How to overhaul the engine? How to make the correct overhaul of the engine so that it is better than the new Stages of engine overhaul.

An overhaul of the engine is carried out in the following cases: destruction of the pistons due to a broken timing belt; natural wear of the piston group; loss of compression in the cylinders.

Before starting work, you can think about tuning (improving) the motor. Whatever the car, it is possible to increase the number of horsepower, and without significant costs. Consider the main stages of repair work, so that you have an idea of ​​\u200b\u200bwhat you will have to face.

Removing the engine from the car

You cannot do without this procedure, since the motor must be removed, otherwise it simply cannot be completely disassembled. At the preparation stage, disconnect the battery to de-energize the power supply system. All attachments must be removed - carburetor, air filter, generator, starter, exhaust manifold, etc. Before dismantling the engine, you can also unscrew the head of the block. It will be worked on separately. Drain the oil from the crankcase, after which you will need a winch and helpers.

Four bolts secure the gearbox to the engine block. The motor with a body on VAZ 2108-21099 cars is attached with one pillow. Hang the engine on a cable and unscrew all the bolts, pre-treating the connections with a penetrating lubricant to facilitate work. For convenience, you can remove the hinges at the very beginning and remove the hood to the side, so you will free up space. After the final extraction of the engine, proceed to disassemble it.

Now it’s worth talking about the requirements for each element of the motor.

Cylinder block

Either way, it needs to be repaired. First of all, clean the entire surface of oil, dirt and other deposits. Repair consists in boring the sleeves to the required size. This procedure cannot be carried out on your own, it is better to trust a specialist. The turner carrying out the boring must have the skills to work on the machine. Do not trust such a thing to an inexperienced person. Its reliability depends on how correctly the overhaul of the VAZ 2109 engine is done.

There are two boring options: under a mirror and a fine mesh. In the second case, honing is done - the entire inner surface of the sleeves is covered with thin lines. Some people claim that this gives a power boost. But in reality, the picture is the opposite - the wear of the piston rings increases, since the surface of the cylinder looks like a regular file. Fortunately, this continues for 10-20 thousand km, after which the sleeve takes on a mirror-like appearance. And not always the geometry is perfect. For this reason, boring is best done under a mirror.

Is it worth it to lighten the pistons

If you are on fire with the idea of ​​\u200b\u200btuning in order to increase power, then the answer is unequivocal: it is necessary to lighten the pistons! But if it is in your interest only to make repairs, then it is enough to install new ones. In any case, the increase in horsepower will be noticeable, as the motor compression will increase. It is best to entrust lightening work to the same turner who is engaged in boring the cylinder block. As you can see, it will not be possible to do a major overhaul of the engine with your own hands; you will have to resort to the services of specialists.

The essence of the process is to get rid of the "extra" metal in the inner part. To do this, aluminum from the piston skirt is carefully ground. Pay attention to whether there are scrapers - recesses for valves in the upper part. If they are present, then purchase repair ones with the same attributes. Otherwise, you will need to sort out the motor every time the timing belt breaks. And do not forget that rings of the right size are needed for each piston - you can find out all the values ​​\u200b\u200bin the car's manual.

Crankshaft and its relief

This is perhaps the most massive element of the entire motor. If you only need to overhaul the VAZ engine, then you can limit yourself to replacing the main and connecting rod bearings. But in the event that you are seeking an increase in power, you will need to do a lot of work. And without the services of a turner, again, it will not be possible to do. After all, only when using professional equipment can you get rid of the "extra" metal on the surface of the crankshaft.

But do not forget about one feature. The crankshaft has an axis of rotation, its center of gravity is located in such a way that no beats occur. In the case when you grind metal, the alignment is disturbed. And by installing such a crankshaft, you simply destroy both the bearings and the cylinder block housing. Therefore, after relief, it is necessary to do balancing in order to restore the shaft alignment. But the engine after a major overhaul will be much more powerful, which will surprise you unspeakably.

