85425ea0 Check of pistons and piston rings

Removal of piston rings

Removing piston rings, try not to scratch the piston.

Profiles of piston rings

Piston rings have different profiles.

The top compression ring has to be established so that the cut was turned up. The tag of TORAHS on the second compression ring also has to be turned up. The oil scraper ring is established by any party.

1. Carefully examine all pistons on existence of cracks on a skirt of the piston and on a surface around a conrod finger. Examine pistons on existence of scratches, zadir, the burned areas or corrosion.
2. By means of the special tool or a piece of the broken piston ring clean flutes of piston rings. After removal of all deposits clear pistons and rods solvent and dry up them.
3. Measure gaps in locks of piston rings. If gaps exceeds admissible limits, rings need to be replaced.
4. Measure a gap between rings and side surfaces of flutes of rings. The gap has to is in limits of 0,075 mm, otherwise replace rings.
5. Measure a gap between the piston and the cylinder, for this purpose measure diameter of the piston perpendicular to a piston finger and measure diameter of the cylinder. Take away diameter of the piston from diameter of the cylinder and divide into two. If the gap exceeds admissible limits, the cylinder needs to be chiseled and installed the new piston and new piston rings. The sizes of the piston are stamped on a piston head.