Maintenance and current repair of crank-connecting and gas distribution mechanisms

Crank-rod (CSM) and gas distribution (timing) mechanisms are the main engine. Any deposits and malfunctions of their parts immediately lead to a decrease in the power, economic and environmental characteristics, and the breakdowns of these parts are to stop the engine and the cessation of the transport process.

The main faults of the CSM are cylinders, pistons, piston rings, piston fingers, sleeves of heads of rods, connecting rod and indigenous bearings, crankshaft necks.

The main failures of the KSM are: breakdowns of piston end, piston enclosure, flowing inserts, cylinder mirrors jackets, block cracks or block cylinder heads.

In case of faults, characteristic noise and knobs appear during engine operation, the compression in the cylinders is reduced, the breakthrough of gases into the crankcase from the alignment space increases, increasing oils.

The main malfunctions of the GDM are the wear of the valve pushers and their guide sleeves, the valve plates and their saddles, cams and the cushioning necks, the gas distribution gears, the change in thermal gaps between the valve rods and the pushers (or rockers), the wear of the oil-challenge caps. When the teeth breakdown, the GEAR GRM, the gap of the chain or belt gear gear, extinguishing valves, damage the valve springs, there is a violation of gas distribution phases and, as a result, the fuel consumption increases sharply, the engine power decreases, up to its complete stop.

The characteristic signs of timing faults serve appearing knobs, cotton and outbreaks in the inlet pipeline and silencer.

The diagnosis of the technical condition of the CSM and the GDM is carried out according to the characteristic stacks with the help of stethoscopes, compression, on air leakage from the epipper space, for the breakthrough of gases to the engine crankcase, on oil to fill and other parameters.

The engine compression that depends on the wear of the cylinder-piston group, the tightness of the landing of the valves and the block laying of the block head, is measured using compressometers (Fig.2.14) or compressorographs (recording pressure gauges).

a - compressometer scheme; b - general type of device

1 - spool; 2 - rubber cone bushing; 3 - check valve; 4 - screw for reset testimony; 5 - case; 6 - manometer

Figure 2.14 - Compressometer device

A spool 1 is necessary that the fuel-air mixture falls out of the cylinder does not leave the instrument body before stabilizing the testimony of the pressure gauge.

When checking compression, the engine must be heated to a normal operating temperature (80 ... 90 ° C) and air and throttle valve Must be fully open. The compressometer is inserted alternately into the windows of the engine and turn the crankshaft with the starter. When checking compression in diesel engines, the compressometer is fixed due to larger pressures (2.0 ... 2.5 MPa) as well as the nozzle.

Compression value for gasoline engines Lies in the range from 0.8 to 1.2 MPa, and diesel - 2.5 ... 3.5 MPa. The difference in cylinder compression should not exceed 0.1 MPa gasoline, for diesel - 0.3 MPa. If data on the amount of compression is absent, then its regulatory values \u200b\u200bin MPa can be roughly determined:

P c \u003d e × k (2.11)

where e.- compression ratio this engine;

to - The coefficient taken in the range of 0.1 ... 0.12.

If the compression is less regulatory, then it is necessary to fill 15 ... 20 grams for a cargo and 8 ... 10 grams for a car of the same oil, which is flooded in the engine crankcase, and test the test. Oil connate gaps between the piston, rings and cylinder. Therefore, if the compression increases significantly, this will indicate the wear of the cylinder-piston group (CPG), and if not, then on a loose landing of the valves.

The relative amount of compression in percent is measured on a motor-tester on the amplitude of the starter current pulsation consumed when scrolling the crankshaft. For 100%, the largest compression of all cylinders is taken, therefore the accuracy of this method is lower due to the different degree of charge of the rechargeable battery.

More accurate and wider possibilities are a method for diagnosing compressed air leakage. Existing devices (K-69M and K-272) have a practically the same functional circuit (Fig.2.15)

1 - clutch quick-consuming; 2 - Entrance fitting; 3 - gearbox; 4 - nozzle entrance; 5 - pressure gauge measuring; 6 - damper; 7 - adjusting screw; 8 - fitting output; 9 - connecting coupling; 10 - fitting; 11 - Rubber seal

Figure 2.15 - Device K-69M NIIAT

When testing through the candle holes, the compressed air of a certain pressure (0.16 MPa) is supplied, which is supported by a pneumatic tutor 3, and the consumption provided by the presence of a calibration pipeline and an adjustment screw 7.

The device is powered by a pressure compressor 0.3 ... 0.6 MPa. The gauge scale can be normalized as a percentage. 0% corresponds to a pressure of 0.16 MPa, and 100% - 0 MPa. The piston of each cylinder is alternately set to the beginning of the compression (when the intake valve) and the position of the NMT compression clock is closed. To install the piston of each cylinder, the simplest devices included in the instrument package are used to these positions. In each position, air pressure is fixed in 1 and in 2. If there is a looseness, then the air will go through them and the pressure will fall. The more pressure falls, the higher the deposits of the CPG and (or) timing. On the difference between leaks DU \u003d in 2 - in 1, it is judged about the wear of the cylinder, since the cylinder wear is larger. It should not exceed 15 ... 30%. The magnitude of the leakage at the position of the piston in the VMT end of the compression tact (in 2) depends on the diameter of the cylinder and should not exceed 25 ... 40% (large values \u200b\u200b- for large diameters). In terms of 1 (no more than 10 ... 15%), the state of piston rings and valves is evaluated. If the value of 1 exceeds the permissible, then the piston in the checked cylinder is set to the end of the compression tact and the air is supplied. By pressing the device under pressure 0.3 ... 0.5 MPa. So that the piston does not go down, you need to turn on the first gear and parking brake. With worn piston rings, the noise of the air in the oil refining neck is heard. If the gasket burned, the noise of the air will be heard in the silent neck of the radiator ( expansion tank) or in the head of the head with the block of cylinders.

In case of looser in the landings of the valves, the emptying of the indicators (included to the instrument kit), inserted into the candleting holes of the adjacent cylinders, where in this position of the checked cylinder is open intake or exhaust valve. Table with valve verification sequence for different engines It is available on the front panel of the device.

The breakthrough of gases into the crankcase is determined by the gas flow meter (KI-4887) or the gas meter (GKF-6). At the same time, the crankcase ventilation system tube is disconnected and covered with plugs (included in the KI-4887) of the holes of the valve covers, the oven probe, the crankcase ventilation tube, etc., so that the crankcase gases leave only through the oil refining neck to which the instrument input is connected (rice .2.16).

The principle of operation of the flow meter is based on the dependence of the volume of gas passing through the choke of the device, depending on the area of \u200b\u200bthe passing section S with a given pressure drop of DR before and after the throttle:

, (2.12)

where m is the expiration coefficient (0.62 ... 0.65);

Q. - gas volume, m 3 / s;

S. - area of \u200b\u200bpassage cross section, m 2;

r. - the density of the gas mixture, kg / m 3;

D. R - Pressure drop, PA.

A vacuum pump is connected to the output part of the device. Permanent vacuum pump performance, and the volume of breaking gases different engineshaving varying technical condition - Various. Therefore, that all breaking gases immediately pumped out the pump through the device, open or close the choke 2 so that the water level in the tubes 6 and 7 becomes the same (that is, the pressure in the crank will become equal to atmospheric).

1 - body of the device; 2 - input throttle to create atmospheric pressure in a crankcase; 3 - choke to create a fixed drop D R; 4 - Carter gases flow meter scale; 5, 6, 7 - Piezometers

Figure 2.16 - Scheme of the Gas Flowometer KI-4887

Wrathic choke 3 set a fixed pressure drop D R\u003d 15 mm of water column. The greater the breakthrough, the smaller the cutting before the throttle 3 and the amounts to the drop-down angle, it is necessary to turn it (increasing the area of \u200b\u200bthe passage section S) to ensure the specified value D R. With choke 3, an arrow is connected, which on the scale of the device will indicate the volume of gases in l / min. For most engines, the limit value is 80 ... 120 l / min.

Ugra oil, which characterizes the wear of the cylindrophone group, is controlled by its level in the engine crankcase. Versimals are considered to be a waste of oil, constituting 0.5 ... 1% of the amount of fuel consumed, with large values \u200b\u200bcorrespond to diesel engines. The method is not applicable if there is leakage of oil from the system.

Maintenance of CSM and graphs checking and pulling down the fasteners entering them elements, adjustment and lubrication.

Fasteners are carried out to check the status of fixtures of all engine connections: engine supports to frame, cylinder head, crankcase pallet to block, inlet flanges and exhaust pipelines, etc.

To prevent gas and coolant passage through the cylinder head laying, check and, if necessary, tighten the nuts to the block. This is done using a dynamometric key. The moment and the tightening sequence of nuts is installed by manufacturers (Fig. 2.17). The cast iron head of cylinders is fixed in a hot condition, and from the aluminum alloy - in cold.

Checking the tightening of the crankcase pallet attachment bolts in order to avoid its deformation and tightness impairment are also produced by observing a certain sequence consisting in alternately pulling into the diametrically located bolts and in two or three receptions.

side of release

a - VAZ engine; b - engine yamz-236; in - engine KAMAZ-740; M - Engine ZIL-130

Figure 2.17 - Tightening sequence of nuts fastening heads to engines cylinder block

Adjustment work is carried out after diagnosing. When the knock is detected in the valves, as well as at T-2, they check and control the thermal gaps between the ends of the rods of valve valves and sinks (Fig. 2.18). When adjusting the gaps, the piston of the 1st cylinder on the compression tact is set to NTC, for which the crankshaft turns to the alkali alignment. In this position, the gaps are adjusted between the rods of the valves and socks of the rumor of the 1st cylinder. The clearances in the valves of the remaining cylinders are regulated in the sequence corresponding to the order of the cylinder, turning the crankshaft on 1/2, 1/3 or 1/4 turn when switching from the cylinder to the cylinder for four, six and eight-liter engine, respectively.

