How do you time a 300D after repairing valves?

Hello, here is the Factory service manual's description of the process for removing the cylinder head.

http://mb.bolinko.org/15/warsztat-mainme...

It tells you to rotate the engine to top-dead-center (TDC) on the 1st cylinder. Then, when installing the head, you want to have the timing marks lines up on the camshaft. Here is a link to pictures of the crank and cam timing marks:

https://mercedessource.com/problems/engi...

If your head is already re-installed and the camshaft timing marks are not lined up you will need to remove the head again to line those up before installing it. The camshaft cannot be rotated separately from the engine while the head is installed since these are interference engines (valves will contact pistons).

If you did not set the engine to TDC before removing the head, or you rotated the engine via the crank bolt while the head was off for any reason, you will need to seek further assistance in getting the engine timed. That is beyond my experience level at this time. Best of luck.