Flywheel and clutch block

For tuning, these nodes should also be finalized. As in the case of the crankshaft, it will be necessary to cut off a layer of metal from the inside of the flywheel. After this procedure, balancing is also necessary so that axial runout and, as a result, vibrations do not occur. The clutch will need to be reinforced. Give preference to samples that are used for newer and more powerful car models. Start with how much horsepower you want to end up with.

Oil pump and cooling system

The improvement of these nodes is essential when tuning. Lubrication of all units may be insufficient, as there is an increase in torque and power due to the lightening of the main elements. Carefully troubleshoot the oil pump gears so that the gaps are minimal. As for the cooling system, it would not be superfluous to install a more efficient pump and a radiator with a larger area. Without these procedures, a major overhaul of the 2109 engine, provided that there is no need to do tuning, can be dispensed with.

Block head repair

This unit is responsible for the quality of the sealing of the combustion chamber at the moment of ignition of the mixture. Therefore, you should achieve maximum contact between the surface of the valves and the seats in the cylinder head. To do this, it is necessary to carry out lapping. The work is not difficult, but tedious and long. You will need a drill with a reverse (even a manual one will do), a piece of rubber hose, two clamps, a metal rod, lapping pastes - finishing and rough. Please note that after the work there are no abrasives left on the surface of the cylinder head. Clean everything and blow with compressed air.

First, a rough lapping paste is applied to the seat. Use a drill to rotate the valve in different directions (it is highly desirable that there be an equal number of revolutions). After getting rid of large surface irregularities, you need to apply a finishing paste and grind to a shine. Maximum contact between valve and seat is now ensured. The main thing is to install them the way you rubbed them in, you can’t swap elements. In this case, it will not be possible to achieve maximum tightness.

AvtoVAZ, the manufacturer set the average mileage for VAZ 2114 cars = 150 thousand km. The same indicators have, on average, all Russian cars. But, if various problems are eliminated in time, the resource of motors can easily withstand 250 thousand km. The resource of engines of foreign cars, on average, is 200,000 - 300,000 km before overhaul.

What is included in an engine overhaul

Overhaul of diesel and gasoline engines is done in stages:

1. Disassembly of the engine.
2. Parts washing and cleaning.
3. After cleaning, an experienced auto mechanic is able to determine how worn out certain parts are, whether they can be repaired or better replaced. Troubleshooting is done, that is, after the cylinder head (cylinder head) has been removed, it and the cylinder block (cylinder head) are checked for chips and cracks; examine the cylinders for scuffs and scratches; determine the gaps of the mating parts; inspect the condition of the pistons for the presence of chips, shells, soot; inspect the crankshaft connecting rods; study of the crankshaft of the internal combustion engine; fingers; bearings; parts of the gas distribution mechanism are also checked (valves, rocker arms, etc.). They also compare the dimensions of important parts with the factory ones.
4. After troubleshooting, it is necessary to assess the degree of wear of the entire engine: what to change, what to leave, what to repair.

• If you have never had to completely disassemble the engine, then it would be more correct and better to invite a friend who understands.
• It is desirable to carry out disassembly in a warm and well-lit garage.
• During disassembly, put all bolts, washers and nuts in a box with partitions, do not throw everything into one bucket.
• During disassembly, remember the sequence if you are doing this for the first time.
• If you don't know what the spare parts are called, take the old parts to the store and show them to the seller.

Do-it-yourself engine overhaul

In our do-it-yourself engine overhaul guide, here is the sequence of actions:

1. Dismantling and disassembly.
2. Parts troubleshooting.
3. Washing of disassembled parts.
4. Order and purchase of spare parts.
5. Block and crankshaft grinding.
6. Block head repair.
7. Verification work.
8. Assembly and installation of internal combustion engines.
9. Running after capital.
10. Conclusion.

Dismantling and disassembly

Depending on the make and model of the car (engine design, number of cylinders, gearbox type), the process of dismantling the engine may differ. The location of the engine on front-wheel drive and rear-wheel drive is also different.

Carburetor engines are much easier and faster to disassemble, since they are not crammed with electronic devices, in the presence of which, in order to get to the engine itself, you have to carefully dismantle them all.

