I developed a head knock in my Ford ZX2, first thought crank bearing, now i think valve Listen: https://www.youtube.com/watch?v=91C3c8ipHjQ?

I developed a head knock in my Ford ZX2, first thought crank bearing, now i think valve Listen:

Take off the serpentine belt and try again - it sounds like a pulley bearing (idler etc).

Go to either Harbor Freight or any auto parts store, and get yourself a 'car stethoscope'.
They're like $10-15. Now start probing near where the noise is coming from. It will pinpoint the source of the noise and you will be able to make a more accurate diagnosis.
From the video, it does sound like it's coming from the upper engine and not a crank bearing.