Pic. 447. Measuring the diameter of the cylinder bore. Insert the inside gauge vertically into the cylinder bore and gradually lower it along the cylinder bore in a perpendicular position to the walls
An inside gauge is required to measure cylinder bores (pic. 447). We would like to warn you that it is not easy to use such a device, because if you tilt the measuring tips, you will get incorrect measurement results. If you do not have a bore gauge or you do not know how to use it, then you will not be able to carry out the following work. In this case, it is better to contact the service station.
Measurements of the cylinder bore should be carried out in the longitudinal and transverse directions. Using an inside gauge, measure the cylinder diameter at a distance of 10 mm from the top edge of the cylinder bore, and then at a distance of 10 mm from the bottom edge of the cylinder bore. Take another measurement at the center of the cylinder bore. There will be six measurements in total. Write down all the values obtained and compare them with the data given in the table of adjustments and control. Remember that the bore gauge in the cylinder bore must be at the correct angle, because even the slightest misalignment leads to incorrect measurement results. If the inside gauge is inserted as shown in fig. 447, it may tilt to the right or left while taking measurements. In this case, the arrow of the device will constantly return to the average value, which is what we are talking about when measuring the diameter of the cylinder bore.
Pic. 448. Scheme for measuring cylinder bores. Take measurements in each bore of the cylinder in directions A (transverse measuring direction) and B (longitudinal measuring direction). Measurements should be taken at three locations, namely at depths 1, 2 and 3
Record all 6 results for each cylinder. If you draw a diagram similar to Fig. 448, then for greater clarity, it is better to enter the measurement results into it. The cylinder diameter must nowhere differ by more than 0.08 mm from the nominal size.
Pic. 449. Piston diameter measurement
To measure the piston clearance, measure the diameter of the pistons (pic. 449) and write down the obtained values of all piston diameters. To determine the clearance, calculate the difference between the diameter of the cylinder bores and the diameter of the pistons.
The engine can be fitted with pistons of two enlarged (repair) dimensions, for which it is necessary to bore the cylinder block.
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