Crankshaft
The crankshaft is steel, forged. The shaft has five bearings. There are lubrication grooves in the upper shells of the main bearings. There are eight counterweights on the decks of the shaft, forged together with the shaft.
Main journal diameter, mm:
- nominal: 54.00-0,022-0,042
- 1st repair size: 53.75-0,022-0,042
- 2nd repair size: 53.50-0,022-0,042
- 3rd repair size: 53.20-0,022-0,042
Diameter of connecting rod journals, mm:
- nominal: 47.80-0,022-0,042
- 1st repair size: 47.55-0,022-0,042
- 2nd repair size: 47.30-0,022-0,042
- 3rd repair size: 47.05-0,022-0,042
Crankshaft axial clearance, mm:
- nominal: 0.07-0.17.
- maximum: 0.25.
Clearance between liners and crankshaft journals, mm:
- nominal: 0.03-0.08;
- maximum permissible in operation: 0.17
Pistons
The pistons are made of aluminum alloy with steel inserts. Each piston has a compression ring bottom and one oil scraper ring. To install the piston in the cylinder, there is a heater on the bottom, which should be facing the camshaft drive. The piston diameter is measured at a distance of 15 mm from the edge of the piston skirt at an angle of 90° relative to the axis of the piston pin. The deviation of the piston diameter from the nominal size should not exceed 0.04 mm.
Piston diameter, mm:
- nominal: 80.98;
- 1st repair size 81.23;
- 2nd repair size 81.48;
- 3rd repair size 81.98.
Distance from the piston bottom to the top point of the piston pin hole in the piston boss, mm:
- for engine "DR": 30.80;
- for engine "DS": 22.20.
Depth of recess in piston bottom, mm:
- for engine "DR": 7.90;
- for engines "DS" and "NP": 4.40.
Piston pins
The piston pin is floating. It is held from axial displacement by two retaining rings.
Piston pin length, mm: 54.
Since July 1985, the piston pin length has been increased from 54 to 57 mm. The grooves for the retaining rings in the piston pin holes have been shifted accordingly. When repairing, only pistons and pins of the same configuration should be installed.
Piston rings
Each piston has three rings: two compression rings and one oil scraper ring.
Characteristics of piston rings
Connecting rods
Connecting rods are steel, forged, with an I-section rod with thin-walled liners. A bushing is pressed into the upper head of the connecting rod.
There are technological lugs on the lower head and the connecting rod cap, showing how to install them correctly. The lugs should be directed towards the camshaft drive.
Maximum permissible clearance during operation between the liners and the crankshaft journals, mm: 0.12.
Maximum axial clearance of the connecting rod on the crankshaft journal, mm: 0.37.
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