4.1. General information and preparatory operations
The description of the most typical and important procedures of service and repair of engines is provided in this chapter, except for the procedures demanding special skills and tools, such as procedures of capital repairs of the engine – these works should be charged to specialists of car service.
The considered cars are completed with turbocharged DOHC engines (with the camshafts located in the top part and with 4 valves on the cylinder) from 2.0 to 3.0 l. Enter their number
4-cylinder line petrol engines (2.0 and 2.3 l) and also petrol and diesel V6 engines (3.0 l).
4-cylinder petrol engines
4-cylinder engines are equipped with two balancing shaft. Balancing shaft are intended for prevention of vibrations from moving parts of the engine, and also for noise reduction during the operation of the engine.
The block of cylinders cast, with the pierced cylinders and oil channels, and also tunnels with the aluminum bearings of balancing shaft pressed in them.
Pistons are manufactured of light-alloy material and an obluzhena by tin; their top parts are anodized. The top compression piston ring has the flat form and is covered with a layer of chrome or molybdenum. The oil scraper ring consists of three sections. The piston is strengthened from within and connects to a rod by means of a finger. Axial movement of a finger is limited to cutting rings. Rods are shod, the plug under a piston finger and inserts of conrod bearings it is possible to replace. Top head of a rod conic. The bent shaft has 5 radical necks, central of which is used as well for centering of a shaft in the axial direction. For greasing of bearings of a shaft in it oil channels are drilled. Inserts of radical bearings can be replaced.
The light-alloy head of cylinders fastens bolts to the block of cylinders. Combustion chambers are hemispherical. The cover of a chain of the GRM drive and a back cover of the block of cylinders fasten to the block with use of means of Loctite 518.
Camshafts are given from a bent shaft by a chain with a self-regulating natyazhitel. Camshafts affect valves directly, through hydraulic pushers. Pushers are regulated automatically according to change of length of the valve depending on temperature. Pushers work in an oil bathtub and are greased via the oil channel in a head of the block of cylinders. Valves are manufactured of steel and have the chromeplated cores. Plates of final valves of a stellirovana. Natyazhitel of a chain of the GRM drive is mounted in a head of the block of cylinders and is easily available.
Lubrication system of 4-cylinder engines
In the engine lubrication system pressure of oil is forced by the rotor pump located in a cover of a chain of the GRM drive and given by a bent shaft. Oil comes to the pump from the case pallet through mesh a maslozabornik and a tube. The reducing valve located in a cover of a chain of the GRM drive is intended for restriction of pressure of oil by return of excess of oil on the soaking-up port of the pump. Oil from the pump via the channel in the block of cylinders goes to an oil filter. The thermostat opening at a temperature of 105 a hail is installed in the case of the holder of an oil filter. and directing oil via the oil cooler. After filtering and cooling oil goes to the main canal of the block of cylinders where D/V of pressure of motive oil including corresponding To/L in a combination of devices with a low pressure of oil is located. Bearings of a bent shaft are greased via channels in the block and in a shaft while pistons and walls of cylinders are greased with spraying. In the lower part of each cylinder the masloraspylitel intended for cooling of the piston by injection of a squirt of oil on the lower party of the piston is established. The external bearing on the final party of a balancing shaft is greased through an opening in the radical bearing No. 1, and the internal bearing – through an opening in the radical bearing No. 1. Both bearings on the inlet party of a balancing shaft are greased via the main oil channel. The additional channel to a head of the block of cylinders for greasing of camshafts and valves departs from the main channel. Through an opening in one of screws of a head of the block of cylinders oil moves to the drilled canals to all bearings of camshafts and pushers of valves. The pallet of a case is manufactured of aluminum and fastens to the lower part of the block of cylinders. On the B235R engine with RKPP to the left of the pallet there is a strengthening adjacent to RKPP. The oil filter is located on the final party of a head of the block of cylinders, in the special holder from whom hoses to the oil cooler depart. In an oil filter the valve opening at pollution of the filter is installed perepuskny.
Arrangement of support of 4-cylinder engines
For clearing of vibrations during the operation of the engine on turns from single to 1800 rpm hydraulic support of the engine (a back and right lobby) are used. These support give the following advantages:
- Damping of horizontal movements of the engine at acceleration;
- Damping of vertical movements of the engine when driving on bad roads;
- Damping of vibrations idling;
- Reduction of noise during the operation of the engine.
The hydraulic support consists of two cameras filled with special liquid. Between cameras there is a membrane and the channel. Resistance of a support grows with growth of load of it.
Petrol 6-cylinder engine
3.0 the l the V-shaped 6-cylinder 24-valvate petrol engine is established cross in a motive compartment.
All camshafts are given by a gear belt, with automatic adjustment of a tension (by means of a natyazhitel with a roller). Inlet and final valves are given from camshafts through pushers. The mechanism of the drive of valves is similar described for 4-cylinder engines. In addition each head is equipped with two nozzles of a purge of air intended for reduction of noise of hydraulic pushers of valves after start of the engine. Cogwheels of camshafts of a back head of cylinders are interchanged, as well as cogwheels of shaft of a forward head of cylinders.
