spun (piston) rod bearing; what does it mean?

the bearing that connects your connecting rod to your crankshaft has worn to the point that it is no longer held in place as it should be.your main and rod bearings will need to be replaced, essentially a complete engine rebuild.

Gday Patryk If you hear a Knocking Sound Lightly at Idle of Engine Or a Louder knock When you Rev up The Engine itlle Mean The Bearing At the Big End of Your Piston ---The larger hole That secures the Bearing in Place --Known as the Big end bearing ---Has worn Or rotated in the Connecting Rod ( con -rod for short and needs replacing --As will all the others if you take the pan of the motor to replace ---

It means you need a complete engine rebuild or replacement. Both the connecting rod and crankshaft may be damaged. There is no quick or partial fix for this. This is usually the result of oil starvation from lack of oil or low oil pressure caused by a very worn engine.