Crankshaft
Crankshaft steel, forged. The shaft is five-bearing. The upper main bearing shells have oil grooves. Axial fixation of the crankshaft is carried out by inserts with thrust collars of the bearing of the 3rd main journal.
Main journals diameter, mm:
- nominal: 54.00-0022-0.042
- 1st repair size: 53.75-0022-0.042
- 2nd repair size: 53.50-0022-0.042
- 3rd repair ra. measures: 53.25-0022-0.042
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. A combustion chamber is made in the bottom of the piston. 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 marked on the piston crown and 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.
Depth of recess in the piston bottom, mm:
- YP engine: 6.3;
- YZ engine: 8.3.
Piston dimensions for EP, DT, DS, DZ engines
Note. Since model year 1982, in YP and YZ engines, the piston pin length has been reduced from 63 to 55 mm and the piston surface has been straightened in the area of the piston pin hole. When repairing, install pistons of only one configuration on engines.
Piston pins
The piston pin is floating. From axial movement are kept by two locking rings.
The outer diameter of the piston pins of engines YP, YZ, mm: 21.996-22.000.
Characteristics of piston pins for engines EP, DT, DS, DZ
*Since July 1985, 57 mm long piston pins have been fitted to all engines.
Piston pins are selected depending on the diameter of the hole for the pin in the piston. When assembling, the pin and connecting rod must be assembled from parts of only one size group. This provides the necessary tightness 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 composite. Install the rings on the piston with a mark «top» up (to the bottom of the piston). When installing pistons in cylinders, the locks of the rings must be displaced by 120°.
Piston brand: Maihe or KS.
Piston ring specifications
*The numerator shows data for YP, YZ engines, the denominator for EP, DT, DS, DZ engines.
Connecting rods
Connecting rods are steel, forged, with an I-section rod, 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 YP, YZ: 136;
- engines EP, OT, DS, DZ: 144.
Maximum allowable clearance in operation between the liners and connecting rod journals of the crankshaft, 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.
Upper bushing hole diameter, connecting rod head (engines YP, YZ), mm: 22.017-22.023.
Hole diameter, mm (engines EP, DT, OS, 0Z):
- the upper head of the connecting rod 20.0;
- bottom end of the connecting rod: 50.6.
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