Crankshaft
Crankshaft - steel, forged. The shaft is five-bearing. The upper main bearing shells have oil grooves. On the decks of the shaft there are eight counterweights forged together with the shaft.
Main journals 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
Axial clearance of the crankshaft, mm:
- nominal: 0.07-0.17.
- maximum: 0.25.
Gap between liners and crankshaft journals, mm:
- nominal: 0.03-0.08;
- maximum allowable in operation: 0.17
Pistons
Pistons are made of aluminum alloy with steel inserts. Each piston has a compression bottom and one oil scraper ring. To install the piston in the cylinder, there is a heating pad on the bottom, which must be turned towards 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 bottom of the piston to the upper point of the hole for the piston pin in the piston boss, mm:
- for engine «DR»: 30,80;
- for engine «DS»: 22,20.
Depth of recess in the piston bottom, mm:
- for engine «DR»: 7,90;
- for engines «DS» And «NP»: 4,40.
Piston pins
The piston pin is floating. From axial shifting, it is held by two retaining rings.
Piston pin length, mm: 54.
Since July 1985, the length of the piston pin has been increased from 54 to 57 mm. Accordingly, the grooves for the retaining rings in the holes for the piston pin are shifted. When repairing, only pistons and fingers of the same configuration should be installed.
Piston rings
Three rings are installed on each piston: two compression and one oil scraper.
Piston ring specifications
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 bottom head and connecting rod cap showing how to install them correctly. The tides should be directed towards the camshaft drive.
Maximum allowable clearance in 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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