1 - rod; 2 - lock nut; 3 - adjusting screw;

4 - screwdriver; 5 - rocker; 6 - probe; 7 - Valve

Figure 2.18 - Adjusting thermal gaps timing

To adjust the gaps in the KAMAZ-740 engine, the crankshaft is set to the position corresponding to the beginning of the fuel supply in the 1st cylinder using the retainer mounted on the flywheel crankcase. Then rotate the crankshaft through the hatch in the clutch crankcase at 60 ° and adjust the gaps of the valves of the 1st and 5th cylinders. Next rotate the crankshaft at 180, 360 and 540 °, adjusting the gaps according to the 4th and 2nd, 6th and 3rd, 7th and 8th cylinders. Regardless of the method of installing the crankshaft in the original position for adjusting the valve must be completely closed.

Characteristic works at the current repair of KSHM and GDM are the replacement of sleeves, pistons, piston rings, piston fingers, rinsers of rolled and indigenous bearings, valves, their saddles and springs, pushers, as well as grinding and tinting valves and their saddles.

Engine repair is best done on a specialized area where it is delivered after removal from the car. Before repairing the engine, it is necessary to drain the coolant from the cooling system and the oil from the lubricant system, turning into the corresponding drain plugs.

Disconnect the battery and all electrical wires from the instruments of the electrical equipment and ignition system installed on the engine. These works are advisable to conduct on a specialized post on the replacement of engines equipped with an outdoor lift or inspection channel and crane (or telfer).

Disconnecting the engine, it is delivered to the repair area and are subjected to outdoor cleaning and washing, and then disassembly. Parts such as piston, sleeves, rings, connecting rods, piston fingers, liners, valves, rods, rockers and pushers if they are suitable for further use, labeled paint so that they are collecting them together with those details and on those places where they fit . The connecting rods with rods and the covers of the indigenous bearings cannot be changed in places, as they are processed in the manufacture of jointly and non-donated.

After disassembly, the parts are cleaned from Nagara, smoliest sediments and dirt mechanical and chemical ways.

The replacement of the cylinder hyilsblock is produced when their wear exceeds the allowable, in the presence of chips, cracks of any size and scaling, as well as with the wear of the upper and lower landing belts.

The sleeves are processed using a special puller, whose grippers engage for the lower end of the sleeves.

The new sleeve is selected by the cylinder block so that its end spoke over the plane of the connector with the block head. For this, the sleeve is installed in the block of cylinders without sealing rings, covered with a test plate and the dipstick measure the gap between the stove and the cylinder block. The sleeve installed in the block without sealing rings should be freely turning. Before the final setulation of the sleeves check the condition of the seating holes under them in the cylinder block. If they are damaged, they are restored by applying a layer of epoxy resin mixed with cast-iron sawdust, which is cleaned after frozen flush. The edges of the upper part of the block, which first come into contact with rubber sealing rings when pressing the sleeve, are cleaned with a grinding eye to prevent damage to the sealing rings during pressing. The sleeves with the rubber sealing rings installed on them are pressed with the press. When equipping sealing rings, they should not be stretched strongly and allow twisting in the groove of cylinders.

The replacement is pistoned by forming on the surface of the skirt of deep scuffs, the bottom and the surface of the piston, with the wear of the upper groove under the piston ring.

Pistons change without removing the engine from the car. Previously drain the oil from the crankcase pallet, remove the head of the block and the pallet of the crankcase, are split and turn off the nuts of the connecting rod bolts, remove the slope cover of the lower rod and remove the damaged piston assembly with rod and piston rings. Remove the lock rings from the holes in the bobbs, the piston finger is scored. If necessary, the same press is issued a bronze sleeve of the tent head.

Pistons pick up the cylinder. Its dimensional group must correspond to the dimensional group of the cylinder sleeve. The gap between the piston and the sleeve is tested with a probe tape (Fig.2.19).

To do this, the piston is inserted into the cylinder head down so that the edge of the skirt coincides with the bottom of the sleeve, and the probe tape, inserted between the sleeve and the piston, was in the plane perpendicular to the finger axis.

1 - dynamometer; 2 - tape-probe

Figure 2.19 - Measuring the gap between the cylinder and the piston

The dynamometer is stretched by the tape-probe, fixing the stretching force, which should be within 35 ... 45 N. Sizes of the probe tape and the stretching force for different models Engines are shown in operating and repair instructions. The thickness of the tape is 0.05 ... 0.08 mm, width - 10 ... 15 mm, length - 200 mm. If the stretching force differs from the recommended one, then they take another piston of the same dimensional group or, in the form of an exception, adjacent size of the group and again pick it up on the cylinder.

Within the nominal and each repair size of the sleeves and pistons for different engines can be up to six dimensional groups. The diameters of the cylinders within each of them differ by 0.01 mm. Dimensional group index (A, AA, B, BB, B, BB for sleeves and pistons of nominal size and g, yg, d, dd, e, it for the 1st repair size, etc.) is indicated on the top end of the sleeve And on the bottom of the piston. For passenger cars The diameters of the cylinders are divided into 3 ... 5 classes: A, B, C, D, E or 1, 2, 3, 4, 5 in increments of 0.15; 0.25; 0.35 or 0.4 mm.

Similar dimensional groups within each repair size have all other car engines.

Cleaning kit "Piston - connecting rod" diameter of the hole in the piston bosses, the diameter of the piston finger and the diameter of the hole in the bronze sleeve of the top head of the rod should also have one dimensional group that is marked with one paint on one of the piston buses, on the end of the finger and the top head of the rod.

When replacing the entire cylindropore group, the piston, finger, piston rings and sleeves entering in the form of spare parts with sets, are selected in advance. Therefore, when assembling, they check the labeling of parts and check the liner-probe gap between the piston and the sleeve. Properly selected piston must under their own weight slowly fall in the sleeve. The piston finger should smoothly enter the hole of the sleeve sleeve sleeve under the pressure of the thumb. The connecting rod is checked on the parallelism of the axes of the heads and during deformation exceeding the permissible, the connecting rod. When assembling, the piston is placed in a bath with engine oil, heated to a temperature of 60 ° C and the piston finger is pressed into the hole of the piston bodies and the top head of the rod with the mandrel. After that, stop rings are inserted into the grooves of the bobbs. If the landing of the finger into the connecting rod head is more dense than in the piston, the connecting rod before assembly.

Similarly, replace the sleeves of the top head of the connecting rod and the piston finger. The annual bushings are scored, and they will press new ones, while providing the necessary tension. Then the sleeves are mounted on a horizontal boring machine or processed using a sweep. The inner surface of the sleeve should be clean, without wrapping with the roughness parameter is not more than RA \u003d 0.63 μm, and the ovality and the cones of the hole is not more than 0.004 mm.

Before installing the piston assembled with a connecting rod to the cylinder block, the set of piston rings in the piston groove is set. The gap between the compression ring and the piston groove is determined by the dipstick (Fig. 2.20), rolling the ring 2 piston roller. Rings are also checked for lumen, for which they are inserted into the upper unavoidable portion of the cylinder liner and visually evaluate the density of the fitness.

1 - probe; 2 - Compression Ring

Figure 2.20 - Measuring the gap between the ring and the piston groove

The clearance in the lock is determined by the dipstick and if it is less than the permissible, then the ends of the rings are stepping. After that, the ring is repeatedly checked on the clearance and only then using a special device, squeezing the ring for ecking the lock, installed in the grooves of the facet's pistons up. They should rotate freely in the grooves of the piston. Sets of rings of the nominal size are used if the cylinders are not cleared. In the boring cylinders, the rings of the repair size corresponding to the new diameter of the cylinder are installed. The joints of the compression rings are uniformly bred around the circumference. Installing the pistons assembled with the rings to the engine cylinders is carried out using a special device (Fig.2.21).

1 - sleeve; 2 - mandrel; 3 - Piston assembly

Figure 2.21 - installation of piston with rings and connecting rod to cylinder

The replacement of the crankshaft liners is at the knocking of bearings and the pressure drop in the oil line below 0.05 MPa at an idle speed and properly operating oil pump and reduction valves. In this case, the nominal gap between the liners and the root cervix exceeds 0.026-0.12 mm and between the liners and the rod cervix -0.026-0.11 mm depending on the engine model.

The clearance in the crankshaft bearings are determined using control brass or copper foil plates with a thickness of 0.025; 0.05; 0.075 mm, 6-7 mm wide and 5 mm long in short in the width of the liner. The plate, lubricated with oil, is placed between the shaft neck and the liner, tighten the bearing cap bolts with a torque wrench with a torque defined for each engine. If the installation, for example, a plate with a thickness of 0.025 mm crankshaft rotates too easily, then the gap is more than 0.025 mm and, therefore, should be replaced with the plate to the next size, until the shaft rotates with a tangible force, which corresponds to the actual gap between the neck and insert. When checking one bearing, the rest bolts should be weakened. Similarly, all bearings are checked. Instead of brass or copper plates, a special calibrated plastic wire can be used. Its small segment equal to the width of the liner is put on the neck in the axial direction and pressed the roof of the connecting rod or the root bearing depending on where the gap is measured. Carefully so that the wire does not move, fix the lid and clamp it using the tightening assembly. Wire is flattened. Then remove the cover and the changed thickness of the wire is estimated to be gap in the conjugation, comparing the thickness of the spurred wire with a scale applied on the coiled wire packaging.

The surface of the crankshaft neck should not have loops. In the presence of loops and wear, the crankshaft is replaced or restored.

Before assembling the inserts of the desired size are washed, wipe and installed in the bed of indigenous and connecting rod bearings, pre-lubricating the surface of the liner and cervix with engine oil.

The adjustment of the axial backlash of the crankshaft row of the engines is made by the selection of thrust washers. The gap between the front persistent end of the crankshaft and the rear stubborn washer should be within 0.075-0.250 mm.

