Maintenance and repair of car engine. Subject: Engine maintenance

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1. Maintenancecar

automobile technical repair engine

To ensure the operability of the car during the entire period of operation, it is necessary to periodically maintain its technical condition with a set of technical actions, which, depending on the purpose and nature, can be divided into two groups: actions aimed at maintaining the units, mechanisms and components of the car in working condition for the greatest period of operation; impacts aimed at restoring the lost performance of units, mechanisms and components of the car.

The complex of measures of the first group constitutes a maintenance system and is of a preventive nature, and the second - a recovery (repair) system.

Maintenance. In our country, a planned preventive maintenance and repair system for cars has been adopted. The essence of this system is that Maintenance carried out according to plan, and repairs - as needed.

The fundamental foundations of the preventive maintenance and repair system for vehicles are established by the current Regulations on the maintenance and repair of road transport rolling stock.

Maintenance includes the following types of work: cleaning and washing, control and diagnostics, fastening, lubricating, refueling, adjusting, electrical and other work, performed, as a rule, without disassembling the units and removing individual components and mechanisms from the vehicle. If during maintenance it is impossible to verify the full serviceability of individual components, then they should be removed from the vehicle for control on special stands and instruments.

According to the frequency, list and complexity of the work performed, maintenance according to the current Regulations is divided into the following types: daily (EO), first (TO-1), second (TO-2) and seasonal (SO) maintenance.

The regulation provides for two types of repair of vehicles and its units: current repairs (TR), performed in motor transport enterprises, and major repairs (CR), performed at specialized enterprises.

Each type of maintenance (TO) includes a strictly established list (nomenclature) of works (operations) that must be fulfilled. These operations are divided into two components - control and performing.

The control part (diagnostic) of maintenance operations is mandatory, and the execution part is performed as needed. This significantly reduces material and labor costs during maintenance of the rolling stock.

Diagnostics is part of the technological process of maintenance (TO) and current repair (TR) of cars, providing initial information about the technical condition of the car. Vehicle diagnostics is characterized by its purpose and place in the technological process of maintenance and repair.

Daily maintenance (EO) is performed daily after the car returns from the line between shifts and includes: inspection and inspection work on mechanisms and systems that ensure traffic safety, as well as the body, cab, lighting devices; cleaning and washing and drying and cleaning operations, as well as refueling the car with fuel, oil, compressed air and coolant. Car washing is carried out on demand, depending on weather, climatic conditions and sanitary requirements, as well as on the requirements for the appearance of the car.

First maintenance (TO-1) consists in an external technical inspection of the entire vehicle and the performance of control and diagnostic, fixing, adjusting, lubricating, electrical and refueling work in the prescribed volume with a check of operation engine, steering, brakes and other mechanisms. Complex diagnostic work(D-1), performed at or before TO-1, serves to diagnose the mechanisms and systems that ensure the safety of the vehicle.

TO-1 is carried out between shifts, periodically at set intervals for mileage and should ensure the trouble-free operation of the units, mechanisms and systems of the vehicle within the established frequency.

An in-depth diagnosis of D-2 is carried out 1-2 days before TO-2 in order to provide information to the TO-2 zone about the upcoming scope of work, and if a large amount of current repair is detected, redirect the car to the current repair zone in advance.

Second maintenance(TO-2) includes the performance of fixing, adjusting, lubricating and other works in the prescribed volume, as well as checking the operation of units, mechanisms and instruments during operation. TO-2 is carried out with the removal of the car for 1-2 days from operation.

At ATP, D-1 and D-2 are combined in one area using combined stationary stands. At large ATPs and at centralized service bases, all diagnostic tools are centralized and optimally automated.

Determining the place of diagnostics in the technological process of maintenance and repair of vehicles allows us to formulate the basic requirements for its tools. To diagnose D-1 mechanisms that ensure traffic safety, high-speed automated tools are required for diagnosing brake mechanisms and steering.

To diagnose the car as a whole (D-2) and its units, stands with running drums are needed to determine the power and economic indicators, as well as the state of systems and assemblies, as close as possible to the conditions for their diagnosis to the conditions of the car. For diagnostics combined with maintenance and repair, mobile and portable diagnostic tools and devices should be used.

Seasonal maintenance (SO) held 2 times a year is the preparation of the rolling stock for operation in the cold and warm seasons. It is recommended to conduct a separate SS for the rolling stock operating in the cold climate zone. For other climatic zones, CO is combined with TO-2 with a corresponding increase in the labor intensity of the main type of service.

2. The concept of maintenance and overhaul

Maintenance (TR) is carried out in motor transport enterprises or at service stations and consists in eliminating minor malfunctions and vehicle failures, contributing to the fulfillment of the established vehicle mileage standards before overhaul.

The purpose of diagnosing during current repairs is to identify a failure or malfunction and establish the most effective way their elimination: on the spot, with the removal of the unit or assemblies with their complete or partial disassembly or adjustment. Current repair consists in carrying out disassembly and assembly, plumbing, welding and other work, as well as replacing parts in units (except for basic ones) and individual components and assemblies in a car (trailer, semi-trailer), requiring current or major repairs, respectively.

poi during the current repair, the units on the car are changed only if the unit repair time exceeds the time required for its replacement.

Capital repair (CR) of cars, units and assemblies is carried out at specialized repair enterprises, factories, workshops. It provides for the restoration of the performance of vehicles and units to ensure their mileage until the next overhaul or write-off, but not less than 80% of their mileage from the mileage standards for new vehicles and units.

During the overhaul of a car or unit, it is completely disassembled into components and parts, which are then repaired or replaced. After completing the parts, the units are assembled, tested and sent to the assembly of the car. With the impersonal method of repair, the car is assembled from previously repaired units.

Cars and buses are sent for overhaul if a major overhaul of its body is necessary. Trucks are sent for overhaul if overhaul of the frame, cab, as well as overhaul of at least three main units is necessary.

During its service life, a complete car is subjected, as a rule, to one major overhaul.

The purpose of diagnostics during a major overhaul is to check the quality of the repair.

Maintenance of crank and gas distribution mechanisms

Maintenance of engine mechanisms and systems begins with its control inspection, which consists in identifying its completeness, leakage of oil, fuel and coolant, checking its fastening and, if necessary, tightening the bolts and nuts of its fastening, as well as fastening the oil pan.

The control inspection allows you to identify obvious defects in the engine and determine the need for its maintenance or repair.

To identify the technical condition of the engine, its general diagnosis is carried out according to diagnostic parameters without identifying a specific malfunction. These parameters are fuel and oil consumption (waste), oil pressure.

Fuel consumption is determined by the methods of running and bench tests, as well as on the basis of its daily accounting and comparison with the standards.

Oil waste is determined by its actual consumption and for a slightly worn engine can be 0.5-1.0% of fuel consumption. Increased oil burnout is accompanied by noticeable smoke at the outlet [З].

The oil pressure at a low crankshaft speed is below 0.04-0.05 MPa for a carburetor engine and below 0.1 MPa for diesel engine indicates its malfunction [Z].

The main signs of a malfunction of the crank mechanism are: a decrease in pressure at the end of the compression stroke (compression) in the cylinders; the appearance of noise and knocks during engine operation;

gas breakthrough into the crankcase, increased oil consumption; oil dilution in the crankcase (due to the penetration of working mixture vapors during compression strokes); oil entering the combustion chamber and getting it on the spark plugs, which causes carbon deposits on the electrodes and sparking worsens. As a result, engine power is reduced, fuel consumption and CO content in exhaust gases increase.

Malfunctions of the gas distribution mechanism are wear of pushers and guide bushings, valve plates and their sockets, gears and camshaft cams, as well as violation of the gaps between the valve stems and pushers or rocker toes.

Failures of the gas distribution mechanism include breakage and loss of elasticity of the valve springs, breakage of the teeth of the timing gear.

Diagnosis of the crank and gas distribution mechanisms is carried out at the D-2 post when low traction qualities of the diagnosed vehicle are detected at the traction and economic qualities stand.

The following methods of engine diagnostics at the D-2 post are the most accessible in ATP conditions: determining the pressure at the end of the compression stroke (compression), determining the vacuum in the intake piping, and leaking compressed air from the over-piston space.

3. Compressometers

Compression serves as an indicator of tightness and characterizes the condition of cylinders, pistons, rings and valves. To measure compression, compression gauges with a fixed arrow are used, with a scale for carburetor engines up to 1.5 M Pa and diesel engines up to 10 M Pa, and compression meters with a recorder - compressographs.

