Crankshaft
Crankshaft steel, forged. The shaft is six-bearing. The upper main bearing shells have oil grooves. On the cheeks of the shaft there are ten counterweights, forged together with the shaft.
Diameters of the main journals of the crankshaft, mm:
- nominal: 58.00-0.022-0.042
- 1st repair: 57.75-0.022-0.042
- 2nd repair: 57.50-0.022-0.042
- 3rd repair: 57.25-0.022-0.042
The diameter of the connecting rod journals of the crankshaft, mm:
- nominal: 46.00-0.022-0.042
- 1st repair: 45.75-0.022-0.042
- 2nd repair: 45.50-0.022-0.042
- 3rd repair - 45.25-0.022-0.042
Axial clearance of the crankshaft, mm:
- nominal: 0.07-0.18;
- maximum: 0.25.
Gap between liners and crankshaft journals, mm:
- nominal: 0.016-0.075;
- maximum permissible in operation: 0.16.
Pistons
Pistons are made of aluminum alloy with steel inserts. Each piston has two compression rings and one oil scraper ring. For the correct installation of the piston in the cylinder, there is an arrow on the bottom, which must be facing the 8th side of the camshaft drive. Measure the piston diameter at a distance of 10 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.
Basic piston dimensions
Piston pins
The piston pin is floating. From axial movement, 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.
Clearance in the lock of piston rings, mm:
- nominal: 0.25-0.50;
- maximum allowable: 1.00.
Gap between piston ring and groove, mm:
- nominal: 0.02-0.08;
- maximum allowable: 0.10.
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 on the connecting rod cap showing how to install them correctly. The tides should be directed to the 8th side of the camshaft drive.
Gap between liners and crankshaft journals, mm:
- nominal: 0.015-0.062;
- maximum permissible in operation: 0.12.
Maximum axial clearance of the connecting rod on the crankshaft journal, mm: 0.4.
The distance between the axes of the holes of the connecting rod heads (model engine «NF»), mm: 144.
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