Can some please help me determine the problem here? I have checked lash adjusters for play and replaced one that was loose. Nothing changed. Timing chain seems tight and smooth while running with valve cover off. All valve stems are equal in height and equal spring pressure. No broken springs that i could tell with cam removed. i posted a video here

 

Sounds like an exhaust manifold leak.

 

I forgot to mention i checked for exhaust leak.Since the posting i dropped the oil pan to check for spun bearings. bearings are tight. however #8 piston is very loose in the cylinder. Looks like the rings are collapsed. The walls look good but i can literally wiggle the piston side to side.

 

Just curious. If that's the case, why so focused on the sound? Now I'm thinking what sound might be expected from de-tensioned rings and piston slap, and your sound could very well be an exact fit.

Seems to me chasing valve train noise and anything else when you know what you know about this motor is a bit like treating a cough when the patient has a spear though the chest??

 

Does the knocking sound get faster when you rev it up? If so I'm willing to bet It's a rod knock or wrist pin going out. I've heard that 100 times. Your motor is about to be trash. If you fix it now maybe the damage won't be that bad.

 

Just wondering if it sounds like a diesel when you first start it up, my 06 does. I was going to put some additive in the engine but when I talked to the counterman at the parts store he said it wouldn't do any good (said it was made that way) some gaps in the wrist pins or something he told me not to worry about it. Been 2 years now and still makes the same rattle like a diesel when first starting up till it warms up. Not using any oil 130k