Crankshaft
Crankshaft steel, forged. The shaft is five-bearing. The upper main bearing shells have oil grooves. On the cheeks of the shaft there are four counterweights forged together with the shaft. Main journals diameter, mm:
- nominal: 54.00-0,042-0,022;
- 1st repair size: 53.75-0,042-0,022;
- 2nd repair size: 53.50-0,042-0,022;
- 3rd repair size: 53.25-0,042-0,022.
Diameter of connecting rod journals
Axial clearance of the crankshaft, mm:
- nominal: 0.07-0.17;
- maximum allowable: 0.25.
Gap between liners and main journals of the crankshaft, mm:
- nominal: 0.03-0.08;
- maximum allowable (when worn): 0,17.
Pistons
Pistons are made of aluminum alloy with steel inserts. Each piston has two compression rings and one oil scraper ring. To install the piston in the cylinder, there is an arrow 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 maximum allowable deviation of the piston diameter from the nominal size in operation should not exceed 0.04 mm.
Piston outer diameters
Distance from the bottom of the piston to the upper point of the hole for the piston pin in the piston boss, mm:
- engines YN, WV, YP: 30.7;
- DT engine: 25.6;
- DS engine: 22.2;
- engine EP: 27.9.
Depth of recess in the piston bottom, mm:
- engines YN, WV, YP: 6.0;
- DT engine: 2.3;
- DS engine: 4.4;
- engine EP: 0.8.
Piston pin hole diameter, mm:
- engines YN, WV, YP: 22;
- engines DT, DS, EP: 20.
Piston pins
The piston pin is floating. From axial movement, it is held by two retaining rings.
Piston pin length, mm:
- engines EP, DT, DS: 54;
- engine YN: 63;
- engines YP, WV: 55.
External diameter of piston pins, mm:
- engines EP, DT, DS: 20;
- engines YN, YP, WV: 22.
Piston pins are selected depending on the diameter of the hole for the pin in the piston. When assembling, the pin, piston and connecting rod must be assembled from parts of only one size group. This provides the necessary interference between the pin and the piston boss and the clearance between the pin and the bushing of the upper head of the connecting rod.
Piston rings
Three rings are installed on each piston: two compression and one oil scraper. The oil scraper ring is made up of two or three elements.
Piston ring specifications
*The numerator indicates the values for a ring of two elements, the denominator of three.
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.
The distance between the axes of the holes of the upper and lower heads of the connecting rod, mm:
- engines YN, YP, WV: 136;
- engines EP, DT, DS: 144.
The connecting rod cap bolts for EP, DT and DS engines are different from those used for YN, YP and WV engines. These differences are shown in the table.
The M8x1 bolts of the connecting rod caps must be replaced every time the connecting rod is disassembled.
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.
Clearance between the piston pin and the upper head of the connecting rod, mm: 0.003-0.007.
Hole diameter, mm:
- connecting rod head: 20.0;
- bottom end of the connecting rod: 50.6.
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