3.6. Useful tips
Wear of tsilindroporshnevy group
The car engine is compared sometimes to heart of the person. Really, it works constantly while the car moves. However, such comparison is not quite correct. Heart, as well as any live organism, continuously self-repairs: in it constantly there are processes of dying off of old cages and replacement their new, young. What you will not tell about the lifeless mechanism in any way – the automobile engine. It, despite all our efforts, wears out is almost irreversible. However intensity of such wear, an engine resource before capital repairs, as well as durability of all car in general, in many respects depend on that, how qualitatively it is made and is competently operated.
The main details of the engine – pistons with piston rings, rods and cylinders are especially subject to wear. Operation of pistons of the engine most impresses. Moving returnable progressively between the top and lower dead points, they cover huge distance. So, at
frequency of rotation of bent shaft 5000 mines-1 and piston stroke, say, of 75 mm the total way overcome by the piston in a minute makes 375 m. For hour of work of the engine this distance will make 2 km 250 m, and for a month of operation on 8 h a day, excepting days off (that, of course, is improbable for the average car), the piston will overcome distance of 460 km. At intensive operation of the car in 5 years (namely such duration of operation of the car before capital repairs of the engine is confirmed by statistics) the piston will cover distance of 24 000 km!
So, wear of the piston and the details (the engine cylinder) interfaced to it is inevitable. However values of wear of piston group (pistons - piston rings) before capital repairs for engines of various firms very strongly differ from each other. So, extreme wear of pistons and piston rings of engines Mercedes-Benz, Volkswagen, BMW, most the American and Japanese firms comes after the run about 300 000 km.
At the same time engines of others, say, of less perfect models, need replacement of pistons and piston rings after 50 000 km of a run (nearly 10 times less).
In what here reason? And how durability of these details depends on service conditions? For the answer to these questions we will consider two typical designs of piston groups of the petrol engine and the diesel. Let's remind first of all that pressure of gases in cylinders of these engines at the beginning of the working course differs approximately twice. In the petrol engine – carburetor or with direct injection of fuel it makes 40–55 kg/cm2, in the diesel –
70–80 kg/cm2. Therefore also pistons of petrol and diesel engines differ one from another though the main constructive decisions at them are identical.
The typical piston of the petrol engine is cast from aluminum alloy and covered outside with a tin layer for improvement extra earnings to a cylinder mirror. Diameter of its top part – the head – is 0,1 mm less, than the internal diameter of the cylinder. It is made for prevention of jamming of a head of the piston in the cylinder at a warming up up to the working temperature. In ring flutes of the piston two compression rings and one oil scraper are placed. The lower part of the piston – a skirt – in cross section oval, and on height of conical shape: in the top part diameter is less, than in lower. Besides, in piston lugs with openings under a piston finger there are two steel temperature-controlled inserts. All this is made for prevention of increase in friction between a skirt and a mirror of the cylinder when heating the piston. At smaller, than at aluminum, coefficient of thermal expansion these inserts pull together a skirt in the direction, perpendicular axes of a piston finger.
The opening under a piston finger in modern engines is usually displaced from an axis of symmetry of the piston to the right side of the engine. For the correct assembly of the piston with a rod and their installations in the engine cylinder about an opening of a lug there is a tag which has to be turned towards a forward part of the engine. Such shift is done for reduction of a side component of the pressure force of gases pressing the piston to one of the parties of the cylinder during the working course.
The rod also has to be correctly focused in the engine. On its forward party openings for giving of a stream of oil on the loaded party of a mirror of the cylinder (in some engines these openings are absent) are executed. Inserts and a cover of the lower head of a rod are also supplied with the corresponding tags for the correct assembly. Its further working capacity and durability significantly depends on the accuracy of production of the piston and its right selection to a cylinder opening. The leading engine-building firms apply today system according to which pistons on outer diameter are broken usually into five or six classes with a step of 0,01 mm. Except
that, they are divided into three or four categories with a step of 0,004 mm according to diameter of an opening under a piston finger. Engine cylinders also have similar division into five classes. Such system allows to pick up more precisely the piston to any, even worn-out cylinder, and a piston finger of the necessary category – to an opening in lugs and to a rod. For the capital repairs of engines consisting usually in boring (increase in diameters) of cylinders, producers of spare parts release so-called repair pistons of the increased sizes.
The piston of the modern diesel is calculated on perception of more high pressures therefore thickness of its bottom and lugs is more. Besides, the diesel piston design differs from a little considered above. The main difference is placement of the combustion chamber directly in a piston head. As combustion of fuel-air mix happens when finding the piston near the top dead point, hot gases heat a piston head stronger, and walls of the top part of the cylinder heat up slightly less, than in petrol engines. For reliable consolidation of the piston in the cylinder on its external surface five flutes for installation of piston rings are made. In three top flutes compression rings are established. In the lower flutes two oil scraper rings are placed. Many firms produce the compression rings of rectangular section almost not different from rings of petrol engines. However more progressive, though more expensive, the design with a conical top working surface of a ring is. The tilt angle forming a cone at such rings is done usually equal 10 °. Application of conical rings provides some increase in their durability as during the working course the component of pressure force of gases on a conical surface of a ring in addition presses it to a cylinder mirror. Feature of service and repair of pistons with conical compression rings is need of exact control of gaps. Gaps between a flute and oil scraper rings control the same as in petrol engines.
