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1. A bolt of fastening of a cover of a rod. 2. Cover of the first main bearing. 3. Crankshaft. 4. Main bearing shell. 5. Pulley key and crankshaft sprocket. 6. Ratchet 7. Front crankshaft oil seal. 8. Insert connecting rod bearing. 9. Crankshaft pulley. 10. Alternator pulley. 11. Connecting rod. 12. Cylinder block. 13. Engine cooling fan. 14. Timing mechanism drive cover. 15. Fan drive belt, water pump and generator 16. Piston pin. 17. Piston. 18. Timing mechanism drive chain. 19. Cylinder head. 20. Camshaft sprocket bolt. 21. Camshaft sprocket. 22. Mounting ledge. 23. Camshaft. 24. Camshaft bearing housing. 25. Oil filler cap. 26. Coolant temperature indicator sensor. 27. Spark plug. 28. Front engine mount. 29. Rear engine mount. 30. Oil level indicator. 31. Flywheel. 32. Oil pressure indicator sensor (VAZ-2103). 33. Low oil pressure warning light sensor. 34. Front support cushion buffer. 35. Rubber pad front support. 36. Front support bracket. 37. Plug hole for draining oil from the crankcase. 38. Oil sump. 39. Oil scraper ring. 40. Lower compression ring. 41. Upper compression ring, a - alignment mark; b - hole for supplying oil to the cylinder walls; c - channel for supplying oil to the chain; g - installation mark.
The cars are equipped with four-cylinder, four-stroke carburetor engines with different cylinder sizes.
The layout of the engines is simple and easy to maintain. All engine components requiring adjustment or maintenance (ignition distributor, spark plugs, carburetor, air filter, valve lever adjusting screws, chain tensioner nut, oil filter, alternator), installed in easily accessible places.
The engine cylinders are combined with the upper part of the crankcase and are a single casting - the cylinder block. This arrangement provides structural strength, rigidity, compactness, reliability and reduces the weight of the engine. Each engine cylinder has one intake and one exhaust valve.
Pistons 17 have two compression rings 40 and 41 and one oil scraper 39 with a spring. The piston is connected to the connecting rod 11 by a piston pin 16 pressed into the upper head of the connecting rod.
The camshaft 23 is mounted on the cylinder head in the housing 24 and is driven from the crankshaft by a double-row roller chain 18. The advantages of the drive are its simple design and lighter weight compared to other types of gears.
Cylinder block 12 is the basic part of the engine and serves to install and fasten the mechanisms, devices and auxiliary units of the engine. The block is cast from special low-alloy cast iron. The coolant channels are made along the entire height of the cylinders, which improves the cooling of the pistons and piston rings and reduces block deformation from uneven heating.
To increase the rigidity of the engine, the lower plane of the block is lowered 50 mm below the axis of the crankshaft. The cylinders of the block are divided by diameter into five classes through 0.01 mm, denoted by the letters A, B, C, D, E. The class of cylinders is indicated on the bottom plane of the block opposite each cylinder. The cylinder and the piston mating with it must be of the same class. When repairing the block, the cylinders can be bored and honed to fit the increased piston diameter (by 0.2—0.4—0.6 mm) taking into account the clearance between the piston and the cylinder, equal to 0.05 0.07 mm.
In the lower part of the cylinder block there are five supports of the crankshaft main bearings with thin-walled steel-aluminum liners 4. The 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 have marks on the outer surface to distinguish them. Bearing supports and their corresponding covers are measured from the front end of the cylinder block.
On the left side of the block, the oil pump drive shaft, ignition distributor and fuel pump are installed. Collapsed steel-aluminum bushings are pressed into the holes for the roller bearings. Their joint processing in the block provides the necessary alignment of the bearings. When checking the technical condition and repairing the block, it is necessary to monitor the coincidence of the lubrication hole in the front bush with the channel in the cylinder block.
In front of the cylinder block there is a cavity for the timing chain drive. This cavity is closed by cover 14. On the rear side, a rear oil seal holder is attached to the cylinder block. Self-clamping seals are installed in the cover 14 and the holder.
On the left side, an oil filter, a fuel pump are attached to the cylinder block, a crankcase ventilation system and an electric oil pressure sensor 33 are installed. The VAZ-2103 car engine is additionally equipped with an oil pressure indicator sensor 32. On the right side, a water pump and a generator are installed on the cylinder block. In the lower part of the cylinder block on the right and left sides there are lugs for mounting the engine on suspension brackets. A breaker-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 38. The crankcase has a baffle to calm the oil. Between the oil pan and the cylinder block, a cork-rubber mixture gasket is installed.
