2. Visually inspect for cracks, rust and corrosion. Look for stripped threads in the threaded holes. It is advisable in a mechanical workshop with special equipment to check the block for hidden cracks. If defects are found, the unit, if possible, should be repaired; if not, a new unit must be purchased.
3. Check cylinder surfaces for wear and gouges.
4. Measure the diameter at the top of each cylinder (immediately below the ledge zone - A), in the middle - B and lower - C parts parallel to the axis of the crankshaft.
5. To determine the diameter of the cylinder, check the length of the gauge with a micrometer
6. Next, measure the cylinder diameter at the same levels in a direction perpendicular to the axis of the crankshaft. Compare results with requirements Tables of sizes and adjustment data at the end of the Guide.
7. If precision measuring tools are not available, then the clearances between pistons and cylinders, although not as accurately, can be determined using feeler gauges.
8. To determine the gaps, select a feeler gauge and insert it into the cylinder along the mating piston. The piston must be installed exactly in the normal position. The feeler gauge must be installed between the piston and the cylinder on one of the thrust surfaces (90°to the finger hole). The piston must pass through the cylinder) dipstick installed) with little effort.
9. If the piston slides down easily, the clearance is large and a new piston will be required. If the piston is stuck at the bottom of the cylinder and moves more freely at the top, then the cylinder is tapered. If, when the piston rotates along with the probe, areas of resistance appear in the cylinder, then the cylinder has an ovality.
10. Repeat the operation for the remaining pistons and cylinders.
11. If the cylinder walls are severely worn or grooved, or if they are tapered or oval above the limits in Table of sizes and adjustment data at the end of the manual, the cylinder block must be ground and honed in a machine shop. After grinding, oversized pistons and rings will be required.
12. If the cylinders are in good enough condition and do not have wear beyond tolerances, and if the clearances between the cylinders and pistons are maintained in the norm, then they should not be ground. All it takes is honing and a new set of rings (see Section Cylinder honing).