How to make a do-it-yourself engine overhaul

In detail: how to make a do-it-yourself engine overhaul from a real master for the site my.housecope.com.

The older the engine becomes, the more often it needs repairs. And sometimes the usual repair is not enough, and then the time comes for a complex and time-consuming operation - engine overhaul... Engine overhaul is the maximum possible engine upgrade, recreating its main characteristics and indicators to the initial level. Unlike the engine bulkhead, during a major overhaul, not only components and assemblies with faults are repaired and brought to a close to ideal condition, but also all the component parts of the motor.

There are several signs by which you can understand that we need a major overhaul for the engine:

Understated compression, increased oil consumption, thick dark gray exhaust.
Low oil pressure, repeated sounds in the crank mechanism.
Large wear of the cylinder-piston group or longitudinal movement of the crankshaft (this wear can only be diagnosed with the help of special equipment).

Usually the question of engine overhaul appears after 150-200 thousand kilometers... However, each engine has its own characteristics, and each machine has its own conditions of use, so in each case this indicator may be different.

Almost all auto repair shops offer overhaul, but some (experienced) motorists prefer to do overhaul of the motor with their own hands.

First you need to pay attention to the fact that engine overhaul - the procedure is long, complicated and laborious... To complete it, you need to be well versed in the structure and operation of the engine, as well as have the necessary tools and skills. If you have the slightest doubt that you will be able to cope, it is better not to take risks and entrust the engine of your car to professionals.

Video (click to play).

After you have completed the overhaul procedure and put the engine in place, you need run in the engine cold... Simply put, you need to start the car and let it idle, so that all the elements are ideally used for subsequent work.

Think engine overhaul is a headache? You think correctly. But when you find out how much they take for work, your head will stop hurting and your hands will start to work. Because for that kind of money, three engines can be repaired. This means that we will save money and master the overhaul on our own.

As you drove along, the engine of your beloved iron horse suddenly knocked. Don't be in a hurry to immediately grab the "capital". We must first check everything.

First, let's immediately determine that this is not an engine bulkhead, when it was disassembled, cleaned, changed gaskets and assembled. There are already more serious reasons. So, let's pay attention to the prerequisites:

How old is the car? How long has she already run? Foreign or domestic car? If the car is more than 10 years old, it is domestic, for example "Zhiguli" or "Moskvich", then its limit is 150 thousand kilometers. For a foreign car - up to 300. Perhaps, the resource of your car is exhausted, and for this reason the power has decreased.
Let's see what's wrong with the oil. Yeah, the pressure has dropped again, while the car is bursting oil shamelessly - another reason for repairs.
We check the compression, since this is the main parameter that influences the choice - whether a major overhaul is or is not needed. We take a compressometer from friends, take measurements.For example, in our case, out of four indicators in one, instead of eight, there is already five - which means that the time has come for a major overhaul.

Of course, with information. We take out a manual, in which it is reported in detail and with diagrams how to repair your particular brand of car. We find on the Internet a catalog in which there are spare parts for this car, in order to immediately determine the prices and, possibly, place an order in the online store.

keys - ratchet, torque;
mandrels for coupling pistons, caps;
desiccant for valves;
micrometer;
heads;
device for adjusting valves;
two-legged or three-legged puller;
stethoscope;
tweezers;
support stand;
hydraulic chain hoist;
a set of pullers.

We drive the car into the garage. We remove the battery. Disconnect the hood so that it does not interfere.

We carefully drain all liquids: antifreeze, oil. To do this, instead of bolts on the radiator and the cylinder block, we install faucets - they are sold in any car dealership - and drain them using hoses into the prepared container.

Considering the age of the car, we very carefully disconnect the wiring, connectors, tubes, hoses, etc., so that they do not crumble in our hands, nothing is damaged or cut off. And then some craftsmen still repair the wiring, the cooling system.

