Lifter noise? Or something else?

[Motorhole]

Looking for a bit of an expert opinion.

In short, I've switched the cams for uprated ones on my M52B30 build. After fitting and timing it up (all seems well on that front), there seems to be a knocking noise from the valvetrain when turned over by hand.

Video:

I figure this might be because the engine has been sitting around (sealed) for a while and all the oil has drained out of the freshly rebuilt lifters? Or is it something I should be worried about!?

Thanks!

Edit: should add, the video seems to make the noise worse than it sounds in real life...

[drakesmith]

What cams are you using as they look like just 2.8 cams.

Id get them lifters out and primed them with oil before you start it up. You have now pushed all the oil out of them.

What torque did you bolts the journal caps down too?

The vid is not too definitive on where the noise is coming from.

Across the whole valve train intake and exhaust. Front and back?

[Motorhole]

High lift/duration regrinds by Just Deutsch. Absolutely no doubt the noise comes from lifters/valves. Moves with firing order and when turned slowly, there is no noise.

Journal cap bolts at 14 NM.

[DanThe]

Seems that the noise is in exactly the same place on every revolution, 3 times per revolution which is the amount of (pairs of) pistons that come to TDC every revolution, did you test build to find piston/valve clearance?

[drakesmith]

Hey dan. Ask him that to mate. It was the lifters slapping back into the tray when he got back to me. But hopefully he will explain to you.

[Motorhole]

Hi Dan. Yeah that was a worry but I spent some time with it and managed to track the noise down to some of the lifters popping against the cam as it passed approx 60 degrees from full lift. Could replicate the noise by hand and filling the lifter wells with oil made it go away. Cam vendor also assured me it's quite normal when the lifters have no oil pressure.