Friction forces between surfaces of a skirt of the piston and a mirror of the cylinder at diesels are higher, than in petrol engines. For increase in durability at a surface of a skirt of pistons put a layer of a special colloidal and graphite covering. It much more improves a piston prirabatyvayemost to the cylinder and increases the term of its work before capital repairs. Similar processing of the rubbing surfaces of pistons is applied today and on petrol engines.
Except wear of surfaces of a skirt, also flutes of compression rings of pistons wear out. Besides, also the flute of an oil scraper ring wears out though such wear is usually much less. At wear of flutes of a ring of the piston begin to move more and more intensively down and up height of a flute and more and more notable is a so-called pump action of rings. This action is shown in more and more increasing expense by the engine of engine oil. Getting to the combustion chamber, oil burns down there, forming gray smoke which comes out an exhaust pipe of the car. At considerable wear of flutes replacement of rings on new improves a situation a little. There comes objective need for replacement of all piston group, at the same time boring of cylinders to the repair size is very desirable. All described types of wear are natural and, unfortunately, inevitable process.
Nevertheless this natural wear can be stretched in time, prolonging thus engine service life. Old stuff does not need to be peddled here. Just it is necessary to fulfill precisely requirements of the producer for operation of the car, to use qualitative engine oil and oil filters, it is correct to adjust the fuel equipment. Good results are yielded by use of high-quality modifiers of oil and fuel, the medicines changing a microstructure of blankets of surfaces of friction of engines.
Along with it wear of the engine, as well as all car in general, in many respects depends on the driver, on his qualification and technical literacy. Not for nothing cars of the same brand at one drivers serve long and smoothly, at others – are under repair nearly every week. The skilled driver almost never allows operation of the engine with an overload and furthermore with
detonation. He constantly listens as the engine of its car works, and immediately reacts to any overload which is usually accompanied with a booming sound of low tone at the lowered frequency of rotation of a bent shaft. Mode of dispersal of the car also
is followed by the increased wear of the engine. Here analogy to a horse and the equestrian arises: the careful owner without special need will not whip the canine friend, forcing it to run straight away, especially when the horse was not warmed yet. Of course, in critical situations the driver is able to afford dashingly, extremely sharply to accelerate the car. But, if such abrupt style of driving becomes a habit, repair of the engine will be provided twice earlier, than it is provided by specifications.
Also another is often observed, the type of wear which is not provided by any instructions. It is emergency breakage of elements shatunno? piston group and first of all rings and crossing points of ring flutes of the piston. In petrol engines it is connected first of all with a detonation. Let's remind that the detonation is the explosion-like combustion of fuel-air mix in the cylinder accompanied with spasmodic increase in pressure in the combustion chamber. It to equivalently sharp blow by a sledge hammer on the motionless piston and rings. Details, naturally, are not calculated on such loading and can break, having damaged then the splinters a cylinder mirror. Detonation reasons a little. However main of them – this operation of the engine on gasoline with lower, than it is provided by specifications, octane number, and also an overheat and work on the reenriched gas mixture. The skilled driver is obliged to hear detonation knocks during the operation of the engine and to immediately reduce supply of fuel at dispersal, and then to remove the detonation causes. A sound of a detonation are the metal clicks of high-pitch tone coinciding on frequency with the frequency of rotation of a bent shaft. They can be hardly heard against the background of other sounds of the working engine, especially at slightly early ignition, and vanish at absolutely insignificant reduction of supply of fuel (gas). Such hardly noticeable detonation testifies to correctly adjusted ignition advancing coal, but happens and so that detonation knocks appear at once when pressing an accelerator pedal that, of course, inadmissibly. To continue the movement in such mode it is equivalent to dissecting by the hammer of interiors of the engine.
Diesel engines are not so sensitive to change of composition of fuel, though in them there are troubles leading to the increased wear of details of the krivoshipno-conrod mechanism. It is first of all an overheat of the engine and the related reduction of viscosity of oil, especially if quality of oil low. The increased wear can be also a consequence of the wrong adjustment of the fuel pump of high pressure and deterioration in dispersion of fuel in combustion chambers because of violation of work of nozzles. And, of course, a lot of things depend on the driver.
So, from everything told it is possible to draw such conclusions. Durability of the engine of your car, as well as all vehicle in general, depends on two factors: qualities of production for which the manufacturing firm, and the level of technical operation for which eventually the driver is responsible is responsible. It is necessary to remember it both upon purchase of the car, and by preparation and training of drivers.
Bearings of engines
What bearings are installed in your engine? Not all motorists can answer such question intelligibly.
Nevertheless bearings are there. And not any, but quite certain. They are durable, but are not eternal and when fail, not to do without understanding of the main point. And for professional repairmen it is the most usual matter.
As the bearing works
In modern automobile engines as support for cranked and camshafts practically in all cases serve sliding bearings. Rolling bearings (ball, roller, needle) apply to the similar purposes only in small motorcycle motors.