The compression of the carburetor engine is checked with the candles turned out with the engine warmed up to a temperature of 70-80C and the air and throttle dampers fully open. Having installed the rubber tip of the compression gauge in the hole of the spark plug of the cylinder being checked, turn the engine crankshaft 10-15 revolutions with the starter and record the pressure gauge readings. Compression for a technically sound engine should be 0.74-0.80 MPa. The maximum allowable compression value is 0.65 MPa.

Check perform 2-3 times for each cylinder. The difference in readings between the cylinders should not be more than 0.07-0.1 MPa.

To identify the cause of the malfunction, pour (20 + 5) cm3 of fresh engine oil into the spark plug hole and repeat the test. An increase in the compression gauge indicates air leakage through the piston rings. If the readings do not change, then the valves may be loose or the edges of the valve plates or their seats may be burned.

Compression in a diesel engine is measured on a running (with a speed of 450-500 rpm) and warm (up to a temperature of 70-80°C) engine. The compression gauge is installed instead of the nozzle of the cylinder being checked. In a serviceable engine, the compression should not be lower than 2-2.6 MPa, and the pressure difference between the cylinders should not exceed 0.2 MPa.

4. Device K-69M

To determine the leakage of compressed air from the over-piston space, the K-69M device is used. Air is supplied to the cylinders of a warm engine either through the gearbox 1 of the device, or directly from the line through the hose into the cylinder through the fitting , screwed into the hole for a candle or nozzle, to which a hose is attached using a quick-release coupling.

In the first case, they check for air leakage or pressure drop due to non-densities in each engine cylinder. To do this, use the gear knob to adjust the device so that when the clutch valve is fully closed, the pressure gauge needle is against zero division , which corresponds to a pressure of 0.16 M Pa, and with a fully open valve and air leakage into the atmosphere - against division of 100%.

The relative leakage of the cylinder-piston group is checked when the piston of the cylinder under test is installed in two positions: at the beginning and end of the compression stroke. The piston from movement under compressed air pressure is fixed, including the gear in the car gearbox.

The compression stroke is determined by a signaling whistle inserted into the hole of the candle (injector).

State piston rings and valves are evaluated according to the pressure gauge readings at the piston position in the top dead center, and the state of the cylinder (cylinder wear in height) - according to the pressure gauge readings at the piston position at the beginning and end of the compression stroke and by the difference between these readings.

The obtained data are compared with the values at which further operation of the engine is unacceptable. The maximum allowable air leakage values for engines with different cylinder diameters are indicated in the device instructions.

To determine the location of the leak (malfunction), air at a pressure of 0.45-06 MPa is supplied from the line through a hose to the engine cylinders.

The piston is installed at the end of the compression stroke at top dead center.

The place of air breakthrough through the leak is determined by listening with a phonendoscope.

Air leakage through the engine valves is detected visually by the fluctuation of the fluffs of the indicator inserted into the hole of the candle (injector) of one of the adjacent cylinders, where the valves are open in this position.

Air leakage through the piston rings is determined only by listening with the piston in the N.M.T. position. in the zone of minimum cylinder wear. Leakage through the cylinder head gasket is detected by bubbles in the radiator neck or in the plane of the connector.

Fixing work at TO-2 is carried out in addition to fixing work performed at TO-1. At the same time, they include control and fastening of the head to the cylinder block by tightening the nuts with a torque wrench. The tightening torque and sequence are set by the manufacturers. The cast-iron cylinder head is fixed in a hot state, and the aluminum alloy cylinder head is fixed in a cold state, which is explained by the unequal coefficient of linear expansion of the material of the bolts and studs (steel) and the head (aluminum alloy). Tightening is performed from the center to the edges diagonally.

Adjustment work is Xia final. If a knock is detected in the gas distribution mechanism, check and adjust the thermal gaps between the mountaineers of the valve stems and the pushers or the noses of the rocker arms (with the valves in the upper position. The gaps are checked with a lamellar muzzle with the valves completely closed, if necessary, adjust on a cold engine. The valve clearances are adjusted starting from of the first cylinder, in the sequence corresponding to the order of operation of the engine cylinders.The gap is changed to the desired value by turning the adjusting screw of the pusher or the rocker screw, lowering the lock nut.The gap must correspond to the factory data.For example, for engines ZAZ-53, ZIL-130, YaMZ-236 the gap should be equal to 0.25-0.30 mm.

5. Checking and adjusting the thermal gap

To install the piston of the first cylinder in v.m.t. during the compression stroke, engine timing marks are used.

Maintenance of the engine cooling system. The engine cooling system keeps it running at optimum temperature regime, equal to 85-90°C, under various operating conditions.

Typical malfunctions of the cooling system are leaks and insufficient engine cooling efficiency. The first is due to damage to the hoses of their connections, the water pump seal, damage to the gaskets, cracks, and the second is due to slipping of the fan belt or its breakage, breakdowns of the water pump, thermostat malfunction, internal or external contamination of the radiator, as a result of scale formation.

Signs of a malfunction in the cooling system are engine overheating and boiling of coolant in the radiator if they are the result of a long and heavy engine load or incorrect adjustment of the ignition system or power system.

Diagnosis of the engine cooling system consists in determining its thermal state and tightness, checking the fan belt tension and thermostat operation. The temperature difference between the upper and lower radiator tanks with a fully warmed-up cooling system should be within 8-12°C. The tightness of the system is controlled on a cold engine. A coolant leak can be detected by traces of leaks through the fluid pump stuffing box, at the junction of pipes, etc. Tightness is checked under pressure of 0.06 MPa.

The tension of the belt 1 of the fan drive or liquid pump is checked by measuring the belt deflection when pressed in the middle between the pulleys with a force of approximately 30-40 N. The deflection should be within 8-14 mm.

The operation of the thermostat is checked when the engine warms up slowly after starting or, conversely, when it warms up quickly and overheats during operation. The removed thermostat is immersed in a heated bath of water, controlling the temperature with a thermometer. The moment of the beginning and end of the opening of the valve should

Checking and adjusting the drive belts of the liquid pump, compressor, generator and power steering pump

occur respectively at temperatures of 65-70 and 80-85C. The defective thermostat is replaced.

With EO, the tightness of the cooling system is checked by carefully inspecting all connections. Tighten connections if necessary. The liquid level in the radiator should be 20-30 mm below the upper edge of the filler neck. Add liquid if necessary.

At TO-1, when performing cleaning and washing work, the engine is thoroughly washed, removing dirt and oil stains from its surface, the radiator is washed with a strong stream, directing it from the engine compartment through the radiator to the outside. Check the tension of the fan and water pump belts and adjust if necessary using the adjustment points provided by the design of this vehicle. Check the operation of the steam air valves, radiator caps. Lubricate the bearings of the water pump and the pulley of the fan device (for YaMZ-236 and GAZ-53A engines). Check the operation of the radiator shutters and its drive.

At TO-2, tighten the fastening nuts of the hub of the fan pulley. Check the operation of the sensor and the coolant temperature gauge. Check the operation of the hydraulic clutch or electric clutch for turning on the fan.

With CO (after 40-60 thousand kilometers), to remove sludge, the cooling system is washed with a jet of water under a pressure of 0.15-0.2 MPa (with the thermostat removed) separately (first the cooling jacket, and then the radiator) in the direction opposite to circulation coolant. Rinsing is carried out until clean water appears.

To remove scale, leading to a decrease in engine power, an increase in fuel consumption (by 5-6%), the occurrence of detonation, intensive wear of parts of the cylinder-piston group, the cooling system is washed with various solutions. The most effective solution is hydrochloric acid with inhibitor, wetting agent and defoamer. The solution is poured into the cooling system, the engine is started and the solution is heated to a temperature of 60 ° C (the thermostat must be removed). After 10-15 min. the solution is drained and the system is flushed hot water.

Drain taps are cleaned with a soft wire.

To reduce the formation of scale in the cooling system, it is necessary to use water of low hardness. Water softening can be ensured by pre-boiling, adding soda, lime or passing it through magnetic filters, as well as adding various anti-scale agents to the water.

The most dangerous thing in winter is the defrosting of the cooling system. To improve the reliability of the system, antifreezes are used (liquids with a low freezing point - minus 40 ° C). Antifreeze has a higher volumetric expansion coefficient, so the system must be filled by 90-95% (if there is no expansion tank).

Maintenance of the lubrication system

The operation of the lubrication system determines the reliability and durability of the engine, in which all the main rubbing pairs are lubricated under pressure. During engine operation, the quality of crankcase oil deteriorates, and its quantity decreases as a result of waste and oil losses through leaks in the lubrication system.

The deterioration of the quality of the oil during engine operation occurs due to its dilution with fuel, contamination with mechanical impurities and oxidation, as well as due to the operation of additives that give the oil better properties.

