The only way the inspection process can take place successfully is if the PF/sometimes with con-rods requires cleaning and the removal of the factory fitted piston rings accompanied by the fitting of new rings each time. Carefully take out the rings from the pistons using a piston ring installation tool without scratching on them. Clean off all the carbon from the top of the piston with a handheld wire brush or fine emery paper the use of a wire brush mounted motor erodes the piston material which is soft. A piston ring groove cleaning tool should be used to clean carbon deposits on the ring grooves or a piece detached from a previous ring should do, ensure you do not harm the grooves. When you have done this, use solvent to clean the piston/rod assemblies and blow dry with compressed air and make sure that the oil return holes are free. If the pistons and cylinder walls are not damaged or excessively worn out and the engine block not rebored for a new bore, new pistons may not be required though new piston rings should always be fit when a rebuil Critical areas to look at every single piston are cracks, scores, scuffs, holes, and burn areas, as these might show signs of overheating and or abnormal combustion, so the cooling and lubrijoint systems must then be checked carefully. Small pitting corrosion indicate leakage of coolant which, should not be repeated in the future. The piston ring side clearance should be checked with a feeler gauge, compared to the standard, and should be measured at different locations, the correct ring to be used has to fit each groove, if the clearance is too large new pistons may be needed. Inspect the piston-to-bore size by measuring the bore size and the piston size and doing a calculation for the clearance size; if it is large do rebore the block and fit new pistons and rings. Twist the piston and rod in opposite directions: there should be some distinct play indicative of wear to be addressed by seating, and a new pin, very likely at an automotive machine shop. If pistons must be withdraw from the connecting rods get them to a machine shop for checking for bend and twist. Before replacing the bearings and tightening the caps inspect the connecting rods for cracks and damage by removing the rod caps and old bearing insert, clean the surface of the rods in order to check if there are nicks or scratch. In case of reinstruction caused by connecting rod knock, new rods should be fitted.