Abstract: In a rotary piston type engine including a casing comprising a rotor housing and a pair of side housings, a sealing member disposed between each of the side housing and the rotor housing for sealing combustion gas from working chambers and engine cooling liquid from coolant passage means in said housings, said sealing member comprising a rubber body and a heat resistant layer integrally moulded with the rubber body and disposed to face the working chamber so as to protect the rubber body against the heat of combustion gas.

Abstract: A seal means which is mounted in a groove means provided between the working chamber and coolant flow passages of a rotary piston engine and is constituted by a main member which is compressively flexed between the groove means and the opposite mating surface of a housing, a first backup element made of a flexible material and a second backup element made of a metal which are provided on the outer side of the main member, and a heat-resistant element which is provided on the inner side of the main member, the first and second backup element preventing movement of main member portions into any gap formed between housing mating surfaces at an interface, whereby the main member is protected from wear and the service life of the seal means is increased.