Clacking noise

[I6V8]

Does anyone know what could be causing this clacking noise:

https://youtu.be/QeOLmfR0dy0?feature=shared

It takes a full 10 seconds at cold start before the knocking even begins so I'm not sure how this could be either piston slap or the valve train. It gets quieter as the engine warms up but never fully goes away.

Engine has 30K on a complete rebuild. Fresh oil change didn't make a difference. I haven't checked valve clearances yet, waiting for parts

Thanks

[TobyB]

It's the valve train.
Check your lash.

If that's all ok,
then use a stethoscope to figure out which one it might be,
and lash it 0.005" tighter and
see if that quiets it.

Flat eccentrics make it harder to quiet things.

The 10 seconds is the pooled oil being squeezed out of the rocker.

t

[I6V8]

Valves were way too tight. Adjusted them to .008 and .009. Idles a little better, slightly more torque down low but the clacking noise is still there. The rocker arms have some side play when they're not under tension from the cam lobe. That's the noise I'm getting so I think you're right. There's play. Wondering if there's wear because of the tight specs it was set to for more top end power.

[I6V8]

OK, so here's an interesting turn of events: I just dropped in a set of rebuilt, flow matched OEM green top injectors and the clacking noise is completely gone.