You need to check the relationship of IP to cam to crank..
and you need to use the 2mm valve movement to do that correctly..
cam tower notch is specified by FSM only as general initial engine build check... a ball park kind of thing... lots of threads in archives..

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html