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Pic. 3: 1. Crankshaft. 2. Cover of the first main bearing. 3. The holder of a forward epiploon of a cranked shaft. 4. The lower protective cover of a gear belt. 5. Toothed pulley of the crankshaft. 6. Crankshaft pulley. 7. Crankshaft pulley key. 8. Ratchet. 9. Camshaft drive cover. 10. Medium toothed belt guard. 11. Fan drive belt, coolant pump and alternator. 12. Alternator pulley. 13. Oil pump drive shaft and ignition distributor 14. Oil pump drive pulley and ignition distributor 15. Engine cooling fan. 16. Cylinder block. 17. Toothed belt tensioner. 18. Camshaft timing belt. 19. Cylinder head. 20. Camshaft pulley. 21. Top protective cover of the toothed belt. 22. The holder of an epiploon of a camshaft. 23. Mounting protrusion on the camshaft bearing housing. 24. Exhaust valve. 25. Inlet valve. 26. Camshaft bearing housing. 27. Camshaft. 28. Valve drive lever. 29. Oil filler neck of the cylinder head cover. 30. Cylinder head cover gasket. 31. Cylinder head cover. 32. Coolant temperature indicator sensor. 33. Spark plug. 34. Piston pin. 35. Flywheel with gear rim assembly. 36. The holder of a back epiploon of a cranked shaft. 37. Thrust half ring of the crankshaft. 38. Front engine mount. 39. Rear engine mount. 40. Front cover of the clutch housing 41. Oil sump. 42. Front support bracket. 43. Front support spring. 44. Buffer pillow front support. 45. Rubber pad front support. 46. Piston. 47. Oil level gauge 48. Connecting rod with cover assy. 49. Oil sump drain plug. 50. Bushings of the oil pump drive shaft and ignition distributor.
The cars are equipped with a four-cylinder, four-stroke model 2105 carburetor engine with a camshaft belt drive. On some cars, the 21011 engine with a camshaft chain drive can be installed. This album describes the 2105 engine.
The layout of the engine is simple and easy to maintain. All components requiring adjustment and maintenance (ignition distributor, spark plugs, carburetor, air filter, etc.), installed in easily accessible places.
The engine cylinders are integrated together with the upper part of the crankcase and are a single casting of the cylinder block. This arrangement provides structural strength, rigidity, compactness, reliability and reduces the weight of the engine. A crankshaft is mounted on five bearings at the bottom of the cylinder block. The front and rear ends of the crankshaft are sealed with self-clamping rubber seals. Pistons 46 have two compression rings and one oil scraper with an expanding spring. The piston is connected to the connecting rod with a piston pin pressed into the upper head of the connecting rod. For each engine cylinder, there is one inlet and one exhaust valve, which are driven by a camshaft 27 mounted on the cylinder head in an aluminum bearing housing 26. The top location of the camshaft allows you to reduce the weight of reciprocating moving parts and thereby ensure high reliability. gas distribution mechanism at a high engine speed.
The camshaft is driven by the crankshaft using a toothed belt 18. The valves are driven by special levers 28.
The engine assembly with the clutch and gearbox forms a power unit and is mounted on the vehicle on three elastic supports. The supports perceive both the mass of the power unit and the loads that occur when the car starts off, accelerates and brakes. The suspension design of the power unit ensures minimal engine vibrations and eliminates the transmission of its vibrations to the body.
With two front supports 38, the engine is attached to the cross member of the front suspension of the vehicle, and the rear 39 is attached to the cross member of the rear engine mount.
The front supports have rubber cushions 45, in which steel washers with fastening bolts are vulcanized. To increase rigidity, there are springs in the hole inside the pillows, and buffers 44 are used to limit the strokes, which are a rubber rod with a vulcanized steel bushing.
The front support pillows are attached to the intermediate plates, and those, in turn, to the brackets 42 of the front engine mount. The brackets are secured to the cylinder block flange with four studs. To protect the right cushion from the hot exhaust pipe of the mufflers, a protective cover is installed under it.
The rear support 39 consists of three steel plates vulcanized to the rubber separating them. The upper plate is attached to the rear cover of the gearbox, and the lower ones to the cross member of the rear engine mount. To prevent crumpling of the cross member shelves when tightening the support mounting bolts, spacers are installed between the shelves.
Cylinder block 16 is the basic part of the engine and serves to install and fasten mechanisms, devices and auxiliary units of the engine. The block is cast from special low-alloy cast iron. To increase rigidity, the lower plane is lowered 50 mm below the crankshaft axis.
