The main dimensions of the piston, connecting rod, piston pin and piston rings
Piston
The piston is made of aluminum alloy and coated with a layer of tin for improved run-in. The piston skirt is oval in cross section and conical in height. Therefore, it is necessary to measure the piston diameter only in a plane perpendicular to the piston pin and at a distance of 52.4 mm from the piston crown.
The hole for the piston pin is offset from the axis of symmetry by 2 mm to the right side of the engine. Therefore, for the correct installation of the piston in the cylinder, there is a mark near the hole for the piston pin «P», which should face the front of the engine.
Repair size pistons since 1986 for all engine models are manufactured with an outer diameter increased by 0.4 and 0.8 mm. Until 1986, pistons of the following repair sizes were produced: for engines 2101 - with an increase of 0.2, 0.4 and 0.6 mm; for 21011 - with an increase of 0.4 and 0.7 mm.
Piston rings
Piston rings are made of cast iron. The outer surface of the top compression ring is chrome-plated and barrel-shaped. Bottom Compression Ring - Scraper Type (with turning on the outer surface), phosphated. The oil scraper ring has slots for oil removed from the cylinder and an internal coil spring (expander).
Piston pin
Piston pin - steel, tubular section, pressed into the upper head of the connecting rod and rotates freely in the piston bosses.
Connecting rod
Connecting rod - steel, forged, with a split lower head, in which the connecting rod bearing shells are installed. The connecting rod is processed together with the cover, so the numbers on the connecting rod and the cover must be the same when assembling.