Fuel dilution of lubricant leads to increased wear of engine parts. Fuel enters the engine crankcase when the cylinder-piston group is significantly worn, the spark plug or nozzle is not working, or the fuel pump diaphragm is ruptured. The ingress of coolant into the lubrication system is possible as a result of a violation of the tightness of the cylinder head gasket or the sealing rings of the cylinder liners.

The presence of water in the oil causes intensive wear of engine parts. The loss of tightness is eliminated by replacing the sealing rings or gaskets. In case of a sharp drop in pressure in the lubrication system (damage to the oil line or oil pump drive), the engine must be stopped.

During EO, the tightness of the lubrication system and its connections is checked by inspection. Control the oil level in the crankcase with an oil dipstick. If necessary, add oil to the upper mark. They control the oil pressure in the system when starting the engine and during the operation of the car.

At TO-1, the fastenings of oil pipelines and devices of the lubrication system are checked. When loosening the fasteners, tighten the nuts and bolts. The sludge from the filters is drained on a warm engine.

At TO-2, the oil in the crankcase is replaced. After draining the used oil, it is recommended to flush the system using a special installation and flushing oil. Flushing can also be done with low-viscosity spindle oil, a mixture of oil and diesel fuel, or a flushing fluid consisting of 90% white spirit and 10% acetone. To do this, flushing fluid is poured into the crankcase in a volume equal to half the capacity of the lubrication system, the engine is started and allowed to run for 4-5 minutes at an increased idle speed (800-1000 rpm), then the flushing fluid is drained and t fresh oil.

The filter element of the fine filter is replaced when changing in the engine. Before changing, it is necessary to drain from the body into the sludge. After removing the filter element, wash the inside of the housing with kerosene and wipe it with a coarse dry cloth, remove it, thoroughly wash it in kerosene with a brush and blow it with compressed air. 1stand and clean the centrifuge. Before installing the casing, check whether the centrifuge rotates by hand. After the final test, the operation of the centrifuge is checked by attenuation of rotation (it will stop 2-3 minutes after the engine stops). An oil change checks the crankcase ventilation system, fastening of parts and the absence of deposits in the pipes and valves.

6. Maintenance of power system devices

The technical condition of the power system determines the power and gnomic performance of the car, its impact on the environment.

Typical malfunctions of the power supply system: leakage, fuel leakage from fuel tanks, pipelines, contamination of fuel and air filters.

For carburetor engines, the throughput of the calibrated holes and carburetor jets changes, the idle jets are de-adjusted, the tightness of the needle valve of the carburetor float chamber is broken, the fuel level in the float chamber changes, the elasticity and length of the spring in the limiters of the maximum crankshaft speed change. In the fuel pump of a carburetor engine, diaphragm breaks and a decrease in the stiffness of the diaphragm spring are possible.

Diesel engines show wear and tear and adjustment of the pump plunger pairs high pressure and nozzles, loss of tightness of these mechanisms. Wear of the nozzle holes, their coking and clogging is possible. These malfunctions lead to uneven operation of the fuel pump in terms of the quantity and angle of the supplied fuel, deterioration in the quality of fuel atomization by the injector, and a change in the moment the fuel supply starts.

As a result of the listed malfunctions, fuel consumption increases and the toxicity of exhaust gases increases.

Diagnostic signs of malfunctions of the power system are: difficulty starting the engine, increased fuel consumption under load, a drop in engine power and overheating, a change in the composition and an increase in the toxicity of exhaust gases.

Diagnosis of the power supply system of diesel and carburetor engines is carried out by the methods of running and bench tests.

When diagnosing by the method of sea trials, the fuel consumption is determined when the vehicle is moving at a constant speed on a measured horizontal section of the road with low traffic intensity. Movement is carried out in both directions.

The control fuel consumption is determined for trucks at a constant speed of 30-40 km/h and for cars - at a speed of 40-80 km/h. The amount of fuel consumed is measured by flow meters, which are used not only to diagnose the power system, but also to teach drivers how to drive economically.

Diagnosis of the car power system can be carried out simultaneously with testing the traction qualities of the car on a stand with running drums, which significantly reduces the loss of time and eliminates the inconvenience of the sea test method. To do this, the car is installed on the stand in such a way that the drive wheels rest on the running drums. Before measuring fuel consumption, preheat the engine and transmission of the car for 15 minutes. at a speed of 40 km / h in direct gear and at full throttle, for which a load is created on the drive wheels by the load device of the stand. After that, for carburetor engines, the operation of the fuel pump is checked (if the stand with running drums is not equipped with a pressure gauge to control the operation of the fuel pump) with a model 527B instrument for the pressure it develops and the tightness of the carburetor float chamber valve. The pressure is measured at a low engine speed and with the shut-off valve open. The results of the check are compared with the data of the table placed on the cover of the instrument case, and, if necessary, troubleshooting is carried out.

The normal pressure at the fuel pumps B-9 and B-10 of ZIL-130, GAZ-53A, Ural-375D and Ural-377 vehicles is 0.025-0.03 MPa. To determine the fuel consumption, having disconnected the 527B device, a flow meter is connected. According to the amount of fuel consumed during the test, the fuel consumption (in l/100 km) corresponding to a certain speed is calculated, and the result is compared with the standard.

Toxicity of exhaust gases of engines is checked at idle. For carburetor engines, gas analyzers are used, and for diesel engines, photometers (smoke meters) are used. For measurements by gas analyzers GAI-1 and GAI-2, the gas sampling device is inserted into the exhaust pipe to a depth of 300 m from its cut. 6 n min (where n min is the rated speed of the engine crankshaft).In the first case, the CO content should not exceed 1.5% by volume, in the second - 2%. Gas sampling is carried out with a warm engine and a fully open air damper. After replacement, the engine must run for at least 1 minute in the test mode.The composition of the exhaust gases characterizes the combustion process occurring in the engine cylinders, and the quality of the working mixture.

The opacity of the exhaust gases is estimated by the light penetration (optical density) of the exhaust gases and is determined by the scale of the device. The basis of the device is a transparent glass tube, which crosses the light flux. The degree of light absorption depends on the smoke content of the gases passing through the tube.

Smoke measurement is carried out at TO-2 after repair or adjustment of the fuel equipment at idle in two engine operation modes: free acceleration (i.e. engine acceleration from minimum to maximum crankshaft speed) and at maximum crankshaft speed. The exhaust gas temperature must be below 70°C.

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General and vocational education Leningrad region

State budgetary educational institution of primary

Vocational education of the Leningrad region

Vocational School No. 24 named after Pyotr Lavrov

Laboratory work onTtechnicalOservicecar

Syasstroy 2013

Subject: Engine Maintenance.

The purpose of the work: to learn how to identify malfunctions of systems and mechanisms of the engine and methods of its maintenance

Material support: a set of locksmith's tools for maintenance of fuel equipment of gasoline engines; gas analyzer; torque wrench; a set of locksmith's tools for maintenance and repair of power systems for diesel engines; stand for adjustment and testing of devices of the power supply system of gasoline engines; stand for checking and repairing diesel fuel equipment; injector tester;

The main malfunctions of the engine mechanisms.

Malfunction		Detection method
1. Decrease in engine power, increased fuel consumption	Caused by the accumulation of soot in the combustion chamber, improper timing adjustment.
2. Increased lubricant consumption and engine exhaust smoke.	Wear of piston rings, wear of piston ring grooves, loss of elasticity of rings, wear and damage of cylinder liners.	Increased opacity (blue smoke).
3. Reduction of pressure in the engine cylinders.	Wear of piston rings, cylinder liners, loose fitting of valves to the seats, damage to the cylinder head gasket.	Low compression.
4. The knock of the main bearings of the crankshaft.	Too early ignition; insufficient oil pressure; flywheel mounting bolts loosened; increased clearance between the journals and the main bearing shells; increased clearance between the thrust half rings and the crankshaft.	A dull metallic thud. It is detected when the throttle valves are suddenly opened at idle.
5. Knock connecting rod bearings.	Insufficient oil pressure; excessive clearance between crankshaft journals and connecting rod bearings	Usually the knock of the connecting rod bearings is sharper than the knock of the main bearings. It is heard at idle with a sharp opening of the throttle. The place of knocking is easy to determine by turning off the spark plugs in turn.
6. The knock of pistons.	Increased clearance between pistons and cylinders; excessive clearance between the piston rings and the grooves on the piston.	The knock is usually not sonorous, muffled. Best heard at low engine speeds and under load
7. Knock intake and exhaust valves.	Increased clearances in the valve mechanism; broken valve spring excessive clearance between the valve and the guide sleeve; wear of the camshaft cams.	Knocking is usually at regular intervals. Its frequency is less than the frequency of any other knock in the engine.