So, if you have to make a capital for Kamaz, for example, then its diesel engine from the Yaroslavl plant YaMZ-236 will take about 10 hours to dismantle. If you do the same work with heavy-duty analogues of Kamaz, it will take more than 30 hours.

And to disassemble the VAZ engine, you need about 3 hours. And the engines of passenger cars will take about 10 hours.

It is necessary to disassemble slowly, throwing bolts and nuts anywhere. With disassembly, the diagnostics, so to speak, have already begun.

Troubleshooting of elements during the capitalization of internal combustion engines

Troubleshooting in this case is mechanical, that is, it is necessary to check visually and with the help of measuring instruments the wear of parts.

The troubleshooting of the internal combustion engine includes the following work:

• inspect the crankshaft and measure its dimensions, check for bends and centering;
• inspect the cylinder block housing (BC);
• check the details of the connecting rod-crank mechanism for backlash and the condition itself: pistons, cylinders, rings, fingers, connecting rods;
• inspect the cylinder head housing (cylinder head);
• details of the gas distribution mechanism;
• determine the maintainability of parts and assemblies.

Washing the engine and individual parts after disassembly

Many neglect such work as washing the motor. It is advisable to rinse each part and clean it of plaque so that you can determine the degree of wear, also rinse the cylinder head and BC to detect macrocracks, if any.

What parts are needed for engine overhaul

After doing the troubleshooting procedure and screening out those that are suitable for restoration and those that are not suitable, it is necessary to order new parts to replace the unusable ones. When you already know what spare parts are needed, you don’t need to pull with their order and purchase, since new parts still need to be prepared for installation.

Spare parts for overhaul for gasoline engines:

1. Inserts (main and connecting rod).
2. Details of the piston group.
3. Connecting rod fingers.
4. Connecting rod bushings.
5. Valves (all, both inlet and exhaust).
6. Oil scraper rings.
7. Gaskets (complete set).
8. Valve guides and valve seats.
9. Pump with repair kit.
10. Oil filter and pump.
11. Other associated parts.

Block and crankshaft grinding

After the issue with spare parts has been resolved, they begin to repair and restore the block and the crankshaft of the internal combustion engine. On a milling and surface grinding machine, a layer of the seat of the cylinder head and the block itself are removed until there are no shells and chips left. It happens that there are several deep shells, because of which you have to remove layers in several passes. Usually, depending on the degree of damage, layers are cut off with a thickness of 1 mm, 0.5 mm, 0.25 mm, 0.1 mm, 0.05 mm. After that, they begin to grind the surface to a mirror finish.

There is a special table for grinding the crankshaft, which indicates the thickness and efficiency after repair compared to a new factory one.

Type of repair	Thickness, mm	Efficiency compared to new
Repair No. 1	0,25	80-90%
Repair No. 2	0,50	70-75%
Repair No. 3	0,75	65-70%
Repair No. 4	1,00	50-55%
Repair No. 5	1,25	40-45%
Repair No. 6	1,50	Less than 30%
Repair No. 7	2,00	Not used since 1995

Repair of the head of the block (cylinder head of the internal combustion engine)

For repair work with the cylinder head, although not difficult, for some reason many try to give it to the service.

Repair of the block head consists of the following types of work:

1. We replace the camshaft (everything that is in this engine).
2. Change suction and exhaust valves.
3. Change guide bushings.
4. with saddles.
5. If there are cracks in the cylinder head, then either we change the head and grind it again, or we weld these cracks with argon.

Verification work

After the main repair and restoration work done, there are still verification and additional ones. This includes clutch alignment and engine pressure testing.

For centering, some services provide special centering stands. The connection between the crankshaft and the clutch must be centered. A balanced crankshaft and clutch will reduce wear and friction as well as end runout.

Assembly and installation of internal combustion engines

Engine assembly sequence after overhaul:

If for the first time you decide to make a capital box with your own hands, after all the work before assembly, it is better to assemble with an experienced specialist in this matter. The resource of the entire car depends on the build quality.