Necessary operability of bearings of sliding is reached by use of effect of a so-called oil wedge. At rotation of a smooth shaft in a gap between shaft and an opening oil moves. As the loading operating on a shaft causes its excentric shift, oil as if drags on in the narrowed part of a gap and forms the oil wedge interfering contact of a shaft with opening walls. The more pressure and viscosity of oil in a gap, the big loading (before contact of surfaces) maintains the sliding bearing.
The actual pressure of oil in a zone of a wedge reaches 50–80 MPas (500–800 kg/cm2), and in some designs more. It is one hundred times higher, than in the giving system (the engine lubrication system). However it is not necessary to think that giving pressure influences operation of the bearing a little. The it is higher, the more intensively there is a pumping of oil via the bearing and better it is cooled with that.
Under certain conditions the operating mode with the minimum friction (it also call liquid) can be broken. It happens at decrease in viscosity of oil, for example because of its overheat owing to insufficient giving, and decrease in frequency of rotation of a bent shaft at increase of loading.
Quite often, especially after repair of the engine, also the non-optimal geometry of knot affects. At an insignificant deviation of a form of surfaces from cylindrical, at a distortion of axes and other defects of details perhaps local increase of specific loading (i.e. the loading carried to surface area) above an admissible limit. Then the oil film in these parts becomes thin, and surfaces of a shaft and the bearing begin to adjoin on microroughnesses. There is a mode of semi-liquid lubricant which is characterized by increase of friction and a gradual warming up of the bearing. Further it can lead to so-called boundary friction with full contact of the rubbing surfaces which consequence the overheat will be, skhvatyvany (teases), jamming, fusion and destruction of the bearing.
It is clear, that in operation the mode of boundary friction is unacceptable. Nevertheless it takes place at oil supply violation, and it most often happens because of its shortage in a case: or owing to oversight of the driver, or at damage of the pallet of a case as a result of arrival on an obstacle.
The mode of semi-liquid lubricant is admissible only for a short time when it does not manage to affect wear of the bearing. An example – launch of the cold engine. However, there is other danger: at very low temperature oil can become too viscous and its normal giving is restored too long (20–30 with and more). In this case and semi-liquid lubricant is capable to affect wear of details considerably.
Improvement of a design of automobile engines is connected with continuous increase in frequency of rotation of a bent shaft and increase in engine capacity. The tendency to increase in compactness of designs, including reduction of width and diameter of bearings is at the same time observed. It means that specific tension grows in a frictional unit. And as load of the bearing during the operation of the engine cyclically changes in size and the direction, the probability of so-called fatigue failure of details increases. To provide operability of bearings in such conditions, special designs, materials and technologies are required.
As the sliding bearing is arranged
Usually bearings of bent shafts in modern engines are carried out in the form of thin-walled inserts or plugs from 1,0 to 2,5 mm thick (is rare more). Inserts of radical bearings of a bent shaft do to thickness because of need to place in them a circular flute for supply of oil to conrod bearings. The general tendency – reduction of thickness of inserts which averages 1,8–2,0 mm at radical and 1,4–1,5 mm at conrod bearings now. The inserts are thinner, the better they adjoin to the surface of the case of the bearing (bed), the heat from the bearing, more precisely geometry, less admissible gap and noise during the work is taken away better, the knot resource is more.
That at installation in a bed the insert precisely took its form, in a free state it has to have a tightness on diameter of a bed (so-called straightening) and not cylindrical form of variable radius. Besides, the tightness is necessary for a good prileganiye to a surface and keeping from a provorachivaniye and on insert length – it is called a vystupaniye. All these parameters depend on thickness, width and diameter of inserts, straightening makes in
average 0,5–1,0 mm, and vystupany – 0,04–0,08 mm. However for reliable operation of the bearing of it still it is not enough. About the line of the socket thickness of inserts is reduced by 0,010–0,015 mm to avoid zadir in these parts. Teases can appear owing to deformation of an opening in the bearing case in the block of cylinders under the influence of working loading when the working gap in the bearing is small.
Materials for inserts can be different. Their choice depends on the choice of material of a bent shaft and its heat treatment, extent of speeding up of the engine and the set resource. To a certain extent also traditions of automobile firm affect here.
Inserts always become multilayered. An insert basis – a steel tape which provides durability and reliability of landing in the bearing case. Apply with various ways a layer on a basis (or several layers) special antifrictional material which thickness makes 0,3–0,5 mm. The main requirements to antifrictional material are low friction on a shaft, the high durability and heat conductivity (i.e. it is good to take away ability warmly from a shaft surface to the bearing case). The first requirement is provided best of all by soft metals, for example alloys with high content of tin and lead (in particular, widely known babbits).
In the past babbits were widely applied on the low-forced low-reverse engines. With growth of loadings durability of such inserts with a thick layer of babbit was insufficient. The problem was solved by replacement of all this layer by peculiar "sandwich" – the lead-tin bronze covered thin (0,03–0,05 mm) a layer of the same babbit. The insert became multilayered.
In modern engines stalebronzobabbitovy inserts usually carry out chetyrekhkhsloyny (under babbit there is still very thin layer of nickel) or even five-layer when for improvement extra earnings from above the thinnest layer of tin is applied on a working surface. Quite so bearings on many foreign engines look.
