Engine overhaul is like a serious illness, which requires hospitalization for professional treatment and costs a lot of money.

How to calculate overhaul

The engine overhaul we often hear has a specific definition, and it can't be called "overhaul" simply by repairing the engine.

There is a paper in the magazine "Automobile Maintenance", which was mentioned in "Fundamentals of Automobile Engine Overhaul".

Engine overhaul refers to the operation of cleaning and inspecting all parts after disassembling the engine, and replacing or repairing necessary parts as needed to restore the engine performance.

The main parts include: crankshaft, piston, connecting rod, cylinder liner, valve assembly, etc.

Needless to say, the engine has a very serious mechanical failure and will be taken apart.

A Lego block, take it all apart, poke it clean with cotton swabs one by one and put it back for you. That's almost what it means.

When should it be overhauled?

Whether the engine should be overhauled or not, the main criterion is the degree of cylinder wear.

There is a paper in the magazine Science, Education and Culture. According to the analysis of cylinder wear of automobile engine, due to various factors, the wear of each assembly will lead to a sharp decline in engine performance.

When the cylinder's out-of-round wear reaches 0. 125mm per 100mm cylinder diameter, or the cylinder's conical surface wear reaches 0.40mm per 100mm cylinder diameter, it is necessary to consider overhauling the engine.

You don't need to remember anything. Simply put, the inside of the cylinder is sealed well. After using for a long time, grinding and grinding, a gap came out.

The door is not firmly closed, the crack of the door leaks, the windowsill shakes and the rain sweeps in. That's almost it. It's about to be overhauled.

For ourselves, there is certainly no way to know the degree of cylinder wear, but through some fault phenomena, we can simply judge whether it is necessary to overhaul.

Mainly used for self-defense, for fear that the repair shop will pit us.

There is a paper on the automobile maintenance technology network, "When does the automobile need overhaul?" .

Generally, domestic cars travel 65,438 438+ 10/00,000 km, while imported cars travel 65,438+05,000 km, which may require overhaul. If you are 20000km, someone will fool you.

At the same time, it is necessary to combine some vehicle phenomena to judge, such as: the power of the car has dropped seriously, the fuel consumption has become very high, the engine burns oil, emits blue smoke, the cylinder knocks seriously, and the engine sounds abnormally.

In addition, the engine is soaked in water and also needs overhaul.

It just happens that it has been raining in the south, and many cars may encounter this situation. Be careful not to click twice when the engine is turned off, and the insurance company may not pay for it.

How different is the engine after overhaul from before?

Performance cannot be the original state.

Although overhaul can make the engine look brand-new, there is certainly no way to achieve a brand-new state in performance. It's brand new, not brand new, right?

The technology, parts precision and assembly technology of automobile maintenance industry can't be compared with the original technology, which is unrealistic.

As mentioned in the previous video, the accuracy of the piston and cylinder of the engine is only a few millimeters, put together.

Almost a hair thickness error, some thinner than this, has caused an impact of about 2%.

It's just a hair seam, a little more or less, 2% influence, what about two hairs? Very troublesome

To put it simply: the overhauled engine is a bit like a man with a prosthetic leg. It can't move, but its flexibility is definitely not as good as that of a real hand.

There is also a paper in Automotive Application magazine. According to the running-in and acceptance of the engine after overhaul, the performance of the engine qualified for overhaul is almost 90% of the original standard. This is qualified.

Is it better to replace the engine or repair it?

Of course, human hands and feet can't be rebuilt, but the engine can be replaced. Is it better to replace the new engine or repair it?

Replacing the new engine is convenient and worry-free: take this away and put that in, but the cost is much higher.

The introduction of engine replacement on the automobile maintenance technology network said above: Generally speaking, the price of replacing a brand-new engine accounts for about 15% of the car price.

Let's take Wuling Light as an example: it costs about 5,000 to 6,000 yuan to replace a new engine and about 2,000 yuan to overhaul it.

And when it comes to overhaul, the price of the car is similar, and the used car itself is only 1000 yuan. It's not worthwhile to spend another 5,000 or 6,000 yuan on a new engine.

And the brand-new engine is over there, the door is rusty, the glass is faulty, and it's boring.

Therefore, if the car is old and its value is not very high, it is better to overhaul it with a new engine.

Engine overhaul refers to the removal and replacement of parts.

Generally speaking, engine overhaul is actually to remove the engine, split it into eight pieces, replace the bad parts and wash them clean.

For our car owner friends, when the car has been driving for a long time, it feels "ah" 65438+ 100 million kilometers or something.

Cylinder wear is serious, engine oil burns, power failure, abnormal sound. These things should be combined with the judgment of mileage, and the master will give you some evidence on the spot to sort it out, so that you will basically not be cheated by him.

Why do I say this is self-defense? Because repairing the engine is very expensive.

After driving a domestic car for two or three years, all the problems came. Really?

Just said, is the overhaul cycle of domestic cars earlier than that of imported cars? Domestic 65438+100000 km, imported 65438+105000 km. Why?

Is it true that, as hearsay says, domestic cars are full of problems after two or three years of driving: "How dare you buy domestic cars if you regret it?"

Many people who have bought domestic cars before say, "I will buy a joint venture car next time, even if it is second-hand." What's wrong with domestic cars now? Are there many questions?