Features of the device of the connecting rod and piston group

Pistons are cast from aluminum alloy. The body of the pistons has steel thermostatic rings. In turbocharged engines, the piston skirt has a cutout for the oil jets. Engine pistons «1Z» and «AFN» have a combustion chamber in the bottom in the form of the Greek letter Ω.

The piston diameter is measured at a distance of 10 mm from the lower edge of the piston skirt at an angle of 90°relative to the axis of the piston pin.

Piston diameters are shown in Table 3-2.



Piston pins are hollow, steel, floating type. Piston pins are manufactured with high precision, carburized and hardened. As spare parts, piston pins are only supplied complete with pistons. Three rings are installed on each piston: two compression and one oil scraper. The joints of the compression rings and the components of the oil scraper ring are separated by 120°.

Rings are installed on the piston with a mark «Thor» («Top») to the bottom of the piston. Piston ring specifications are shown in Table 3-3.



Connecting rods are steel, forged, with an I-section rod. A cap of the lower head of a connecting rod of direct section. The maximum permissible gap in operation between the liners and the connecting rod journals is 0.12 mm. The maximum axial clearance of the connecting rod on the crankshaft journal is 0.37 mm. Details of the crank mechanism are shown in fig. 3-8.