Please repost to anyone it's not difficult.
When installing the root liners, it turned out that they were of a slightly different type than those that stood.
Although when ordering, these made their way as an analogue (and where I looked)
The difference is in the neck liner, where the persistent half rings are (neck number 3)
In the original, there is a regular liner and separately persistent half rings.
In my ordered set (KS 87722600), the liner and thrust washers are one piece.
They fall into place normally
After tightening the caps with the right torque, the crankshaft is turned by hand with some effort (as it should be according to the book), everything is lubricated, of course.
The axial displacement has not yet looked, is there or not.
Is such a replacement acceptable? Or is it the same thing, only in a different performance and I'm worrying in vain?
In the original, on the number 4 main bearing cover there is (unlike all other covers) the same liner as on the block beds, that is, with a groove and an oil channel.
2nd from the top (cover of the 4th journal of the crankshaft)
In the purchased kit, there is no such thing, that is, in its place there is a regular insert.
I did not put the usual insert in its place, but left the old one in its original place, because his condition is perfect. And put a new insert on the bed of this neck. That is, on one neck there is (on the lid) the old insert in its original place, and on the bed there is a new insert. Is this acceptable? Or you need to buy a new insert for the cover (I wonder if it is possible to buy 1 insert at all)
Necessary special tool and accessories:
- micrometer;
- passimeter;
- torque wrench with heads 15, 17 and 19 mm;
- probe plate 0.08 mm thick.
When deciding whether to change the bearing shells, it should be borne in mind that the diametrical wear of the shells and journals crankshaft does not always serve as a determining criterion. During engine operation, a significant amount of solid particles (wear products of parts, abrasive particles sucked into the engine cylinders with air, etc.) are interspersed into the antifriction layer of the liners. Therefore, such liners, often having insignificant diametrical wear, can cause further accelerated and increased wear of the crankshaft journals. It should also be borne in mind that connecting rod bearings operate in a more difficult conditionsthan indigenous. The intensity of their wear is somewhat higher than that of the main bearings. Thus, to resolve the issue of replacing the liners, a differentiated approach is required with respect to indigenous and connecting rod bearings.
In all cases of a satisfactory condition of the surface of the antifriction filling of the main bearing shells, the criterion for the need to replace them is the size of the diametrical clearance in the bearing.
When deciding whether to replace connecting rod bearing shells, the following rule must be followed.
If the connecting rod bearing shells at the time of disassembly or repair of the engine have worked for a time corresponding to the vehicle's mileage of 45,000 km or more, they should be replaced with new ones, regardless of the surface condition and degree of wear. In such cases, normal or first repair size liners are suitable for replacement. Preventive replacement of bushings allows maintaining the connecting rod journals for a long time.
When assessing the condition of the liners by inspection, it should be borne in mind that the surface of the antifriction layer is considered satisfactory if it does not have scoring, chipping of the antifriction alloy and foreign materials (inclusions) pressed into the alloy. Dark color of the pouring surface is not a rejection sign.
To replace worn or damaged liners, main and connecting rod bearing shells of normal and six overhaul sizes are supplied to spare parts. Repair size inserts differ from normal size inserts reduced by 0.05; 0.25; 0.50; 0.75; 1.00 and 1.25 mm inner dia. The liners are sold as a set, in quantities required for one engine.
After replacing the liners, both with the simultaneous regrinding of the crankshaft journals, and without it (and for the main journals, also if old liners are used in the engine), it is imperative to check the diametral clearance in each bearing. This will allow you to check the correct selection of the repair liners.
You can check the diametral clearance in the bearing by measuring the diameters of the journal of the crankshaft and the liners (in pairs) of this bearing with subsequent simple calculations. The bearing diameter is measured with the bushings inserted and the bearing cap bolts tightened to the required torque.
Diametral clearances in the main bearings should be in the range of 0.025-0.082 mm, and in the connecting rod - in the range of 0.025-0.076 mm.
It is also possible to check the diametral clearance in the bearing using a feeler gauge plate a, placed between the shaft journal and the bushing.
The plate for both the connecting rod and the main bearing should be 0.08 mm thick, 13 mm wide and 5 mm shorter than the bearing length. The plate is cleaned along the edges with a touchstone, lubricated with oil used for the engine, and placed on the surface of the liner so that its long side is located along the longitudinal axis of the bearing.
Figure: Laying the control plate-probe in the connecting rod bearing: a - plate-probe
When checking, tighten the cap bolts only of the bearing in which the probe plate is placed, while the bolts of the caps of the remaining bearings remain loose. Tighten the bolts carefully, turning the crankshaft from time to time.
If significant resistance is felt when turning the crankshaft by hand behind the flywheel, the diametral clearance in the bearing is within acceptable limits. If the crankshaft turns almost as easily as without the check plate, the bearing clearance is greater than normal.
