2. Using a wire brush or fine sandpaper, clean the piston crown of any deposits.
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3. Clean the piston ring grooves using a special tool or a piece of a broken piston ring.
4. After removing all deposits, clean the pistons and connecting rods with solvent and dry them.
5. If the pistons and cylinder walls are not significantly worn and the cylinders have not been bored, there is no need to install new pistons.
6. Carefully inspect all pistons for cracks in the piston skirt and on the surface around the connecting rod pin.
7. Inspect the pistons for scratches, scoring, burnt areas or corrosion.
8. If the piston skirt is heavily scratched, the cause is overheating or abnormal combustion of the fuel mixture. In this case, it is necessary to carefully check the engine lubrication and cooling systems. The presence of a hole in the piston head indicates abnormal combustion of the fuel mixture (its premature ignition occurs). The causes may be a leak from the intake manifold, poor fuel mixture, incorrect ignition timing, or faults in the exhaust system.
9. Corrosion spots on the piston indicate that coolant is leaking into the combustion chamber.
10. Measure the side clearances of the piston rings. If the clearance exceeds the permissible limits, the piston must be replaced.
11. Measure the clearance between the piston and the cylinder by measuring the piston diameter perpendicular to the piston pin and measuring the cylinder diameter. Subtract the piston diameter from the cylinder diameter. If the clearance exceeds the permissible limits, the cylinder must be bored and a new piston and new piston rings must be installed.
12. Check the clearance between the piston and the connecting rod.
13. Inspect the connecting rods for cracks and other damage. For a more detailed inspection of pistons and connecting rods, please contact specialists.
14. Measure the thread length of the connecting rod bolts. On four-cylinder engines, the bolt threads must be no longer than 45 mm, and on six-cylinder engines, no longer than 48 mm, otherwise the bolts must be replaced.