Crankshaft
It is cast from high-strength cast iron and has five bearing (main) journals, hardened by high-frequency currents to a depth of 2-3 mm. At the rear end of the crankshaft there is a socket for installing the bearing of the input shaft of the gearbox.
The connecting rod and main journals of the crankshaft are connected by channels through which oil is supplied to lubricate the connecting rod bearings. The technological outlets of the channels are closed with cap plugs, which are pressed in and, for reliability, calked at three points.
The axial movement of the crankshaft is limited by two thrust half rings installed in the cylinder block on both sides of the rear main bearing (see fig. 51, a). A steel-aluminum half-ring is placed on the front side of the bearing, and a metal-ceramic half-ring is placed on the back side (yellow color). Until 1980, both semicircles (front and back) steel-aluminum ones were installed. Metal-ceramic and steel-aluminum half rings have the same dimensions and are made with a thickness of 2.31-2.36 mm and 2.437-2.487 mm (repair). When assembling the engine, the half rings are selected by thickness so that the axial free play of the crankshaft is within 0.06-0.26 mm.
The crankshaft is balanced separately from the flywheel. Therefore, these parts are interchangeable separately. The crankshafts of the 2101 and 21011 engines are the same and also interchangeable.
To extend the service life of the crankshaft, it is possible to regrind the crankshaft journals when their surfaces are worn or damaged. Grinding reduces the journal diameters by 0.25; 0,5; 0,75; 1.00 mm. In this case, the diameters of the main journals after regrinding should be equal to 50.545-0,020; 50,295-0,020; 50,045-0,020; 49,795-0,020 mm, and the diameters of the connecting rod journals are 47.584-0,020; 47,334-0,020; 47,084-0,020; 46,834-0,020 mm.
Main and connecting rod bearing shells
All of them are thin-walled, bimetallic, steel-aluminum. The liners of the 1st, 2nd, 4th and 5th main bearings have a groove on the inner surface (since 1987, the lower shells of these bearings are installed without a groove). The central (3rd) main bearing shell differs from the other shells by the absence of a groove on the inner surface and by its greater width. All connecting rod bearing shells are grooveless, identical and interchangeable.
The liners of each bearing consist of two identical halves. They are prevented from turning by projections that enter the corresponding grooves of the connecting rod or main bearing.
The nominal thickness of the main bearing shells is 1.831-0,007 mm, and connecting rod bearings 1.730-0,007 mm. The liners of repair sizes are supplied for crankshaft journals, reduced in diameter by 0.25; 0,50; 0,75; 1.00 mm. The thickness of the connecting rod bearing repair liners is 1.855-0,007; 1,980-0,007; 2,105-0,007; 2,230-0,007 mm, and the root ones are 1.956-0,007; 2,081-0,007; 2,206-0,007; 2,331-0,007 mm.
Flywheel
It is fastened to the crankshaft flange with six self-locking bolts, under which one common washer is placed. It is not allowed to replace these bolts with any others. The arrangement of the bolts is such that the flywheel can be fastened to the shaft only in two positions. It must be installed so that the mark - a cone-shaped hole B (see fig. 11) — was located opposite the crankpin of the 4th cylinder. The mark serves to determine the TDC in the first and fourth cylinders. The flywheel is centered with the crankshaft by the front bearing of the input shaft of the gearbox.
The flywheel is cast from cast iron and has a steel toothed ring for starting the engine with a starter. The ring is pressed onto the flywheel while hot. The teeth of the ring are hardened with high-frequency currents to increase wear resistance and strength.