Abstract: A variable length connecting rod 13 for changing a compression ratio of an engine is provided. The connecting rod 13 includes a first locking assembly 36 for locking the connecting rod 13 in a first effective length setting corresponding to a high compression ratio. The connecting rod 13 further includes a second locking assembly 38 for releasably locking the connecting rod 13 in a second effective length setting corresponding to a low compression ratio. When a length change is initiated, hydraulic fluid unlocks one of the locking assemblies 36, 38, allowing inertial force to effect the length change during an engine cycle. At completion of a length change, the other locking assembly 36, 38 automatically locks. The locking assemblies 36, 38 are self-contained units that are assembled to a bearing retainer 24.

Abstract: The lost motion arm 44 has first and second contact surfaces 102 and 104. A latch mechanism is connected on the body with an extendable plunger 120 having a first contact surface 124 and a second contact surface 126. The plunger 120 has a first position for first contact surface 124 engagement with the lost motion arm first contact surface 102 to prevent angular movement of the lost motion arm 44 with respect to the body 10 in a first angular direction. When angular movement in the first angular direction is prevented, the motion of the lost motion arm 44 imparted by the cam lobe 66 is transmitted to the body 10 to provide for a first state of operation of the valve stem 18. When the plunger 120 is in a second position, non-contacting with the lost motion arm 44, the lost motion arm 44 is allowed to pivot relative to the body 10. Accordingly, the rocker arm assembly 7 will be in a second state of total or partial deactivation of the valve stem 18.

Abstract: An internal combustion engine includes separated oil drain-back and crankcase ventilation passages. The oil drain-back passages extend from the cylinder head to a position below the top level of oil in the engine's crankcase. The crankcase ventilation passages extend from passages formed in the main bearing bulkheads from positions above the oil level in the crankcase and ultimately through the cylinder head. Oil dams surrounding the uppermost portions of the crankcase ventilation passages prevent oil from running downwardly through the crankcase ventilation passages.