Along with it also steel-aluminum inserts were widely adopted. As antifrictional material serve aluminum alloys with tin, lead, silicon, zinc or cadmium both with coverings, and without them here. Most often in world practice aluminum alloy from 20% of tin without covering is used. It well resists to high loadings and speeds of rotation of modern engines, including
diesels, and at the same time has satisfactory "softness". Nevertheless steel-aluminum inserts are more rigid, than babbitovy (or with a babbitovy covering) therefore are more inclined to teases in the conditions of insufficient lubricant.
Auxiliary and camshafts of engines rotate, as a rule, with a smaller frequency, than cranked, and experience much smaller strain therefore it is easier than a condition of their work. Inserts and plugs of these shaft usually do of the materials similar described. Besides, here sometimes apply babbit or bronze without covering. Often these bearings have no plugs or inserts at all and are formed directly by boring of openings in a head of the block of cylinders. In such designs the head is made of aluminum alloy with silicon which has quite good antifrictional properties.
The general for bearings of modern engines, especially if it is about support of bent shafts, compliance of material and a design of inserts to material and operating conditions of a shaft is (frequency of rotation, loading, lubricant condition, etc.). Therefore any replacement of details when, for example, at repair put inserts from other engine, cannot be recommended. Otherwise durability of the repaired unit can turn out very small. to make up the mind to such step, it is necessary to have the relevant information.
Inserts of bearings of sliding represent very exact (precision) details. to guarantee small, but quite certain (on average 0,03–0,06 mm) working gaps in bearings, at production maintain thickness of an insert with an accuracy about 5-8 microns, and length – 10–20 microns. Violation of these requirements can lead to change of a working gap in the bearing or density of landing of an insert in the case that is inadmissible as can lead to decrease in reliability and a resource of all engine in general.
Who makes sliding bearings
Complexity of all circle of the problems connected with creation of high-quality automobile bearings of sliding led to the fact that their production gradually passed to specialized firms. Abroad many of such firms at the same time release also other details for engines, and deliveries go both on conveyors of automobile plants, and to sale – in the form of spare parts. Some firms such are a part of the known multinational production and commerce and industry corporations. From world manufacturers of bearings of sliding for engines it should be noted Kolbenschmidt (KS), Glyco, TRW, Sealed Power, Glacier, Clevite, Bimet first of all. In recent years bearings began to do also such "korifei" as Mahle and Goetze. Among "young people" it is worth mentioning the specialized King (Israel) which began release of bearings in the early eighties of the last century. Most of the listed producers issues the huge nomenclature of bearings and delivers the production in spare parts everywhere including on our market (through dealers or the wholesale trading companies). Generally of course, it is bearings for engines of foreign cars – European, Japanese and American.
It is possible to find inserts in sale as standard, and various repair sizes (differing from standard, as a rule, no more than on 0,75 mm) for the majority of widespread models. On less widespread models, and also in need of purchase of inserts of the bigger repair size usually it is necessary to make out the order and to wait on average for 5-10 days (at different trading companies these terms are various).
Quality of such production usually does not raise doubts neither on geometry, nor on materials. Though if there is a choice and doubts in what firm manufacturer to give preference, it must be kept in mind the following. Such firms as Kolbenschmidt, Glyco, Glacier are one of the main suppliers for mass production. Upon purchase of their products it is possible even to receive the same inserts that put on engines "at the birth". The difference consists only in absence on new details of an emblem of firm – manufacturer of the car. By the way, search of "family" (or so-called original) inserts of the repair sizes can be problematic. Not all automobile firms deliver repair inserts in the spare part and the price of inserts in "original" packing is, as a rule, much higher, than directly from their producer.
Inserts of production of other, less eminent firms are usually cheaper though it will be difficult to find differences as production. Moreover, if there is a choice, then here it is possible to try to consider also service conditions of the car. So, rather cheap inserts, strangely enough, resist to the low-quality oils and oil filters "walking" on our shops and the markets than more expensive stalebronzobabbitovy slightly better. It was shown, in particular, by practice of use under repair of steel-aluminum inserts of King instead of regular bronzobabbitovy: such replacement does not cause damage to reliability of engines, but allows to save considerably.
Gear belt of the drive of the mechanism of gas distribution
Today gear belts found "second wind". Practically all car makers equip the cars with the elastic drive. The German designers went further away. They widely apply a double gear belt (Duplex) as reliable connection of the camshaft with the krivoshipno-conrod mechanism.
The gear belt has a number of advantages before a driving chain. The last it is obvious more expensively. It is much simpler to make a belt, than a chain. In essence the gear belt is the closed tape from maslobenzostoyky rubber reinforced by a kapron cord with teeths, privulkanizirovanny to it. If to compare a belt to a chain, then comparison will appear not in favor of the last. The belt is much lighter than a chain that, naturally, cannot but affect the mass of the engine. Besides, the engine supplied with a belt, the fellow much more quietly equipped with a chain. Also "elastic band" out of an engine casing is mounted that affects time of its installation or replacement. For example, on replacement of a belt of the drive of the gas-distributing mechanism of the four-cylinder eight-valve engine with the subsequent its installation on tags about 25-30 min. leave. With a chain such focus will not pass.
