Judging by the noise in the video I would say that your plastic chain guides have come apart. I've seen a few of these on higher mileage M62's as of late. These were on fairly poorly "dealer maintaned" 150k plus engines.

Basically what happens is the plastic that covers the guide rails for the timing chain to ride on gets hard and brittle and just breaks apart, essentially disentegrating into the oil pan. I've seen 4 total in the past 6 months. Two of them were salvageable. Two of them had bent valves due to the cams jumping teeth.

It is a huge job to replace the chain sliders. The entire front half of the engine has to be dissasembled. The 20 something hours for chain replacement is relatively accurate. It's hard to give exact labor times on a job of that size.

Get the engine properly diagnosed and find out EXACTLY what is wrong. Have a compression test performed to check for engine damage. There is no need to replace chain guides on a lunched engine. Let us know what happens. Good Luck!

-Ben