What is the main system used to lubricate overhead camshaft bearings?

The main system used to lubricate overhead camshaft bearings is the engine's oil lubrication system, which typically includes an oil pump that circulates engine oil from the oil sump to various components. This system ensures that oil reaches the camshaft bearings through oil passages, providing necessary lubrication to reduce friction and wear. Additionally, some engines may use a combination of splash lubrication and pressurized oil systems to effectively lubricate these bearings. Regular oil changes and maintenance are essential to ensure the system functions properly.