Good morning guys, I am a newbie to the MB diesel world and have a few questions. Firstly, taking this engine/tranny out of my 1981 300SD was a bear (partially because I didn't really have any service manual or anything to follow, partially because of the previous owners lack of maintenance). When I bought the car it was running and driving but the radiator was busted so it was only for short little trips up onto a trailer or into the garage. The PO said there was a rod knock in the engine and while I could hear a tapping sound, it did not sound like a rod or main bearing issue. The oil pressure was rock steady at all RPMs, the tapping sound was at a mid RPM range (not at idle usually indicating main failure or at high RPM usually indicating rod failure). I am thinking my tapping sound is coming from the injection pump or the injectors themselves.

Either way it is pulled and after figuring out the puzzle of getting the OM617 mounted to the engine stand and still being able to remove the oil pan, I have it off and prepared for modifying it for my Jeep project. I am staring at a super clean bottom end with no indications of a failed bearing. The rod play on the crank journals are very small in a linear forward to back motion, no play up and down. There also doesn't appear to be any up and down crank movement in the mains, only a very small amount of linear motion.

My questions are:
-should I replace the main/rod bearings since I have it opened up?
-where is the best place to buy said bearings if I do need them?
-is the mating surface between the engine and the upper oil pan gasketless?
-how can I make sure the tapping sound is from the IP or injectors?
-is there anything else I should do while I have this thing out and partially disassembled?