Lubrication system of the petrol V6 engine
The lubrication system is similar described for 4-cylinder engines. Oil for lubricant of piston fingers is delivered to them via channels in cranked to a shaft and a rod.
Arrangement of support of the petrol V6 engine
For fastening of the engine three support from which back and right – hydraulic type (see the description for 4-cylinder engines) are used.
Diesel 6-cylinder engine
3.0 the l the V-shaped 6-cylinder 24-valvate diesel engine with direct injection of fuel is established cross in a motive compartment.
The engine is completely manufactured of aluminum. Grinding of the block and a head of cylinders are not admissible.
Fuel moves to nozzles on the general fuel highway. Nozzles spray a certain amount of fuel and at some point, separately for each cylinder. The quantity and the moment of supply of fuel pay off an electronic control unit the engine (ECM). The throttle case, thus, is absent as superfluous. Is absent as well system of ignition.
Guides and saddles of valves can be replaced. Pushers of valves – mechanical, the valvate gap is regulated manually by selection of an adjusting washer of the necessary thickness. Nozzles are located on the center of cylinders. Valves are located at an angle the 8th hail. to each other what provides the most compact and effective combustion chamber.
For consolidation of connection of the block with a head of cylinders metal laying is used.
Inlet camshafts are given by a gear belt from the fuel pump of high pressure (FPHP). The belt is located behind the top plastic cover. Final camshafts are given from inlet. Behind the lower cover the oil pump given directly from a bent shaft and also the water pump and TNVD given from a bent shaft through gear wheels are located. The tension of a belt of the GRM drive is automatically supported by a natyazhitel of eccentric type.
The bent shaft leans on 4 radical bearings, the third of which plays a role of the persistent bearing.
The vacuum pump is located on a back row of cylinders, from a flywheel. The drive of the vacuum pump is carried out from the inlet camshaft.
Scheme of the lubrication system of the diesel engine
The lubrication system of the diesel engine is similar to the lubrication system of petrol engines. Gear wheels of camshafts are greased via bearings of camshafts. Pistons and piston fingers are greased by means of masloraspylitel and spraying from the case pallet.
The pallet of a case consists from lower (steel) and top (aluminum) sections. In the top section are located a maslozabornik and the sensor of pressure of motive oil. The oil filter is installed in the case combining also the oil cooler.
The engine is installed on four support, two of which – hydraulic type.
Arrangement of support of the diesel engine
Before holding any procedures of service of the engine make cleaning of a motive compartment and the external surfaces of the power unit with use of special solvent. Such processing will allow to avoid hit of dirt in the engine.
In case of need, the forthcoming work determined by character, it is possible to remove a cowl for the purpose of ensuring freedom of access to the components which are subject to service (see the Head Kuzov). In order to avoid casual damage of a paint and varnish covering cover car wings with special covers or old blankets.
The excessive consumption of motive oil can be considered a signal of need of conducting check of a condition of piston rings, maslootrazhatelny caps and/or the directing plugs of valves. Naturally, first of all, it is necessary to make sure that losses of oil are not connected with development of its external leaks. Check a compression in cylinders (see the Section Check of Compression Pressure) to define the general condition of the engine.
Loss of the developed power, violation of stability of turns, excessive noise of the valvate mechanism and the increased fuel consumption usually are rather characteristic signs of need of performance of capital repairs of the engine, in particular, when all these factors are shown at the same time. If performance of a full range of settings does not help with elimination of problems, carrying out the general mechanical works on restoration of the engine will be the only way out.
Capital repairs of the power unit mean restoration of all its working parameters to the level characteristic of the new engine. During capital repairs replacement of piston rings and restoration of mirrors of cylinders (a pro-point and/or a honingovaniye) is without fail made. Replacement of radical and conrod bearings of a bent shaft is usually carried out, the pro-point and restoration of his necks can be in case of need made. Service of valves which condition at the time of emergence of need for performance of capital repairs of the engine almost for certain leaves much to be desired is without fail carried out. In parallel with carrying out the general repair of the power unit also recovery repair of a starter and the generator is usually made.
Such critical components of the cooling system as hoses, driving belts and the thermostat when carrying out capital repairs of the engine have to be replaced with new without fail. Besides, it is necessary to check attentively a condition of a radiator (see the Head of the Cooling system of the engine, heating, ventilation and air conditioning). In case of identification of signs of development of leaks or violation of passability the radiator should be replaced. Do not forget to check a condition of the oil pump also.
Capital repairs of the engine do not demand from the performer of high vocational training at all, however take away a lot of time. It is necessary to plan refusal of use of the car for the term of not less than two weeks, in particular in need of the request for the help in a mechanical workshop for the purpose of performance of separate recovery work.
The most part of works can be executed with use of usual set of the metalwork tool, however some of checks by definition of suitability of separate components to further use demand use of the precision measuring equipment. In doubtful situations ask for the help experts HUNDRED.
Do not forget that in a question of expediency of performance of capital repairs of the engine the condition of the block of its cylinders is decisive factor. Frequent cheaper and more reliably it appears to replace the worn-out engine restored.
In conclusion it is possible to notice that all efforts on performance of recovery repair of worn-out components will be spent for nothing at the negligent relation to the requirement of respect for purity at assembly of the unit.