Tractor Repair: MF50B Perkins engine diesel, crankshaft bearings, perkins engine

Question
From ASustralia. Experianced retired auto mechanic. Blocked fuel supply - ran out of fuel. R&R fuel tank cleaned out, including filters. Bleed system prior to restart. Obviously did not clear all air out of system. Started engine with wiff of ether. Knocked badly on restart. Did not clear. Re-bled injectors & knock stopped. Started next day, very bad mettalic knocking noise. Appears to be from timing case & low down. Does not miss! Bleeding injector does not reduce noise but does produce a miss in each cylinder. No excess smoke! Where do I look?
Regards Ged

Answer
  Noises can be hard to find sometimes because the noise travels through the metal and may sound like it's coming from somewhere other than where it actually is.  Too much ether can damage rings, but then it would probably miss.  I would probably remove the oil pan first and check all the crankshaft bearings and check for a broken crankshaft, and look for loose wrist pin bushings or broken piston.  If everything is OK there, then I would remove the timing gear cover and check for a loose gear.