The noise you mention can be due to two things:
1st that the injection pump is out of point, more concretedly advanced, so that the diesel is injected early and causes a strong rod chopped, (such as a metallic rattle similar to when you put an engine to an engine)
2nd that the rod caps are crushed due to a lack of oil or the deterioration of the connecting rod directly on the crankshaft doll.
I do not think it is the second because as you say you have rebuilt the engine completely, and I suppose you will have put new caps.
So what I think is that you must open the distribution belt cover and make sure all brands are in place.
The tachy slack of that engine is 0.10 m/m in admission and 0.15 m/m in exhaust.
The tanes can be made in two ways, you can search for the crossing or overlap of the 4th cylinder to make the 1st, then the 2nd to do the 3rd, then the 1st to do the 4th and finally the 3rd to do the 2nd.
Or you can make it easier by putting the 1st in compression and making it whole AD/s, the 3rd only ad, and the 2nd only in is, and the 4th you will not be able to because the two footsteps are.
Then you turn the engine, put the 4th in compression and make the valves that you have left, that is, and 4th integer ad/s, the 3rd is only, the 2nd only AD, and the 1st is made and also will have the two torn valves.
It seems a tongue twenty ...
Anyway, ask the manual in the space dedicated to it in this forum.
All the best.