Withdrawal

The pistons are made of a special aluminum alloy. Each piston made star-shaped combustion chamber 1 (Fig. 47) and two circular recesses for the valve head. The neck serves prechamber into the combustion chamber of the piston. Two circular recesses (see. Fig. 47) are designed for plates of valves. With their help excluded piston strokes of the valves.

Each set of three piston rings. The top two ring - compression, they prevent the breakthrough of gases from fuel burnt in the engine crankcase. Lower ring - scraper and is intended to remove the oil from the cylinder wall to prevent it from getting into the zone of fuel combustion. The top ring has a rectangular cross section, the middle ring is provided with an internal chamfer and the oil ring is chromed outer surface. Only in this installation sequence piston rings to carry out their functions. The connecting rods connecting the pistons to the crankshaft. The piston pin and connecting rod connects the piston.

After removing the connecting rod bearing caps and liners pistons with rods can be pushed out of the cylinder up with the handle of a hammer. Before performing these works please follow the following instructions below regarding labeling and mounting position of parts.

Pistons and cylinders are divided into three size groups within certain tolerances and have letter designations A, X and Q. These designations are engraved on the cylinder block near the cylinder liner, as shown by arrows A in Fig. 48. Dimensional group of pistons must comply with labeling, applied close to the cylinders.

Also lettering stamped on the bottom of the piston and the 7th and 8th digits of the spare part. In addition, each piston is applied to the arrow with the inscription ?�Vorn?� (?�Before") to indicate the mounting position of the pistons.

To repair the pistons are supplied exclusively with the designation H. These pistons can be used in engines with cylinders symbols A or B.

If there is a need for honing cylinders, they must be ground to size group pistons considering the prescribed working gap.

Each piston and connecting rod must be equipped with tag number of the cylinder from which they were removed. This is best done with paint on the bottoms of the pistons can be applied simultaneously, and arrows to indicate the mounting position of the pistons, as the factory of the arrow may not be visible under a layer of varnish.

When removing the piston rod must always mark the installation position of the connecting rod bearing caps, and after removal of the piston rod - immediately be identified with reference number of the cylinder. This can be accomplished punch (a punch mark - a first cylinder, two labels - a second cylinder, and so on), as shown in Fig. 49.

Bearing shells marked with the connecting rod and connecting rod bearing cap. Upper inserts have holes for lubrication of the piston pin.

Connecting rod inserts may have different diameters. On the underside of the connecting rod bearing caps punch marking - one or two labels (Fig. 50). In the presence of a label should be placed inserts with blue markings installed on the side of the liner. If there are two labels, as shown below, install the inserts without the color marking.

Crankshaft may undergo quadruple polishing. Accordingly, the need to establish appropriate bearing shells, which produce repair sizes differing by 0.25 mm.

Remove bearing covers and inserts, push the pistons of the cylinders with rods. If necessary, remove using a scraper belt sludge formed at the top of the cylinder.

After removing the locking rings to push the piston pin. The incisions in the piston lugs allow us to use a screwdriver (screwdriver must be inserted next to the junction of the retaining ring) or a thin beard to remove the piston pin retaining rings (Fig. 51). Pulling out the piston pin to hold a suitable mandrel.

Remove the piston rings alternately using special forceps, as shown in Fig. 52. If the piston rings to be reused, they should be appropriately labeled. If you do not have the forceps to remove the piston rings, you can use the metal plates inserted under the piston rings on the opposite sides, as shown in Fig. 53. One of the plates have to be inserted at the piston ring zone in the lock, so as not to scratch the piston. In Fig. 54 shows the details after dismantling the piston and connecting rod.