At the correct service the gear belt goes long. Domestic manufacturers, we will remind, give a guarantee for a run of 60 thousand km, foreign – and that it is more. Rover managed to postpone the time of replacement of a belt to 160 thousand km of a run.
What the correct service of the belt drive consists in? At least each 15–30 thousand km have to be checked a belt tension. However it does not mean that it is only necessary to unbend a casing and to check, whether on the place a belt. It is the best of all to examine it, having removed from the engine. Sometimes it is difficult to notice that one of teeths is cut. If it already occurred, then be sure that long he will not stretch. Therefore, having taken off a belt, make on it a mark chalk, and further tooth behind tooth examine it. After installation it is also necessary to check the provision of the directing and tension rollers. All these elements have to be in one plane, otherwise the belt will work with a distortion that considerably will reduce its resource.
Important factor for work of a belt – absence on its surface of oil. Whatever was maslobenzostoyky rubber of which the belt is made, nevertheless it is not that case when "oil you do not spoil porridge". Here oil just to the detriment. Therefore it is periodically necessary to pay attention to a condition of epiploons of distributive and cranked shaft. And if you noticed an oil leak, try to eliminate somewhat quicker it. As practice shows, stay of a belt in oil cuts its resource by half, and even three times.
If to ignore this control, then consequences will not keep themselves waiting long. Through 40–50 thousand km at the expense of a belt pulling its tension will weaken and it will begin "to whip". As a result of it the "heavy" camshaft rotates not synchronously with a bent shaft, and with lag. This "asynchronous" work leads to a bigger weakening of a tension of a belt. As a result there is excessive load of teeths.
The break of several teeths in a row can lead to the fact that once the camshaft will remain motionless whereas the bent shaft rotates. At this moment open valves of cylinders "will meet" pistons. Result – breakage of a core or a bend of the valve, the broken directing plugs, breakage of the camshaft. There are, however, also exceptions when the break is painless practically. However it is possible only on those cars in which engines especially for such case pro-points in pistons are executed. Our VAZs, namely the VAZ-2105 cars with the engine 1300 of cm3 and VAZ-2108 with the cm3 engine 1500, for example, concern them.
It is possible to reanimate any "tired" car. However technical difficulties at the same time are big. Here not to do without spare parts, machines, the welding equipment and other technological support. The main thing – factory repair manuals (and they are available now) tell nothing about possible alternative decisions, especially about a choice problem among details, materials and tools which are in the domestic market. Such is a circle of questions which both the loner enthusiast, and mechanics of small automobile repair shop lack for information.
Sooner or later any engine becomes a source of troubles: becomes deaf in way, it does not want to be let in the mornings, pulls worse, "eats" excess fuel and oil. It is quite probable that the reason of his whimsical behavior is plain: it is enough to clean the carburetor or nozzles of system of injection, to adjust ignition and to replace oil scraper caps that everything entered norm. But happens that traditional approaches do not help maintenance of the engine, and at measurements of a compression it becomes clear that in one or several cylinders it is lower than admissible.
Then first of all specify the nature of malfunction: wear of tsilindroporshnevy group, a podgoraniye of plates or wear of cores and the directing plugs of valves. Technology of diagnosing is rather simple and described in many grants on repair of engines.
After that decide on repair. Here it is only necessary to take itself for the rule to be
far away from any miracle liquids. The effect in principle is possible, but is reached seldom; usual result – excess expenses and efforts. It is better to be guided by the full-fledged repair procedure at once.
To find a workshop where engines treat, today it is already simple, and not only in the large cities. But here is how work and what its quality is organized there? Life shows that at all importance of experience and qualification of employees good results of work without the special equipment and equipment are unattainable, and in this plan the dispersion of technical armament of our service stations and mechanics, alas, is high. And if told above concerned generally the motorist operator, then further is addressed not so much to it how many to the mechanic, it will be a question of technology.
In cases when results of diagnostics indicate malfunction of the mechanism of gas distribution, the head of the block of cylinders should be removed. The first that needs to be made after removal, dismantling and the general survey, – to estimate gaps between cores of valves and the directing plugs. If they it is more maximum permissible, then valves replace with new. But when this vague measure is insufficient, it is necessary to replace also plugs.
For a small workshop such work presents already known difficulties: pig-iron plugs press in the aluminum case with a tightness. At the same time to avoid microcracks and a smyatiya, plugs should be cooled previously in liquid nitrogen (which temperature of -196 °C), and to heat a head of the block to 160–170 °C (when heating to more high temperature there can be harmful consequences). All this is quite difficult, labor-consuming and is often simply impracticable in semi-handicraft conditions. Therefore in rare workshops do not deviate from the conditions ordered by the repair manual that directly develops into loss of quality of landing and distortion of geometry of connection. It is corrected then, processing "in the place" saddles of valves, and valves long and tiresomely grind in.
But today there is also other technique, extremely profitable both on labor input, and on investment of capital which at the same time guarantees high-quality results. It is based on use of the original and almost unknown tool of the American company Neway in our practice.
With its help restoration of worn-out guides of plugs is carried out on the place without vypressovka. Special knives rollers cause plastic deformation of metal, compensating wear of an internal surface of the plug, at the same time forming in it a spiral fillet which improves valve core lubricant conditions, and also serves as the peculiar labyrinth consolidation facilitating work to oil scraper caps.