Works are performed during maintenance of engine mechanisms.

With EO - the engine is cleaned of external contaminants, inspected and listened to its operation in different modes.

At TO-1 - the fastening of the engine mounts is checked, they are tightened, the seals are checked, the tightness of the connections of the cylinder head and the pan, as well as the seal of the crankshaft.

With TO-2 - in addition to the work performed during TO-1, in addition to them, they tighten the cylinder head, the oil pan, adjust the thermal clearances of the valves and the tension of the timing chain.

The main malfunctions of the power supply system of the carburetor engine.

Malfunction	Characteristic features
Re-enrichment of the combustible mixture.	Decrease in engine power, increased fuel consumption, pops in the muffler, black smoke from the muffler.	High fuel level in the carburetor float chamber; clogged air filter; wear of holes in the fuel jets of the carburetor; clogging of air jets; gasket damage; violation of the adjustment of the drive control of the air damper, as a result of its incomplete opening.
Re-leaning of the combustible mixture.	Loss of engine power, pops in the carburetor, engine overheating	Air leaks through leaks in the places where the carburetor and intake pipe are attached to the engine cylinder head; low fuel level in the carburetor float chamber; clogging of the fuel jets and channels of the main metering device and the idle system;
Lack of fuel supply.	The engine does not start.	Clogged fuel filters, the atmospheric valve in the fuel tank cap does not open, the valves in the fuel pump do not fit tightly, the fuel pump diaphragm ruptures, the pump drive lever wears out, air leaks in the intake line.
Insufficient fuel supply.	Low fuel pressure at the outlet of the pump, lowering the fuel level in the float chamber with the engine running.	Damaged pump diaphragm, clogged filter elements, loss of elasticity of the diaphragm spring.

Work performed during maintenance of power supply systems of a carburetor engine.

When EO, the power system is inspected, paying attention to the absence of gasoline leakage. When operating the car on roads with a lot of dust, the air filter is cleaned. Check the level of gasoline in the tank and fill it up if necessary.

During TO-1, they check the operation of the engine at different crankshaft speeds and, if necessary, adjust the carburetor for stable engine operation, at idle, check the operation of the carburetor control drive, if necessary, adjust, drain the sediment from the filter - sump and fuel tank.

At TO-2, they check: fastening, tightness of the fuel tank (tanks), pipeline connections, carburetor, fuel pump, operation of the carburetor control drive (fullness of opening and closing of the throttle and air dampers), if necessary, eliminate the malfunction; fuel level in the carburetor float chamber; operation of the fuel pump; ease of starting the engine, in addition, they remove and wash the air filter (the filter element is changed in dry filters), wash the sediment filter and fine fuel filter, check the operation of the valves in the fuel tank filler cap and blow them with compressed air, if necessary, wash the fuel tank, adjust the carburetor.

With CO, the fuel tank (tanks) are washed and the pipelines are blown with compressed air, the fuel level in the carburetor fuel chamber is checked and, if necessary, its adjustment is checked.

Carburetor maintenance work, the implementation of which does not require removing it from the engine, includes: adjustment of the carburetor control drive; adjustment of idle revolutions of the crankshaft of the engine; checking the tightness of the carburetor elements. Carburetor maintenance work related to its removal from the engine and disassembly includes the following checks: the throughput of the carburetor jets, the elasticity of the plasticity of the diffuser block; delivery of the accelerating pump, as well as checking and adjusting the fuel level in the fuel chamber of the carburetor.

Maintenance of the air filter must be carried out, because. the filter becomes clogged with dust, which leads to a drop in engine power, a violation of the composition of the combustible mixture and, consequently, to excessive fuel consumption. When the air filter is dirty, dust enters the cylinders. This causes accelerated wear of cylinders, pistons, piston rings and other parts. As a result, the life of the engine before the next repair is reduced. Maintenance of the filters consists in periodically draining the sludge of dirt and water and washing the filter element in kerosene, gasoline or acetone, followed by blowing with compressed air.

Maintenance of the fuel pump must ensure that the pump reliably supplies fuel from the tank to the carburetor. Pump flow, maximum discharge pressure, vacuum when fuel is sucked in and the tightness of the pump valves are important.

When carrying out maintenance of the power supply system of carburetor engines, it is necessary to strictly observe safety regulations. They consist mainly in preventing work with open fire, in preventing sparking, and inadmissibility of smoking during maintenance.

The technical condition of the power supply system changes during operation. Air and fuel filters gradually become clogged. As a result, the purification of air and fuel deteriorates, the supply of the fuel pump decreases.

Carburetor adjustments and checks 21083.

The tightness of the needle valve is checked on a stand that supplies fuel to the carburetor 21083 at a pressure of 30 kPa. After setting the fuel level in the test tube of the stand, its fall is not allowed for 10-15 s. If the level of fuel in the vial drops, this indicates a fuel leak through the needle valve. If there is a fuel leak, replace the needle valve.

Setting the fuel level in the float chamber.

The fuel level necessary for the normal operation of the carburetor 21083 is provided correct installation serviceable elements locking device. Correct installation of the float 1 (Fig. 1) check the gauge 4, for which set it perpendicular to the cover 2, which is held horizontally with the floats up. There must be a gap of no more than 1 mm between the gauge along the contour and the floats. Adjust if necessary by bending the tongue and float arms. The bearing surface of the tongue must be perpendicular to the axis of the needle valve 5 and must not have dents or nicks.

Rice. 1 - Setting the fuel level in the float chamber of the carburetor 21083: 1 - float; 2 - carburetor cover; 3 - gasket; 4 - gauge for checking the position of the floats; 5 - needle valve

Carburetor drive adjustment 21083.

With the throttle control pedal 1 (Fig. 2) fully depressed, the throttle valve of the first chamber should be fully open and sector 11 should not have additional travel. With pedal 1 released, the throttle should be fully closed. If this is not the case, adjust the position of the pedal and throttle valve with adjusting nuts 10 on the front end of the drive cable.

Rice. 2 - Carburetor control drive 21083: 1 - throttle control pedal; 2- return spring; 3 - pedal stop gasket; 4 - bracket; 5 - bushing; 6 - locking bracket; 7 - cable tip; 8 - cable sheath; 9 - adjusting tip bracket; 10 - adjusting nuts; 11 - sector with throttle control lever; 12 - return spring

Starting gap adjustments.

Perform the adjustment on a cold engine, when the air damper is covered by the starting device. Remove the air filter and check the air damper starting gap. If the gap does not match the value (2.5±0.2 mm), remove the stopper of the adjusting screw and adjust the given gap with this screw. The starting clearance at the throttle valve of the first chamber must be adjusted on the removed carburetor VAZ 21083. Close the throttle valve of the first chamber. Use a screwdriver to turn the cam counterclockwise and set the lever stop to the largest step along the radius. Use a screw to adjust the clearance at the throttle valve equal to (1.1 ± 0.05 mm). Install the removed components and parts, start the engine, check, 15-20 s after starting, the crankshaft speed of the cold engine, which should be equal to (2400 ± 200) min. "The crankshaft speed of the warm engine at idle should be 750- 800 rpm

Engine idle adjustment.

Adjustment is provided by adjusting screw 2 (Fig. 3) of the quality (composition) of the mixture and adjusting screw 1 of the amount of the mixture. The adjusting screw 2 is closed with a plug 4. To access the screw, remove the plug with a corkscrew. Idling adjustment must be carried out on a warm engine (coolant temperature 80-95 ° C), with adjusted gaps in the gas distribution mechanism, with a correctly adjusted ignition timing. Using the adjusting screw 1 of the amount of the mixture, set the engine crankshaft rotational speed in the range of 750-800 min using the stand tachometer. Adjusting screw 2 of the quality (composition) of the mixture, achieve the content of carbon monoxide (CO) in the exhaust gases within 1 ± 0.3% at this position of the screw 1 (CO content is reduced to 20 ° C and 101.3 kPa (760 mm Hg .)). Screw 1 restore the crankshaft speed to 750-800 min. If necessary, use the adjusting screw 2 to restore the CO content within 1 ± 0.3%. At the end of the adjustment, sharply press the throttle pedal and release it, the engine should increase the crankshaft speed without interruption, and when it decreases, it should not stall. In case of engine stop, use screw 1 to increase the crankshaft speed within 750-800 min. Install a new plastic plug 4 into the hole for adjusting screw 2 of the mixture quality.

Rice. 3 - Screws for adjusting the idle speed of the engine: 1 - adjusting screw for the amount of idle mixture; 2 - adjusting screw for the quality (composition) of the idle mixture; 3 - sealing ring; 4 - plug of the adjusting screw

The main malfunctions of the diesel power system.