W. motors YAMZ The axial clearance of the crankshaft is regulated depending on the length of the rear root neck by installing the semi-colts. Axial gap in a thrust bearing should be 0.08-0.23 mm.

During operation due to wear, the axial gap increases. At tr, it is adjusted by setting the stubborn washers or semiring of repair dimensions. They compared with the nominal size have an increased (respectively by 0.1; 0.2; 0.3 mm) thickness.

The main faults of the heads and flowing cracks on the pairing surface with the cylinder block, cracks on the cooling shirt, the blocking of the pairing surface with the cylinder block, wear of the holes in the guide sleeves of the valves, wear and sinks on the chapels of the valves, loosening the landing of the valve saddle in the sockets.

Cracks with a length of no more than 150 mm, located on the surface of the pairing of the cylinder head with the block, brew. Before welding in the ends of the cracks, made of aluminum alloy, drill holes with a diameter of 4 mm and separated it along the entire length to a depth of 3 mm at an angle of 90 e. Then the head is heated in the electric furnace to 200 ° C and after stripping the seam of the metal brush, the crack is welded smooth Switching direct current reverse polarity Using special electrodes.

At gas welding, the wire of the brand al4 with a diameter of 6 mm is used, and AF-4A is used as a flux. After welding, the remnants of flux are removed from the seam and washed with its 10% solution of nitric acid, and then hot water. Finally, seams are cleaned with the basic metal grinding circle.

Cracks up to 150 mm long, located on the surface of the cylinder head cooling shirt, close up epoxy paste. Pre-crack is separated in the same way as for welding, they are degreased with acetone, two layers of epoxy composition mixed with aluminum sawdust are applied. Then the head is maintained for 48 hours at 18-20 ° C.

The blocking of the conjugation plane of the head with a block of cylinders is eliminated by grinding or milling. After processing the head is checked on the check plate. A clause 0.15 mm thick should not pass between the head plane and stove.

When the holes in the guide sleeves of the valves are replaced with new ones. Holes of new bushings unfold to nominal or repair sizes. For expressing and pressing guides, use mandrels and hydraulic press.

Wearing and sinks on the chamfer Sadls of the valves are eliminated by wipe or grinding. Figure is performed using special devicesallowing you to perform reciprocating and rotational movements, an electric or pneumatic drill to the worker, on the spindle of which the sucker is installed. For the wiring of the valves, the gay paste is used or a bias (15 g of a white electrocorunda micropowder M20 or M12, 15 g of carbide M40 and engine oil). Pretched valve and saddle should have a smooth matte strip of at least 1.5 mm along the entire length of the circumference of the chamfer.

The quality of the wipes is checked with an overpressure of air 0.15 ... 0.20 MPa, created above the valve. It should not be significantly reduced for 1 min.

The saddle is annoyed if you cannot restore the chamdes of the saddle of the saddle. After the cencing the work champers, the valve saddles are grinding abrasive circles under the appropriate angle, and then the valves are torn. To restore the saddle, special devices can also be used for the cutting cutter for the formation of working and auxiliary champers, having different angles of inclination. If there is shells on the facek and when weakening the landing of the seat in the socket of the block head, it is processed using the puller. The hole is cleaned under the seat of the repair size. Made of high-strength cast iron of the repair size are compressed using a special mandrel into a preheated head of the unit, and then the zenching is formed by the saddle chamfer.

Characteristic malfunctions Valves are wear and sinks on the valve chamfer, wear and deformation of valve rods, valve wear wear. When defecting the valves, the straightness of the rod and the beating of the head of the head of the head relative to the rod are tested. If the beating is more permissible, the valve is ruled. With the wear of the valve rod, it is grouped under the repair size on a powerful grinding machine. Worn out the end of the valve rod grin on the sharpening machine.

Valve sleeve guides wear out the inner surface. When the gap is reached between the valve terminal and the guide sleeve more than 0.15 ... 0.20 mm, it is recovered. If the repair of the engine is provided for the repair of the valves of the repair dimensions, then the sleeve is deployed under a new repair size. Otherwise, the sleeve is replaced.

Worn bronze bushings in the rockers are replaced with new and reset to a nominal or repair size.

On specialized sites repair crankshafts and distributional shafts. Worn indigenous and connecting rod cervical crankshafts, as well as the supporting necks of the camshafts are grinding under repair sizes. After grinding the neck polished abrasive ribbon. Worn fists of the camshaft are grinding on a copy-grinding machine.

Engine maintenance consists of checking its technical condition by external inspection and in the process of work, identifying malfunctions, performing control and adjustment, lubricating and fastening work on crank-connecting and distribution mechanisms, cooling, lubrication, power and ignition systems.

CSM faults

they are determined by the natural wear of the conjugate details.

Basic signs of malfunction The crank-connecting mechanism are:

• reducing compression in cylinders;
• the appearance of noise and knocks;
• breakthrough gases in the crankcase and the appearance of bluish smoke with a sharp smell from the oil-solid neck;
• increasing oil consumption;
• oil discharge in the crankcase (due to the penetration of the vapor of the working mixture with compression tacts);
• throwing the oil spark plugs, which is formed on the electrodes, the tart is formed and sparking deteriorates. As a result, fuel consumption increases and the engine power is reduced.

Fault gas distribution mechanism Most often manifest in violation of the gaps between the rods of valves and pushers. This leads to a violation of the phases of gas distribution, deterioration of cylinders (due to the delay of the opening of the inlet or exhaust valve with increased gaps).

Increased gaps between the rods of valves and pushers cause knocks and premature wear of the distribution mechanism parts. Small gaps or their absence lead to a loose landing of valves and skipping the working mixture in the intake and exhaust pipelines. As a result, compression is reduced in the engine cylinders and its power. Signs of these faults are the appearance of outbreaks in the carburetor and cotton in the silencer.

Maintenance of crank-connecting (CSM) and gas distribution mechanisms (timing)

Main works:

• checking the stability of the state and pulling up the mounts (fasteners) of the engine support to the frame, cylinder heads and the crankcase pallet to the block, flanges of inlet and exhaust pipelines and other connections;
• verification of the technical condition or performance (test work) of crank-connecting and distribution mechanisms;
• adjustment work and lubrication.

Fasteners

To prevent gas and coolant passage through the cylinder head laying, it is necessary to periodically check the head mount with a dynamometric handle with a certain force and a sequence. Tightening torque and tightening sequences of nuts are installed automotive plants.

The cast iron head of celinders is fixed when the engine is in the heated state, and the head of the aluminum alloy is cold.

The need to pull up the attachment of the aluminum alloy heads in the cold state is explained by the non-alignment coefficient of the linear expansion of the material of the bolts and studs (steel) and the head material (aluminum alloy). Therefore, tightening nuts on the hot engine does not provide after its cooling the necessary density of the adjustment of the cylinder head to the block.

The tightening of the crankcase pallet attachment bolts in order to avoid the deformation of the crankcase, the tightness disorders are also checked by compliance with the sequence, i.e. Alternately pulling the diametrically opposite bolts.

Control of the state of CSM and TRM

The technical condition of these mechanisms can be determined:

• according to consumption (ugar) oil oil and pressure drop in the lubrication system;
• on the change in pressure (compression) in the engine cylinders at the end of the compression stroke;
• on vaccination in the inlet pipeline;
• by the number of gases breaking into the engine crankcase;
• on the leakage of gases (air) from cylinders;
• the presence of knocks in the engine.

Ugra oil In the most important engine is insignificant and can be 0.1-0.25 l / 100 km of mileage. With a significant overall wear of the engine, the avgar can reach 1l / 100 km and more, which is usually accompanied by a strong smoking.

Pressure B. oil system The engine must be within the limits installed for this type of engine and the used variety of oil. Reducing the oil pressure on the small rollers of the kneading shaft of the heated engine indicates unacceptable wear of the engine bearings or malfunction in the lubrication system.

The drop in the pressure of the oil gauge to 0 indicates a malfunction of a pressure gauge or a reduction valve.

Increased pressure in the lubrication system may occur as a result of high viscosity or clogging of the oil highway.

Compression serves as an indicator of the tightness of the engine cylinders and characterizes the state of cylinders, pistons and valves. Tightness of the cylinders can be determined compressometer.

Compression is checked after preheating the engine to 70-80 ºС with candles. By installing the rubber tip of the compressometer into the candle hole, the starter of the engine crankshaft by 10-12 revolutions and record the compressometer readings. The check is repeated 2-3 times for each cylinder.

If the magnitude of the compression is 30-40% below the norm, this indicates the presence of faults (breakage or burning piston rings, leakage of valves or gasket damage colenov heads).

Plusion in the inlet pipeline The engine is measured by a vacuum. The magnitude of the vacuum at the steady mode of engines can vary not only from the wear of the cylinder-piston group, but also on the state of the parts of the gas distribution, the ignition installation and the adjustment of the carburetor.

In this way, this method Control is general and does not allow you to select one or another malfunction in one indicator.

Number of gases breaking into the engine crankcase, Changes as a result of a looseness of mating cylinder-piston ring, increasing as the specified details wear. The number of broken gases is measured at full engine load.

Ministry of Education and Science of the Russian Federation

Syktyvkar Forest Institute Branch

Federal State Budgetary Educational Institution

higher professional education

St. Petersburg State Forestry University

them. S.M. Kirova

Faculty of LTF.

Department Ayah

Laboratory work number 1,2

Discipline: TEA

Topic: Maintenance of CSM and MRM

Perched Arteva T. P., gr. 141.

Checked Yushkov A. N., K.T.N.

Head Department of Miracles V.I., Ph.D.

Syktyvkar - 2011.

Content Introduction .................................................................................... ... 3

Major faults KSM ...................................................... 4

Major malfunctions Timing ................................................... 8

Maintenance of KSHM and MRM ....... .............................. .10

Current repair of KSHM and Timing .................................................. .14

Introduction

The main mechanisms of the engine are crank-connecting rod (CSM) and gas distribution (timing).