The cylinder head 19 is common for four cylinders, cast from aluminum alloy, has a wedge-shaped combustion chamber. Valve guides and saddles made of cast iron are pressed into the head. The intake valve seat is larger than the exhaust valve seat.
A gasket is installed between the head and the cylinder block, made of asbestos material on a metal frame, impregnated with graphite; along 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 powder before assembly.
The cylinder head is attached to the cylinder block with 11 bolts. For a uniform and tight fit of the head to the block and to avoid 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). At the first reception, tightening is carried out in advance (tightening torque approx. 4 kgfm for 10 main bolts and 1.5 kgfm for one bolt at the tide). In the second step, the final tightening is performed (tightening torque 11.5 kgf·m for 10 bolts and 3.8 kgf·m for a bolt at high water).
The cylinder head bolts should be tightened after the first 1500-2000 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 stamped steel cover. In the upper part of the cover has a neck for filling oil into the engine. To eliminate oil leakage between the cylinder head and the cover, a gasket made of cork-rubber mixture is installed. The cover is attached to the cylinder head with studs and nuts. To improve the fit of the cover to the head, wide hard washers are installed under the nuts.
The engine assembly with clutch and gearbox is mounted on the car 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.
With two front supports 28, the engine is attached to the cross member of the front suspension of the vehicle, and the rear support 29 is attached to the cross member of the rear engine suspension.
The front supports have rubber cushions 35, in which steel washers with fastening bolts are vulcanized. To increase the rigidity in the hole, there are springs inside the pillows. To limit the moves, buffers 34 are used, which are a rubber rod with a vulcanized steel bushing.
The pillows are attached to the intermediate plates, and those, in turn, to the brackets 36 of the front engine mount; the brackets are fixed to the flange of the cylinder block with four studs.
The rear support 29 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 are attached to the cross member of the rear engine mount.
Auxiliary drive
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1. Oil crankcase. 2. Connecting rod cap. 3. Oil sump gasket. 4. Connecting rod. 5. Cylinder block. 6. Starter. 7. Heat-insulating starter shield. 8. Exhaust manifold. 9. Tube inlet pipe drainage. 10. Fitting of the hot liquid outlet pipe to the carburetor. 11. Inlet pipe. 12. Cylinder head. 13. Cylinder head cover gasket. 14. Valve. 15. External valve spring. 16. Valve spring internal. 17. Spring plate. 18. Oil deflector cap. 19. Valve cracker. 20. Retaining ring for valve guide. 21. Valve guide bushing. 22. Valve drive lever. 23. Cylinder head cover. 24. Valve lever spring. 25. Adjusting valve bolt. 26. Adjusting bolt locknut. 27. Bushing adjusting bolt. 28. Plate locking springs of the valve lever. 29. Valve seat. 30. Timing chain tensioner. 31. Ignition distributor. 32. Cracker of the clamping rod of the chain tensioner. 33. The ring for turning off the cracker of the chain tensioner. 34. Nut fixing the chain tensioner rod. 35. Chain tensioner housing. 36. Chain tensioner rod. 37. Chain tensioner plunger. 38. Chain tensioner spring. 39. Washer supporting springs of the chain tensioner. 40. Locking ring of the plunger of the chain tensioner. 41. Chain tensioner plunger spring. 42. Camshaft sprocket. 43. Chain guide. 44. Timing mechanism drive chain. 45. Asterisk of the oil pump drive shaft and ignition distributor. 46. Chain tensioner shoe. 47. Oil pump drive shaft and ignition distributor. 48. Fuel pump. 49. Gear drive oil pump and ignition distributor. 50. Bushing gear drive oil pump and ignition distributor. 51. Shoe mounting bolt. 52. Eccentric roller drive oil pump and ignition distributor. 53. Crankshaft sprocket. 54. The limiting finger of the timing chain drive. 55. Oil filter. 56. Fitting for fastening the oil filter. 57. Gasket. 58. Oil pump roller. 59. Oil pump housing. 60. Oil pump driven gear axle. 61. Oil pump cover. 62. Oil pump drive gear. 63. Spring pressure reducing valve oil pump. 64. Pressure reducing valve of the oil pump. 65. Washer supporting springs of the pressure reducing valve. 66. Receiving branch pipe of the oil pump. 67. Gear driven oil pump. Alignment marks: a - on the camshaft bearing housing; b - on the camshaft sprocket; in - on the crankshaft sprocket; g - on the cylinder block; d - on the pulley; e - on the camshaft drive cover.
