It is carried out by circulating fresh water between the outer surface of the liner and the cylinder jacket or sleeve in which it is supported. The water space extends over the upper part length of the liner. Silicone rubber rings placed in grooves in the liner create a watertight seal at the bottom while still enabling the liner to be thermally expanded. The upper end is sealed by the landing of the liner flange.
water enters at the lower end of the jacket, following upwards and leaving at the top to pass on to call the cylinder cover. Passage may be fitted within the cooling spaces to ensure positive circulation and assist venting of any entrained air.
For large engines these consist of individual iron castings,supported on the engine farming or entablature and bolted together to form a rigid block into which the cylinder liners are fitted.The jacket are held in compression by the tie bolts.
In smaller engines the jacket may be formed in one large casting or fabricated in box firm and termed the cylinder block.It may act as the main strength member of the engine construction.cleaning access to the cooling spaces must be provided.