Apparently the M115 has a similar valve cover to the OM617, right?
If so, means this is a M102.
Das ist gut! Eliminates the temptation, all the waste, and temptation!
Plan returns to what it was: remove the driveline from the '79TD and replace with the driveline of the '85TE.
However, there will be some Euroness going on the '85TD-T!