7.13. Pistons and rods


Removal of piston rings

Removal of a lock ring of a piston finger

Extraction of a piston finger

Opening for oil in a rod head
On 4-cylinder petrol engines and 6-cylinder SOHC engines the small opening for oil in a head of a rod has to settle down from a driving chain.

Grooves for inserts and a ledge under the piston bottom
On 6-cylinder petrol DOHC engines grooves for inserts (1) have to settle down from an inlet collector, and the ledge (2) under the bottom of the piston has to be from a flywheel.

PERFORMANCE ORDER
1. Before check of pistons with rods remove piston rings from pistons and carefully clear pistons.
2. For removal of piston rings from pistons unclench a ring and insert under a ring evenly on a circle two or three old edges of the probe and on them shift a ring from the piston. Be careful, do not scratch the piston the ends of a ring. Rings very fragile can also burst if to unclench them very strongly. Working edges of piston rings very sharp therefore handle with them very with care not to be cut. You hold each set of rings together with pistons for repeated installation them on the places.
3. Clear all traces of a deposit from the top part of the piston.
4. Remove a deposit from flutes under piston rings in the piston, using an old piston ring.
5. After removal of a raid clear the piston with a rod the corresponding solvent and wipe dry.
6. Carefully examine each piston on existence of cracks around a skirt and openings under a piston finger.
7. Check wear on a piston skirt, an opening in a piston head, and also burned in the top part of the piston.
8. Traces of pointed corrosion on the piston specify that cooling liquid got to the combustion chamber. It is necessary to find the reason of hit of liquid in the combustion chamber and to eliminate it.
9. Measure diameter of the piston.
10. Define a piston gap in the cylinder for what from diameter of the cylinder take away diameter of the piston and divide into two.
11. Check each rod for wear and existence of cracks, and also distortion of a form.
12. Piston fingers are established on the sliding landing and recorded in the piston by two lock rings. On these engines pistons and rods can be divided as follows.
13. Using an edge of the thin screw-driver, remove a lock ring from the piston and a hand squeeze out a piston finger. At repeated installation of a piston finger use only new lock rings.
14. Check a piston finger and the bearing of the top head of a rod for wear.
15. Rods usually do not demand replacement if before it there was no jamming of the engine.
16. Collect pistons with rods as follows (see rice. An opening for oil in a rod head, Grooves for inserts and a ledge under the piston bottom).
17. On 4-cylinder petrol engines and 6-cylinder petrol SOHC engines a small opening for oil in the top part of a rod and an arrow have to be directed to the bottom of the piston to a driving chain.
18. On 6-cylinder petrol DOHC engines grooves for an insert of the conrod bearing in a rod and a cover have to be from an inlet collector, and the arrow has to be directed to the bottom of the piston to a driving chain. The ledge under the bottom of the piston has to be directed to a flywheel.
19. On diesel engines grooves for inserts of bearings have to be in a rod and a cover of a rod from the fuel pump of high pressure, and the arrow has to be directed to the bottom of the piston to a driving chain.
20. Grease a piston finger and implant it into the piston and the top head of a rod. Check that the piston easily and freely turned on a piston finger then record a piston finger new lock rings.