The crank-connecting rod is called a mechanism that exercising the workflow of the engine. The crank-connecting mechanism is designed to transform the return and progressive movement of the pistons into the rotational motion of the crankshaft. The crank crank mechanism includes a cylinder block with a crankcase and cylinder head, a connecting rod-piston group and a crankshaft with a flywheel.

The gas distribution mechanism is intended for timely, in accordance with the procedure for the operation of the opening and closing and closing of the valves, ensuring the workflow of the engine. It consists of a camshaft connected by a special gear with a crankshaft chain or a timing belt.

1. Major faults KSM.

Technically, a serviceable engine must develop full power, work without interruptions on full loads and at idle, not overheat. On the good engine there should be no oil leakage through seals. The malfunction of the crank-connecting mechanism can be determined by external features without engine disassembly. Such signs include: the appearance of foreign knocks and noise, the drop in engine power, increased oil consumption, fuel consumption, the appearance of smoke in the exhaust gases, etc.

Knocks and noise The engine arises as a result of the appearance of increased gaps between the conjugate details, which indicates their wear. The stuffs in the engine are listening with a stethoscope, which requires a certain skill.

With the wear of the piston and the cylinder, as well as with an increase in the gap between them, there is a ringing metal knock, well listened when the cold engine is operational. A sharp metal knock on all modes of engine operation indicates an increase in the gap between the piston finger and the sleeve sleeve sleeve. Stroking the knock with a sharp increase in the number of rotation of the crankshaft indicates the wear of the indigenous or connecting rod bearings, and the knock of the deaf tone indicates the wear of the indigenous bearings.

With a large wear of the liners, their antifriction layer is usually paid, which is accompanied by a sharp drop in oil pressure. In this case, the engine must be immediately stopped, as its further work can lead to a breakdown of parts.

Motor power drop It occurs when wear or occurring piston rings in grooves, wear of pistons and cylinders, as well as with a bad tightening of the cylinder head. These faults cause drop compression in the cylinder.

When checking the compression, the compressometer is twisted the ignition candle of the checked cylinder and the compressometer tip is installed instead. Then completely open the throttle, the air damper of the carburetor and turn the engine crankshaft using the starter for 2-3 s. The compression value in a good cylinder should be within 7.0-8.0 kg / cm2 (0.7-0.8 MPa). The difference in compression in different cylinders should not be greater than 1 kg / cm2 (0.1 MPa). Thus, consistently check compression in each cylinder.

Elevated oil consumption, Fuel reserves, the appearance of smoke in the exhaust gases (at a normal level of oil in the crankcase) usually appear when wear and occurring the piston rings or wear cylinders. Ringing the rings can be eliminated without disassembling the engine, for which in each cylinder of the hot engine should be poured over the night hole for the spark plug of 20 g of a mixture of denatured alcohol and kerosene in equal parts. In the morning, the engine should be laid, give to work 10-15 minutes, then replace the oil.

Nagara deposition On the bottoms of the pistons and combustion chambers located in cylinder heads, reduces thermal conductivity, which causes engine overheating, drop its power and increase fuel consumption. To remove the nagar, it is necessary to release the coolant, remove the devices that are reinforced on the cylinder head, and, unscrew the nuts, carefully separate the cylinder head without damaging the gasket. If the gasket was glued to the block or head of the cylinders, it should be separated, using a blunt knife or thin metal strip.

Nagar should be removed with wooden scrapers or soft metal scrapers so as not to damage the bottom of the pistons or walls of the combustion chamber. Remove the nap should be alternately from each cylinder, closing the neighboring cylinders with a clean rag.

In order to make it easier to remove the Nagar, it should be softened, putting on it a rag moistened with kerosene. After removing Nagara, all items must be cleaned and installed in place.

Cylinder head bolts and nuts are tightened with a dynamometric key on a cold diesel engine or no earlier than 30 minutes after its stops in order of increasing numbers, as shown in Fig. 1. Moments of tightening cylinder head bolts for the KAMAZ-740 diesel engine must be: in the first reception - 4-5 KTS-M; In the second reception - 12-15 kgf; In the third reception - 21-19 kgf.

Fig. one. Tightening bolts block head

The moment of tightening nuts fastening of the cylinder heads of the YMZ-238 diesel engine should be 22-24 kgf. It is impossible to tighten the nuts with a big moment to avoid the destruction of edging of the cylinder heads and the gaskets themselves.

The bolts of the head of the 5-cylinder gasoline cylinder head are tightened with a dynamometric key in a sequence of 1 to 12 V two receptions: at first with a force of 40 N · m, and then 60 N · m. After that, additional tightening is performed by a rigid key: 1/2 turn (180 °). Additional tightening of 90 ° x 2 (2 times 90 ° each) is allowed. When the cylinder head bolts are tightened to estimate the angle of rotation by the location of the key handle relative to the engine: 1/4 turnover (90 °) corresponds to the position of the knob across the engine.

Fig. 2. Tightening bolts block head

§ 54. Repair of the details of the crank-connecting mechanism

The cylinder block of most engines is made of gray cast iron with plug-in wet sleeves. The main defects of the cylinder block are: platforms, chips, cracks of various sizes and location, cylinder wear or strain holes under the sleeve, wear of the nest of the indigenous bearings, the nests of the valves, swabs of the studs, breaking the thread in the holes.

The defects of the cylinder block are made careful inspection, measurement of cylinders and crimping. The inspection is discovered by holes, chips, visible for the eye cracks, thread breaks, the state of the cylinder mirror. Cracks are detected by cracks that are not observed during inspection. One of the used stands used for the hydraulic test of the cylinder block is shown in Fig. 70. The water cooling shirt under the pressure of 4-5 kgf / cm 2 is injected with water. At the same time, the block of the block should be installed on the block of cylinders or instead of it a cast-iron stove with a rubber gasket. Turning the frame of the stand, view the block and install, whether there are flows of water.

If there are cracks passing through the cylinder mirror, the valve sockets and the plane of the connector, the cylinder block is braked. In the available places, the crack brew. Pre-ends cracks depart

drill with a diameter of 5 mm and are separated along the entire length of the grinding circle at an angle of 90 ° to the depth of 4/5 of the wall thickness. It is recommended before welding a block of cylinders heat to a temperature of 600-650 ° C. The crack is brewing with gas welding, applying a neutral flame, flux and a cast-iron-copper fruit bar with a diameter of 5 mm. The seam should be smooth, solid and perform over the surface of the base metal not more than 1.0-1.5 mm. After welding, the cylinder block is slowly cooled into the thermoshkafu or in a tomilny pit, the cracking of cracks can be carried out without heating the block. In this case, the crack is brewed by electrical welding, applying a constant current of reverse polarity. Good results are obtained during welding of cracks between the belt of cylinders with electrodes made of mono-metal, and the next welding mode: current power - 120 A, voltage 65-75 V.

The welding seam is cleaned with a flush with the plane of the base metal with a file or emery circle. Then the cylinder block is subjected to crimping on the stand, checking the tightness of the welding seam. The flows of water through the seam are not allowed.

Crops and holes of the cylinder block can be closed with epoxy pastes. The process of seal is as follows. The surface of the block from two sides of the crack is cleaned up to the gloss with a metal brush or bone crumb on the setting for cleaning parts. At the ends of the crack, the holes drill with a diameter of 3-4 mm are drilled, the threads are cut into them and the flush caps of copper or aluminum wire are screwed down. The crack is treated at an angle of 60- 90 ° chisel or abrasive circle to a depth of 3/4 of the wall thickness.

On the surface of the block around the crack at a distance of up to 30 mm, it creates a roughness of a chisel or shot blasting. Acetone or gasoline degreases the prepared surface of the block. The spatula is sequentially applied by layers of epoxy paste on the prepared dry surface. Initially, the first layer of pasta is applied to 1 mm thick, dramatically moving the spatula on the surface of the block. Then they apply a second layer of pasta with a thickness of at least 2 mm, thoroughly rubbing it. The overall thickness of the paste layer on the entire surface should be 3-4 mm.

After sealing cracks, the block of cylinders leave 25-28 hours until the paste solidification. The process of solidification of the paste can be accelerated by heated by an electric reflective stove to a temperature of 100 ° C or when preparation of paste is evaporated with a hardener (polyethylene polyamine) by heating to a temperature of 105-110 ° C and subsequent shutter speed at a given temperature for 3 hours. The repaired surface is cleaned with a drakel or abrasive circle. Latest paste chisels cut.

Robbles that can be repaired are close by overlaying. Initially, stretching and degreasing the edges and surfaces around the blades. Then they apply a paste and put the patch from the fiberglass with a thickness of 0.3 mm and rolled the roller. The distance from the edge of the patch to the edge of the bar must be at least 15-20 mm. After that, the second layer of paste is applied and put the second patch so that it overlaps the first 10-15 mm from all sides. Patta roll roller. In such a sequence, apply up to eight layers of fiberglass. The last layer of patch covers paste to protect it from damage.

The holes can be chopped by welding patches made of soft steel as the same thickness as the wall wall. The shape of the patch must correspond to the form of a damaged area, and its dimensions by 1.5-2.0 mm are less than the size of the samples. The edges of the samples and patch are treated at an angle. The pay at first is welded in two places, and then welded throughout the perimeter. Apply electrical welding and copper electrodes wrapped by tin. It is recommended to seal the damaged epoxy resin section.

After restoring the samples by patch and mechanical processing of the applied paste layer, the block of cylinders is subjected to crimizer on the stand. If no water seepage is detected for 5-6 minutes, the repair of the block is made high quality.

Cracking the cooling shirts of the block can be sealing the pins. The procedure for performing work is the following. At first, at the ends of the crack, drill holes with a drill with a diameter of 4-5 mm. Then the same drill drill holes along the entire length of the crack at a distance of 7-8 mm one from the other. Cutting the threads and screw the copper rods to a depth equal to the thickness of the block wall.