Malfunction		signs
Fuel circulation disorder	Reducing the fuel supply to the injection pump	Difficulty starting engine malfunction
Violation of dosage, insufficient fuel supply, violation of the moment of fuel supply	Wear of high-pressure fuel pump parts (plungers, plunger sleeves, pressure valves), violation of pump adjustment.
Fuel supply failure.	Coking of nozzle nozzle openings, violation of the needle lift pressure adjustment, loss of tightness of the nozzle needle.	Loss of engine power, black smoke from muffler
Violation of the all-mode regulator	Violation of adjustment, breakage of parts.	Irregular rotation of the crankshaft, engine stop at idle or excessively high speed

The injector test can also be performed on the engine using a maximeter or a reference injector. To ensure the normal operation of the diesel air supply system, it is necessary to perform maintenance operations in a timely and high-quality manner. Depending on the dustiness of the air, and mainly at one or the TO-2, it is necessary to check and clean the outlet slots of the cap and the grid of the monocyclone of the front chimney of tractor diesel engines of the SMD-18N and SMD-60 types. At TO-2, and in case of operation of the IZV-700 indicator and earlier, it is necessary to clean the filter cartridges of the air cleaners. To do this, the filter cartridges are removed and blown with compressed air, first inside and then outside until the dust is completely removed, so as not to tear the paper curtain, the air pressure should not exceed 0.2-0.3 MPa. In this case, the air flow should be directed at an angle to the side surface of the filter cartridge and the air pressure should be regulated by changing the distance from the hose tip to the surface of the filter cartridge. In the absence of compressed air, as well as in case of soiling or contamination of the main filter cartridges with combustion products, they must be immersed for 2 hours in a cleaning solution, rinsed well in the same solution for 20 minutes, then rinsed clean water, heated to a temperature of 35-45 ° C, and dry for 24 hours. The filter cartridges are also washed if they are not restored after purging with compressed air. The washing solution is prepared from soap paste OP-7 or OP-10 (GOST 8433-81) and water heated to 40-45 ° C, at the rate of 20 g of paste per 1 liter of water. It is allowed to use universal washing powder, paste, laundry soap diluted in warm water (100 g of soap per 10 liters of water) for washing filter cartridges. The soap solution must be filtered. Maintenance of safety filter cartridges with paper filtering curtains is similar to the main filter cartridges. Do not blow through the main filter cartridges with exhaust gases or flush with diesel fuel.

High pressure fuel pump adjustment and equipment requirements for adjustment.

The power and economic performance of the engine, as well as the reliability of its operation, largely depend on the thoroughness and quality of the adjustment of the parameters of the fuel pump. Therefore, adjustment of the fuel pump must be carried out by qualified personnel and on special equipment. The pump is adjusted with a set of proven injectors attached to the sections. They are installed on the engine in the order they are attached to the pump sections. At the same time, the beginning of the fuel supply by the pump sections, its size and uniformity are regulated. The start of the fuel supply is regulated without an automatic clutch, the injection advance at the beginning of its movement in the momentoscope (Fig. 4) and is determined by the angle of rotation of the pump camshaft when it is rotated clockwise (when viewed from the drive side). The first section of a properly adjusted pump begins to supply fuel 37-38 degrees before the axis of symmetry of the cam profile. To determine it, it is necessary to fix on the limb the moment when the fuel begins to move in the momentoscope when the camshaft is turned clockwise. Then you need to turn it clockwise by 90 degrees and fix on the limb the moment the fuel starts to move in the momentoscope when the shaft is turned counterclockwise. The middle between the two fixed points will be the axis of symmetry of the cam profile.

To determine and adjust the moment of the start of the fuel supply on the SDTA stands, momentoscopes Fig. 4 are used.

Rice. 4 - Momentoscope: 1 - glass tube; 2 - adapter tube; 3 - segment of the high pressure fuel line; 4 - washer; 5 - union nut

Rice. 5 - Device for checking injectors: 1 - transparent fuel collector, 2 - injector, 3 - injector mounting handwheel. 4 - tank, 5 - pressure gauge, 6 - distributor housing, 7 - stopcock, 8 - plunger pump, 9 - pump drive lever

Works performed during maintenance of the diesel power system.

With EO, they check the oil level in the injection pump housing and the regulator, top up if necessary, clean the fuel equipment from dirt, check its tightness, check the fasteners. In the cold season, sediment is drained from the filter housings for coarse and fine fuel cleaning. Check the operation of the fuel equipment by a trial run of the engine.

At TO-1 - inspect and evaluate the condition of the instruments of the fuel transfer system and air supply; the tightness of their connections and, if necessary, eliminate the detected malfunctions; control the operation of the fuel supply control drive and, if necessary, adjust; sediment is drained from the fuel tank and coarse and fine fuel filters.

At TO-2 - perform the following: check the fastening and tightness of fuel tanks, fuel lines, fuel pumps, filters, injectors; serviceability of the drive fuel supply control; check the passage of fuel from the tank to the nozzles and, if necessary, remove air from the fuel supply system; after starting the engine, adjust the crankshaft speed at idle and check the operation of the engine; check the operation and, if necessary, adjust the high-pressure fuel pump and the automatic fuel injection advance clutch, injectors; check the tightness of the intake stroke connections from the air filter to the engine and the connections of the exhaust system; remove and check coarse and fine filters; clean the air filter element by blowing or washing; check the filter element by pressure testing with compressed air in water.

With CO, the sludge is drained and the fuel tanks are checked, the air filter element is replaced, the injectors are removed, cleaned and adjusted, the tightness of the engine air supply system, as well as the exhaust gas exhaust system is checked and, if necessary, the leaks are eliminated. In preparation for winter operation, the high-pressure fuel pump and the fuel priming pump are removed, checked and adjusted on the stands. Change the fuel according to the operating season. Maintenance of the air filter consists in the fact that the filter housing is washed in gasoline, diesel fuel or hot water, blown with compressed air and dried. The need to service the filter element is signaled by the red flag of the air filter clogging indicator in the second pipelines (collectors) of the engine. When a vacuum of 0.007 MPa is reached, the indicator is activated, i.e. the red drum covers the indicator window and does not return to its original position after the engine is stopped.

Nozzle adjustment.

When servicing, each nozzle must be adjusted to a needle lifting pressure of 180 + 5 kgf / cm2.

It is recommended to adjust the nozzles on a special device KP-1609 or another device of a similar design with adjusting washers installed under the spring, with the atomizer nut, atomizer, spacer and rod removed. With an increase in the total thickness of the shims (increasing the compression of the spring), the pressure increases, with a decrease, it decreases. A change in the thickness of the washers by 0.05 mm leads to a change in the pressure at the beginning of the needle lift by 3-3.5 kgf/cm2.

The quality of sawing is considered satisfactory if, when fuel is supplied to the nozzle at a speed of 70–80 swings of the device lever per minute, it is sprayed when injected into the atmosphere to a foggy state and is evenly distributed over the cross section of the jet cone. The start and end of the injection must be clear. Injection with a new nozzle is accompanied by a characteristic sharp sound. The absence of it in used nozzles when checking on a manual stand does not serve as a criterion for determining their poor performance. In case of coking of one or several holes, the nozzle should be disassembled, its parts cleaned and washed in gasoline. If fuel leaks along the cone or if the needle sticks, the atomizer must be replaced.

engine diesel injector mechanism

Rice. 6 - Nozzle of the KamAZ engine - 740: 1 - spray needle; 2 - copper washer; 3 - annular cavity; 4 - atomizer; 5 - union nut; 6 - pin; 7 - ball; 8 - body; 9 - rod; 10 - spring plate; 11 - spring; 122 adjusting screw; 13 - a glass of a spring; 14 - locknut; 15 - cap; 16 - gasket; 17 - bushing; 18 - mesh filter; 19 - fitting seal; 20 - fitting; 21 and 23 - channels; 22 - annular groove; 24 - brass glass; 25 - cylinder head; 26 - prefix; 27 - sealing ring; 28 - adjusting washers; 29 - support washer 3 and at the lower end of the needle will exceed the resistance of the spring 11

The main malfunctions of the lubrication system

Malfunction		signs
1.Lower oil pressure	Insufficient lubricant level, decrease in viscosity, clogging of the oil receiver mesh, wear of oil pump parts, wear of crankshaft and camshaft bearings, jamming of the pressure reducing valve in the open position.	See KIP.
2. Increased oil pressure	The use of high viscosity lubricant, clogged lubrication lines or oil filter, pressure reducing valve sticking in the closed position.	See KIP.
3.Lubricant pollution, rapid oil aging.	Water ingress, prolonged operation of the engine in modes other than nominal, significant wear of the parts of the cylinder-piston group, poor quality of the lubricant.

