done to try and eliminate culprits to the noise. I Changed the lifters, bled properly before install, no more ticking...hooray. I changed A/C armature and pulley, ac might work now. I've resealed valve cover with new gasket and sealant. PCV checks good, no leaks. Timing belt is halfway through its life at 30k miles. Ran car with serpentine belt off, so its not a bad pulley there. Noise is ungodly loud and can't pinpoint where. Still sounds like its coming from under the valve cover but everything checked fine, no metal shavings in oil or under cover. No cracks in cover. No exhaust heat shields loose. Video below for noise reference. Noise goes away at around 2500k rpm and higher. But under 2500 and at idle noise is constant. No check engine light. Fresh mobile 1 synthetic 10w30 with oem filter. Boost pressure is good, boost leak test good. My next guess would be a valve. Im not versed in extensive engine maintainance so ill have to take it in to my mechanic friend.
Any suggestions on what it might be will be greatly appreciated.

 

 

i would do a compression and leak down test

 

The mystery loud rattle is gone after putting the car back together. New serpentine belt, it still rattles but just half as loud as before. Now there's a prominent buzzing sound at low rpms, and the car wanted to die after i cut the A/C to off. Good news though, my A/C is fixed.

 

Likely the timing belt tensioner and even if it isn't chunking grease it can have play. It makes a loud clacking noise that sounds like it is coming from the cam area.