2. Perform an external inspection of the block to detect traces of corrosion, cracks and other damage. Check the condition of the threads of the bolt holes. It would also be reasonable to test the block for hidden cracks in a car service workshop using special diagnostic equipment. If defects are detected, the block is subject to restoration repair or replacement.
3. Check the condition of the cylinder mirrors.
4. Estimate the values of the conicity and ovality of the cylinders:
- a) Measure the diameter of each cylinder in the upper (directly below the boundary of stepped wear), central and lower sections in a plane parallel to the crankshaft axis;
- b) Now measure the diameters at the same three levels, but in a plane perpendicular to the block axis;
- c) The cylinder taper value is determined by the difference between the measurement results in the upper and lower sections. Ovality is the difference in diameters in the parallel and perpendicular axis of the crankshaft in each plane.
- d) Compare the test results with the nominal values (see Specifications).
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5. Proceeding in the manner described, check all cylinders in turn.
6. If noticeable defects are detected or the measurement results deviate from the standard requirements, the cylinder block is subject to mechanical restoration in the conditions of the auto service workshop. If the cylinders were bored during the restoration repair, the engine must be equipped with new pistons of the corresponding repair (exceeding) size.
7. If the condition of the cylinder mirrors during the inspection is found to be satisfactory while simultaneously complying with the regulatory requirements for the shape of the cylinders and clearances for the pistons to fit in them (see Section Checking the condition of the connecting rod and piston group components), there is no need to bore the cylinders. It will be enough to simply hone their mirrors (see Section Honing of cylinder mirrors).
8. Check the flatness of the block surface mating with the head. Compare the measurement result with the requirements of the Specifications; if necessary, have the block reground.