2. On the top edge of each cartridge case there is a mark in the form of 1-4 lines indicating the size class of the case. The size class is defined as the average diameter of the liner, obtained by measuring at 6 different points, and is used to select the liner for the piston, which also has a marking, but only a letter one. Four classes of piston sizes are designated by letters from "A" to "D", with a piston of class "A" to be used with a liner marked with one line, a piston of class "B" to be used with a liner marked with two lines, etc. The classes of liner and piston sizes are specified in the Specifications.
3. Sleeves must be checked for ovality, taper, abrasion and scratches. Start by inspecting the tops of the shells. If they are worn, there will be a small protrusion at the top of the piston stroke. Wear of the cylinder liners and piston rings can be detected even before disassembling the engine by excessive oil consumption and a blue tint of the exhaust gas.
4. Using an inside micrometer, measure the diameter of the sleeves immediately below the protrusion and compare the obtained value with the diameter of the sleeves in their lower part, which is less subject to wear. Also compare the diameters of the liners in the direction parallel to the direction of the piston pin and at right angles to it to assess the ovality of the liners. The taper and ovality of the sleeves will decrease from the top down to the base.
5. In general, any difference between the obtained values that exceeds 0.25 mm indicates the need to replace the sleeves. If this difference does not exceed 0.25 mm, then it is possible that the excess clearance between the pistons and the cylinder liners can be reduced by installing new piston rings. If the cylinder liners have a lip at the top, the top ring on each piston must have a special recess. Otherwise, the protrusion must be removed using a whetstone. When replacing the liners, it is also necessary to replace the pistons and piston rings.
[Material copied from the resource: peugeotbook]