2. Perform an external inspection of the unit for signs of corrosion, cracks and other damage. Check the condition of the threaded 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 found, the unit must be repaired or replaced.
3. Check up a condition of mirrors of cylinders.
4. Estimate the values of the existing taper and ovality of the cylinders:
- a) Measure the diameter of each of the cylinders in the top (directly below the step wear boundary), central and lower sections in a plane parallel to the axis of the crankshaft;
- b) Now measure the diameters at the same three levels, but in a plane perpendicular to the axis of the block;
- c) The value of the taper of the cylinder determines the difference between the results of measurements in the upper and lower sections. Ovality is the difference in diameters in the parallel and perpendicular to the axis of the crankshaft in each of the planes.
- d) Compare test results with nominal values (see specs).
5. Acting in the manner described, check all cylinders one by one.
6. If noticeable defects are detected or the measurement results deviate from the regulatory requirements, the cylinder block is subject to restorative machining in a car service workshop. If the cylinders were bored during the refurbishment, the engine must be equipped with new pistons of the corresponding repair (in excess) size.
7. If the state of the mirrors of the cylinders during the inspection was found to be satisfactory, while at the same time complying with the regulatory requirements for the shape of the cylinders and the clearances of the pistons in them (see Section Checking the condition of the components of the connecting rod and piston group), there is no need to turn the cylinders - it will be enough just to honing their mirrors (see Section Honing cylinder mirrors).
8. Check up flatness of a surface of the block interfaced with a head. Compare the measurement result with the requirements Specifications, if necessary, give the block to the groove.