The engine oil passages are full of your old bearings and such. if you completely tear down the engine and re clean the oil passages, pistons ring lands, etc. and re check all machine work, you may be able to run again with out problems if you keep oil pressure in the future. The crank will require at the least a polishing on a crank grinder to keep the journals round and true. Hand polishing is not advised ever on any bearing surface. Sorry about the un welded pick up. Weld the next one on.
Bruce