Five knives and a set of development for finishing processing of the plug are included in the package. It is characteristic that all operations with the Neway tool are conducted manually and are not connected with power supply or receiving from the outside of other type of energy.
Now about saddles of valves. At traditional methods of their processing directing a sharoshka or a vertical drill freely rotates in the valve plug. Mills of Neway have a motionless axis which is densely fixed already in the restored plug by the self-established broad collet clip. The mill is put on an axis with a precision gap of 0,5 microns that provides the minimum admission of processing. Neway mills due to unique sharpening and a form of the cutting edges form on a valve saddle surface a special microrelief like "comb": extra earnings of the valve and a saddle passes quickly and effectively, and need for grinding in disappears. Their productivity is high: any facet on a saddle of the valve turns out for 3–4 turns of the tool.
The last stage – restoration of working facets of valves. For this operation Neway offers the special Tizmatik-2 tool. The valve is not movably fixed in special adaptation which is installed, in turn, in usual table vises. There are enough several turns of a mill (axial giving is provided with the microelevator) to receive the ideal concentric surface of the valve. Let's notice that on its working surface, as well as when processing a saddle, the special microrelief is also formed.
Here, actually, and all. It is necessary only to wash out and grease all details then it is possible to collect a head.
And grinding in? Let's remind once again: during the work as the Neway tool in this tiresome, long and tiresome operation there is no need. After processing of couple "valve saddle" interface of both details happens on very narrow corbel, practically on the line.
It is reached small (to 1 °) by a divergence of angles of processing of working surfaces of a saddle and the valve (between them the so-called interferential corner is formed). In the first seconds of operation of the engine the area of interface increases for the account a smyatiya of superficial ledges of the created microrelief on facets, and then there is a necessary 100% consolidation.
At the cost of set of the equipment about $400 (depending on a complete set) Neway can pay off in the first month of work, and at repair of engines of foreign cars – besides to bring in the noticeable income.
What needs to be known when replacing oil
First, it is recommended not only to give to old oil to flow down completely, but also to turn a bent shaft of the engine on 5–7 turns to remove the remained oil from oil highways. It is also useful to wash out the engine (for this purpose apply special oil to washing) within 20–25 min., at the same time the engine has to work in the idling mode.
Changing oil, it is always necessary to replace also the filter. Old, though washed out, will be "as a fly in the ointment".
Oil should be changed indoors where there are no dust and wind.
When checking level of oil in an engine case the rag with which wipe the masloizmeritelny probe has to be pure. Even, apparently, the insignificant particles of dust which got to the engine considerably reduce the term of its service.
When replacing oil change also laying of a stopper of a drain opening in the oil pallet of the engine, and also the case of an oil filter (if it is established). Laying is included in the package of an oil filter.
After replacement of oil it is useful to record a car run, date of replacement, oil brand that at the subsequent its replacement or a dolivka there were less problems.
It is not necessary to be afraid of the fact that oil will darken after 1000 km of a run. It demonstrates only that it "works" correctly – holds in itself a deposit and washes surfaces of details.
What should be known to the owner of the car with the injector engine
Injector motors surpass carburetor in many parameters, to take at least their profitability and trouble-free start-up in a frost. Nevertheless carburetor under our conditions sometimes are more advantageous. Some car makers even deliver on our market cars with such engines. It is all about quality of gasoline which is sold at us.
The injector engine is calculated on high-grade gasoline which at our gas stations you will find infrequently. Besides different systems of injection have the specific features, they need to be considered at operation of the car. And in our market there is a lot of such systems: mechanical – K-Jetronic (KE-Jetronic), electromechanical – L-Jetronic and electronic – Motronic, Lucas, Magneti Marelli.
Many systems have two operating modes: the main and emergency, used at malfunction of one of sensors. The driver can not notice such malfunction: on the dashboard there is no corresponding control lamp, and the engine continues to work (but not in the optimum mode any more). Similar quite often happens on the Audi cars equipped with engines with the central injection of fuel. About a third of the motorists having such cars do not even guess that they go in emergency operation. And it leads to the increased fuel consumption, power deceleration, uneven operation of the engine and the complicated start-up. Malfunction only at the next maintenance comes to light. Therefore it is worth dwelling upon "weak" places of the systems of injection which are shown under our conditions.
Systems with mechanical injection.
They more than others, are subject to physical wear. The regulator of pressure of fuel fails usually through 80–120 thousand km of a run (launch of the engine considerably worsens), nozzles – through 60–80 thousand km (uneven operation of the motor, the increased fuel consumption). The refusal of nozzles is especially artful as you will notice it not at once. Diagnostics and repair require the special equipment.
Sore point of systems with electromechanical injection – an air suction through the numerous vacuum hoses tending to cracking after 4–5 years of service. Especially on the BMW cars and in a little smaller degree on Audi. To define such defect quite difficult.
Electronic systems of injection.
They have problems. For example, the accumulator "sat down", and you on an old habit decided "to light" from other car. As a result the electronic control unit of system of injection fails. And use of ethylated gasoline, in turn, puts out of commission the sensor of concentration of oxygen (lambda probe) and catalytic converter.
