Help identifying a rattle

[IrReapz]

Hey guys been trawling the forums for a while and decided to sign up. I need help trying to work out this rattle on my ca Its a very weird rattle sound most obvious when you let of throttle. Sethoscope is telling me its in the head region but cant quite work it out. I have checked under the timing and valve covers and it all looks clean.

Here is a video doing exactly what my engine is doing. The car still drives and boosts fine with no power loss or rattle through the rev range. Only when you let off the throttle and a little at idle it makes this sound.

Video:
https://www.youtube.com/watch?v=V1JtSajKOJ4

Anyone else out there heard of/have had the same issue/noise?

[float_6969]

To me it sounds like an exhaust leak, but it could be bad rod bearings too.

[louiswun]

seems like more than one rod's bearing totally gone

[boost_boy]

Don't know exactly what that noise is, but it is not the rod bearings. I'll take a wild guess and assume it's in the timing belt area (Possibly a loose crank pulley). Or worst case scenario a loose flywheel or clutch components.

[blownhemi]

If it's louder throttle-off/engine brake (high vacuum situation), my guess is broken piston pin(s). When you were still driving it, did you hear it the loudest during off-throttle as well?