We remove without haste everything that can interfere with getting the engine: air filter, carburetor, gas pump - do not forget to screw the bolt, oil separator, distributor, cylinder block cover, camshaft, cylinder head studs, and then the head block, crankcase protection, generator with belt, fan, radiator. We unscrew the bolts that secure the engine. The engine can now be removed.

Before you get to the insides of the engine and start doing the overhaul, try to safely remove it from the car. Call an assistant - you can't do it alone.

Prepare four tires by stacking them on top of each other. Place two pieces of wood on top. Then lay the engine on them.

Now fix the talcum powder, i.e. the lift, to the ceiling beam, it can be attached to the tripod by positioning it above the hood.

Do you know how much the engine weighs? How do you like an aggregate of 140 kilograms? Serious thing? It is clear that you cannot lift it with your hands, and if it falls down, you cannot do without injury. To prevent this from happening, be extremely careful, check the attachment of the talcum powder, and only then start lifting.

Carefully, without too much fuss, pull the engine up, bring it to the stack of tires that have already been laid out in front of the car, lower it, turn it over so that the crankcase is on top, on wooden blocks.

When disassembling, remember or mark somewhere where you are shooting from and where the part was originally located, so that later there will not be superfluous ones, like some homemade ones.

Start gutting the flywheel: first remove the clutch, then get to the crankcase boot. Go to the oil filter. After unscrewing the fasteners, remove the bolts and remove the crankcase, being careful not to break the oil intake.

Now remove the front and rear covers of the block together with the oil seal. Take care of the piglet sprocket, remove it using a puller. Go to the chain stop and unscrew, remove the tensioner shoe, and then the chain, the crankshaft sprocket.

Go to the crankshaft. Remove the nuts from the connecting rod caps, then the caps, carefully pull out the pistons, remove the liners, carefully inspect them for reuse. If you can no longer use them, take a sample and buy new ones from a specialist store or from the car market. Just first decide whether you need a groove for the necks, and only then fit the liners under them. Take out the crankshaft with persistent half rings.

Remove piglet, oil pump and its drive gear.Turn over, placing it sideways, remove the pistons with connecting rods from the cylinders. Buy a new piston system according to the old model. You still need to contact a car repair shop.

Take new pistons, let the block be bored under them, and also grind the crankshaft and press the piston pins. Measure with a micrometer the crankshaft journal, look in the manual for what size the earbuds should be, buy them. If you choose the correct liners, you will be able to rotate the crankshaft by hand - this will be the fit test.

Begin assembly by removing carbon deposits. Remove all metal shavings, rinse the beds, lubricate them and the liners with engine oil, reinstall, referring to the manual. On the rear wall of the block, place thrust half rings so that the grooves are turned on the plane of the crankshaft.

Now you can replace the crankshaft with liners and covers, checking the marking guide, the places where the locks are located. Make sure they are all on the same side. Take a torque wrench, tighten the bolts, turn the crankshaft - if it turns easily, then everything is in order. Otherwise, replace the earbuds with thinner ones.

Ask in the workshop to assemble the piston, because you yourself will not be able to heat the connecting rod heads to more than 100 degrees, but you need to heat them over 200. Check the process.

Now carefully lubricate the piston pins through the holes, throw in the piston rings without haste, make sure that the slots, holes are preserved, tighten the mandrel with a wrench. Lay the block on its side, insert the piston with the connecting rod, not forgetting the markings.

Take a wooden block and, gently knocking, push the piston into the cylinder. Flip the block over to its original position, but do it so that the crankshaft is at the top. Tighten the bolts.

Lightly begin to pull the connecting rods to the necks. Then rotate the crankshaft to make sure everything is set correctly and the liners do not need to be changed. Now you can tighten the bolts.

Put a new oil seal on the cover, install it on the block, pre-coat the joints with sealant. Proceed with installing the clutch boot and flywheel. Remember that the flywheel groove must be turned to the fourth knee of the crankshaft - this is important.

Now install the sprocket, piglet, tensioner shoe, front oil seal, oil pump, flywheel clutch.

