Hi,
I'm digging this question out, because I was asking the same question.
Getting a D24 from a '92 240 (planned as spare in case for my 740 D24T or 940 D24TIC), it has hydraulic lifters (started from 1990 and on?), the previous need valve adjustion time by time. The roof block has no additional water cooling lanes for additional oil cooling, they are not drilled and can't be upgraded at all. Necessary to make them "turbo-capable", otherwise it's risking overheating. Additional, there are some differences with the pistons (turbo/non-turbo; later versions etc).
Cilynder-head: Depending of the roof engine, if the timing belt is tensioned by a pulley or water pump there are - as I know - some differences with the holes / camshaft. But I'm not sure.
The turbo versions use natrium-filled outgoing-valves.
...Any additions/corrections/things I missed out?
Best regards,
Bernd
