(1) Piston and piston ring leakage fault characteristics

The fit between the piston and the cylinder wall clearance is directly related to the engine's maintenance quality and service life. During engine maintenance and inspection, put the piston upside down in the cylinder bore, and insert a gauge of appropriate thickness and length into the cylinder at the same time. When the side pressure is applied, the cylinder wall and the piston are in line with the thrust surface of the piston. Use a spring balance to press the specified pulling force to It is appropriate to pull out the thickness gauge gently, or first measure the diameter of the piston skirt with an outside micrometer, and then measure the cylinder diameter with a cylinder bore gauge. The cylinder bore minus the outside diameter of the piston skirt is the fit clearance.

(2) Diagnosis and troubleshooting of piston and piston ring leaks

Put the piston ring flat in the cylinder, push the ring flat with the old piston (when changing the ring for minor repairs, push it to the position where the next ring moves to the low point), and measure the opening gap with a thickness gauge. If the opening gap is too small, use a fine file to file a little at the opening end. Frequent inspections should be made during file repair to prevent the opening from being too large, and the opening should be flat. When the ring opening is closed for testing, there should be no deflection; the filed end should be free of burrs. Check the backlash, put the piston ring in the ring groove and rotate, and measure the gap with a thickness gauge without issuing a pin. If the clearance is too small, place the piston ring on a flat plate covered with emery cloth or a glass plate covered with sand valve and grind thin. Check the backlash and put the piston ring into the ring groove, the ring is lower than the groove bank, otherwise the ring groove should be turned to a proper position.