Finally, you can install the engine and bolt it. Tighten carefully to avoid stripping threads or bursting parts. Return the pump, generator, radiator, fuel pump to their original places, connect the wires, hoses, terminals, check the fastening strength.

As soon as an overhaul of the engine is completed, it is imperative to carry out a cold run-in before installing it on the car. This is done so that the new parts rub against each other, and is carried out in passive, bench mode or in hard towing, when, due to the movement of the wheels, the crankshaft starts to spin and a cold break-in occurs.

So, in the garage, connect the hoses for the air filter, cooling system, oil supply, outlet to the engine. Install the plugs. Connect the unit to an electric motor.

Fill in the coolant that was drained during disassembly, heating it to 85 degrees, then oil heated to 80 degrees. At low revs, from 600 to 1000, let the engine run for 2 minutes, at high revs, from 1200 to 1400, for 5 minutes.

Before the car has run two and a half thousand kilometers, do not accelerate sharply, pick up speed gradually, do not overload the engine.
After the first run, drain the oil, replacing it with a clean one, but of the same brand (preferably).

Now you are convinced that a do-it-yourself engine overhaul is possible and profitable, because it costs three times cheaper.In addition, it will allow you to operate the car for several more years as a result of extending the resource, prevent unexpected breakdowns on the road, and help avoid an accident.

The following video will tell you what spare parts are needed for the overhaul of the VAZ 2103 engine:

Almost all car owners, sooner or later, make major engine overhauls. In principle, there is no exact period of time after which it is necessary to overhaul the engine. Many people think that high mileage of the car is the agenda for the "capital". But this is not true. The need for this type of repair may arise even on a car with a fairly low mileage. It all depends on your driving style and how well and how often you take care of the "heart" of your "steel beauty". In order for a woman's heart to be always faithful and reliable for you, it requires fresh flowers and great attention. Likewise, the "heart" of your car should receive fresh oil and careful care on time. Only then will it serve you faithfully for a long time.

Overhaul is a forced necessity

The fact that the "engine" of your car needs "capital" can be notified by the details of the cylinders. You will notice this by the increased need of your car for oil (consumption will be more than one liter per thousand kilometers). The characteristic gray smoke from the tailpipe is a clear sign of engine breakdown. But when such symptoms appear, there is no need to jump to conclusions right away. For example, oil consumption that is too high may indicate that the valve stems have lost their former elasticity.

You should pay attention to the crank mechanism - a characteristic knock may appear, which indicates serious damage to the crankshaft liners, bearings and other sliding components. A knock can be detected with a stethoscope, and a pressure gauge will help determine the pressure in the cylinders. An increase in engine noise, loss of power and an increase in fuel consumption can serve as a serious sign that an engine overhaul is required.

If you find most of the above symptoms in your car, then, most likely, you cannot avoid overhaul. But in order to make sure for sure whether a "capital" is required or not, it is still better to contact a specialized service station. The service station will check the degree of wear of all engine parts. During such a check, special devices (measuring brackets, micrometers, dial indicators, internal gauges) are used at the stations, with the help of which it is possible to accurately determine the need for a "engine" for overhaul.

belts;

chain;

liners of bushings;

piston rings;

asterisks;

fuel pump;

sets of gaskets and oil seals;

oil pump;

guide bushings and valves;

water pump.

This is not a complete list of what you need. First, it's best to disassemble the engine and see which parts really need to be replaced. And only after that, purchase all the necessary spare parts. If you decide to entrust the overhaul to car services, then upon completion of the diagnosis, the wizards themselves will tell you which parts you need to purchase for subsequent replacement.There can be no standard instruction on how to make a capital account. It all depends on the specific brand and, in particular, the model of your car, as well as the wear of one or another part of the engine. One thing is clear for sure: for overhaul, you will have to completely disassemble the "engine". This is a very time-consuming and long process, which cannot always be done at home.Many people think that doing an engine overhaul with your own hands is cheaper than contacting a service station. But this is not always the case.For example, in some cases it will be necessary to grind and adjust the cylinder mirrors, as well as replace the piston rings. At home, it is extremely difficult to perform operations such as grinding cylinder mirrors and requires special devices, which are often very expensive. Therefore, in this case, it is better to contact the service center.Also, during the overhaul at service stations, they carry out diagnostics of the generator, distributor and starter of your car. If any faults are found, they will be replaced.For those who are not afraid of difficulties, we have prepared a small engine repair guide:

It is necessary to remove the engine from the vehicle. In order for the "heart" of our car to lose weight, some units will need to be dismantled. Disconnect the carburetor, remove the cylinder head cover, dismantle the generator, disconnect the gearbox, remove the manifold, then dismantle the flywheel and clutch. Then we unscrew the pillows and take out the "engine".

The crankcase cover must be removed to gain access to the pistons and crankshaft. Next, the connecting rods are unscrewed. Having gained access to the pistons, we take them out. Then it is necessary to remove the fingers from the pistons. Now you need to remove the crankshaft, as well as its liners.

Inspect carefully for wear on the crankshaft journal and liner. If necessary, they will need to be bored. Be sure to also get new bushings, piston rings and pins.

Having purchased the necessary parts, we begin to assemble the "engine":Do not subject the vehicle to high stress after repair. First, warm up the engine thoroughly. Start the engine and let it idle for ten minutes, then turn it off and cool. Such manipulations must be done several times. Then give the "heart" about ten hours of idle work. Only after that you can hit the road.For the first fifty kilometers of the journey, do not accelerate the car more than forty kilometers per hour. Then you can accelerate the car to sixty kilometers per hour. Further, every hundred kilometers of the way, increase the speed of the car by ten kilometers per hour. Also watch the compression level increase. If it is not there, then it is worth sending the car for repeated diagnostics. Also try not to make sudden acceleration and deceleration.And in conclusion, I would like to wish you to do major engine overhauls as rarely as possible. And if you still had to, then an easy overhaul to you. Do not forget about flowers and oil for the hearts of your loved ones - and you will be happy!Car engine - one of the main parts that takes up most of the space under the hood. The ability of the machine to perform its main task - to drive, transport people and goods - completely depends on its work.The condition of the motor is directly related to the operating conditions, care and mileage. Every motorist knows that over time, parts inside the internal combustion engine are triggered and need to be replaced. In this case, it is necessary to overhaul the worn out engine in the garage with your own hands. Image - How to make a do-it-yourself engine overhaul

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Overhaul of the VAZ engine - rather laborious work, requiring knowledge of the device and the principle of operation of the unit.

This process will take a lot of time. You will have to remove the motor from the car and carry out its complete disassembly. All removed spare parts are checked for suitability for further operation, if necessary, they are replaced with new ones. Particular attention is paid to the crankshaft: it is restored and brought into perfect condition. The existing systems are also checked: cooling, lubrication, fuel supply, the crank mechanism is being repaired.

During repair work, the parts and assemblies of the internal combustion engine are brought to perfect condition.After assembling the unit, its condition and performance should be identical to the new engine just released from the assembly line. Capital is necessary if the motor has fully or partially exhausted its resource, there are corresponding signs indicating this. You cannot ignore them. With further operation of the car, the engine may completely fail and it will not be possible to restore it. There will remain one option - the purchase of a new part. Naturally, the purchase of spare parts is more expensive than repairing them.

The service life of the engine before overhaul can be extended if you follow simple rules when operating the machine.

Check the oil level and change it regularly.
Monitor the coolant level to avoid overheating the machine.
Fill with quality fuel recommended by the manufacturer.
Operate the machine wisely and avoid overloading.
Limit the idle speed of the vehicle to a minimum.
Refuse extreme driving that requires high revs. Do not allow the tachometer needle to enter the red zone.

Car engine wear occurs gradually.

There are a number of signs indicating a malfunction of the internal combustion engine.

