Originally Posted by DieselPaul

When we put the motor in on an automatic car the flexplate somehow bound up. It was nearly impossible to turn over. Unbolted the bell housing bolts and I heard it pop back. We paid closer attention on our next approach and all was well, car has been on the road for a while. This was an auto 220 gas W115. So not the same situation, but I have seen them bind up. However if the car was previously on the road running, it wouldn't randomly bind up that way. I reread you post on my computer and my comment on that front is probably irrelevant.

1 bar of oil pressure at idle is fine, it should peg the gauge on the highway though.

Are you sure you don't have a blown headgasket and you are temporarily hydrolocking the motor? You don't see many blown HGs on 615s, but I have seen motor hydrolock from tons of fluid in the cylinders from a bad HG.

Rebuild parts will probably prove tough to find. I have a 220D motor in Ohio out of a '72 220D 4speed that ran for a couple minutes until it ran out of fuel, its overall condition is fairly unknown but I could attempt to compression test it on the bench if you decided you needed a motor and you're near Ohio.