Crankshaft
The crankshaft is steel, forged. The shaft has five bearings. There are lubrication grooves in the upper liners of the main bearings. The axial fixation of the crankshaft is carried out by liners with thrust flanges of the bearing of the 3rd main journal.
Main journal 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 size: 53.25 -0022-0,042
Diameter of connecting rod journals
Crankshaft axial clearance, mm:
- nominal: 0.07-0.17;
- maximum permissible: 0.25.
Clearance between liners and main journals of the crankshaft, mm:
- nominal: 0.03-0.08;
- maximum permissible (when worn out): 0,17.
Pistons
The pistons are made of aluminum alloy with steel inserts. The piston bottom has a combustion chamber. 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 should face the camshaft drive. The piston diameter is marked on the piston bottom 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 permissible deviation of the piston diameter from the nominal size during operation should not exceed 0.04 mm.
Depth of recess in piston bottom, mm:
- engine YP: 6.3;
- yZ engine: 8.3.
Piston sizes for EP, DT, DS, DZ engines
Note: Since the 1982 model year, the YP and YZ engines have had their piston pin length reduced from 63 to 55 mm and the piston surface in the piston pin bore area has been straightened. Only pistons of one configuration may be installed on engines when overhauled.
Piston pins
The piston pin is floating. It is held from axial movement by two retaining rings.
Outer diameter of piston pins of YP, YZ engines, mm: 21.996-22.000.
Characteristics of piston pins of engines EP, DT, DS, DZ
*Since July 1985, all engines are equipped with 57 mm long piston pins.
Piston pins are selected depending on the diameter of the hole for the pin in the piston. When assembling, the pin and connecting rod are assembled from parts of only one size group. This ensures the necessary tension between the pin and the piston boss and the gap between the pin and the bushing of the upper connecting rod head.
Piston rings
Each piston has three rings: two compression rings and one oil scraper ring. The oil scraper ring is composite. The rings should be installed on the piston with the "top" mark facing up (to the piston bottom). When installing pistons into cylinders, the ring locks must be offset by 120°.
Piston brand: Maihe or KS.
Characteristics of piston rings
*The numerator contains data for YP, YZ engines, the denominator contains data 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 lower head and the connecting rod cover, showing how to install them correctly. The lugs should be directed towards the camshaft drive.
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 permissible clearance during operation between the liners and the 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 piston pin and upper connecting rod head, mm: 0.003-0.007.
Upper bushing hole diameter, connecting rod head (yP, YZ engines), mm: 22.017-22.023.
Hole diameter, mm (engines EP, DT, OS, 0Z):
- upper connecting rod head 20.0;
- lower connecting rod head: 50.6.