The rods are cut off with a hacksaw, leaving the ends protruding by 1.5-2.0 mm above the surface of the part. Drill holes between installed pins so that they overlap them by 3/4 diameters. Cut the threads, screw the copper rods and cut them with a hacksaw, leaving the appropriate ends. Next, light blows of the hammer the ends of the pins are designed, forming a dense seam. If required, the seam is leveled with a file. Then the block of cylinders is subjected to crimping.

A block of cylinders having chips permissible for repair is restored by surfacing or welding patch.

The value of cylinders or sleeves is determined by an indicator zeromer (Fig. 71). Measurements are made in two mutually perpendicular directions and in three belts. One direction is set parallel to the axis of the crankshaft. The first belt is located at a distance of 5-10 mm from the upper plane of the block, the second - in the middle part of the cylinder and the third - at a distance of 15-20 mm from the bottom edge of the cylinder. Depending on the value of wear, the type of repair is set. Typically carry out and subsequent adjustment or setting (pressing) of the sleeves.

Plug-in sleeves can also be repaired by boring, followed by final processing of honing. The results of the research showed that at least .80% of the SIL-130 engine sleeves enrolled in the auto repair plants for the first time, it is possible to restore.

Rastaching is the main way to repair cylinders and sleeves. Cylinders or sleeves are treated to repair sizes on stationary or portable boring machines. The sleeves are fixed in a special device installed on the table of the boring machine.

In fig. 72, and a device is shown, applied with the reassurance of the ZIL-130 engine sleeve. Sleeve 6 It is installed in the sleeve 7, which is located in the package 1 package. The mount is carried out by clamps 3 and 5. The clamping force is transmitted to the sleeve through two spherical rings 4 and 2.

After robing, the sleeve is exposed to honing. Gilz. 6 (Fig. 72,6) fasten on the table of the machine in a special device, which consists of a housing 1, two sleeves 7, ejecting device 8, Setting Ring 9 and clamping bolt 10.

When processing, the honing head connected to the spindle of the machine is introduced into the processed hole (the bars are in compressed state). First, they are preliminary and then final honing. Apply a honing head with a mechanical, hydraulic or pneumatic expansion device.

In fig. 73 shows one of the designs of the honing heads with a pneumatic drive.

Pneumatic drive provides a constant pressure of bars on the walls of the cylinder, which improves the quality of the processing and performance of the honing process. At the same time, it is possible to adjust the pressure of bars to the surface being processed and automate the process of defering the bars as the diameter changes in the liner.

To obtain the proper geometric shape of the cylinder during the honing process, it is necessary to establish a certain length of the head of the head. It should be such that abrasive bars to go beyond the cylinder end by a value that does not exceed 0.2-0.4 their lengths. With a greater magnitude of the honing head, the errors of the form are observed, in particular, concaveness, and at a lower progress - barrelness.

Honing is carried out with a continuous and abundant supply of lubricating and coolant into the process of processing. A kerosene or a mixture of kerosene with spindle oil is used as a lubricating fluid.

For preliminary honinging, Bruks of synthetic diamonds A10MX50 are recommended, and for final honinging - BC-100X 11 kh9k38bs bars. Processing is conducted under the modes: the circumferential speed of rotation of the head 280 rpm, and the speed of the reciprocating movement is 90 double strokes per minute. The allowance for pre-honing is set not more than 0.08 mm, and for final honinging 0.04 mm.

The final processing of the engine cylinders can be carried out by ball rolling heads and allowing to obtain the surface of the required accuracy and roughness. The process is carried out after the rocketing or at the same time in one pass, the cylinder hole is treated with a cutter and a head ball.

Regardless of the method of final processing of cylinders (sleeves), their inner diameter should have the same repair size.

Cylinders can be restored by pressing sleeves if their wear exceeds the last repair size or on the walls there are deep risks and jackets. For this, the cylinders are processed under the repair sleeve, the thickness of which should be at least 3-4 mm. In the upper part of the cylinder, the ring pulley under the brown of the sleeve is reset. The sleeves are pressed with a tension of 0.05-0.10 mm on the hydraulic press, pressed and treated (melted and honing) to a nominal size. Sometimes the sleeves are treated under the size less than the nominal to use the flushed old pistons.

Plug-in sleeves will be pressed and pressed using special pullers.

The deformation of the nests of the main bearings is checked by calibration rolling pin. If it enters the nests and turns without much effort, there are no deformations.

Wear, as well as the magnitude of the inconsistency of the nest of the indigenous bearings, can be installed by a special device. NIIAT has developed a device for controlling the alignment of the nasal of the indigenous bearings of the blocks of engines ZIL (Fig. 74). The principle of work is that the rod 2 With the help of sleeves 3, fixed in the jacks of indigenous bearings. At the horse, there are (sequentially when entering into the socket) indicators to control each hole. Levers I indicator devices are introduced into the measured hole. The indicators are installed on zero and secured on the rill. When you rotate the rejection of the arrows of the indicators will show a double value of the inconveniency of each hole.

Worn and deformed jacks of indigenous bearings are cleaned to the nominal size. Removed bearing caps must be labeled (set the number of the cylinder block and the sequence number of the cover). The plane of the lid connector is milled for a certain value (0.6-0.8 mm) and control the indicator device. Also, the external grooves in the front and shaped groove in the back of the rear root bearing. Processed and received sections of the lids are collected with a block of cylinders, respectively, their marking.

The collected block of cylinders with covers is installed and fixed on the plane of the boring machine. The holes of the indigenous bearings are mounted in one pass to the cutters, reinforced on Barkene to the size established by the drawing or specifications. After the boring, the sizes of the hole, the surface roughness and the intercentrose distance between the holes of the indigenous bearings and the camshaft sleeves are checked.

Repair of the head of the cylinder block and valve saddle. The main defects of the cylinder heads are: cracks in various places, warping the pairing surface with a block of cylinders, hole wear in the guide sleeves of valves and threads, loosening the landing of valve saddle in the sockets.

The head of the cylinder block with the details of the valve mechanism works in very heavy conditions - at high temperatures and the effects of mechanical and thermal loads.

Therefore, depending on the defect and its location, it is necessary to correctly establish a method of repair. Cracks can be embedded with epoxy pastes, welding with overall heating of the head, overlaying patches, pins.

The blocking of the conjugation of the head with the cylinder block is eliminated by grinding or milling with subsequent grinding. At the same time, the minimum permissible depth of the combustion chamber, which is indicated in technical conditions should be suppressed. The blocking value of the plane is installed on the stove across the paint or with the help of the control line and the probe.

Worn openings in guide sleeves and under the guides of the valve sleeves are treated with rates to a nominal or repair size. When wear, more permissible value is replaced by replacement of the sleeve.

Wearing and sinks on the chamfer Sadls of valves are eliminated with grinding or replace the saddle. Produce the wrap of the seat with a valve or cencing with subsequent grinding and ticking. During censorship, a set of four centers, having angles of inclination of cutting edges 30 or 45, 75 and 15 °. Zenkovka with angles of 75 and 15 ° are auxiliary and apply to obtain the necessary work chamfer. In fig. 75 shows the sequence of cencing the valve seat.

Work chamfer valve saddles are grinding abrasive circles under the appropriate angle. For the engine ZIL-130, the intake valves are grinding at an angle of 60 °, and the exhaust valves are an angle of 45 ° to the axis of the guide sleeves. The width of the work chamfer of the valve seat must be 1.5-2.0 mm for the engines of gas and 2.5-3.0 mm - for the engines ZIL.

With large wear of the valve seat, when the caliber is drowning exceeds the permissible value specified in the technical specifications, the valve seat replaces the new one. For this, the worn valve seat is mounted, and then the plug-in valve seat is pressed, designed by a special mandrel. Next, they grind or annpitate the working chamfer before obtaining the desired size. Then gripped with the valve working surface.

Figure is performed on special machines, which fully mechanize the process and allow you to carry out the processing of all valves at the same time. For wipes are used by the prior paste or gay paste. It is recommended to initially produce more rough paste. Thin paste is used to obtain a final finishing surface. The trigger should ensure a dense, hermetic connection of the valve and saddles of work champers, eliminating the possibility of the penetration of gases. Pretty valve and saddle must have a solid matte strip across the chamortion but a certain width (Fig. 76). For engines ZIL strip width must be equal to L / 2 width of the work chamfer.

The quality of the wipes is tested by the device (Fig. 77), with which the excess air pressure is created above the valve (0.7 kgf / cm 2). Pressure is set to the manometer and it should not be significantly reduced for 1 min.

When weakening the landing of the valve seat in the nest, it is processed, and the hole is mounted for installing the seat of the repair size. During exercise, various pullers apply. In fig. 78 shows one of the applied puller designs.

Piston repair.

The main defects of the piston are the tag on the bottom and grooves, the wear of the grooves under the rings, holes in bobbs, cracks and scratches on the walls.

To clean the grooves of the piston from the car, the device is used in the form of a steel tape with handles, on the inner surface of which the cutters are fixed. By inserting the cutters into the groove and turning the adaptation around the piston, remove the nagar.

Pistons with worn grooves for piston rings are replaced with new corresponding dimensions.

The worn hole in the piston bosses is restored by deployment with the subsequent installation of the piston finger of increased size. Minor risks or scratches on the outer surface of the piston are removed by stripping emery skurt. Pistons with cracks and deep scratches are replaced with new ones.

Selection of piston rings.

Worn and elastic, piston rings replaced new. Selection of new rings are made according to the size of the piston and cylinder. When selecting a piston of rings (Fig. 79, a), it makes a rolling through the groove and if there are no hots, then the probe is determined by the gap. In the case of the ring in the groove or small gap, the ring is grined on a sheet of fine-grained emery paper, laid on the calibration plate. The magnitude of the gap of the groove should not exceed 0.052-0.082 mm for the upper and 0.035-0.70 mm for the remaining compression rings.

