Thanks very much for sharing your experience. Although it may need mounts, the vibration does not feel metallic in any way. I will do the drip method timing check, it will at least find any gross error that may exist.
My experience has been that once timing is set nothing changes it very much until overhaul time unless there's some big problem. However, my experience base in this area is limited to a half dozen 123 diesels. It would seem to me that if there was any jamming of the chain in the pump area, there would be catastrophic failure, or at least an engine that wouldn't run.
Thanks to everyone for the continuing input,
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in