I believe that many of my friends are very troubled by the process of engine repair, because this process is very complicated, especially when it comes to major engine repairs, I don't know how to start. So today we are going to discuss engine repair The reasons and preventive measures!

First of all, let's understand: what causes the engine to disintegrate and overhaul, as follows:

1. Severe blockage and severe carbon deposition inside the engine

Although the internal combustion engine has been developed for more than 100 years, there is still a large space for the development of its technology. However, in terms of carbon deposition and oil channel blockage, in addition to the artificial driving habits, it is also related to the characteristics of the product. Many people think that the oil The blockage of the road must be caused by the wrong selection of the oil or the poor quality of the oil. Of course, the quality of the oil has a certain relationship with the composition of the lubricating oil and the performance of the engine. The oil is in our knowledge. The high and low temperature viscosity and adhesion rate are similar to the characteristics of SN and SL grades. I don’t know that the engine oil has the characteristics of high temperature emulsification and high temperature sulfide phosphating, etc. Many blockages are caused by unstable temperature environment, deterioration under extreme pressure and extreme temperature, or chemical reactions.

It can be said that carbon deposition is also a substance that properly "destroys" the engine. It exists everywhere. In addition to corrosion to the cylinder piston, the carbon deposition is solid when the temperature is low, and it will be "topped" when the engine is not hot. "Cylinder" and "top valve" will make the engine have more obvious vibration and noise, and seriously damage the engine.

2. The internal parts of the engine are severely worn and the seal is aging

We can't see the inside of the engine, and the inside of the engine is very complicated, especially the number of valve components is staggering. We all know to replace the belt or timing chain, but when we travel to a certain mileage, there will be valve rocker arm wear, cam wear, valve and valve hole pit wear, and cylinder inner wall wear and so on.

Seal aging occurs all the time in every car. In addition to the hardening and aging of the rubber gasket, the wear of the piston ring on the piston body in the cylinder is also a representative of this type of problem, and the piston ring is divided into air tightness. ring and slinger. Many problems of burning oil and emulsification of engine oil are caused by it.

Of course, there are many reasons that may lead to engine repair, but the most common ones can be divided into two categories: fouling and wear, and there are many reasons for these two types of problems. Of course, "temperature" must be the most important reason. After the disintegration and overhaul, the function decline and the complicated faults are also the reasons why we are afraid of not repairing. The reasons are as follows:

1. The quality of accessories is far worse than before

After the overhaul, many parts of the engine (especially the worn parts) are not original, or even not the original factory. They are generally born in a subsidiary factory or an auto parts city. Maybe there is no problem with the naked eye and type. However, the material, density, hardness, wear resistance and other characteristics of the parts are very different, because the wear and tear of the car records the driving habits of a driver, and the parts installed in the future will make the engine enter a new "run-in" again. stage.

2. Technician equipment level

An engine has tens of thousands of screws. After the dismantling is completed, the experienced masters are all clustered together with the screws and nuts, which are very pleasing to the eye, and those who have experienced shortages will still be left after the engine is reassembled. Fewer screws or nuts.

Strictly speaking, when the engine is original, every screw nut is designed to ensure that the engine can guarantee the temperature, pressure, and the impact of vibration on the engine during operation, so it will bring certain risk factors at the technical level. , Of course, it also laid a deep foreshadowing for the subsequent engine problems.

Of course, there is another point that cannot be handled by manpower, that is, "manpower" cannot be accurately controlled. When the engine is processed from the main engine factory, most of the processing is automatically controlled by machinery to improve productivity and accuracy, so the torque is calculated. Yes, some OEMs even have strict requirements on the control of processing temperature. High standards bring high functions. No matter how fierce the experience of the mechanic is, it is impossible to restore the engine to the factory condition, which is also impossible to do by manpower.

3. Air tightness is difficult to guarantee

The biggest problem that will be left after the disintegration of the engine is the damage to the airtightness.

Having said so many reasons for engine disintegration and overhaul, let's take a look at the preventive measures for engine repair, as follows:

1. Cylinder wall wear repair---Fluorocarbon surface modification

In fact, the earliest beginning of this technology was not used in cars. The development of this technology began as early as before the collapse of the former Soviet Union. The fluorocarbon coating will adhere to the cylinder wall to form a "film". This film will smooth the wear marks on the cylinder wall and also block the piston ring and the cylinder wall from direct contact. However, this technology is also not recommended for use in new cars or in low-wear conditions because it is too anti-air, because the fluorocarbon coating itself is very lubricating, which makes the inner wall lubricating oil that completes the fluorocarbon coating completely unable to adhere, (even if it is cold The castor that is launched also cannot be attached), so that the engine is completely in a "dry grinding" state when it is launched, but it is undeniable that this is definitely an upgrade for the severely worn engine.

2. The original piston head and cylinder gasket are no longer used

Many car parts are divided into "casting" and "casting". In terms of processing technology and raw materials, "modification" prefers to choose "casting" with lighter weight and harder hardness, because lighter weight can reduce energy consumption , Improve the power, and the processing is more accurate and the hardness is higher, which can add a lot to the performance of the engine. There are also differences between naturally aspirated and turbocharged:

① The most important way to improve the power of a naturally aspirated engine is to increase the compression ratio. To put it bluntly, it reduces the space when the engine compresses the oil and gas mixture. The increased compression ratio can improve the explosive power of the engine, and the effect is more obvious, so you can choose a cast piston with a convex top.

② The most important way to improve the power of turbocharged engines is to increase the volume of the cylinder. Because of its high compression ratio, the choice of concave casting piston heads has a good effect on the improvement of power; the same is true for the cylinder head gasket. Thicker or thinner cylinder head gaskets can be selected according to the above principles, which have good results in performance improvement.

3. Select the rubber with better shock absorption function

Generally speaking, this thing is directly neglected by mechanic. Many people think it is a buffer glue, but these two seemingly inconspicuous things have great effects: one is to affect the effect of oscillation on the engine; the other is to affect the vehicle. overall work status.

A good base rubber can absorb too much vibration energy to ensure the airtightness of the engine, and also make the working condition of the car look smooth. The machine foot glue is also one of the parts that is relatively easy to harden and age.

4. Remove excessive sound insulation cotton

Many cars are now equipped with a large area of ​​sound insulation cotton in the engine room. This sound insulation cotton is seamless with the hood and is very beautiful and can block the noise from the engine room. However, the sound insulation cotton is one of the minions that lead to engine overhaul. It is like a thick quilt covering the engine, because the heat is conducted upwards, so the results can be imagined.

The hood of the car has the effects of diversion, heat dissipation and dust prevention in the car body. In the structural design of the car, it is required to be designed as a sheet metal part that must be deformed when a collision occurs. In terms of function, I actually feel that there is no hood. It is more conducive to the heat dissipation of the engine, but it is ambiguous and the temperature is definitely the killer of the engine.

After reading the above reasons for engine repair and the methods to prevent engine overhaul, everyone must be very useful. Although there are many contents, it is not difficult. To prevent the overhaul of the engine, we usually adopt the above preventive measures and regular maintenance.