Mercedes diesels are listed by number following "OM" which denotes "oil motor" OM 617 comes in various versions- and those versions are denoted by three numbers. All 617's are called 617-9XX. 617-912 is a NA version, 617-95X is a turbo version. There are various sub-versions that are denoted by different numbers. The four cylinder version of the 61X is 616. It also has various versions. The germans are quite precise- myself not so- so i guessed. 617A 300-TD is not a mercedes engine designation- but the 300TD has a 617 in it. So does the Mog. You are a newbie that seems to be just starting to ask about the engine so I guessed you used incorrect nomenclature. Others here will post the facts and figures pdf's that will corroborate this.