The cylinders of the block are subdivided by diameter through 0.01 mm into five classes, denoted by the letters A, B, C, D and E. The cylinder diameters corresponding to these classes are as follows, mm:
- A - 79.000-79.010
- B - 79.010-79.020
- C - 79.020-79.030
- D — 79,030-79,040
- E - 79.040-79.050
The cylinder class is indicated on the bottom plane of the block against each cylinder. The cylinder and the piston mating with it must be of the same class. During repair, cylinders can be bored and honed to fit a larger piston diameter (by 0.4, 0.8 mm) taking into account the clearance between the piston and the cylinder of 0.05-0.07 mm.
For the repair of the crank mechanism, parts of repair dimensions are produced: pistons and piston rings, increased in diameter by 0.4 and 0.8 mm; liners of main and connecting rod bearings for crankshaft journals, reduced in diameter by 0.25; 0.5; 0.75 and 1.00 mm.
In the lower part of the cylinder block there are five crankshaft main bearing supports with thin-walled steel-aluminum liners. Bearings have removable covers 2, which are attached to the block with self-locking bolts. The holes for the crankshaft bearings in the cylinder block are machined complete with covers. Therefore, bearing caps are not interchangeable and marks are made on their outer surface to distinguish them. For the caps of the first four bearings, the number of marks corresponds to the number of the cap. On the fifth cover there are two risks with a large gap between them. Bearing supports and their corresponding covers are measured from the front end of the cylinder block.
On both sides of the rear main bearing, sockets are machined for installing thrust half rings 37 that hold the crankshaft from axial movement. A steel-aluminum semi-ring is placed on the front side of the bearing, and a metal-ceramic semi-ring on the back side (yellow color), oil soaked. It should be borne in mind that the grooves located on one side of the half rings must face the thrust surfaces of the crankshaft.
The value of the axial clearance of the crankshaft when assembling the engine is provided in the range of 0.06-0.26 mm. If the clearance in operation exceeds the maximum allowable (0.35 mm), it is necessary to replace the thrust half rings with new or repair ones, increased by 0.127 mm.
In front of the cylinder block there is a cavity for driving the gas distribution mechanism, separated from the crankcase by three seals and. The cavity is closed with three plastic covers 4, 10 and 21. On the rear side, a holder 36 of the rear oil seal is attached to the cylinder block.
On the left side, an oil filter and a fuel pump are attached to the cylinder block, a crankcase ventilation system and an oil pressure sensor are installed. On the right side, a coolant pump and a generator are installed on the cylinder block. An ignition distributor is installed on the upper plane of the block in its front left part.
From below, the cylinder block is closed with a stamped steel crankcase 41. The crankcase has a baffle to calm the oil. Between the crankcase and the cylinder block, a cork-rubber mixture gasket is installed. A plug 49 is provided for draining oil from the crankcase. A permanent magnet is installed in the plug, which attracts small steel particles that have fallen into the oil during engine operation.
The cylinder head 19 is common for four cylinders, cast from an aluminum alloy, with wedge-shaped combustion chambers made above each cylinder. Each chamber has a threaded hole for a spark plug. On the left side in the front and rear of the cylinder head there are channels for draining oil into the oil sump. Valve seats made of special cast iron are pressed into the head to provide high impact strength. The intake valve seat is larger than the exhaust valve seat. Seat chamfers are machined after pressing into the cylinder head assembly to ensure exact alignment of the chamfers with the holes in the valve guides.
The valve guides are also made of cast iron and are pressed into the cylinder head with an interference fit. In the holes of the guide bushings, helical grooves are cut for lubrication. The inlet valve bushings are grooved up to half the length of the hole, and the exhaust valve bushings are grooved along the entire length of the hole.
Between the head and the cylinder block there is a gasket made of asbestos material on a metal frame and impregnated with graphite. On the edges of the holes for the cylinders, the gasket has a mild steel edging. The opening of the oil supply channel to the camshaft is edged with copper tape. To prevent the gasket from sticking to the block and cylinder head, it is recommended to rub it with graphite before assembly.
The cylinder head is attached to the cylinder block with eleven bolts. For a uniform and tight fit of the head to the cylinder block and to prevent warping, the bolts must be tightened on a cold engine in two steps using a torque wrench and in a strictly defined sequence (from the center to the periphery to the left and right alternately). In the first step, the tightening is carried out pre-tightening torque of approximately 39.2 Nm (4 kgf·m). In the second step, the final tightening is performed with a torque of 112.7 N·m (11.5 kgf·m).
The cylinder head bolts should be tightened after the first 2000-3000 km run, and later after the removal of the cylinder head or when there are signs of gas breakthrough or coolant flow between the block and the cylinder head.
From above, the cylinder head is closed with a cover 31. The cover is cast from aluminum. In the upper part of the cover there is a neck for pouring oil into the engine. A gasket is installed between the cylinder head and the cover to eliminate oil leakage. The cover is attached to the cylinder head with studs and nuts.