What component on a four-cycle engine's connecting rod could be part of the lubricating system?

The dipper on a four-cycle engine’s connecting rod is an integral part of the lubricating system. Its primary function is to pick up engine oil from the oil sump or pan and splash it onto various engine components. This splash lubrication helps ensure that moving parts, such as the crankshaft and camshaft, receive adequate lubrication to reduce friction and prevent wear. The dipper effectively creates a more efficient system for distributing oil throughout the engine, particularly in engines where oil pumps may not be able to circulate oil to all areas rapidly enough.

The knuckle, rod cap, and rod bolts serve different purposes—primarily structural and mechanical rather than lubricative. The knuckle aids in connecting the piston to the connecting rod, the rod cap secures the connecting rod to the crankshaft, and the rod bolts are fasteners that hold the rod cap in place. None of these components play a direct role in the engine’s lubrication system like the dipper does.