Abstract: The cylinder liner of an internal combustion engine includes a wet-type upper portion and a dry-type lower portion. The interior wall of the cylinder and the corresponding lower portion of the liner are machined to have an interference fit under operating conditions. The liner is firmly supported by this interference fit engagement of the liner with the cylinder bore over approximately two-thirds the length of the liner. The cylinder wall is machined to provide a shoulder substantially at the junction of the upper and lower portions of the liner and a corresponding shoulder is formed at this point on the liner. These shoulders are forced into firm sealing engagement by the torque applied to the cylinder head screws during asssembly of the cylinder head on the engine block. The vertical dimension of the shoulder on the cylinder liner is formed to be a minimum of 1/8 of the vertical dimension of upper portion of the liner.

Abstract: A centrifugal oil filter assembly has a disposable rotor mounted on a reusable permanent shaft which is screwed into an adaptor mounting the filter to an engine block. A reusable permanent open top filter casing is connected to the support shaft and sealed at its top by a replaceable gasket to a vented top member carried by the adaptor so that by rotating the filter casing the shaft is unscrewed and the rotor (and gasket) can be replaced.