This connecting rod bushing is the replaceable bearing surface between the connecting rod and the crankshaft journal. It sits in the big end of the connecting rod and provides a low-friction interface that allows the rod to pivot on the crankshaft as the piston moves through its stroke. A worn bushing increases clearance, which produces a knocking sound and reduces oil pressure at the journal. The bushing is machined to the same inner diameter as the original component so that the oil-film clearance against the crankshaft is maintained without additional fitting. On installation, verify that the oil hole in the bushing aligns with the oil passage in the connecting rod, and lubricate the bore before assembly.