The knock moved with the injector? Bit of dirt got in when the pipes were off, or internal scale was disturbed. This forms on the inside of injector pipes and can flake off if the pipes are bent when injectors are removed. These pipes should be removed completely, never at one end only, and bent out of the way.
bad seat yes, but that doesnt just happen so suddenly, I am certain a bit of crud is under the needle. Still a good diesel shop can regrind the needle and seat, or provide a new nozzle complete. I had all the injectors tested and reset and one new nozzle all for under twenty pounds. If you like, you could fit a head and pistons from a 3ad 152, they are direct injection!
Just as well D B engines are easy to work on, early ones too few head studs so head gaskets were a constant trouble.
Pistons are Bowl in piston type, and injector lines would probably be best made to suit,not sure about the inj pump I cant see any reason why it should be a problem, but did get bitten by a Peugeot 1.9 xud engine where the owner had fitted a Bosch pump in place of a failed rotodiesel type, of which he failed to inform me. took ages to find the problem and itwas cured by accident really,I had decided to change the injectors and owner supplied the rotodiesl ones from his spares car. Problem solved!
Early AD3 may be ok, still has the rope seals( even if they are moulded plastic, poss ptfe) About 45 hp, so a bit below the major. The one in my leyland is doing well pulls the plough with no trouble, and will dig holes rather than stall. The downside was it managed to bend the plough while digging said holes!
Errr I do! it now has two replacement legs and one replacement frog. Legs and frog modified to provide pitch adjusment, and also a method of lifting either leg as required for the start and finish, Holes in frog altered to fit mouldboard( super hydrein thank god for the plasma cutter) All I need now is some dry weather so I can go out and try the thing out
Local farmer had a kv reversable, dont know the type but they pulled the headstock out of it in the first year! I welded it all back together, and they did it again! My welds were still there though, the metal tore away half an inch or so from them. Its gone now it was costing too much to replace all the bits which kept bending or dropping off!