Break-in after capital

The most enjoyable process in such work is the running-in necessary for the engine with new parts. During the break-in, new parts are rubbed in, so it is not recommended to immediately give a large load. It is recommended to run a run-in up to 2000 km without jerks and a sharp start.

There are several ways to roll:

1. Running on a cold stand.
2. Cold running without stand. This method is common, especially in the CIS countries. After preparing everything you need (engine oil and coolant are filled in), without starting the engine, roll the car in tow at 3 speeds for 2 hours. This method is not recommended. By the way, a very important reminder: engine oil has a code and designations for additives, before purchasing it, it is advisable to learn, after which you can make the right choice yourself.
3. Hot run. This method consists in starting the engine and letting it idle for 3 minutes, then turning off the engine. And so they do it several times, only waiting for the engine to cool down. Then, after short-term starts, the engine is started and allowed to run for 1 hour. During the break-in, the engine is inspected for tightness and other indicators. After running in, adjust the valve clearances and set the desired ignition. If contact ignition is installed, then it is recommended, instead of the old one,. It reduces fuel consumption and generates a high voltage of up to 24 kilovolts, while contact ignition is capable of supplying no more than 18 kilovolts to a candle. Thanks to this, they even give a spark.
4. Natural rolling. It is run in under the following conditions: smooth driving, speed no more than 60 km. After overhaul without installing new liners, running-in is carried out up to 2 thousand km. If new sleeves were installed, then 4 thousand km.

Abroad, they say, in car services there are break-in and test benches for internal combustion engines. This stand with the help of special electronics shows the resource of the restored engine.

If you still decided to do the overhaul not on your own, but to give it to the service, then you will receive a guarantee for the repaired motor. The guarantee is given by someone like, someone is 20 thousand kilometers, someone is 30 thousand km. run.

Do-it-yourself engine overhaul is only partially possible. Because, we need machines, the cylinder head and cylinder head have to be given for boring and grinding. The rest of the work can be done by yourself. The simpler the car, the easier it is to make repairs. It is not difficult to independently make capital on VAZ, GAZ, UAZ, NIVA cars.

To increase the engine resource of any car, you need:

• buy high-quality spare parts and consumables;
• timely maintenance;
• the most important thing is to change the engine oil every 6-7 thousand kilometers;
• a neat smooth ride without jerks also increases the life of the car.

After an overhaul of the engine, the oil must be changed at the following intervals:

1. After 500 km - the first change.
2. After 1000 km - the second replacement.
3. After 1500 km - the third oil change.
4. After 2000 km - the fourth replacement and, further on schedule, every 10-15 t.km.

The video shows some types of work on the overhaul of internal combustion engines.

Engine overhaul - this phrase cuts through every motorist to the marrow and bones. Of course, because its cost can vary from 10 to 150-200 thousand rubles, depending on the brand and model of the car. Each engine has its own resource. Having exhausted it, the mechanism needs to be repaired. What does it mean Let's look at its stages.

First you need to remove the unit from the car and clean it of dirt, fuel oil, because then these accumulations can get inside and bring all the work down the drain. And then it will be easier to handle the details, since they can be freely picked up and do whatever you want with them. After cleaning, you can get to work.

Let's start from the heart - with pistons, since this is the most difficult and expensive part of the repair, requiring equipment and an accuracy of up to 0.01 mm. For example, a major overhaul of a VAZ engine is difficult mainly because the piston pins are inserted into the upper connecting rod head at a temperature of about 800 degrees, so this will simply be impossible to do without a certain skill and sleight of hand. Naturally, such things as cylinder boring will be carried out by specialists. These are inevitable expenses, the same as grinding the necks.

It takes quite a lot of time and space, so you should take care of the place of work in advance and ensure its cleanliness and order.

After boring the block, it indicates the class of pistons that corresponds to its size. Pistons and piston rings are selected according to it. When selecting, it is worth remembering that for all cylinders the combination of piston + connecting rod + pin + piston rings of the same weight is selected. For all cylinders, the difference should not exceed 2 grams. It is logical to assume that weighing should be carried out on the same electronic scales.

