Thanks, John.

The noise seems to be every cam revolution, not crank. That could mean something in the valve train, or perhaps a piston/wrist pin problem on compression stroke. Loosening the injector lines on all 8 injectors did not make the knock go away, so I'm fairly certain it's not an injector.

I have a set of DSG timing gears sitting here waiting to be installed. Both my valve covers are starting to leak oil as well. Might as well tear it all down at once, and hopefully I can find the culprit.

The sound reminds me of a knock I had on another 6.2L. It turned out to be a burr on the injection pump drive gear. However, the gear was damaged when the camshaft key sheared off due to a loose cam bolt. After filing the teeth on the drive gear, the noise went away. I don't think that's my problem now, but perhaps my timing chain is getting so worn out, it's clanking around in there? Or maybe something else being damaged by the loose timing chain?

Casey