produce a new smooth and round surface (although the diameter of the cylinder is slightly increased). Another repair technique is 'sleeving' the cylinder— boring it and then installing a sleeve in the extra space created by the boring. Most engines use 'dry liners', where the liner is surrounded by the engine block and does not make contact with the coolant. However, cylinders with 'wet liners' are used in some water-cooled engines, especially French designs. The wet liners are formed separately from the main casting so that liquid coolant is free to flow around their outsides. The advantage of wet liners is better cooling and a more even temperature distribution, however this design reduces the rigidity of the engine. See also Bore (engine) Cylinder (locomotive) Engine displacement Internal combustion engine Steam engine Stroke (engine) References Engine technology