When selecting the cylinder (Fig. 79, b), determine the gap in the junction of the ring installed in the cylinder. The ring can be installed in a caliber, the inner diameter of which is equal to the diameter of the cylinder. In the absence of or low size of the gap, the joints of the rings of the rings are carried out. At the same time, the planes of the kershes should be parallel. Specifications are installed for each engine a certain amount of gap. For compression rings, the gap should be 0.3-0.5 mm, and for low-pressure rings -0.15-0.45 mm. In the gap, more than the normal ring is married.

Repair of the piston finger.

Worn piston fingers are restored by chrome. Exercise porous chromium extension, which retains oil well. After applying the chromium layer, the fingers are grinding under the necessary "size. When wear the diameter of more than 0.03 mm, the fingers are repaired or replaced with new ones. It is recommended to install piston fingers only with a nominal size. To facilitate the assembly, their dimensions are sorted to a number of groups.

Roleberry repair.

The main defects of the connecting rod are: bending and twisting the rod, wear opening of the sleeve of the upper head and holes under the sleeve, wear of the hole and the end head surfaces.

Worn rod head sleeves are usually replaced with new ones. Sometimes the hill of the bushings are cleaned or deployed under the increased repair size of the piston finger.

The worn hole of the head under the sleeve is restored by processing under the repair dimensions (rods of the EMZ-236 and YAMZ-238 engines) or rods with this defect are selected (engine connecting rods ZIL-130, ZIL-164, GAZ-51).

The hole of the lower head of the connecting rod under the liner is mounted and grind under the nominal size after processing the butt surfaces of the cover with a shep. The last milling or grinding using special fixtures. If there is an electroplating area, it is advisable to repair the lower head of the connecting rod. After leaving the hole is restored to the nominal size. This repair method allows you to save the stiffness of the part and the intercentrose distance between the holes of the upper and lower heads of the rod.

Bending and twisting rod rod eliminate edited. For editing and control of rods, various devices are used. In fig. 80 shows one of the designs of the applied devices. On this fixture simultaneously check the bending and twisting of the connecting rod, as well as the distance between the centers of its heads. If the deviations exceeding the permissible values \u200b\u200bare detected, the connecting rod rule with a special key without removal from the device. At the same time, the top head of the connecting rod should occupy the position between the vertical and horizontal plates.

The connecting rod is tightly installed in the device with a large rolling pin 8; Missed through the rack 9. Small rolling pin 10 insert the rod head into the treated hole. Initially, the junction of the connecting rod is tested. For this, the connecting rod installed in the horizontal layer is manually rotated so that the small rolling pin 10 Alternately rested on croutons 11. The presence of a gap will indicate the rod twisting.

The determination of twisting and bend is made when the connecting rod is in a vertical position. At the same time a small rower 10, In contact with the stops of the rocker 4, is in contact with pins 2 Indicators / and 7, which indicate the magnitude of the junction of the connecting rod. Indicator 5 Sets the distance deviation between the axes of the top and bottom heads, and the indicator 6 - non-parallelity axes of holes.

After editing and control, dramatically moving the handle 13, knock out a large rolling pin 8, freeing the rod.

Before starting operation, the fixture indicators are set up on the reference connecting rod.

Repair of the crankshaft.

The main defects of the crankshaft are: bend, wear of connecting rolled and indigenous necks, wear opening under the bearing of the drive shaft gearbox and holes of the shaft flange under the fastening bolts of the flywheel.

The bending of the engine crankshaft is checked on the stand, on the prisms installed on the control plate or in the lathe centers using the indicator. Bending (the beyon of the average indigenous neck relative to the extreme) above the permissible specifications are eliminated by editing on the press.

The crankshaft is installed on the prism with extreme root cakes, and the press of the press through the copper or brass gasket pressure on the middle neck from the opposite bending. At the same time, the magnitude of the deflection must be about 10 times more than the bend. The shaft is kept under the press on the press for 2-4 minutes. After editing, the shaft is recommended to undergo thermal processing, i.e. Heat to 180-200 ° C and to withstand at this temperature for 5-6 hours. The shaft is then tested for the beating. The base of medium necks in relation to extreme cervices should not exceed 0.05 mm.

Worn connecting rod and native cerulus of the crankshaft are restored by grinding under the repair size. Set one repair size for all connecting rods and one repair size for indigenous necks, depending on the smallest diameter obtained as a result of the measurement and recommended by the technical conditions of the repair size. Complete treatment of shaft shaft by polishing or superfining before obtaining the required surface roughness. Then washed with oil canals and the outer surface of the kerosene shaft in a special bath.

In cases where all repair dimensions were used and a further decrease in the shaft diameter is unacceptable, and its strength is sufficient, the necks can be recovered with subsequent treatment under the nominal size.

When restoring the neck of the crankshaft, it is important to choose the correct installation base. It is recommended to install a crankshaft on the machine to the same basic surfaces that were used in the manufacture. Then the minimum errors are obtained related to its installation. In the designs of the crankshafts of engines ZIL-130, GAZ-53, YAMZ-236 and others there are chamfer from two sides (from the side of the hole for the ratchet and the holes under the ball bearing of the guide end of the drive shaft). Chamfering data is taken as installation bases. Previously check them and determine or corrected if necessary.

In the designs of the crankshafts of GAZ-51 engines, ZIL-164 The center holes used in the manufacture are subsequently removed. Therefore, it is necessary when grinding the neck of the crankshaft correctly choose new installation bases that would satisfy the requirements. For such shafts, it is possible to be taken for installation bases: when grinding. The necklace of the hole for the ratchet and the hole under the bearing of the guide end of the driving shaft, when grinding the connecting rod neckcoon under the gear and the outer cylindrical surface of the flange under the flywheel. To ensure the required processing accuracy, the selected mounting surfaces are pre-prepared.

As a technological base, lambed indigenous cervix can be taken when grinding connecting rod necks. At the same time, the axis of rotation of connecting skeins must accurately coincide with the axis of the machine spindle.

Wearing a hole under the bearing of the drive shaft of the gearbox restore the staging of the sleeve. In fig. 81 shows the sketch of the engineered crankshaft engine ZIL-130, the hole in the shaft is mounted on the shaft cutting machine to the diameter

then the repair sleeve is pressed until it stops, the hole is cleaned in the sleeve until size 52 and the 3x30 ° chamfer is removed

The worn hole in the flange of the shaft under the fastening bolts of the flywheel is treated with a scan to the repair size assembly with the flywheel. When assembling, they put the fastening bolts of the woven of increased repair size.

After repair, it is necessary to monitor the crankshaft to establish the quality of the work performed and the identification of possible shells and cracks.

Maintenance.For EO The engine is cleaned of dirt, check its condition visually and listened to work in different modes.

For TO-1. It is performed by the work of the EO, as well as check the tightness of the crankcase pallet connection with the crankshaft unit or oil seals (the absence of oil flows), as well as the engine mount to the frame. The mount is checked without loving nuts. If necessary, the connection is tightened. The inspection determines the state of rubber elements that should not have detachments and rubber destruction (if there are defects - replace). Listen to the operation of the valve mechanism, if necessary, regulate thermal gaps.

For TO-2 and SO Perform all the works of it-1, and also check and, if necessary, tighten the fastenings of the cylinder heads, regulate thermal gaps in the timing. Check and adjust the tension of the chain or the camshaft drive belt (when it is upper arrangement), tighten the mounting of the front cover of the engine (distribution gear cover).

Diagnostation.When diagnosing crystrum-connecting (CSM) and gas distribution (MRM) mechanisms, the mechanisms check the compression in the cylinders, the place and nature of the noise and knocks, the technical condition of the engine at the places and the magnitude of the air leaks when it is supplied to the cylinders under certain pressure, the elasticity of the valve springs and the volume of gases Drinking in Carter.

Compression Engine ( maximum pressure In the cylinder at the end of the compression tact), it is determined by the compressometer when turning the crankshaft starter, inserting the rubber cone tip of the compressometer into the hole for the nozzle or the spark plug (Fig. 50a). The compressor is equipped with a recorder for recording pressure on the cylinders (Fig. 50b, B). To obtain the most reliable results, the compression is determined on a heated engine, dismantling all the spark plugs or nozzles from it. The specified rotation frequency of the crankshaft is ensured by a serviceable charged battery.

Before measuring compression in each cylinder, the pressure gauge arrow must be installed in the zero position. The minimum allowable compression for diesel engines is about 2 MPa, for gasoline and gas engines, it depends on the degree of compression and is 0.6-1.0 MPa. The difference in the testimony of the pressure gauge in individual cylinders should not exceed 0.2 MPa for diesel engines and 0.1 MPa for gasoline and gas engines. Insufficient compression in the cylinders indicates wear of the sleeves, piston rings or leakage of valves. A sharp decrease in compression (by 30-40%) indicates a breakdown or lounge of piston rings.

Fig. fifty. Compressometer (a) and compressographers (B, B)

Availability, place and character of knocks and noise Determine with the help of stethoscopes and vibroacoustic equipment (Fig. 51). According to the nature of the knock or noise and the location of its occurrence, the engine malfunction. Any extraneous noise and stuffs in the engine during operation are not allowed. Using a stethoscope, an increase in the gaps in connecting rod and native crankshaft bearings, between the piston and the cylinder, valves and pushers, valves and sleeves, etc.

Fig. 51. Stethoscopes for car diagnostics: a - mechanical; b - combined electronic

Knocking pistons about the cylinder - deaf, clicking; They are listened to an immentable engine at a low frequency of rotation of the crankshaft or its sharp decrease. Knobs in native crankshaft bearings - strong, deaf, low tone; They are listening to the engine with a sharp change in the speed of rotation of the crankshaft, as well as when the individual cylinders are disconnected. The knocks in the connecting rod bearings are sharper than in the root; Appear with a sharp change in the speed of rotation of the crankshaft (when this cylinder is disconnected, the knock disappears or decreases significantly).

