For future reference, the tightening procedure for the delivery valve seals is in the TDM (Tech Data Manual), not the 602/603 engine manual - don't ask me why.
IIRC (!) - it says to tighten, then loosen & tighten a second time, then loosen again (or not?) and the third time go to a higher spec. I think it was 30Nm the first two times and 35Nm the third time (basically the same as Peter's lb-ft numbers). If you do it wrong, the pump body can warp, resulting in rough idle, leaks, or permanent pump damage. So be careful! If the engine is running OK you probably did it right.
Photos of what happens if you do NOT have the proper clips in place are at this link - scroll to the bottom:
http://www.meimann.com/images/mercedes/OM603_injection/