Further, the overhaul of the engine affects the crank mechanism, which includes the crankshaft and connecting rods. If the budget is unlimited, then the necks should be polished anyway. If there are any restrictions, then you need to take measurements and decide whether repairs are required. Naturally, the liners need to be changed in any case. This is where the oil pump is located. The fact is that its malfunction leads to a drop in pressure in the smear system, which also makes all work in vain. Here the gap in mating parts is measured, this is done using the appropriate probe.

Well, this is completed. Now we can move on to the head. Here is located. It includes a valve mechanism with a camshaft. Here you need to pay attention to its condition, also take measurements and replace the valve stem seals, dressed on the valve guides. In addition, you need to grind the valves. This is done using an appropriate fixture and lapping paste of various grits.

After all the procedures carried out, it is worth paying attention to the power supply system, as well as to the ignition, since if they malfunction, the engine will not respond to repairs as it should. At the very beginning, it is worthwhile to understand that do-it-yourself engine overhaul is not such a terrible thing, which almost every car owner who has the initial skills in handling equipment can do. After the completion of the repair work, it is worth remembering an equally important part - running in. During it, it is not necessary to subject the engine to heavy loads and exceed a speed of more than 100 km / h, since at this time all parts are lapped and heat treated.

The trends of modern automotive industry are such that classic cast-iron blocks for several piston repair sizes have already become an endangered species, more often engines are "disposable". There are no repair dimensions of the cylinder-piston group, there are no repair dimensions of the crankshaft liners.

What can happen to such a motor and what to do if it still breaks down, and replacing it with a new unit is not an option due to the too high price? Motors are different, but you can almost always find an alternative path and bring it back to life. Another question is, does it make sense from a financial point of view?

Aluminum blocks with cast iron sleeves

The simplest option is a "regular" motor with cast iron sleeves, and sometimes even with a block made of the same cast iron, but not having the repair dimensions of the piston group and crankshaft.

And by the way, why? There is a "conspiracy theory" according to which manufacturers specifically limit the release of parts for repairs, as long as the consumer goes to the showrooms in a shoal for new cars. But if this is true, then in part. The fact is that many modern cast-iron motors in terms of wear resistance are not like the old ones.

Due to the progress in materials, the cast-iron sleeve in terms of wear resistance has come close to very expensive technologies using alusil and nikasil, which we will discuss in detail below.

The natural wear and tear of cast iron is essentially a thing of the past. Often, the natural development of the cylinder with a run of more than three hundred thousand kilometers is minimal. And if the wear is less than the honing depth (two or three hundredths of a millimeter), then there is no need for boring.

Of course, this is a good reason for the manufacturer to abandon repair sizes and produce only a few gradations of "nominal" pistons and rings. But, unfortunately, wear is not only natural. If piston rings lie, abrasive enters the cylinders, overheating, detonation or other troubles with the motor, one or all cylinders may fail.

Seizures, ellipticity or even annular wear appear on them, and violations of the geometry of the connecting rod and piston group are possible. If boring was possible, then the problem would be solved simply by regrinding to a new size, defects of this kind are usually removed without problems. But you can't sharpen! There are simply no new size pistons on sale, and if there are problems with the crankshaft, then it cannot be sharpened either - there are no liners.

Repair Method #1: Buying a Shot Block

So the motors are still disposable? Not at all. There are several ways to solve the problem of such a motor. The first of them is standard, recommended by the manufacturer. And often, by the way, not the worst. This is the purchase of a so-called shot block, that is, a cylinder block complete with pistons and a crankshaft. Put the block heads, crankcase, attachments on it - and the motor is ready.

Usually the downside of such a solution is the price, but if you remember that the original pistons are usually not cheap either, and the work costs a lot, then ... The question, as always, is the price of specific instances. For example, the well-known Opel Z22SE or Saab B207 engines as GM products have a large selection of shot blocks, and not only from the manufacturer. Their price in the USA is very pleasant - from one and a half thousand dollars. For two and a half, you can buy a tuning reinforced block with a 2.5-2.7-liter stroker kit or one designed for higher boost pressure and solid torque. But for middle-aged Toyotas, a shot block will cost at least three and a half thousand. At the same time, a fair part of large-volume engines have shot blocks that cost about five thousand. And here you already have to think about an alternative to a simple replacement.

