1947 d7 3t caterpillar pre crank check ??????????

You are inquiring about valve adjustment and oil priming, so we need to assume you tore into the engine?
1. Adjust the valves before you crank to verify correct adjustment to prevent damage do to misalignment.
2. Fill coolant using the bleeder valve on top of the pony motor to insure the least amount of air present in system.
3. Fuel system priming is a chapter in itself, do a search for previous threads on it.
4. Now your systems are full crank the engine with the run/start lever in the start position waiting for the oil pressure to buildup, this minmizes load on the crank/rod bearing because if the valves are properly adjusted, one set should now be held open.

In answer to the oil type, do a search on that subject also but Delo or Rotella are 2 of my favorite diesel grades of oil. As to detergent it will wash any crud out of the engine and may possibly plug the oil pump pickup screen or oil filter. But your questions are written in a way that we assume you worked on it so I say don't worry about it.
Good Luck!
Jeff

Also, we're assuming that any bearings you went into were reassembled with a good assembly lube or light grease, or at least lots of oil. That will protect them until the oil pressure comes up. I suggest cranking slowly--pony at idle speed--until oil pres starts to rise, or if you have one with the two-speed starter drive, drop it down to low speed for a bit.

My 3T doesn't have a bleeder on top of the pony. Don't spend too much time looking for it. The back mounted starters have them and in that case you'd better use them.

Joke is on me, I was tired when I replied saying there is a bleeder on the pony. I thought it was asking about a D4-3T!!!! I just looked at the Forum this morning and noticed the startup on the D4 was gone but there was one on a D7???? 😆