Harbingers of "disease" can appear in following sequence:

Increased fuel and oil consumption. When parts wear out, gaps appear between them, which during operation are filled with fuel. An increase in oil consumption occurs due to clogging of the piston rings or loss of elasticity of the valve stem seals.
Vehicle power is reduced.
Noticeable dark blue smoke from the tailpipe. This indicates that oil has entered the fuel mixture.
The oil pressure light starts to blink or is constantly on.
The engine emits an atypical extraneous knock during operation. It is possible that the bearings of the crank mechanism were worn out.
When measuring the compression, the devices show a significant deviation from the norm (decrease). Low compression indicates damaged gaskets, worn out piston rings.
When unscrewing the candles, carbon deposits, oil, and dirt are always found on them.
Frequent overheating for no apparent reason.

Engine bulkhead implies doing following actions:

Dismantling the motor.
Complete disassembly and removal of accumulated dirt by rinsing and cleaning.
Identification of defective parts of the block to be replaced: examination of the engine block for cracks, measurement of possible formed gaps, assessment of the condition of the crankshaft, identification of worn parts.
Overhaul of the cylinder head.
Cylinder block restoration.
Assembly of the unit and installation on the car.

Removing the machine from the machine may vary depending on the vehicle model. Dismantling a carburetor engine is much easier than an injection engine. It has less electronics that you have to remove beforehand. Also, a different disassembly process will be for brands with front and rear wheel drive.

The preparatory stage prior to dismantling will be the removal of interfering mechanisms and unscrewing the retaining bolts. Removal of a heavy unit from the car body is carried out using a special hoist or winch. If such a device is not available, then all possible engine parts and spare parts are removed to reduce weight, and it is pulled out manually. This will require the help of several people.

Disassembly follows. The work should be done sequentially, carefully examining the parts for wear and laying them out in order.

It is worth knowing that a VAZ engine is disassembled in about 3 hours, it takes more time to disassemble a foreign-made engine: about 10 hours.

Flushing is an important step in the job that many people miss.

It is not right.Every detail has a specific meaning. If the parts are not washed and the plaque is not removed, then the degree of wear can be incorrectly determined, which can cause a quick failure of the entire motor. Also, with special care, you need to flush the block and cylinder head in order to investigate for possible cracks.

Defects are detected visually and using measuring instruments. All parts are checked for wear, scratches, cracks and chips. Particular attention should be paid to the following details.

The cylinder block and head are checked for integrity, with particular attention paid to cracks and chips.
The crankshaft is inspected and measured to check for wear, and is also checked for centering and bending.
Details of the connecting rod-crank mechanism: the general condition and the presence of backlash are determined.
Gas distribution mechanism.

The repair of this spare part is not too difficult, but many car owners turn to the service for help. If you decide to do the repair yourself, then you will need to replace or repair the following parts.

Camshafts.
Valve.
Guide bushings.
Valve stem seals.

If cracks are found on the block head, then it needs to be replaced or polished. It is possible that there is a specialist who can weld the damage with argon.

After cleaning and flushing the block, it is necessary to restore it, bringing it to a quality close to the factory one. It is necessary to grind the seat of the head to a mirror shine, eliminating the existing shells and chips. For this, a surface grinding or milling machine is used. Depending on the degree of damage, the cut thickness can vary from 0.05 mm to 1 mm. If cavities are too deep, sanding may involve several stages.

A car's crankshaft can be repaired and bored a certain number of times, depending on the model. For example, a crankshaft on a VAZ must be repaired 4 times and bored out for different sizes of liners with their subsequent increase. After dismantling the spare part, the first thing to check - can it be restored. If so, you can buy larger earbuds and get started.

The second thing to pay attention to - these are the crankshaft journals. If, upon examination, undulating grooves and risks are found on them, then you need to get rid of them. This is done by grinding on a special machine. Remember the main thing! Replacing the liners without grinding is not permitted. Do-it-yourself car engine repair will be in vain, the result will be zero.