Repair method No. 2: cylinder block liner and "native" pistons

Sleeves are made, as they say, "at face value", that is, the same size as in the original. If you successfully choose the material of the sleeve and the accuracy of the "preload", then only the heat transfer will suffer a little, because the "native" sleeve is precisely poured into the molten metal, and the repair sleeve, depending on the method of fit, can either have almost no mounting gap or maintain a gap from one to three hundredths.

Then everything depends on the accuracy of machining and on the quality of the assembly. The original nominal size piston group will work fine in such a motor. It is possible to sleeve only a damaged cylinder and thereby reduce the cost of work. Much depends on the skill of the performers, but if your city has precision machines, then this is a relatively inexpensive way to restore the motor.

But remember that during the heat treatment of the cylinder block, deformations and geometry violations are possible. Therefore, it is recommended to line all cylinders at once and bore with the new geometry from the "base" of the block, and not the old cylinder axes. If it is necessary to repair only one cylinder, it is better to use the technology of cold landing of liners with a press or an installation with a gap.

Repair method No. 3: "native" bored liners and larger diameter pistons

The cylinder block is simply bored for new custom pistons - not original, but custom-made, to the desired size. Usually we are talking about the so-called forging - pistons obtained by machining from a blank obtained by isothermal stamping. Such pistons are noticeably stronger than ordinary cast ones, but, like any individual work, it may not be the most successful.

Even pistons from a reputable manufacturer require a larger thermal gap due to the higher expansion coefficient of forging alloys and unaccounted for thermal distortion. And of course, a stronger piston does not always mean longer engine life, as both the rings and the cylinder itself wear out. In this case, much will depend both on the processing of the cylinder itself (in this case, it retains its heat transfer and geometry parameters, unlike the sleeve), and on the new piston.

The same applies when the original piston group is very expensive or rare, and the motor is built for everyday use. This is a good way if the pistons for the engine being repaired have already been mastered at least in a small series or there are tested samples. After all, no one wants to work as a test engine tester.

However, if you collect those who want to order five hundred or a thousand pistons, then your order has every chance of being produced using the original Kolbenschmidt or Mahle technologies, however, the price of the pistons will be at least as good as the original ones, but the size is any within a reasonable tolerance to the regular and fully developed design in the series.

Full aluminum blocks without sleeves

It is extremely profitable to make cylinder blocks from aluminum without cast-iron liners. Firstly, it is a smaller mass of the motor. Secondly, the thermal conductivity of aluminum is higher than that of cast iron, which means that heat removal from the most loaded parts of the motor is better. Finally, both the pistons and the cylinder head are also made of aluminum, which means that their coefficient of thermal expansion will be close to the expansion coefficient of the block. Therefore, it is possible to reduce thermal gaps to a minimum due to the temperature difference between the piston and the cylinder block.

Technologies of all-aluminum cylinder blocks can be conditionally divided into three groups of materials, and in all cases it will not be "pure" aluminum, but a block of "winged" metal with a durable cylinder coating.

Nikasil aluminum blocks

First of all it is Nikasil, which was the first to gain mass acceptance as a way to produce reliable all-aluminum engines without cast iron liners. The name from the Mahle company has become a household name, although, perhaps, the trademark of a similar coating from the Kolbenschmidt company - Galnical - turned out to be not so harmonious and secondary ...

It was primarily intended for rotary engines, but became widespread in the nineties, and is still used in Formula 1, as in motorcycle engines. For example, the "monster" Suzuki Hayabusa has just such a cylinder coating. A more durable and successful material for cylinders has not yet been invented, its layer is hard and quite viscous, it is thick and does not crack, it can be squandered a little if it has already been somehow demolished. But this is extremely rare, the coverage is almost eternal.