In some cases, the required diametrical clearance in the bearing can be achieved without regrinding the journal, only by using repair liners reduced by 0.05 mm. In all other cases, the required clearances are obtained by grinding the journals and installing repair liners in the bearings.
If, as a result of repeated regrinding, the diameters of the crankshaft journals are reduced so much that the liners of the last repair size are unsuitable, then at the next repair it is necessary to assemble the engine with a new shaft. For such a case, the spare parts kit 408-1000107, consisting of a crankshaft from a set of bearings of normal size.
Thin-walled replaceable crankshaft and main bearing shells are manufactured with high precision. The required diameter clearance in the bearing is ensured only by the correct diameters of the crankshaft journals obtained by regrinding. Therefore, during engine repair, the liners are replaced without any adjusting operations and only in pairs. Replacement of one liner from a pair is not allowed. It also follows from the above that in order to obtain the required diametrical clearance in the bearing, it is strictly forbidden to cut or trim the joints of the liners or bearing caps, solder the joints of these parts with babbitt or install gaskets between the liner and its bed.
Failure to comply with these instructions leads to the fact that the correctness of the geometric shape of the bearings will be violated, the heat removal from them will deteriorate and the liners will quickly fail. But the more dangerous thing is that it is impossible to install new liners of repair sizes in bearings with sawn off or pinned caps. At the same time, bearing caps damaged by mechanical adjustment cannot be replaced with new ones, since they are processed at the factory together with the cylinder block and the connecting rod. Since the bearing caps are not interchangeable, they are not supplied as spare parts, and therefore a motor with damaged caps cannot be repaired later.
When installing connecting rod and main bearings, it is necessary to ensure that the retaining lugs a at the joints of the liners freely (by hand force) enter the seats b in the bearing cover (or body).
This solution allows the loaded parts to move freely and easily, while at the same time, such an interface of the loaded elements is achieved, in which there are no gaps and backlash. Such plain bearings should be understood as a high-strength steel sheet of a special shape, on which a special anti-friction coating is applied.
Rotation of the connecting rod or crankshaft bushings is a serious fault that must be rectified immediately. Most often, the driver becomes aware of the problem due to the appearance of a distinct characteristic connecting rod knock or knock of the engine crankshaft. Further operation, in which the liner is turned, is highly discouraged, since breakdowns of this kind cause significant damage not only to the associated parts, but also to other components power unit... Next, we will talk about what to do if turned connecting rod bearing, what could be the cause and consequences as a result of such a breakdown.
Why does the connecting rod bearings or crankshaft bearings turn
The liners in the engine are installed in special mounting locations (liner bed). Installation involves special fixation, since the liners have holes in their body, which allows them to supply engine oil. The holes shown must match the holes drilled in the parts themselves for the lubrication passage. Also, fixing the liner is necessary taking into account the fact that during engine operation, friction occurs along the surfaces of the mating elements.
Taking into account the above information, it becomes clear that if the connecting rod bearing is turned, the reason may be as follows:
- insufficient fixation of the liner;
- strong friction on the surface of the liner;
As you know, friction occurs as a result of sliding of two bodies in relation to each other under a certain load. The total value of the friction force will depend on the value of the load on the friction pair, as well as on the coefficient of friction. In order to reduce the frictional force in the manufacture of parts, special antifriction materials are used that have a low coefficient of friction.
As for the liner, an anti-friction material is applied to its surface. The crankshaft in relation to the liners makes a rotational movement, at the interface of the liner and the crankshaft a friction force arises, which tends to turn the liners in relation to their mounting locations. For protection against twisting and displacement, the liner holds a special tendril. Also, during installation, the liners themselves are inserted with a certain interference, the value of which is calculated by the designers of a particular internal combustion engine.
It becomes clear that excessive friction or insufficiently secure fixation (weak interference) are the main reasons why it is not possible to hold the liner on its seat... It should be noted that during the manufacture of the engine at the factory, insufficient tension of the liners during the assembly of the internal combustion engine is extremely rare. Most often, problems with the main or connecting rod bearings appear after the engine has been repaired. In other words, improper selection of repair liners and other defects that do not allow achieving the required interference lead to cranking. Since uneven loads are acting on, liners with a weakened fit begin to vibrate, the oil film on their surface is destroyed, and the liner can "grab". In such a situation, turning is inevitable, since the fixing antenna is simply not able to withstand the moment of turning on the liner itself.
As already mentioned, another reason for the cranking of the engine liners is the exceeded frictional moment, that is, the design conditions for the operation of the plain bearings themselves are violated. Normal work liners involves the so-called fluid friction, that is, the surface of the liner and the journal of the crankshaft are separated by an oil film. This avoids direct contact of loaded parts, provides the necessary lubrication and cooling, and minimizes friction.
