The invention is directed to a valve actuating device comprising a body with a bore and a bottom, an actuating element sealingly housed in the bore of the body and forming a first chamber with the body, a piston sealingly extending through a bore in the actuating element, the piston and bore delimiting a second actuating chamber, a passage for an auxiliary fluid between the first and second chambers so that a movement of the piston in the bore of the actuating member can increase the pressure in the first chamber and move the actuating element. The fluid passage comprises a restriction and a check-valve, both arranged in parallel, so as to limit the flow of the auxiliary fluid from the second chamber to the first chamber.