The last picture you attached shows what happened. The hole is the
engine block that is missing a piece of cast iron. In the hole shows a shinny part which is the crankshaft journal, where the connecting rod connects. Just above is the connecting rod cap. The bolts are missing. What happened is that the connecting rod broke and whipped around and hit the edge of the engine block and broke the cast iron from inside out. Then the connecting rod cap bolts and dropped in the
oil pan. The other end of the connecting rod is still attached to the piston and the piston is now at the top of the cylinder. You are lucky that the engine is still running, usually you cannot start the engine after a major break like this. To fix this... will be very costly, the block will need to be repaired, the crank will have to be rebuilt, and the
parts that are very hard to source out, like one piston (maybe more), connecting rod (maybe more), reconditioning of the cylinder
head while you are at it. It will probably be cheaper to source out a used or reconditioned more modern engine. All depends who will guide you through this
project... Good luck in the
repair.