Thanks for the repsonses to all. I see LarryBible's point, "depends". I guess I am used to American car engines typically being rebuilt at about 100K b/c that is their "shelf life" . Then again, to rebuild a small block Chevy is only about $1K-$2K.
So, taking this "depends" model, lets assume on a one owner M103, all maintainance, etc..... it could last even 200K +++ miles before you might have problems in there reflected by lower compression, etc.
So, at what point , do these parts start showing their age? There has to be an expected life, no? As an example diesel tractors have different powerplants (cat, Navistar, etc) and certain powerplants are spec'ed to last say 300K miles before rebuild, and if there is a customer need for high mileage, we then might order a powerplant 800K miles or one that will substain 500K miles before rebuild.
I am not complianing. I just don't want to miss something, and 200K miles from now find out I might have to spend $5K on a new engine
. I guess that leads to my next question, how much would a typical rebuild run? I assume you would probably use the same crank and rods. Then add new pistons, rings, oil pump, etc. I read somewhere here that you can buy a new or rebuilt engine from MB, but I would prefer to have the original motor rebuild (if I ever ever get to that point) so I would still have a numbers matching car.