Knocks in the pair of "piston finger - rod" - ringing, metal; Listed with a sharp change in the speed of rotation of the crankshaft (when the cylinder is disconnected). The knocks in the inlet valves are silent, smooth; Listed in the location of the sleeves of valves at idle. The knocks in the distribution gear - frequent, merging into general noise indicate a large wear or breakdown of gear teeth. The knocks in the bindings of the camshaft are smooth, middle tone; Listed with increasing the rotation frequency of the crankshaft. The knocks in the conjugation of the batter of the rocker - the end of the valve rod "- sharp; Listen in all modes of work and indicate an increased gap.

Air leakage supplied to cylinders under a pressure of 0.4 MPa is determined by special devices. Under the leaks of air, it is possible to determine excessive wear, loss of elasticity, stroke or breakdown of piston rings, wear of piston grooves, wear of cylinders, loss of tightness of valves and cylinder head gaskets. To determine the state of the piston rings, the piston is set to the top of the compression tact and, feeding into the cylinder air, is measured by the pressure gauge of its leakage (pressure drop).

The scale of the device is placed on the zones: a good engine condition, satisfactory and requiring repair. Cylinder wear is also determined, but when installing the piston near NMT compression tact. Air leakage more than 15% indicate strong wear of cylinders. Air leaks through the valves are determined by ear, and the tightness of the cylinder head laying - by the appearance of air bubbles in the neck of the radiator or at the junction (heads with a cylinder block), moistened with soap solution.

The pairing state "Piston - piston rings - cylinder sleeve" can be estimated by the number of gases breaking into the Carter. This parameter is determined by means of flow meters (for example KI-4887-1) after preheating the engine. Measuring the amount of gases that break through into the Carter, and comparing this value with the regulatory, make a conclusion about the state of the cylindrophone group. The elasticity of the valve springs is determined by special devices (Fig. 52).

Fig. 52. Device for checking the elasticity of valve springs

When disassembling the engine, the geometric dimensions of the parts are diagnosed (measured) and comparing the obtained values \u200b\u200bwith nominal and permissible, make conclusion about their suitability to further operation (measurement of the shafts of the shafts is carried out by micrometers, and the diameters of the holes are micrometeric chutes).

Repair of the crank-connecting mechanism (CSM). Malfunctions of the crank-connecting mechanism - The most serious engine malfunctions. Their elimination is very laborious and costly, as it often suggests the overhaul of the engine.

The main faults of the crank-connecting mechanism include:

Depreciation of indigenous and connecting rod bearings;

Wear of pistons and cylinders;

Wear of piston fingers;

Breakdown and lounge piston rings.

Basic reasons Problems These are the development of an installed motor resource or violation of the engine operation rules ( using non-quality oil, increase maintenance time, long-term use of a car under load and other.).

Almost all malfunctions of the crank-connecting mechanism (CSM) can be diagnosed by external features, as well as with the help of simplest devices (stethoscope, compressometer). CSM faults are accompanied by streedy noise and knocks, smoking, compression drop, increased oil consumption.

External signs and the corresponding faults of the CSM are listed in Table 1.

Table 1

External signs and the corresponding faults of CSM

Signs of malfunction	Fault
· Deaf knock at the bottom of the cylinder block (enhanced with increasing revolutions and load). · Reduce oil pressure decreased (warning lamp	Wear indigenous bearings
· Floating deaf knock in the middle part of the cylinder block (enhanced by increasing revolutions and load, disappears when the corresponding spark plug is disconnected). · Reduce oil pressure decreased (warning lamp	Wear connecting rod bearings
· Call knock (knock of clay dishes) on a cold engine (disappears when heating). · Blue smoke exhaust gases	Wear pistons and cylinders
· The ringing knock at the top of the cylinder block on all modes of the engine (enhanced with increasing revolutions and load, disappears when the corresponding spark plug is disconnected)	Wear piston fingers
· Blue smoke exhaust gases. · Reducing the oil level in the engine crankcase. · Engine operation with interruptions	Breakdown and running rings
· Weak compression in the cylinders. · Engine works with interruptions and does not develop the rated power	Worn parts of the piston group (sleeves, pistons, rings)
· The engine suddenly stops	Enchanting pistons in the sleeve or crankshaft
· Leather oils in the location of the pallet and block	Damage to the gasket or insufficient tightening of the bolts (nuts) attachment of the pallet
· Leather cooling fluid from block (heads)	Cracks or holes in the block (block head)

When diagnosing the wear of indigenous and connecting rod bearings, the further operation of the car is categorically prohibited. In other cases, with maximum caution, it is necessary to follow the place of repair.

The repair of the crank-connecting mechanism is mainly in identifying and replacing the details failed.

Options of KSM details.Piston selection It is carried out by weight and size groups. Pistons are selected for each cylinder in accordance with the size of the sleeves, since the technical conditions of the CSM assembly between the sleeve and the piston should be a certain gap. With the simultaneous replacement of the sleeves and pistons, they are equipped with dimensional groups (sleeves and pistons should relate to one dimensional group). With a boring of cylinders, pistons are selected in strict accordance with the size of the sleeves. All pistons installed on one engine must be selected by weight. The difference in the masses of the heavy and easiest pistons of one set is allowed not more than 0.5%.

Selection of piston rings It is carried out taking into account the size of the piston and cylinder. When choosing a rings on the piston, they are rolled along the piston groove and the dipstick measure the clearance between the end of the ring and the piston groove (Fig. 53).

Fig. 53. Checking the side gap between the ring and the piston groove: 1 - Piston Ring, 2 - Piston, 3 - Property Set

When choosing a rings on the cylinder, the ring is installed in the zone of the lowest wear of the cylinder (but within the stroke of the piston rings) and are measured by the dipstream gap in the ring lock (Fig. 54). The required values \u200b\u200bof the gaps are indicated in the manuals for the operation of specific car brands.

Fig. 54. Checking the gap in the Piston Ring Castle: a - using a special mandrel; B - directly in the engine cylinder

Selection of piston fingers and rods. When repairing the engine, it is not recommended to displaced the set of its connecting rods, which at the factory are selected by weight. The replacement of individual connecting rods of one set is carried out taking into account the mass (the fitting by weight is performed by removing the metal from the bobbies on the cover and the connecting rod). It is not allowed to change the lid of the lower heads of the rods, as the lower head and the head cover are processed together in the factory conditions. The connecting rods are sorted on the size of the hole diameter in the upper head sleeve and mark the paint of a certain color. The same groups share piston fingers (according to their external diameter) and pistons (by the inner diameter of bobbs). The piston, the finger and the connecting rod of one set should refer to one dimensional group.

The assembly of the crank-connecting mechanism is carried out in the following sequence:

1. Collect the connecting rod-piston group. The connection of the piston, the finger and the top head of the connecting rod is produced when heated to 240 ° C connector. Pressing the finger in the piston bosses and the top head of the connecting rod with a special device (Fig. 55). The finger is installed in the device, the connecting rod, heated to 240 ºС, clamping in the vice, put on the piston on the connecting rod so that the hole under the finger coincided with the hole of the top head of the connecting rod. The device pushed the piston finger into the piston hole and the top head of the connecting rod so that the roller cushter suits the piston.

To properly connect a finger with a connecting rod, to press the finger should be as quickly as possible: after cooling the rod, it will not be possible to change the position of the finger. When assembling the piston with a connecting rod and installation of a connecting rod-piston group to the cylinder, follow the correctness of the mutual position of the piston and connecting rod and their orientation in the cylinder. On the piston and the connecting rod have labels (on the piston - the arrow, on the connecting rod - tide), which should be directed in one direction (usually to the front cover of the engine).

Fig. 55. Pressing the piston finger into the top head of the rod: a - fixture; b - the process of pressing; 1 - roller fixture; 2 - piston finger; 3 - guide; 4 - stubborn screw; 5 - Device

When installing the rings on the piston, their locks should not be located in the same plane. This will lead to a significant gase breakthrough from the combustion chamber in Carter. Angle α The relative position of the castles of piston rings is determined by the formula α \u003d 360 / Nwhere n. - The number of rings on the piston. Removal and installation of rings on the piston is carried out using a special device (Fig. 56).

2. Install connecting rod-piston groups to cylinders in accordance with the sequence numbers of the cylinders specified on the bottoms of the pistons and on the connecting rods. To install the piston with rings to the cylinder, special devices (firing) are used (Fig. 57).

Fig. 56. Pillter piston rings: 1 - handle; 2 - protrusions; 3 - stops; 4 - Captures

Fig. 57. Installation of piston in cylinder

3. Install the crankshaft and liners in the pastels of the block, then install the lids of the indigenous bearings (Fig. 58). The tightening of the fastenings of the indigenous caps (and connecting) bearings is carried out by a torque wrench (tightening torque values \u200b\u200bare indicated in the operation manuals for specific car brands). Before installing the crankshaft, connecting connecting rod and native cervix, remove burrs at the edges of the holes, the shaft is washed and the channels for lubricant are blurred with compressed air.

Fig. 58. Setting the crankshaft in the cylinder block

4. Install: connecting rod liners in the lower head of the connecting rod and its cover; Bottom heads on connecting rod crankshafts; covers on the lower heads of the rods (in accordance with the numbers of the cylinders specified and on the connecting rod head and on its cover, it is impossible to change the lid places, they are not interchangeable); Tighten the fastenings of the covers (Fig. 59).

5. Install the front and rear covers of the block.

6. Install the flywheel on the crankshaft flange. The crankshaft is balanced at the factory assembly with the flywheel and clutch, so before removing the adhesion from the flywheel and the flywheel from the crankshaft flange, it is recommended to apply on the conjugate surfaces of the risks for which the node is collected again.