Work performed during maintenance of the lubrication system.

When EO - check the oil level, the tightness of the system, add oil if necessary, after stopping the engine, check the operation of the centrifugal filter.

At TO-1, they check the tightness of the components and pipelines, check the oil level in the high-pressure fuel pump. Under conditions of high dustiness, the oil in the crankcase is changed, the sediment is drained from the centrifugal filter, on engines with a coarse oil filter, the cover and drain sediment are unscrewed, the air is washed and filled with oil.

At TO-2 - in addition to the work performed at TO-1, they replace the lubricant in the engine according to the schedule, replace the oil filter, check and clean the crankcase ventilation channel, check and change the lubricant in the compressor filter.

With CO, they are carried out together with TO-2, fill in the lubricant corresponding to the season, check the serviceability of the oil pressure sensor, in preparation for winter, turn off the oil cooling radiator, and connect it by summer.

The main malfunctions of the cooling system.

Malfunction		Detection method
1. Overheating	Insufficient amount of coolant in the system, poor fluid circulation, pump belt loosening, leakage, valve sticking in the closed position, cooling fan motor does not work, large scale deposits in the system.	The operating temperature rises.
2. Hypothermia	The thermostat valve sticking in the open position, the radiator shutters jamming in the open position, the absence of insulating covers in the winter.	The temperature does not rise.

Work performed during maintenance of the cooling system.

When EO - check the absence of fluid leakage in all connections of the cooling system; if necessary, eliminate the malfunction, check and, if necessary, add fluid to the radiator.

At TO-1 - check the absence of fluid leakage in all connections of the cooling system; if necessary, eliminate the malfunction, lubricate the water pump bearings (according to the lubrication schedule), check the tightness of the pipelines.

At TO-2 - in addition to work on TO-1, check the tightness of the cooling system and, if necessary, eliminate fluid leakage, fix the radiator, its lining, blinds and insulation hood (in the cold season), fix the water pump and check the tension of the fan drive belt; if necessary, adjust the tension belts, check the condition of the thermostat, drain valves and the tightness of the heating system.

When CO - combined with TO-2, check the tightness of the cooling system, in preparation for winter, check the operation of the starting heater, install insulation covers, check the operation of the blinds or radiator shutters, the operation of the drain valves of the system, in preparation for summer operation, check the operation and preserve the starting heater.

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Typical malfunctions and engine diagnostics

Car owners are faced with such engine malfunctions:

The work of the internal combustion engine became unstable.
The appearance of extraneous noise when the engine is running in the form of clicks and crackling.
The appearance of an unpleasant smell in the cabin of the car, which was previously absent.
Change in color and density of exhaust gases (become thick and dark).

An engine malfunction is signaled by indicators on the dashboard. In such cases, you need to urgently contact the technical center for diagnostics, which will help determine the cause of the defect.

Engine repair

We accept cars with both petrol and diesel engines for repair. After diagnosing and establishing the cause of a malfunction in the engine, the following operations are performed:

The engine is removed and cleaned. Then the engine is disassembled, the parts are washed.
A visual inspection of assemblies and parts is carried out and their degree of wear/deformation is measured using measuring instruments. When examining the crankshaft, microcracks that have appeared are revealed, the beating of the necks is measured.
The collected information is checked against the nominal values, after which the specialists of our technical center in Moscow determine the method of repair and the list of parts to be replaced: cylinder head, timing belt, camshaft gear, crankshaft main bearings.
Repair work is underway, the engine is installed in place. After installation, tests and balancing of the repaired internal combustion engine are necessarily carried out to achieve stable operation.

The cost of maintenance and repair of internal combustion engines

Timely maintenance of the car engine guarantees the prevention of many malfunctions and the maintenance of the internal combustion engine in a technically sound condition. Car owners can choose the best maintenance package for themselves in our technical center. The cost of maintenance will be determined by the list of works included in the selected package and the type of internal combustion engine, repair work - their volume and the number of standard hours that are necessary to perform each technological operation.

We guarantee each client an attentive attitude to his problems, fast and high-quality maintenance and repair, stable and reliable operation of the engine during the entire warranty period.

To keep the engine running and in good condition appearance, reducing the wear rate of parts, preventing failures and malfunctions, as well as identifying them in order to eliminate them in a timely manner, perform engine maintenance.

Maintenance of the engine as a whole is reduced to a number of the following works and operations: cleaning the engine and attachments from dirt, cleaning engine parts from carbon deposits, tarry and ointment deposits; checking and, if necessary, tightening fasteners; replacement of oil, coolant, fuel, oil and air filters; adjustment work. A significant amount of work during TO-1 falls on the control and restoration of the tightening of the threaded connections that fasten the equipment, pipelines and exhaust pipes of the muffler, as well as the engine itself on supports. At TO-2, they check and, if necessary, tighten the fastening of the cylinder heads, adjust the thermal clearances in the gas distribution mechanism, check and adjust the tension of the generator drive belts, etc.

Cleaning the engine and attachments from contamination is carried out periodically as necessary. To clean engine parts from soot, tarry and ointment deposits, as well as to remove water from the fuel system, special additives are used that are added to fuel and oil during engine operation at intervals of once every 3-5 thousand kilometers of the car.

The main work during the technical maintenance of the crankshaft and timing: EO: Clean the engine of dirt and check its condition. The engine is cleaned of dirt with scrapers, washed with a brush dipped in a soda solution or a solution of washing powder, and then wiped dry. During TO-1, the fastening is checked: equipment on the engine, pipelines and exhaust pipes of the muffler, engine on the frame. At TO-2, they check and, if necessary, fix the engine cylinder heads; adjust the gaps between the valve stems and rocker toes. With significant wear of the parts of the gas distribution mechanism, the engine is repaired.

The main work during the maintenance of the cooling system: EO: Check the fluid level in the radiator or in expansion tank. Check for fluid leakage in the cooling system. TO-1: Check for fluid leakage at all cooling system connections; repair leaks if necessary. Lubricate water pump bearings. TO-2: Check the tightness of the cooling system and, if necessary, eliminate the leakage of liquid. Check the fastening of the water pump and the tension of the fan drive belt; if necessary, adjust the tension of the belt and tighten the mount. Check fan mounting. Lubricate the water pump bearing (as scheduled). Check the operation of the steam-air valve of the radiator cap.

The main work during the maintenance of the lubrication system: EO: Check the oil level with an oil gauge before starting the engine and on the road during long trips and top up if necessary. TO-1: Visually check the tightness of the devices of the lubrication system and oil pipelines. Troubleshoot if necessary. Drain sediment from oil filter. Before draining the sludge, warm up the engine, clean the filter housing from dust and dirt. Check the oil level in the crankcase and top up if necessary. Change the oil in the crankcase according to the schedule, while replacing the filter elements, and also remove sediment from the centrifugal filter. TO-2: Visually check the tightness of the connections of the engine lubrication system and the fastening of devices, if necessary, eliminate the malfunctions. Drain sediment from filter. Change the oil in the crankcase.

The main types of adjustment work carried out during engine maintenance include: tensioning the drive belt of the generator and coolant pump; checking the coincidence of the marks of the gas distribution phases; tension of the chain (belt) of the timing drive; adjustment of thermal gaps in the valve drive; adjustment of the initial ignition timing; adjustment of fuel supply, idle speed and the content of harmful substances in exhaust gases (adjustment of the fuel system); adjustment of the fuel injection advance angle (for diesel engines).

The repair of the engine includes its disassembly, cleaning using special detergents, assessment of the degree of wear of parts. All worn parts must be replaced or restored by boring liners, cylinders, pistons, piston rings in order to give them the desired shape. After assembly, the engine is tested on a special stand, which makes it possible to determine whether all problems have been resolved during the repair.

Ticket number 23.

1. 1. Classification and main characteristics of car service enterprises.

The classification of car service enterprises by type of service covers public and private enterprises and is divided into the following groups:

1) STOA (separately for domestic cars and foreign cars);

2) auto repair shops;

3) garages;

4) technical service points with filling stations;

5) trade enterprises.

STOA - city, road can be equipped with car washes, both universal and special, depending on the structure of the station (names of sections, maintenance posts).

Auto repair shops received in Lately the most widespread as a service station for 2-3 posts, for example, on the basis of garage cooperatives, or special auto repair shops, such as:

Tire repair (vulcanization, installation, dismantling of tires);

Repair of the electrical system (generators, starters, electrical wiring, replacement of candles);

Body work (painting, drying);

Engine repair, etc.

These mini-workshops have a wide range of placement - from the farmstead of a private trader to the industrial site of the ATP or in the rented premises of any organization.

