1. Retaining ring
2. Piston pin
3. Arrow on the piston head
4. Piston
5. Connecting rod
6. Connecting rod mark
Examination
1. Before checking pistons with connecting rods, remove the piston rings from the pistons and thoroughly clean the pistons.
2. To remove the piston rings from the pistons, open the ring and insert two or three old feeler blades evenly around the circumference under the ring and slide the ring off the piston along them.
Warning! Be careful not to scratch the piston with the ends of the ring. The rings are very brittle and can crack if unclenched too much. The piston ring lips are very sharp, so handle them very carefully to avoid cuts. Keep each set of rings with the pistons to reinstall them.
3. Clean all carbon deposits from the top of the piston.
4. Remove carbon deposits from the piston ring grooves in the piston using the old piston ring.
5. After removing deposits, clean the piston with connecting rod with a suitable solvent and wipe dry.
6. Carefully inspect each piston for cracks around the skirt and piston pin holes.
7. Check for wear on the piston skirt, hole in the piston head, and burns on the top of the piston.
8. Pitting marks on the piston indicate that coolant has entered the combustion chamber. It is necessary to find the cause of the liquid entering the combustion chamber and eliminate it.
9. Measure the piston diameter.
10. Determine the piston clearance in the cylinder, for which subtract the piston diameter from the cylinder diameter and divide by two.
11. Check each connecting rod for wear, cracks, and distortion.
12. On all petrol engines, the piston pins are pressed into the upper head of the connecting rod, so the connecting rods must be replaced in a specialized workshop.
13. On diesel engines, the piston pins are fitted with a sliding fit and are fixed in the piston with two circlips. On these engines, the pistons and connecting rods can be separated as follows.
14. Using the blade of a thin screwdriver, remove the retaining ring from the piston and press out the piston pin by hand. When reinstalling the piston pin, use only new circlips.
15. Check the piston pin and connecting rod bearing for wear.
16. Connecting rods usually do not require replacement unless the engine has seized beforehand.
17. On a 1.7L engine, assemble the piston and connecting rod so that the alignment mark on the piston head (arrow) was on the same side as the mark on the connecting rod (arrow).
18. On 2.0L engines, assemble the piston and connecting rod so that the arrow on the piston head points away from the mark on the connecting rod.
19. Lubricate the piston pin and insert it into the piston and connecting rod top end. Check that the piston turns easily and freely on the piston pin, then fix the piston pin with new circlips. Check that each circlip is correctly positioned in the piston groove. On 2.0L engines, install the circlips with their locks facing up.
20. On 2.0L engines, the circlip cut must point up the piston.
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