To measure the cylinder diameter, a bore gauge is required, which is first set to the nominal size (see table below).
The bore gauge is inserted approximately 1015 mm below the inner edge of the cylinder.
If, when measuring the diameter of the piston and cylinder, it is found that the working clearance is close to 0.2 mm, then the piston together with the cylinder must be replaced as a set with a new one from the same size class. The difference in mass between the pistons must not exceed 10 g. A piston whose cylinder shows signs of wear must not be replaced separately. But if, on the contrary, the piston is damaged, and there are no signs of wear on the cylinder, then it is enough to install a new piston of the size class corresponding to this cylinder.
Attention! Only cylinders and pistons of the same size class should be installed in the engine. When deciding whether to install new pistons and cylinders, the determining factor, along with the presence of wear marks, is oil consumption. If it exceeds 1 liter per 1000 kilometers, then engine repair is necessary. Pair distribution "cylinder-piston" in three size classes is produced according to the following scheme:
Engine | Piston size class | Label color | Cylinder diameter, mm | Piston diameter, mm |
1200, 1300 | Nominal | Blue | 76,992-77,008 | 76,95 |
Rated 77.0 mm | Pink | 77,002-77,018 | 76,96 | |
1st repair | Blue | 77,492-77,508 | 77,45 | |
Rated 77.5mm | Pink | 77,502-77,518 | 77,46 | |
2nd repair | Blue | 77,992-78,008 | 77,95 | |
Rated 78.0 mm | Pink | 78,002-78,018 | 77,96 | |
1600 | Nominal | Blue | 85,492-85,508 | 85,45 |
Rated 85.5mm | Pink | 85,502-85,518 | 85,46 | |
1st repair | Blue | 85,992-86,008 | 85,95 | |
Rated 86.0 mm | Pink | 86,002-86,018 | 85,96 | |
2nd repair | Blue | 84,492-86,508 | 86,45 | |
Rated 86.5mm | Pink | 86,502-86,518 | 86,46 |
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