Garages group in the system of the new classification by type of service includes garage cooperatives and car parks - closed and open.

In combination with a gas station (gas station), fitting into the fire safety standards (NPB) and the requirements of the instructions for the installation of lightning protection for buildings and structures (RD 34.21), any car service enterprises are designed, including a car wash and a distribution network, which are located on the wind rose on the leeward side in relation to gas stations.

A special place in the classification is occupied by trade enterprises: car markets, car dealerships, car shops and just retail outlets on the territory of car markets, at the entrance to gas stations, etc. Retail outlets or just stalls are divided according to the type of goods sold: auto parts and related products (varnishes, paints, oils, etc.).

4. Maintenance of the engine, cooling and lubrication systems

A good engine should develop full power, run smoothly at full load and idle, not overheat, smoke, or leak oil and coolant through the seals. The malfunction can be determined by diagnosing by outward signs without dismantling the engine.

The crank mechanism has the following symptoms of a malfunction: extraneous knocks and noises, a drop in engine power, increased oil consumption, excessive fuel consumption, the appearance of smoke in the exhaust gases.

Knocks and noises in the engine occur as a result of increased wear of its main parts and an increase in the gaps between mating parts.

When the piston and cylinder are worn, as well as when the gap between them increases, a sonorous metallic "knock" occurs, which is well heard when the engine is running cold. A sharp metal knock in all engine operating modes indicates an increase in the gap between the piston pin and the head sleeve

Carbon deposits are removed with wooden or soft metal scrapers so as not to damage the piston bottom or the walls of the combustion chamber. When removing carbon deposits, cover adjacent cylinders with a clean rag. The soot is removed more easily if it is softened by putting a rag moistened with kerosene on it.

When installing the cylinder head gasket, it must be rubbed with powdered graphite.

Cracks in the walls of the cooling cavity of the block and cylinder head can appear when water freezes or the cooling jacket of a hot engine is filled with cold water.

The gas distribution mechanism has two characteristic malfunctions - a loose fit of the valves to the sockets and incomplete opening of the valves,

A loose fit of the valves to the sockets is detected by the following “signs: a decrease in compression, periodic pops in the intake or exhaust pipeline, a drop in engine power. valve heads; broken valve springs; stuck valves in the guide bushings; lack of clearance between the valve stem and the toe of the rocker arm.

Incomplete opening of the valves is characterized by knocking in the engine and a drop in power. This malfunction appears as a result of a large gap between the valve stem and the rocker toe. The malfunctions of the gas distribution mechanism should also include wear on the camshaft gears, pushers, guide bushings, an increase in the longitudinal displacement of the camshaft and wear on the bushings and rocker arm axles. In ZIL-130 engines, the exhaust valve turning mechanism may malfunction as a result of jamming of the balls and springs of the turning mechanism. Carbon deposits must be removed with a scraper; valves with small shells on the working surface should be ground in, the broken spring replaced. The broken gap is restored by adjustment.

To grind the valves, the valve spring is removed, a weak spring is laid under its head, a layer of paste consisting of abrasive powder and oil is applied to the working surface, and a reciprocating rotational motion is imparted to the valve using a brace or lapping device. When changing the direction of rotation, the valve must be lifted. Lapping is completed if continuous matte stripes 2–3 mm wide appear on the surface of the seat and the working surface of the valve. The tightness of the valve seat after grinding is checked using a device or kerosene. In the latter case, the valve is installed in the seat, a spring is put on and fixed on the rod, the cylinder head is turned over and kerosene is poured into the combustion chambers. The appearance of kerosene on the rod and guide sleeve indicates poor grinding.

To adjust the gap between the stem, valve and rocker toe, you must: remove the valve cover by removing the parts previously attached to it; install the piston at the end of the compression stroke (so that the valves are closed); check the gap and, if necessary, adjust it, to do this, unscrew the lock nut of the adjusting screw on the rocker arm and, turning the adjusting screw, set the desired gap (Fig. 193), tighten the lock nut and check the gap again.

The necessary limitation of the displacement of the camshaft is achieved by selecting the thickness of the spacer ring. With significant wear of the parts of the gas distribution mechanism, the engine is repaired.

The cooling system is one of the most important in the engine. If it is faulty, the engine overheats or overcools. Diagnosis of the cooling system is carried out by external signs.

Insufficient engine cooling, and as a result, boiling of the coolant in the system may occur from an insufficient amount of it in the cooling system, slipping of the fan belt with a weak tension or as a result of oiling, contamination or scale deposits in the system and improper operation of the thermostat.

An overcooled engine can be caused by a malfunctioning thermostat or a blind stuck open. In winter, at low air temperatures, if you do not take protective measures (cover the blinds, put on insulating fur, etc.), hypothermia of the engine and further freezing of the water in the system are also possible.

Insufficient level of coolant in the upper tank of the radiator when it leaks from the cooling system or boils away; Leakage of coolant from the system can occur through seals, leaks in the connection of pipes, drain cocks and damaged areas of the radiator. A leak when the seals are worn is detected by the leakage of coolant through the control hole in the lower part of the pump housing.

When this malfunction occurs, it is necessary to drain the coolant, loosen the fan belt and remove it, loosen the clamp, disconnect the rubber hose and carefully remove the water pump so as not to damage the gasket.

Loosen the bolt securing the impeller, remove it. In the stuffing box, either the rubber cuff or the self-supporting washer can be damaged: the damaged parts must be replaced, the pump must be assembled and installed. If the cylinder head gasket is damaged, replace it. If the water pump impeller breaks, it must be replaced.

Leaks in the connections of the nozzles with hoses are eliminated by tightening the clamps (if the thread of the tightening bolt of the clamp is fully used, then a metal strip is placed under the removed clamp), and the faucets that allow fluid to pass through are rubbed. To do this, they are removed from the engine, disassembled, lapping paste is applied to the working surface and rubbed with a rotational movement until a matte surface appears on all working parts of the faucet.

A damaged radiator must be removed and sent in for repair.

Fan belt tension. A correctly tensioned belt bends by 8 ... 10 mm when pressed by hand with a force of 29.4 ... 39.2 N. Slippage can also be caused by grease that has fallen on the belt and pulleys.

In the ZIL-130 engine, the fan pulley is driven by two belts. The tension of one of them is regulated by the movement of the generator, and the second - by the movement of the power steering pump. In the ZMZ-53 engine, the fan belt tension is changed with a tension roller.

Sticking the thermostat in the closed position stops the circulation of fluid through the radiator. In this case, the engine overheats, and the radiator remains cold. If the thermostat sticks open, the engine will overcool. In both cases, after releasing the liquid from the cooling system, carefully remove the pipe and thermostat.

The thermostat is checked by lowering it into water. Heating the water, follow! behind the thermostat valve and thermometer. The valve should begin to open at a temperature of 70 ° C and open completely at a temperature of 83 ... 90 ° C. When examining the thermostat, it is necessary to pay attention to the absence of scale and the cleanliness of the hole in the valve designed to pass air.

Blinds sticking due to insufficient lubrication or drive failure. The cable together with the sheath must be removed, washed in kerosene and, having lubricated, put in place.

During the operation of the car, scale is deposited on the walls of the cooling cavity, as a result of which the heat removal from the parts worsens. The channels of the cooling system devices are clogged with scale and corrosion products, which leads to engine overheating. Scale is removed by flushing the cooling system devices separately, since the solutions used to flush the radiator cannot be used when flushing the cooling cavity of the block and cylinder head made of aluminum alloy.

Before washing, the radiator is removed from the car and filled with a 10% solution of caustic soda (caustic soda) heated to 90 ° C. This solution is kept in the radiator for 30 minutes, and then drained and a mixer is attached to the lower tank pipe, to which bring hot water and compressed air. To control the pressure of compressed air, a pressure gauge is attached to the pipe coming from the lower radiator tank to the heater.

The radiator is flushed simultaneously with hot water and compressed air so that water flows out through the pipe of the upper tank and the pressure in the lower tank does not exceed 0.1 MPa. The caustic soda solution must be handled very carefully to avoid skin burns and corrosive clothing.

If the scale deposit on the walls of the cooling cavity in the radiator pipes is insignificant, it is removed with a chrompic solution without removing the radiator from the car. Chrompic solution is prepared at the rate of 4...8 g per 1 liter of water and poured into the system.

"When the cooling system is filled with such a solution, the car is operated for a month (when water boils away from the solution, water is added, if it leaks through leaks in the connection, the solution). After draining the solution, the system must be thoroughly rinsed with clean water in the direction opposite to circulation, skipping 10-15 - times the volume of water.