Auxiliary units of the engine, as well as the valve mechanism, are driven from the crankshaft using a chain drive, which is located in the front cavity of the cylinder block and is closed with an aluminum cover.
The chain drive consists of a two-row bush-roller chain 44, a drive sprocket 53 mounted on the crankshaft, a driven sprocket 45, a driven sprocket 42 of the camshaft, a chain damper 43 and a tensioner 30 with shoe 46.
The tensioner shoe and chain guide have a steel frame with a vulcanized rubber layer. A restrictive pin 54 is installed at the bottom of the cylinder block, which prevents the chain from falling into the crankcase when removing the camshaft sprocket (when removing the cylinder head on a car).
The shaft 47 of the oil pump drive and the ignition distributor is installed along the engine and has two support journals, a helical gear and an eccentric 52, which drives the fuel pump through the pusher. Roller helical gear 47 meshes with gear 49 and drives the ignition distributor and oil pump. Gear 49 is mounted vertically and rotates in a ceramic-metal bushing 50 pressed into the cylinder block. The gear has a slotted hole, which includes the splined ends of the rollers of the ignition distributor and the oil pump.
The ignition distributor housing is mounted on the upper plane of the cylinder block and is attached to it with a steel plate. The oil pump is bolted to the bottom plane of the cylinder block.
Valve timing
In one working cycle, four cycles occur in the engine cylinder - the intake of a combustible mixture, compression, power stroke and exhaust gases. These strokes are carried out in two revolutions of the crankshaft, i.e. each stroke occurs in half a turn (180°) crankshaft.
The inlet valve begins to open ahead, i.e., before the piston approaches the top dead center (V. m. t.) to a distance corresponding to 12°of rotation of the crankshaft to c. m. t. This is necessary so that the valve is fully open when the piston goes down, and as much fresh combustible mixture as possible enters through the fully open inlet.
The intake valve closes with a delay, i.e. after the piston has passed the bottom dead center (n. m. t.) at a distance corresponding to 40°rotation of the crankshaft after n. m. t. Due to the inertial pressure of the jet of the combustible mixture being sucked in, it continues to flow into the cylinder when the piston has already begun to move upward, and thus the best filling of the cylinder is ensured. Thus, the intake practically occurs during the rotation of the crankshaft by 232°.
The exhaust valve begins to open even before the full end of the working stroke, before the piston approaches n. m. t. at a distance corresponding to 42°of rotation of the crankshaft BC. m. t. At this moment, the pressure in the cylinder is still quite high and the gases begin to intensively flow out of the cylinder, as a result of which their pressure and temperature drop rapidly. This significantly reduces engine work during exhaust and prevents the engine from overheating.
The release continues after the piston has passed through. m.t., i.e. when the crankshaft turns 10 after c. m. t. Thus, the duration of the release is 232°.
From the valve timing diagram, it can be seen that there is such a moment (22°crankshaft rotation approx. m. t.), when both valves, intake and exhaust, are open at the same time. This position is called valve overlap. Due to the short time interval, the overlapping of the valves does not lead to the penetration of exhaust gases into the intake manifold, but, on the contrary, the inertia of the exhaust gas flow causes the combustible mixture to be sucked into the cylinder and thereby improves its filling.
The described valve timings take place with a gap of 0.30 mm between the camshaft cam and the valve lever on a cold engine.
To ensure the timing of the opening and closing of the valves with the angles of rotation of the crankshaft (i.e. to ensure the correct installation of the valve timing), there are marks on the crankshaft and camshaft sprockets, as well as on the cylinder block and camshaft bearing housing. If the valve timing is set correctly, then when the piston of the fourth cylinder is in c. m.t. at the end of the compression stroke, mark a on the camshaft bearing housing must match mark b on the camshaft sprocket, and mark c on the crankshaft sprocket must match mark d on the cylinder block.
When the camshaft drive cavity is closed with a cover, the position of the crankshaft can be determined by the marks on the pulley and the camshaft drive cover. With the piston position of the fourth cylinder in c. m.t. mark d on the pulley must match the long mark e on the camshaft drive cover.