Dingbo Power Generation Equipment will be continue to introduce the inspection, selection, and repair methods for the pistons of diesel generator sets.
4. Inspection and adjustment of compression chamber height
(2) The method for checking the height of the compression chamber is to place a lead block or lead wire (the thickness or diameter of the selected lead block or lead wire should not be less than the specified compression chamber height, but should not be too large, generally 1.5 to 2 times larger than the specified compression chamber height) on the piston crown (pay attention to avoiding the valve), tighten the cylinder head to the specified torque, then slowly rotate the crankshaft to make the piston pass through the top dead center, and finally take out the lead block (or lead wire), Use a micrometer to measure its thickness, which is the height of the compression chamber.
Note: The height of the compression chamber must be checked after the connecting rod bearing bush is repaired. The measured height of the compression chamber cannot exceed 5% of the specified value of the original machine.
(3) There are usually two methods for adjusting the height of the compression chamber. One is to use the thickness of the cylinder pad to adjust. The cylinder pad is thickened, and the height of the compression chamber rises; The cylinder cushion is thinned and the compression chamber height decreases. The other is to adjust the thickness of the gasket between the connecting rod bearing shells, thicken the entire piece, and decrease the height of the compression chamber; The gasket is thinned and the compression chamber height rises. The latter method is commonly used for adjusting the height of the compression chamber, while the former method is commonly used for adjusting the height of the compression chamber of diesel generator sets.
5. Piston selection. The selection of pistons for diesel generator sets should be determined based on the repair dimensions of the cylinders. Since the cylinders have six repair dimensions, the pistons also have corresponding six repair dimensions (mm): 0.25, 0.50, 0.75, 1.00, 1.25, and 1.50. When selecting pistons, it should be noted that a diesel generator set should use pistons of the same brand in groups to ensure consistent materials, performance, weight, and dimensions. The diameter difference of the same group of pistons shall not be greater than 0.025 mm; The weight difference of each piston shall not exceed 1% to 1.5% of its own weight. Each model has clear regulations.
6. Piston repair
(1) If the wear of the piston skirt of a diesel generator set, and the out-of-roundness and taper of the piston skirt are greater than the specified values, they should be replaced.
(2) When the wear of the piston ring groove widens, making the side clearance of the diesel generator set piston ring greater than the specified allowable value, the piston ring groove can be turned on a lathe according to the enlarged piston ring.
(3) When the wear of the piston pin seat hole exceeds the specified value, the pin hole should be reamed to the repair size with a reamer, and an oversized diesel generator set piston pin should be installed.
(4) The piston should be replaced when it comes off the top and the skirt is severely strained.
(5) When repair conditions are not available, it is usually resolved by replacing standard size pistons or cylinders (sleeves).
The above are the relevant knowledge about the inspection, selection, and repair of diesel generator set pistons compiled by Guangxi Dingbo Power Equipment Manufacturing Co.,Ltd. When you encounter similar problems, you can compare and solve them.
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