Crankshaft
Cast iron crankshaft, five-bearing with five counterweights. Main journal diameter, mm:
- nominal: 49,940-49,956;
- wear limit value: 0.05.
Diameter of connecting rod journals, mm:
- nominal: 39,940-39,956;
- wear limit value: 0.05.
It is possible to regrind the crankshaft journals during repairs with a diameter reduction of 0.25; 0.50 and 0.75 mm. Crankshaft axial clearance, mm:
- nominal: 0.10-0.15;
- maximum permissible wear clearance: 0.30.
Pistons
The pistons are cast from aluminum alloy. The piston pin is pressed into the upper head of the connecting rod and rotates freely in the piston bosses. Each piston has three rings: two compression rings and an oil scraper ring.
Piston characteristics
Piston rings
Thickness of compression rings, mm:
- top: 1.47-1.49;
- lower: 1.97-1.99.
Clearance between ring and groove, mm:
- upper compression ring: 0.03-0.065;
- lower compression ring: 0.035-0.065.
Maximum allowable gap (when worn out), mm: 0.15.
Gap in the lock, mm:
- upper compression ring: 0.15-0.30;
- lower compression ring: 0.15-0.30;
- oil scraper ring: 0.30-0.90.
Maximum allowable gap (when worn out), mm: 1.0.
Piston pins
Diameter, mm: 19.976-19.988.
Clearance between pin and piston, mm: 0-0.024.
The force of pressing the piston pin into the upper head of the connecting rod, tf: 0.5-1.5.
Connecting rods
Connecting rod, steel, forged, I-section with a straight section lower head cover.
Distance between axes of connecting rod head holes, mm:
- E1 and E3: 141.15-142.25;
- E5: 135.95-136.05.
Maximum permissible longitudinal bending of the connecting rod, %: 0.04.
Hole diameter, mm:
- upper connecting rod head: 19.948-19.961;
- lower connecting rod head: 43.000-43.016.
Width of the lower connecting rod head, mm: 21.838-21.889.
Clearance between connecting rod and piston, mm:
- nominal: 0.110-0.262;
- maximum permissible (when worn out): 0,30.