The engine oil is drawn in by the sump by means of the vacuum created by the rotation of the gears on the crankshaft.There is a vacuum from the partition (2) for the gears as far as the oil sump suction head.The pressure develops starting from the partition (2) in all the engine supply ducts. (4).When the pressure exceeds 5 bar, the force exerted on the restricter valve (5) overcomes the reaction of the spring underneath and moves the valve until the connecting duct between the pressure chamber (3) and the low pressure chamber (1) opens.
