2. Gently pry the rings out of the grooves. Use two or three old feeler gauges to prevent the rings from springing back into the vacated grooves (pic. 12.2). Be careful not to scratch the piston with the ends of the ring lock. The rings are brittle and if unclenched too much, they will break. In addition, they are very sharp - protect your palms and fingers. Keep in mind that the third (oil scraper) ring built-in spacer (expander). Always remove rings through the top of the piston. If you install «old» rings, store each set of rings with the corresponding piston.
Pic. 12.2. Remove piston rings with a feeler gauge
3. Remove carbon deposits from the top of the piston with a scraper. After removing most of the deposits, you can use a wire brush (or fine sandpaper).
4. Remove carbon deposits from the piston grooves. To do this, use «old» ring. Break the ring in half (be careful not to cut your fingers—piston rings are very sharp). Be careful to only remove carbon deposits - do not remove metal or scratch the sides of the grooves.
5. After removing carbon deposits, clean the piston and connecting rod assembly with kerosene or a suitable solvent and dry thoroughly. Clean the oil return holes (in grooves).
6. If pistons and «mirrors» cylinders are not damaged and do not have increased wear, and the cylinder block does not require cylinder boring (if it is possible), you can replace the original pistons. Normal piston wear shows up as uniform vertical wear on the side pressure surfaces of the pistons and slight slack in the top ring in the corresponding groove. Be sure to use new piston rings when assembling the engine.
7. Carefully inspect each piston for cracks in the skirt, near the piston pin bore, and in the areas between the piston ring grooves.
8. Inspect the piston for holes in the piston head, «burnt» area on the edge of the head and scratches and wear on the skirt. If the skirt is scratched or frayed, the engine may have been overheated and/or abnormal combustion has occurred resulting in an excessively high operating temperature. The cooling and lubrication systems should be carefully checked. Traces of burning on the walls of the pistons indicate a breakthrough of gases. hole in the piston head or «burnt» areas on the edge of the piston head indicate abnormal combustion (pre-ignition or detonation). If any of these defects are present, their causes should be found out and eliminated. Otherwise, the damage will happen again. The reasons may be a malfunction of the injectors or the engine management system.
9. Pitting of the piston indicates coolant seepage into the combustion chamber and/or crankcase. The cause must be eliminated. If this is not done, the problem may also appear on a rebuilt engine.
10. On engines with an aluminum cylinder block with «wet» sleeves cannot be used to replace pistons individually. Pistons are supplied with piston rings and liners only as part of an assembly, all elements of which are supplied together (see paragraph 11). On engines with a cast iron cylinder block, pistons are available from your Peugeot/Citroen dealer or engine rebuilder.
11. Carefully inspect each connecting rod for signs of damage such as cracks near the upper end and lower end bearings. Check if the connecting rod is bent. Unless the engine has been seized or severely overheated, damage is very unlikely. A detailed inspection of the connecting rod assembly should only be performed by a dealer or engine rebuilder with the necessary equipment.
12. Connecting rod bearing cap nuts should be replaced after each unscrewing. Although Peugeot/Citroen does not recommend that the bolts be replaced as well, it is recommended that nuts and bolts be replaced as a set.
13. Piston pins are installed in the bearings of the upper heads of the connecting rods with a press fit. Therefore, the replacement of pistons and/or connecting rods should be entrusted to an engine rebuilder who has the necessary set of tools to remove and install the piston pins.