I've fixed a 220D and a 240D with broken timing chains. On both cars the camshaft towers were broken and had to be replaced. The cam itself was OK, I did not pull the head on either engine.

Larry has made a great point here - Its quite a bit of work to fix this problem (even if the head does not have to come off) I would not be willing to do all the work unless I could verify the engine had good compression numbers and did not use oil.

W115 cars are pretty prone to rust also.

Good luck

Tim