Turned the liner: possible causes, description and features of solving the problem

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

Often on numerous forums devoted to automotive topics, you can read topics about knocking in the engine or about cranked liners. This is an emergency situation in the ICE. When they say that the liner has turned, this means that the plain bearings on the crankshaft and on the connecting rods were pulled out of their seats and they became unusable. This is a serious breakdown that happens quite often. Motorists see the reason in low-quality engine oils from an unknown manufacturer.

But there are many more reasons, and they are not directly related to the lubricant and its quality. As proof of this, there are many examples when the main liners fail if branded original oil is poured into the engine. Or vice versa - bearings work for more than one hundred thousand kilometers on medium-quality oils. Let's see why the crankshaft liners turn, what factors affect it and what is the main reason for this phenomenon.

Connecting rod bearing - what is it?

There is one very highly loaded part in the internal combustion engine. This is the crankshaft. The element is not installed on traditional bearings. Due to the design features, plain bearings are used. The design of these same parts may be different. But the constant improvement of engines has led to the fact that a steel sheet coated with a special anti-friction layer is now used.

This is the connecting rod bearing. These elements are installed in special places - beds. Inserts are fixed. The need to fix these parts is due to the fact that they have holes for the movement of oil. They must necessarily correspond to those in the beds. Also, with the help of fixation, friction is provided on special surfaces intended for this purpose. The connecting rod bearing is a kind of protective element, thanks to which the life of the crankshaft is significantly increased.

Difference between main and connecting rod bearings

You need to know that there are two types of earbuds. These are connecting rod and indigenous. The first are located between the connecting rod and the crankshaft journal. The root element is similar to the first in its purpose. However, it is located where the crankshaft passes in the engine housing. Inserts vary in size. Dimensions depend on the type of internal combustion engine for which a particular part is made. There are also special repair inserts. They are different from the original new ones installed in the engine. Repair inserts differ only in marks that are multiples of 0.25 mm. So, their dimensions are approximately the same - 0.25 mm, 0.5 mm, 0.75 mm, 1 mm.

Reasons for turning earbuds

So, the crankshaft isa part that works under harsh conditions, and it has to withstand enormous loads in extreme temperatures. In order for the mechanism to be securely held on the axis and to ensure the correct operation of the entire crank mechanism, liners are necessary. The journals on the shaft act as an inner race. Inserts - as outer.

The engine block has channels for pressurized lubrication. Due to the oil film that envelops the liners, the crankshaft can rotate. Why do car owners face situations when the crankshaft liners turned in the engine? There are several possible reasons. Let's take a look at them below.

Mechanical wear

The first reason why main and connecting rod bearings are replaced during engine repairs is wear. Parts wear out due to mechanical stress. Many people try to save the earbuds, but it is useless. Physics is involved here, and physical processes cannot work differently. Wear is inevitable. The anti-friction layer on the liner is erased over time. This leads to free wheeling of the crankshaft. Loops appear. As a result, the oil pressure is reduced, and quite significantly. On most engines that are highly reliable, if the liner is turned, this indicates wear.

Cranking the connecting rod bearings of the crankshaft

This is also one of the most popular faults. Many car owners have faced this problem. But not everyone knows about the reasons. Let's figure out whatsame happens with the element. The connecting rod bearing plate is quite thin.

It is installed on a special seat. The outer walls on the half-rings have special protrusions, which, even in an unrolled and undeveloped engine, abut against the front part of the cylinder block. At some point, the seat simply cannot hold the connecting rod bearing. As a result, a typical situation - cranked the liner. The plate not only rotates, but also sticks to the crankshaft journal. In this case, the engine stalls and will not start again.

Causes of connecting rod bearing failures

Combustion engine rebuilders see several reasons why plain bearings spin. Often this is due to excessively thick oil, into which metal particles fall. Chip lubrication is abrasive to the bearings. Often there is a complete lack of oil. This is especially true for vehicles with worn oil scraper rings. Part of the lubricant just goes "into the pipe". As a result, the liner was cranked and the engine was sent for repair. The bearing caps may not be sufficiently tightened together. And finally, one more reason. It's too thin oil. Especially such products are harmful to motors operating under high loads.

Preload violation

If you cranked the liners, the reasons may be in this. In production cars assembled at the factory by qualified specialists, this will not happen. But if the motor has already been repaired, then,most likely, the selection of liners was performed incorrectly and the tightness was violated.

When the motor is running, the bearings experience increased friction torque. This moment tends to crank the liner. And because of the reduced force that holds the part in place, the risk of turning increases exponentially. When subjected to an uneven load, a loose fit of the friction bearing causes the bushing to vibrate. The lubricating film is also broken. As a result, the part rotates, and the retaining nut is not able to prevent this.

How to identify a breakdown

When turning the main bearings, the crankshaft and cylinder block immediately fail. If the connecting rod bearings turn, the connecting rod itself, the crankshaft, and the cylinder block will fail. As a result, only a major overhaul of the motor can help the car owner. This breakdown can be identified. There are some signs of twisted liners. One of them is a characteristic metallic knock throughout the motor.

It does not stop even at idle, and with increasing load, it knocks even more intensely. Another symptom is low oil pressure. If the engine is cold, then there may be no sound. If the situation is hopeless, the engine will stall, and the only way to revive it is by repair.

Repair and consequences

Typical situation - cranked the liners. What to do? You can solve the problem in different ways, depending on the nature of the damage. In some cases, you can doreplacement of liners with grinding of the crankshaft. In difficult situations, repairs will be significantly more expensive.

If a connecting rod bearing has turned, this is not a serious problem in modern engines. But this does not apply to the root. It often happens that the damaged liner simply changes, and the motor continues to work. Experts do not recommend this approach. The resource of the connecting rod-neck pair of the crankshaft restored in this way can be greatly reduced. A much more acceptable option is to replace the connecting rod with which the problem occurred. Also, if the liners are cranked (including the VAZ-2172), the lock on the connecting rod will also break. It would be more optimal to bore the crankshaft to the next repair size and perform a complete replacement of the liners and connecting rods. Grinding the shaft after turning is mandatory.

Scoring occurs on the neck of the movement. This is the only way to achieve the desired surface condition and the engine will work correctly.

What is the result

If something knocked in the engine, then this is a signal for the immediate termination of the operation of the car. You shouldn't start the engine. Most likely, the liners are turned inside the engine. Repairing this breakdown can be quite expensive. It should be taken into account that the temperature conditions of the motor operation also affect the resource of the elements. Do not overheat the engine. As far as oil is concerned, it is safest to use products that fully comply with the requirements and tolerances of the manufacturer.

Conclusion

So, we found out for what reasons the crankshaft liners turn. To avoid damage, do not keep the engine at high speeds for a long time, change oil and filters on time and observe the temperature regimes of the engine.