Fig. 59. Installing the bottom head of the crankshaft neck

7. Install the pallet of the crankcase with the gasket.

8. Install the block head. Before installing the head, the mating planes of the block and cylinder heads are wiped with a clean rag, and the gasket is rubbed with powder graphite. When the head of the nut block (bolts) is tightened with a dynamometric key with a certain force (which is specified in the technical specifications), ranging from the center of the head, gradually moving towards the edges (Fig. 60).

9. Install the valve cover with a gasket.

Fig. 60. Tightening sequence nuts (bolts) fastening cylinder head

Repair of the gas distribution mechanism.

Major malfunctions of the gas distribution mechanism (timing):

Violation of thermal gaps of valves (on adjustable gap engines);

Bearing wear, camshaft cams;

Malfunctions of hydrocompensers (on engines with automatic adjustment of gaps);

Reducing the elasticity and breakage of the valve springs;

Valve hangs;

Wear and lengthening of the chain (belt) of the camshaft drive;

Wear of the gear pulley of the camshaft drive;

Wear of oil caps, rods of valves, guide sleeves;

Nagar on the valves.

Maintenance causes of TRG faults - Development of the installed engine resource and, as a result, high wear constructive elements and violation of the rules of engine operation, including the use of low-quality (liquid), polluted oil, the use of high resins gasoline, long operation of the engine on the limit revolutions.

The most serious malfunction of the gas distribution mechanism is valve hangswhich can lead to serious engine breakdowns. There are two reasons for a malfunction. One - the use of poor-quality gasoline, accompanied by a resin deposition on the valve rods. Another reason is the weakening or breakage of the springs of the valves. In this case, on high revolutions The engine valve does not have time to sit in the "saddle", twisted and encourages (hangs) in the guide sleeve. Fortunately, this malfunction on modern cars is rare enough.

Faults of hydraulic components arisewhen using liquid or severely contaminated oil. The hydrocompensator stops performing its main function - automatically compensate for the gaps in the gas distribution mechanism. Further operation of the engine can lead to the encoding of hydrocomathers.

Violation thermal clearance On the adjustable gap engines can occur due to wear of the bearings and camshaft camshafts, the wear pulley of the camshaft drive, as well as due to improper adjustment.

The timing malfunction is quite difficult to diagnose, since similar external signs can correspond to several faults. Often, a specific malfunction is established by direct inspection of the design elements of the TRW with the removal of the cylinder head cover.

Most malfunctions of the gas distribution mechanism leads to violations of the phases of gas distributionIn which the engine begins to work unstable and does not develop the rated power.

External features and the corresponding timing of the timing fault are listed in Table 2.

table 2

External signs and the corresponding timing of timing

Signs of malfunction	Fault
· Metal knock in the head of the cylinder block on small and medium turns. · Engine reduction	· Violation of the thermal clearance of valves. · Bearing wear, camshaft camshafts
· Metal knock in the cylinder head on a cold engine. · Engine reduction	· Faults of hydrocompensators
· Noise in the area of \u200b\u200bthe camshaft drive. · Shots in the muffler	· Wearing and lengthening of the chain (belt) of the camshaft drive. · Cotor pulley wear
· Blue smoke exhaust gases. · Reducing the oil level in the engine crankcase. · Engine reduction	· Wear oil reflecting caps, valve rods, guide sleeves. · CSM fault
· Write metal knocks (detonation stuffs) when overclocking the car. · Engine operation with interruptions	· Nagar on the valves. · CSM faults. · Gasoline low quality
· Short-term failures in the work of the cold engine. · Reduced engine power. · Engine overheating	· Reducing the elasticity and breakdown of springs of valves. · Valve hangs
· Cotton listened when the engine is working: intake manifold in the muffler	· Violation of tightness: inlet valve Exhaust valve
· The engine does not start	· Phases of gas distribution. · Insufficient tightness of the valves

Adjusting the gas distribution mechanism.

Verification and adjustment of the heat gap between the rocker liner and the end of the valve rod is performed at a motor temperature of 20-25 ºС in the next sequence.

1. Remove the valve cover.

2. Check and if necessary, bring the tightening force of nuts, fastening the block head to the desired value.

3. Install the piston of the first cylinder in the NWT on the compression tact (both valves are closed). The installation of the piston is made by tags on the crankshaft pulley and the cylinder block or using a special mounting pin (Fig. 61). Rotating the crankshaft (special key) clockwise, combine the installation label 1 on the camshaft sprocket with the adjusting tide 2 on the body of the camshaft bearings. In this case, the piston of the fourth cylinder is located in the VMT at the end of the compression cycle and both valves are closed.

Fig. 61. Installing the first cylinder piston in NTC on compression tact for valve adjustment: 1 - installation label on a stricter of the camshaft; 2 - Installation tide on the camshaft bearings

4. Measure the gaps between the fusion liner and the end of the rod of the intake and exhaust valve (Fig. 62). The check is carried out by a special metal probe (the thickness of which should correspond to the value of the heat gap specified in the instruction manual of this car brand). With a normal gap value, the diploma must move between the valve and the corner of the hand.

Fig. 62. Checking the heat gap in the timing: a - timber with roller levers (rockers); b - timing with biscuit levers (rocker); 1 - probe; 2 - adjusting screw; 3 - locknight of the adjusting screw; 4 - rocker; 5 - Pressing Screw Tip

5. If necessary, adjust the gap in the inlet and exhaust valves.

Adjustment is carried out in the following sequence:

Release the lock nut of the adjusting screw;

Insert the probe between the valve and the rocker;

By turning the key adjustment screw, set the desired clearance (in which the probe will move to the arm force);

Holding the adjusting screw in the set position, tighten the lock nut.

6. Turning the crankshaft each time an angle α \u003d 720 / N (Where n. - The number of cylinders of this engine), similarly adjust the valves of the remaining cylinders in accordance with the order of their work.

7. Install the valve cover, start the engine and listen to the valve mechanism.

Adjusting the tension of the chain (or belt) of the camshaft drive. From the tension of the chain (or belt) of the camshaft actuator largely depends on the operation of the MRM, so it is necessary to periodically check and adjust the tension of the chain (belt).

Chain tension adjustment is carried out in the following sequence: let the stop bolt of the tensioner per 1/2 ... 2/3 turns; Turn the crankshaft to 3 ... 4 turns (while the tensioning device will automatically establish the required degree of tension of the chain); Tighten the tensioner stop bolt.

Adjusting the tension of the toothed belt is carried out in the following sequence: remove the top protective cover; Loosity bracket mounting bolts tensioner roller and smoothly rotate the crankshaft for 2-3 turns (at the same time the bracket spring will automatically install the required belt tension); Tighten the bracket mounting bolts and set the protective cover.

The main defects of timing parts and ways to eliminate them.

The main defects of the camshaft are bending (beating), wear of support necks and cervix under the distribution gear, cams wear. If the beating (bending) exceeds the allowable values, the shaft rule under the press or is written off. Worn necks are grinding to a smaller diameter to one of the repair dimensions, and the support sleeves set new repairs. The cervical cervix released from the repair dimensions can be restored to chromium or residue to a nominal or repair size. Small wear of the cams are eliminated with grinding, and significant wear - with a surfacing of siming No. 1, followed by grinding.

The pushers wear a cylindrical and spherical surface. Worn pushers replace or restore. The cylindrical surface (rod) to the repair size is restored by grinding or chrome. At the same time, the hole in the guide pushers is treated with a scanning of the size of the rods installed or for pressing the repair sleeve. The spherical surface wear is eliminated by grinding on the template, withsting the height-established technical conditions.

In the valve rocker, the sleeves are wearing, which are replaced with new, replete hole in them to a nominal or repair size. Oil holes drill in the new sleeve. The worn spherical surface of the rocker sock is grinning.

The main defects of the valves are the wear and oversight of the work chamfer, the deformation of the plate (heads), wear and bending of the rod. When bending, the rod and deformations of the plate valve rule on a special device or replace new. The wear rod of the valve can be restored by chrome or leaving, followed by grinding to a nominal size. Worn out the end of the valve rod grind before receiving smooth surface. With significant wear or burning of the working chamfer, the valve is replaced with a new one.

An insignificant wear or burning of the valve's work chamfer is eliminated by his wipe to the saddle. Valve trigger to the saddle is as follows. The timing is disassembled by disconnecting the axis of the rumor from the head of the cylinders, then remove it assembly with rocker, racks and other details. A fixture is installed on the cylinder head (Fig. 63) to remove and install valve springs. Squeezing the valve spring, remove the valve crumbs and remove the device from the head of the cylinders. The released parts are removed from the valve rod (valve springs with a support washer), take out the valve from the guide sleeve, purify it from the car and washed.

Fig. 63. Removing and installing valve springs fixture: 1 - adaptation A.60311 / R; 2 - mounting board A.60335

For ticking valves, special or independently prepared trigger pastes are used. The thin layer of pasta is applied to the valve champper, the valve rod is lubricated with clean engine oil and installed valve in the saddle. With the help of a tonfold device or coofer with the valve, the valve reports the return rotational movement. Slightly pressing the valve, turn it on 1/3 turns, then lifted, pressed again and rotate 1/4 in the opposite direction. Periodically lifting the valve, apply new portions of pasta on the chamfer. The wrap is finished when there will be solid matte belts with a width of 1.5-3 mm on the chamfer and saddles.

After ticking the valve, the saddle, the channel and the guide sleeve is washed with kerosene and wipe dry. Quality of wipes can be checked before and after assembling the valve mechanism. Before the assembly: across the champers with a soft graphite pencil through the same gaps are applied 15-20 wrappings. By inserting the valve in the saddle and strongly pressed, it is rotated by 1/4 turns. If all the risks are erased, the quality of the wipes is satisfactory. After the assembly: turn over the head and kerosene pour into the combustion chambers. If after 3 minutes, the kerosene seepage will not be detected, then the quality of the wipes is satisfactory.