In general both mechanical, and electronic systems of injection have the pluses and minuses. At mechanical the thicket is refused by gasoline pumps and batchers distributors. At electronic the gasoline pump is more durable and is cheaper, but elimination of any malfunction of an electronic control unit will cost very much. Besides, we, alas, have more reasons for failure of any system, than in Europe: low-quality gasoline, dirt on roads and chemicals which strew in the winter. Therefore it is worth listening to recommendations of experts. If there is an opportunity, for removal of moisture from fuel-supply lines during each filling fill in special medicine in a tank; through each 10 000–15 000 km of a run do full washing of system of injection.
Cars with catalytic converter in system of production of the fulfilled gases
The Hyundai cars serially equip with catalytic converter. At its existence use of unleaded gasoline is obligatory. Cars with the operated catalytic converter, besides, have to be equipped with the device of an adjustable smeseobrazovaniye.
The device of an adjustable smeseobrazovaniye is understood as system of injection of fuel in which a ratio fuel/air can constantly change depending on service conditions and the content of oxygen in the fulfilled gases.
The device of a smeseobrazovaniye receives teams of management from the sensor of concentration of oxygen (lambda probe) which is installed before catalytic converter or in a final collector and is blown by a stream of the fulfilled gases. The lambda probe is the electric sensor registering the residual content of oxygen in the fulfilled gases and the giving-out corresponding electric signal. The size of a signal allows to draw a conclusion on composition of fuel-air mix. In fractions of a second the lambda probe can give the corresponding signal on an electronic control unit, at the expense of it the composition of mix can constantly be corrected. It, on the one hand, is necessary as service conditions (for example, full gas, idling) constantly change, on the other hand, because optimum reburning happens in catalytic converter only if in the fulfilled gases there is enough particles of carbon (not burned down gasoline).
So that at a temperature of 300-800 °C in catalytic converter in general there could be a reburning, the fulfilled gases have to contain bigger amount of fuel, than it is required for full combustion in engine cylinders. In this regard at operation of the car equipped with the engine with catalytic converter, fuel consumption increases approximately by 5%. Catalytic converter is in a motor compartment of the car in the place of the forward muffler. Converter consists of the ceramic cellular block covered with noble metal catalyst – platinum or rhodium. For fastening of the ceramic block, sensitive to blows, the elastic heat resisting wire grid is used.
The used catalytic converter represents so-called three-component catalytic converter. It means that in it at the same time there is an oxidation of carbon monoxide (SO) and hydrocarbons (SN) and decrease in content of nitrogen oxides (NOx).
Service regulations of cars with catalytic converter in system of production of the fulfilled gases
To avoid damage of the sensor of concentration of oxygen (lambda probe) and catalytic converter, it is necessary to follow the following instructions.
It is obligatory to refuel unleaded gasoline.
If ethylated fuel was by mistake filled in, it is necessary to replace a final collector and catalytic converter. Before installation of new elements of system of release not less than two times should be filled completely the fuel tank with unleaded gasoline.
Launch of the heated-up engine pushing or towage is inadmissible. It is necessary to use an electric cable for launch of the engine. Not burned down fuel at ignition can lead to an overheat of catalytic converter and its subsequent destruction.
It is necessary to avoid the frequent cold start-up following one by one. Otherwise in catalytic converter not burned down fuel which is burning down when heating with explosion at the same time gathers converter is damaged.
At difficulties at launch of the engine do not allow a starter to work long as during start-up there is a fuel injection. It is necessary to find and eliminate malfunction, and then to launch the engine.
At interruptions in work of system of ignition before definition of a cause of defect do not allow injection of fuel at launch of the engine.
Do not check existence of a spark at the removed spark plug tip.
It is impossible to carry out balance test by shutdown of a high-voltage wire of ignition of one of cylinders. At a detachment of a high-voltage wire of ignition of the separate cylinder, even by means of a special tester, not burned down fuel will get to catalytic converter.
At interruptions in work of system of ignition avoid operation of the engine with high frequency of rotation of a bent shaft. Eliminate malfunction as soon as possible.
Do not park the car on the dried foliage or a grass. Temperature of system of production of the fulfilled gases in an installation site of catalytic converter very high, the radiation of heat occurs even after switching off of the engine.
When filling engine oil it is necessary to watch that the maximum level of oil on the probe was not exceeded. Otherwise its surplus can get to catalytic converter and damage a covering or completely destroy it.
How to save converter
Replacement of the refused converter will run into money therefore well to foreknow as the situation with converters in the market of automobile spare parts is and what problems arise at their operation.
Until recently we knew about converter only the following: it is such piece which it is unclear why it is necessary, it is unclear as works, our gasoline "kills" it, generally one troubles. To cut out – and any problems! But gradually we began to get used that converter – a thing after all reasonably useful, at least thoughts of "surgical intervention" in system of production of the fulfilled gases visit more and more seldom and the lesser number of the heads.
In the spring when traffic police officers begin "fight for purity of air", one more problem falls down us – it is necessary to adjust WITH. Owners of the cars equipped with converters do not even think of it, and check posts WITH pass without shiver in knees and fear for the purse. However, the same purse can decently "lose weight" for other reason. Penalties for excess of the SO level will seem cheap in comparison with expenses on purchase and replacement of converter if it fails. That is why it is necessary to know how to treat it, and for this purpose at first it is necessary to understand as it is arranged and as works.
