Finally tore down my old engine that had thrown the rod on #5. Turns it it broke the piston in half. Unfortunately I won't have any spare pistons from that engine as they are all scored on the skirts. I began the tear of my donor motor, so far seems to be in good shape. The question I have (and I'm sure this has been beat up a thousand times before) is when ordering parts is there any differences between a .951 and a .952 engine. When I do the parts look-up it states that the 1982 300SD came with the .951 engine. Interestingly mine had a .952, its stamped in the block clear as day. I'd chalk it up to maybe someone put a different engine in that car except the engine that I pulled from a junkyard donor also is a .952. This engine came from a 1983 300SD. From what I've came across online only the 300D had the .952 engine, but that doesn't really seem to be the case so far. Ideas? Should I order parts (bearings, rings etc) based on the car being a 300SD with a 617.951 or should I use a different model with the 617.95 engine? Does it make a difference?

The differences between .951 and .952 are the engine mount arms and oil pressure sender. The longblock itself is identical.

I'd go with parts that match the numbers on the block that you want to rebuild.

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