Crankshaft
The crankshaft has five bearings, with five counterweights. It is possible to regrind the crankshaft journals during repairs with a diameter reduction of 0.25; 0.50 and 0.75 mm.
Main journal diameter, mm:
- nominal: 49.938-49.956;
- maximum permissible (when worn out): 49,890.
Diameter of connecting rod journals, mm:
- b3 and B5 engines;
- nominal: 39,940-39,956;
- maximum permissible (when worn out): 39,89;
- b6 and B6 EGI engines:
- nominal: 44,940-44,956;
- maximum permissible (when worn out): 44,89.
Ovality and taper of the surfaces of the main and connecting rod journals, no more than, mm: 0.05.
Non-straightness of main and connecting rod journals, no more than, mm: 0.04.
Pistons
The pistons are cast from aluminum alloy and have three piston rings.
The piston pin is pressed into the upper head of the connecting rod and rotates freely in the piston bosses. The pin is secured from axial movement by retaining rings.
Piston characteristics
Piston rings
Characteristics of piston rings
* The values in brackets are for the B3 engine.
Piston pins
Engines B3, B5 and B6:
Outside diameter, mm: 19.974-19.980.
Tension between the pin and the upper head of the connecting rod, mm:
- engines B3 and B5: 0.013-0.037;
- b6 engine: 0.013-0.032.
Pressing force, kgf·m: 500-1500.
Engine B6 EGI:
Outside diameter, mm: 19.987-19.993.
Tension between the pin and the piston boss, mm: 0.010-0.027.
Connecting rods
The connecting rod is steel, forged, with an I-section rod and a straight section lower head cover.
Distance between axes of head holes, mm:
- engines B3 and B5: 135.95-136.05;
- engine B6: 132.85-132.95.
Maximum permissible longitudinal bending of the connecting rod, mm: 0.04.
Connecting rod upper head bore diameter, mm:
- engines B3 and B5: 19.945-19.961;
- engine B6: 19.948-19.961.
Connecting rod lower head bore diameter, mm:
- engines B3 and B5: 43,000-43,016;
- engine B6: 48,000-48,016.
Width of the lower connecting rod head, mm: 21.838-21.890.
Clearance between connecting rod and piston, mm:
- nominal: 0.110-0.262;
- maximum permissible (when worn out): 0,30.