The lubrication system has two main symptoms of a malfunction:< понижение или повышение давления масла. Ухудшение смазки бывает в результате попадания сконденсированного топлива, частиц нагара, осмоления и т. д. Диагностирование техническое состояния системы смазки осуществляется контрольным мачометром и по цвету масла.

A decrease in oil pressure may be due to oil leakage in the oil line, wear of the oil pump and bearings of the crankshaft and camshafts, low oil level in the oil pan, insufficient viscosity, sticking of the pressure reducing valve in the open position. Oil leakage occurs at the point of loose fittings and plugs or through cracks in the oil lines. To eliminate the leakage of the fitting and plug, they must be tightened, and tubes with cracks should be replaced. Malfunctions of the pump, pressure reducing valve and bearings are eliminated in repair shops.

A low oil level in the sump may be due to oil burnout, leakage through crankshaft oil seals and gasket damage.

Old oil or oil of insufficient viscosity must be replaced.

An increase in oil pressure in the system occurs as a result of clogging of oil lines, the use of oil with a high viscosity, and the pressure reducing valve sticking in the closed position. Clogged oil lines are cleaned (in a disassembled engine) with a wire, washed with kerosene and blown with compressed air. To check the correctness of the readings of the oil pressure gauge, instead of one of the plugs of the central line, the fitting of the control pressure gauge is screwed in and, after starting the engine, the readings of the control pressure gauge and the oil pressure gauge are compared.

Basic maintenance work on the crank and gas distribution mechanism. EO. Clean the engine of dirt and check its condition. The engine is cleaned of dirt with scrapers, washed with a brush dipped in a soda solution or a solution of washing powder, and then wiped dry.

The condition of the engine is checked by external inspection and listening to its operation in different modes,

TO-2. Tighten the cylinder head nuts. Tightening is carried out on a cold engine with a torque wrench or with an ordinary wrench from the driver's tool kit. After the “difference of tightening the nuts of the cylinder head kreilekm-” of the ZMZ-53 engine is shown in Fig. 194. The force (torque) is pr! tightening should be 73...78 11. Threaded connections should be tightened evenly, without jerks, in a strictly defined order for each type of engine. Tighten the block head nuts from the center, gradually moving towards the edges. On V-shaped engines, before tightening the cylinder heads, drain the water from the cooling system and loosen the intake manifold nuts. After tightening the cylinder head nuts, re-tighten the intake manifold nuts and adjust the clearances between the valves and rocker arms.

The crankcase pan is fastened at the viewing room. At the same time, the car must be braked with a parking brake, turn on a lower gear, turn off the ignition, and put blocks under the wheels. Check the gap between the valve stem and the toe of the rocker arm and adjust if necessary.

When tightening the fastening nuts, it is necessary to use serviceable tools, selecting the keys exactly according to the size of the nuts. It is not allowed to work with wrenches with non-parallel, worn jaws. It is forbidden to unscrew and tighten nuts with a wrench. large sizes with placing metal plates between the faces of the nut and the key, lengthening the key handle by attaching another key or pipe.

CO. Twice a year, check the condition of the engine cylinder-piston group.

Basic maintenance of the cooling system. EO. Check the fluid level in the radiator or in the expansion tank (KamAZ). The liquid level in the radiator should be 15...20 mm below the filler head.

When filling the cooling system with antifreeze, it is necessary to fill it with 6 ... 7% less than water by volume, since when heated, it expands more than water. When the antifreeze evaporates, it is necessary to add water, and when it leaks, antifreeze. Check for fluid leaks in the cooling system.

TO-J. Check the absence of fluid leakage in all connections of the cooling system; repair leaks if necessary. Lubricate the water pump bearings (according to the lubrication schedule). The lubricant is pumped with a syringe through the oiler until it appears from the control hole of the pump. Further injection of grease can lead to extrusion of oil seals.

TO-2. Check the cooling system for leaks and repair fluid leaks if necessary. Check and, if necessary, fix the radiator, its lining and blinds. Check the fastening of the water pump and the tension of the fan drive belt; if necessary, adjust the tension of the belt and tighten the mount. Check fan mounting. Lubricate the water pump bearing (as scheduled). Check the operation and tightness of the heating system, the operation of the blinds. At the extreme forward position of the handle, the shutter plates should be fully open, gradually closing when the handle is moved towards itself. Check the operation of the steam-air valve of the radiator cap.

CO. Flush the cooling system twice a year. Check the condition of the insulating cover (in winter) and the reliability of its fastening. When preparing for winter operation, check the condition and operation of the starting heater and other auxiliary means to facilitate starting the engine installed on the vehicle, and, if necessary, eliminate the malfunction. When storing cars without garages in the cold season, after the end of work, it is necessary to drain the water from the cooling system by opening the taps on the block and the lower radiator pipe, the radiator filler cap and the tap of the body heating system.

Basic maintenance work on the lubrication system, EO. Check the oil level with an oil gauge before starting the engine and during long journeys and top up if necessary. In winter, when the car is stored in an open area and at a low temperature, upon completion of work, drain the oil from the crankcase of a warm engine, and before starting, pour oil heated to 90 ° C into the crankcase, except when using the starting heater. Check for oil leaks.

TO-1. Visual inspection to check the tightness of the devices of the lubrication system and oil pipelines. Troubleshoot if necessary. Drain sediment from oil filter. Before draining the sludge, warm up the engine, clean the filter housing from dust and dirt. The sediment must be drained into the dishes, while unscrewing the screw plug, so as not to contaminate the engine. Check the oil level in the crankcase and top up if necessary. Change the oil in the crankcase according to the schedule, while replacing the filter elements (KamAZ), and remove sediment from the centrifugal filter.

TO-2. External inspection check the tightness of the connections of the engine lubrication system and the fastening of the devices, if necessary, eliminate the malfunctions. Drain sediment from filter.

Change the oil in the engine crankcase (according to the schedule). Change the oil under average operating conditions of the car according to the factory instructions (after a run of 2000 ... 3000 km). This is usually combined with one of the maintenance. With an oil change, the filter elements (KamAZ) are replaced and the centrifugal oil filter is cleaned. To completely drain the oil, the engine must first be warmed up.

If, when draining the oil, it is found that the lubrication system is contaminated (strong darkening of the oil and the presence of a large amount of mechanical impurities), then it is necessary to flush it. To do this, pour flushing oil (industrial oil) into the crankcase pan to the bottom mark of the oil gauge, start the engine at a low crankshaft speed (^2 ... 3 min), and then, having opened all the plugs, drain the flushing oil. The filter housing is washed with a brush with the cover removed and the drain plug unscrewed. After flushing the housing, new filter elements (KamAZ) are installed. After washing the filter, wrap the plugs in place and pour fresh oil into the oil pan through the oil filler pipe in the amount specified in the factory instructions. The engine is started and warmed up to normal temperature. Then the engine is stopped and after 3 ... 5 minutes the oil level is checked. To remove sediment from the centrifugal filter of the ZMZ-53 engine, it is necessary to remove the crankcase ventilation air filter from the oil filler pipe, unscrew the lamb, remove the casing, unscrew the round nut with one hand, holding the cap from rotation with the other hand, and carefully remove it. Then remove the mesh, clean the cap from precipitation, rinse it and the mesh. Install the mesh and cap in place, avoiding damage rubber seal rotor, tighten the cap nut (not tight) by hand, making sure that the cap is in place without distortion. .After that, install the cover and tighten the wing nut. Flush the crankcase ventilation system. Reinstall the crankcase ventilation filter, start the engine and check for oil leaks. After removing sediment and changing the lubricant, the engine must not be immediately allowed to operate at a high crankshaft speed. When checking the operation of the centrifugal filter, it is necessary to increase the engine speed, and then stop it. If the filter is in good condition, then after stopping the engine for 2 ... 3 minutes, a characteristic hum of a rotating rotor will be heard. If it is found that the filter does not work well, it is necessary to disassemble it and clean the jets and bushings.

After overcoming water obstacles, it is necessary to check the units; if veda is found in them, the old oil should be drained and the unit filled with new oil. If the car often has to work in water, then lubrication must be added to the swivel joints more often.

Oil after draining must be collected for subsequent processing and reuse, which gives great savings. Used oils must be stored separately by brand, avoiding mixing them.

CO. Flush the engine lubrication system twice a year and change the type of oil depending on the season. When preparing for winter operation, turn off the oil cooler.

Timely elimination of faults and high-quality maintenance of rolling stock ensures the prevention of increased wear of parts, components and assemblies of vehicles, an increase in overhaul runs, a reduction in repair costs, an increase in the duration of a vehicle’s operation during the day, an increase in productivity, a reduction in the cost of transportation and ensuring trouble-free and safe operation .