Abstract: A mounting to hang an engine to a frame, adapted to insulate the frame from predetermined high-frequency and small-amplitude vibrations. The mounting comprises an envelope, a cover in the form of an elastomeric diaphragm associated with the side walls of the envelope, a pin adapted to receive the engine weight, engagement parts connecting the envelope to the frame. The mounting is comprised of a rocking system consisting of two masses and three elastomeric bodies with rigidities K2, K3, K4. The two masses are connected to each other by one elastomeric body and are in parallel to the elastomeric diaphragm being connected to the pin and envelope by interposition of the two other elastomeric bodies. The diaphragm and the parallel system when high-frequency and small-amplitude vibrations occur, give rise to a dynamic rigidity defined by two peaks and a valley therebetween; one of the peaks has a lower height than the other.