As converter works
At combustion of fuel-air mix a number of unhealthy products of the person – carbon oxide (SO), various hydrocarbons (SN) and nitrogen oxides (NO) and so forth is formed. In spite of the fact that these substances also make only 1% of total amount of an exhaust (the rest is a nitrogen, carbon dioxide and water vapor), they are very harmful and demand neutralization. There are several ways of fight against harmful components of an exhaust, for example impoverishment of mix which the engine uses, or recirculation of the fulfilled gases, but any of them will not be compared by efficiency to result of work of catalytic converter.
As experts speak, catalytic converter is a simple device in which there is a difficult chemical process. In the case from stainless steel there is ceramic or metal "brick" with cellular structure. At this monolith huge surface area, and all it is covered with the thinnest layer of special alloy – actually the catalyst containing platinum, rhodium and palladium. These rare metals are responsible for wonderful properties of converter, they determine its high cost.
The fulfilled gases "wash" a monolith surface, and when temperature reaches "critical" value of +270 °C, catalytic reaction begins. Carbon oxide turns into dioxide (carbon dioxide), hydrocarbons – in water and besides in carbon dioxide, and nitrogen oxides – in water and nitrogen. All this is less harmful to the environment.
Catalytic converters are capable to reduce quite effectively toxicity of an exhaust, at the same time they practically do not influence consumption of fuel and engine capacity. In the presence of converter the return pressure of an exhaust slightly increases from what the engine loses 2–3 h.p., but it is practically all "payment" for purification of the fulfilled gases. However installation of catalytic converter – not the ideal decision. Theoretically it has to serve infinitely as above-mentioned metals serve only as the catalyst which at chemical reaction, as we know, is not spent. In practice life expectancy of converter has a limit...
Converter causes of failure
The refusal of catalytic converter can happen for several reasons though usually it is process gradual which cannot be caught without the special equipment.
"Core" of the majority of converters is made of ceramics – the material known for the fragility. The car can get at a speed to a hollow, hit against something or it is even simple "to strike" the converter case on a stone from what catalytic "brick" can burst. After that loss by "core" of the working qualities – a matter of time.
The converters of new generation containing a metal monolith are not so vulnerable in this respect. It is possible to break them, of course, but in any case it is not so simple.
Except physical destruction, there is one more frequent reason of an exit of converter out of operation – fuel. It is extremely sensitive to composition of fuel. If gasoline ethylated, then the tetraethyllead which is contained in it is laid on an active surface of catalytic "brick" and quickly "pollutes" it from what any reactions stop. Apparently, at gas stations and tips of hoses put the different size, and paint distributing columns in different colors, and write about it at every turn, and all the same consumers sometimes confuse and fill not in that gasoline. And it is enough "to burn" a half-tank of such gasoline "to kill" converter.
But not only ethylated gasoline – the enemy of converter. It can be ruined and unleaded if the control system of the engine is faulty, fuel-air mix not completely burns down or the engine is strongly worn-out.
Threefold catalytic converters ("threefold" because as the catalyst serves set of three metals) install only on those cars which engines are equipped with the closed exhaust control system. Before converter the sensor of concentration of oxygen which estimates composition of the fulfilled gases and transfers these data to the central block of an electronic control system of the engine is installed. Depending on the content of oxygen in gases the central block regulates composition of gas mixture and ignition so that their optimum values were maintained. It serves as the main protection of converter and provides fuel economy, high profitability of the engine. Converter does not transfer big deviations to this or that party as a part of mix. Badly adjusted engine with the increased content of hydrocarbons in an exhaust just ruins converter. Too poor mix can cause a sharp overheat of converter what the monolith, only already "physically" again will suffer from. Thus, "life" of converter depends on serviceability of a control system of the engine.
A lot of things depend also on serviceability of the most oxygen sensor. With "age" it becomes "lazy" or absolutely fails that affects composition of working mix and according to serviceability of converter.
Can spoil converter also an exhaust of strongly worn-out engine burning oil. The last, getting together with an exhaust to converter, "is baked" on a monolith surface, like a varnish, and does not allow converter to work.
There are also other harmful factors. For example, candles. Improper candles will not give full combustion that can cause pernicious reaction of fusion in converter.
Be careful when using gasoline additives or to engine oil. Most of drivers do not think of it, and additives can harmfully influence converter too. If on a product it is not written "it is compatible to catalytic converter", do not risk better.
One more dangerous case – launch of the engine towage. At the same time there can be a hit in converter of pure gasoline. It poisons converter, and also can cause instant reaction and even explosion.
Still you watch where you go, try not to get to deep pools. Working temperature of converter makes about +900 °C. Its sudden hit in water can be fatal.
In general it is noticed that service life of converter is influenced also by service conditions. More converters by the cars operated in the city mode when the engine is often launched suffer and stopped. Nevertheless at long driving with a high speed in the country converter also suffers, but already from an overheat.
At last, you arrive reasonably if you begin to examine system of release regularly. If arms are broken or rubber pillows of a suspension bracket of mufflers fell off, the exhaust pipe will vibrate, transferring unnecessary loads to converter.