An electro-hydraulic actuator system for a variable valve lift system of an engine, the electro-hydraulic actuator system comprising: a medium pressure chamber formed in a cylinder head assembly and adapted to be in fluid communication with a source of hydraulic fluid; a high pressure fluid circuit positioned in the cylinder head assembly and in selective fluid communication with and receiving hydraulic fluid from the medium pressure chamber; a control valve positioned in the cylinder head assembly and in fluid communication with the medium pressure chamber and the high pressure fluid circuit; a pump configured to pump hydraulic fluid in the high pressure fluid circuit; and an actuator in fluid communication with the pump, control valve and high pressure fluid circuit, the actuator in engagement with an intake valve of the engine; wherein the control valve is configured to be controlled to selectively block fluid communication between the high pressure fluid circuit and the medium pressure chamber thereby providing for the hydraulic fluid pumped by the pump to displace the actuator to open the intake valve; said system being characterized in that the medium pressure chamber and the actuator are each positioned in the cylinder head assembly at a location higher than the control valve such that during an engine shutdown event, hydraulic fluid is retained in the medium pressure chamber and the control valve, in that the high pressure fluid circuit includes a first fluid passage fluidly coupled between the pump and the control valve, and a second fluid passage fluidly coupled between the control valve and the actuator, the second fluid passage having a valve end coupled to the control valve and an opposite actuator end coupled to the actuator, and in that the second fluid passage is inclined such that the hydraulic fluid flows upwardly in the second fluid passage from the valve end toward the actuator end when the engine is in a level operating position. a medium pressure chamber formed in a cylinder head assembly and adapted to be in fluid communication with a source of hydraulic fluid; a high pressure fluid circuit positioned in the cylinder head assembly and in selective fluid communication with and receiving hydraulic fluid from the medium pressure chamber; a control valve positioned in the cylinder head assembly and in fluid communication with the medium pressure chamber and the high pressure fluid circuit; a pump configured to pump hydraulic fluid in the high pressure fluid circuit; and an actuator in fluid communication with the pump, control valve and high pressure fluid circuit, the actuator in engagement with an intake valve of the engine; wherein the control valve is configured to be controlled to selectively block fluid communication between the high pressure fluid circuit and the medium pressure chamber thereby providing for the hydraulic fluid pumped by the pump to displace the actuator to open the intake valve; said system being characterized in that the medium pressure chamber and the actuator are each positioned in the cylinder head assembly at a location higher than the control valve such that during an engine shutdown event, hydraulic fluid is retained in the medium pressure chamber and the control valve, in that the high pressure fluid circuit includes a first fluid passage fluidly coupled between the pump and the control valve, and a second fluid passage fluidly coupled between the control valve and the actuator, the second fluid passage having a valve end coupled to the control valve and an opposite actuator end coupled to the actuator, and in that the second fluid passage is inclined such that the hydraulic fluid flows upwardly in the second fluid passage from the valve end toward the actuator end when the engine is in a level operating position.