Having prepared the head, cylinder block and crankshaft, we proceed to the assembly of the motor. For the capital of the engine, you may need to purchase at a car dealership the following parts:

Valves, guide bushings and seats for them;
Connecting rod and main bearings;
Pins of connecting rods and bushings for them;
Rings for pistons;
Pump repair kit;
Oil filter;
Gasket set.

The engine is assembled in the following order:

Installation of liners and crankshaft shrinkage.
Installation of pistons and connecting rods.
Fixing the crankshaft with yokes.
Installation of the gasket.
Installing the motor cover.
Mounting the pump and oil pump.
Installing the crankshaft pulley.
Head installation.
Fastening the pallet and crankcase.

When installing the liners and the piston group, we lubricate the parts and cylinder walls with special grease. Its further performance and resource depends on the high-quality assembly of the internal combustion engine. It is advisable that it be carried out by a person who knows the principles of operation and the device of the motor.

We install the unit in its original place using a lifting device. After successful installation, its fastening is carried out, then the removed equipment and the electrician are installed in the reverse order.Before starting the engine, it is additionally recommended to align the clutch and pressurize the engine.

Having turned off the engine, it is imperative to run it in correctly.

Otherwise, the motor will quickly fail without having worked out even half of the resource. During the running-in period, the parts are lapped in, and excessive stress will harm them. According to the existing standards, it is necessary to drive a car in about 2-3 thousand km. In this case, the speed of movement should not exceed 60 km / h.

After overhauling the engine with your own hands, the car must be operated carefully. During the run-in, the basic rules must be observed, the ride must be calm. During this period, frequent oil changes are required: every 500 km of the track. When the mileage reaches 2000 km, the oil is changed unscheduled for the last time. Then it needs to be changed as in any car after 10-15 thousand.

After carrying out an overhaul of the engine with your own hands, with proper operation, the car will delight the owner for many years. The main thing is to change consumables in time and use quality proven products.

You can see how the overhaul of the vaz engine is going on in the video.

Engine overhaul is a procedure that can be compared to dental prosthetics in humans. Just as a person at a certain age needs to install new jaws in order to properly and fully process food, so the engine needs to update units and parts so that it can normally “digest” fuel, develop optimal power, in a word, fully function. There are several reasons that can lead to overhaul of the motor:

- "aging" of components and assemblies during long-term operation;

- non-observance of the operating conditions of the engine (untimely replacement of oil, air and oil filters, refueling the car with low-quality fuel, and so on);

- operation of the power unit at maximum loads in unfavorable conditions.

To understand that the engine of your car has already needed a major overhaul, you should pay attention to one of the signs indicating a serious malfunction of the power plant. These include:

- engine knocking, which appears when liners and journals of the crankshaft, sleeve bearings located in the crank mechanism become unusable. This symptom can also be diagnosed by measuring the oil pressure. If it is low, the indicated parts are worn out;

- increased oil consumption and gray-colored exhaust, which indicate the maximum wear of the elements of the cylinder-piston group;

- engine jamming, which occurs due to the destruction of the elements of the piston group, the crankshaft, or a broken connecting rod.

If one of the listed signs is observed, the driver should immediately contact the service station where his car is serviced and carry out a full diagnosis of the power unit. Based on the diagnostic data, specialists will determine the specific cause of the engine breakdown and carry out the necessary engine overhaul operations in this case.Of course, you can repair the engine yourself, but for this you need to have special knowledge and remember that only the owner of the car will be responsible for operations with the engine, and not the manufacturer or dealer who sold you the car.

Now let's talk about what, in fact, is the overhaul of a car engine. First of all, the engine is removed from the engine compartment. For these purposes, the workshops have the necessary equipment with which you can disconnect all the power and cooling systems of the motor, control its electronics, unscrew it from the frame, remove attachments, lift and move it to a special machine (assembly slip), on which the unit is cleaned from accumulated dirt, complete disassembly and flushing of parts.