It is quite obvious that if the oil film is insufficiently thick or breaks through, the coefficient of friction will begin to increase. The operation of mating parts that are subjected to a constant load in such conditions will mean that the cranking torque has increased. If it is simpler, the greater the friction force, the more the risks of cranking the crankshaft liners increase at such increased loads.
An increase in loads in a pair of liner-crankshaft leads to a decrease in the thickness of the oil film or to complete rupture (dry friction). In parallel with the increase in the friction force, an increased heat release occurs, and local overheating occurs in the friction area. With an increase in heating, the temperature stability of the oil is disturbed, the thickness of the oil film decreases even more, the liner can stick to the surface of the crankshaft journal.
It should also be added that the thickness of the oil film between the mating parts directly depends on the speed with which these parts move relative to each other (hydrodynamic friction). The faster the parts move, the more oil gets into the gap between the rubbing elements. It turns out that a thicker oil wedge-film is created in comparison with the same film at a lower speed of movement of the mating parts. In this case, it is necessary to take into account the fact that an increase in the speed of movement of parts also increases the friction force, and also increases the heating from such friction. This means that the temperature engine oil begins to rise, the lubricant liquefies, the film thickness becomes thinner.
The friction force is also influenced by the accuracy with which the surfaces of the mating parts are made, the degree of roughness of these surfaces, etc. If, for example, the surface of the liner or neck is uneven, then there will be zones in which there will be practically dry friction or parts will contact in conditions of insufficient oil film thickness. At the same time, such dry friction zones can also arise in cases where mechanical particles are present in the engine oil, that is, the oil is contaminated.
For these reasons, after assembling a new ICE or overhaul engine, the power unit must go through a running-in process, which involves moderate loads and frequent engine oil changes. The fact is that the loaded vapors must run in to each other, since lapping gradually eliminates possible existing microdefects, which affect the efficiency of formation and the subsequent stability of the formed oil film.
We add that the viscosity of the engine oil also has a certain effect. More viscous oils cause an increased frictional moment in loaded vapors. In parallel with this, the thickness of the viscous oil film is also greater at the interface of the parts. However, this does not mean that loaded parts will be protected from increased or dry friction. The fact is that a viscous lubricant may simply not reach the place of friction in the required amount, which, in turn, leads to a decrease in the thickness of the film or even its rupture.
For this reason, it is not so easy to give an answer as to which oil is better in relation to liners and their cranking, taking into account only one viscosity index. Do not forget that essential characteristic is also the lubricity of the oil, that is, the property of the lubricant to adhere to metal surfaces. It should also take into account the stability of the film of a particular oil under conditions of various loads and temperatures.
Cranked connecting rod bearing: consequences and repair
To begin with, turning the engine connecting rod bearings with timely detection of a breakdown is a less serious problem than turning the crankshaft bearings. If the problem was identified late, then the consequences for the internal combustion engine may be different. It so happens that after turning the connecting rod bearing, the engine may need an expensive one.
A common situation is when the rotated connecting rod bearing is simply changed to a new one and the engine runs on. Note that it is not recommended to do this due to the fact that the resource of the crankshaft connecting rod-journal pair repaired in this way can be greatly reduced (by 60-70%). A more acceptable option is considered to be the approach when the connecting rod, in which the liner turned, changes. Also, the connecting rod often needs to be replaced due to the fact that as a result of turning the liner, the connecting rod lock breaks. The best repair method is considered to be crankshaft bore and replacement of liners / connecting rods.
Grinding the crankshaft after turning the liner is usually a necessary operation, as the neck appears scored. After disassembling the engine, the crankshaft must be measured, after which it is boring, taking into account the subsequent installation of new oversize liners. This is the only way to achieve the required state of the surfaces and the correct tension of the liner after installation.
What is the result
Taking into account the above information, it can be concluded that the appearance of a knock in the engine is a hearth for the immediate termination of the vehicle's operation. It should also be borne in mind that the condition of the earbuds is strongly influenced and temperature regime operation of the power unit. In other words, overheating of the engine can lead to cranking of the connecting rod or main bearings, seizure of the motor, etc. In this case, the engine may become completely unusable, since the crankshaft bed breaks, the crankshaft itself fails, etc.
As for engine oil, it is necessary to use only those fuels and lubricants that meet all the requirements and necessary approvals of the power unit manufacturer. Also oil and oil filter it is necessary to change in a timely manner, do not allow dirt and mechanical particles to enter the lubricant. The lubrication system itself deserves increased attention, since reduced performance or malfunctions can lead to oil starvation, as a result of which the risk of the bushings being twisted significantly increases.
Finally, we add that benzie new engine needs, then it is necessary to drive without loads until the moment of exit power plant on operating temperatures. In the case of the motor warming up in motion, it is not recommended to load the unit sharply until it warms up completely. It should also be remembered that both a new engine and a motor after repair needs to be run-in, since loaded pairs and mating elements need to be lapped.
