An internal combustion engine has a plurality of cylinders containing pistons
connected with a crankshaft for transmitting power. The cylinders have closed ends,
intake and exhaust ports communicating with the cylinders through the closed ends,
valves operable to open and close the ports to air and exhaust flow to and from
the cylinders, and a lower end pressure oil lubrication system operative to lubricate
at least the cylinders, pistons and crankshaft of the engine. The engine includes
hydraulic actuators operable to actuate the valves and forming part of a separate
upper end hydraulic oil actuation system operative to selectively supply high pressure
hydraulic oil to the hydraulic actuators to actuate the valves in a predetermined
manner. Optionally, the hydraulic system may have an oil reservoir within the engine
block, such as in the valley between the cylinder banks of a V type engine.