The first stage of overhaul is to determine the degree of wear of engine parts. The mechanic examines in detail the condition of the crankshaft, measures the diameters of the scuff marks on the necks. This is followed by the procedure for measuring the runout of the journals, the flywheel with the crankshaft, and in the cylinder block - the axial play of the shaft. Also, a specialist, by measuring the diameters of the cylinders in the longitudinal and transverse planes at three levels, determines whether there is a deviation in their dimensions and geometry. The next measurement is to determine the size of the gaps between the friction pairs (camshaft, valves and guide bushings, and so on). The housings of the engine parts, which are carefully inspected in search of cracks, are also not ignored - this is helped by the pressure testing equipment. Having determined how worn out all the listed engine components are and comparing the values obtained as a result of diagnostics with normal values, experts determine which overhaul operations should be carried out. As a rule, such engine components as the cylinder block, cylinder head, and crankshaft have to be repaired. Let's consider them separately.

Cylinder block repair operations include replacement of removable liners, boring and honing of cylinders. There are engines in which removable sleeves are not provided, in which case the locksmith installs the so-called repair sleeve. To do this, he bores a cylinder on the machine, and inserts a repair sleeve into the resulting slot, then processes it to obtain a size similar to other cylinders. The honing procedure is the application of strips with a specific profile to the surface of the cylinder, which help to retain oil there, which allows better lubrication of the piston rings and piston skirts. The cylinder is processed to the so-called overhaul size so that it corresponds to the diameter of the overhaul piston, while taking into account the size of the thermal gap (the value between the piston skirt and the cylinder wall). Also, the repair of the cylinder block includes such operations as restoring the crankshaft bed, eliminating cracks in the block itself, milling the mating plane before its subsequent alignment.

If you have to repair the cylinder head, then here the locksmiths carry out many small and time-consuming operations. They consist in welding cracks, replacing the valve guides (if the degree of wear of the guides is not critical, they are restored by making the diameter of the hole for the valve stem smaller) and the chamfers of the valve seats. In addition, the repair of the cylinder head involves the restoration (replacement) of valves, replacement of the camshaft and pushers, restoration of the deformed mating plane using grinding, and another mandatory operation - the installation of new valve stem seals.

Another time-consuming operation carried out during the overhaul of the engine is the restoration of the crankshaft to optimal operating condition.It is carried out as follows: the washed and dried parts of the connecting rod and main journals are first ground and then polished, achieving alignment of the tops of the relief of the surface of the journals and the edges of the holes of the oil channels. Also, the complex of work on the repair of the crankshaft includes its editing and diagnostics of the surface, which is usually deformed with prolonged beating of the necks.

When these engine components are repaired, they are cleaned of the formed shavings (with particular attention to the lubrication and cooling channels), washed, and then blown with air and dried. After drying, the process of assembling the elements of the power unit begins, which is performed on the assembly slip, observing and controlling all the gaps in the friction pairs. When the engine elements are installed, you need to weigh the pistons, piston pins and connecting rods, adjust all clearances and check the tension of all belts (chains).

The tightening of the bolts holding the engine housing parts together must be carried out sequentially in order to prevent distortion and subsequent deformation of the newly repaired elements. Before installing the assembled engine in the engine compartment, the mechanics manually check the operation of the shafts, making sure that they rotate without effort. If a hitch occurs, it means that something has been installed incorrectly, and, therefore, you will have to disassemble the element and again measure and re-install.

One of the important stages of a car engine overhaul is its cold run-in. That is, even before installing the motor in the engine compartment and connecting all the "supply" systems to it (fuel, cooling, and so on), you need to pour oil and coolant into the unit, connect the electric motor and arrange the so-called crankshaft run. Cold running-in is necessary so that friction pairs and replaced (rebuilt) engine parts run in under low load. Sometimes the minders carry out a cold run-in of the engine already installed in the engine compartment, letting it idle for a while (up to 4 hours).