Take a look at this. It came out of an engine I am preparing to install in a 1979 300SD. It is the vacuum pump roller "surface". This is what destroys stuff like the vacuum pump roller and it actually looks like a bearing race failure (which, in a way, it is). It would have eventually made mince meat of the vacuum pump "roller"
and the more load on it the quicker it would have gone bad. We have a vibration crew at work that can pick up stuff like this all over a papermachine.
I've been working on this engine since around 9 am this morning. New bearings, rear main seal, chain, chain guides and tensioner. When I tore it down the chain was showing 11 degrees of stretch
. This is the worst thing I have seen in this engine so far. It was time for a new oil pump tensioner slide too.