Today I will explain to you the maintenance of Bitzer 4TC piston, piston pin and piston pin lock ring.
     The piston is divided into top, head and skirt. The main damage of the piston is the wear and carbon deposition of the piston ring groove, the wear of the piston skirt, and the carbon deposition and burning loss of the top of the piston. When overhauling, first visually inspect the piston for burns, scratches, and ring groove edges for broken edges, and then use measuring tools to check the wear and deformation of the piston ring groove and pin holes. The carbon deposits on the top of the piston and in the piston ring groove can be removed and continue to be used. Other technical indicators exceed the limit or have ablation or damage. Because of its low price, it is generally not repaired and replaced with a new piston. The maintenance of the piston is mainly to repair the worn pin hole, or to ream the new piston due to the tight fit between the pin hole and the piston pin.

When the pin hole size of Bitzer 4TC piston does not meet the technical requirements and the wear is less, it can be matched with the piston pin by reaming. Piston pins should be often used for trial fitting when hinged. If the piston pin can be pushed into about 1/3 of the pin hole with one hand, it is suitable. When the processing allowance is very small, the reamer (or round rod) can be wrapped with fine emery cloth for rotary smooth grinding. The surface of the processed pin hole should be smooth and free of tool marks, and the roundness and cylindricity errors should meet the requirements.