But the nickel-carbide-aluminum coating, so strong and wear-resistant, is afraid of sulfur compounds. And on cars in the US and Canada that used high-sulphur gasoline, the coating quickly failed. You won’t find such gasoline now, but there is another reason why the coating was abandoned. It is eternal, but it is also expensive - the technology requires a complex method of electroplating and machining of high-strength material.

Alusil aluminum blocks

Therefore, Kolbenschmidt proposed using the very old (patented back in 1927 by Schweizer & Fehrenbach) Alusil technology for the production of cylinder blocks. Since Kolbenschmidt belonged to the Audi Group at that time, the technology was quickly brought to practical use.

The basic idea is quite simple: the liner or the entire cylinder block is entirely made of an aluminum alloy with a high silicon content, it contains at least 17% - this is the so-called hypereutectic alloy. In this case, silicon is contained in the material not in a dissolved form, but as crystals.

And if you "precipitate" aluminum, then you get a continuous layer of protruding silicon crystals, very hard, "slippery" and wear-resistant, the hardest piston rings can already work on it. This method is simpler and much cheaper, and the coating is chemically etched or obtained by special processing in a layer of high-silicon aluminum. In terms of hardness, alusil is not inferior to nikasil.

An additional advantage of the technology is the proximity of aluminum alloys of the block and piston - they are also cast from hypereutectic aluminum, which means that the thermal gap will be the smallest. That's just the hardened layer is much thinner than that of Nikasil, and the coating itself is much more fragile, under the thinnest shirt of silicon crystals is still the same aluminum. It is afraid of overheating, and the ingress of solid particles, and even soot from the rings. It is also afraid of aggressive chemical compounds of sulfur and others.

At the same time, the method of its production often allows the formation of cavities and zones with a non-uniform quality of the coating. And even though now this is the most common technology for all-aluminum motors, it still has its own scope of application and it could not displace simple cast-iron liners.

But there is one almost unused plus: it is theoretically possible to bore and restore the coating layer. All that is needed here is a special boring technology that removes a layer of aluminum, and then forms a layer of solid silicon on the surface and slightly "smoothes" the crystals. But it requires mass character, and hence, large factories for the restoration of cylinder blocks. And they don't exist yet.

Kolbenschmidt also has Locasil technology in his asset - an alloy in which the silicon content is all 27%, but it is no longer possible to cast a cylinder block from it, it is too fragile, but you can make a sleeve for a cylinder block, it will be more wear-resistant than alusil, but the technology for repairs they have the same ones.

Exotic: plasma spraying

There are also rarer variants. For example, VW in the cylinder blocks of the infamous 2.5 TDI engines use plasma spraying. A similar technology of laser silicon deposition instead of chemically etched Alusil is used on the new BMW engines of the "global series" B38-58. Theoretically, this technology is progressive and makes it possible to obtain a sufficiently thick hardening layer with good characteristics, but obviously it has not yet been perfected.

Repair Method #1: Boring Coated Aluminum Blocks

Of course, all technologies with surface hardening of the aluminum layer do not provide for the wear of the cylinder mirror, which means that there are almost no motors with repair dimensions of the piston group. Unless the very old BMW engines under Nikasil had a couple of repair sizes, but it quickly became clear that the coating either serves and does not wear out, or is damaged, and then it is necessary to change the cylinder block assembly. Accordingly, the repair dimensions for nikasil motors quickly disappeared.

Newer designs usually do not even allow you to buy "original" pistons from the factory catalog - only the shot block assembly. This is justified, as usual, by concern for consumers and high quality standards. But since the parts of the piston group are ordered by the manufacturer of the machine "on the side", you can find original spare parts in the catalogs of piston manufacturers, you just need to find out which of the dozen manufacturers supplied them to the conveyor.

Sometimes it is possible to order repair dimensions, for example, if you have the possibility of restoring an alusil type coating, then this option will ensure that all the factory characteristics of the motor are preserved. Full factory restore allows electroplating or plasma spraying of a nickel-like or chrome coating with subsequent boring or high-precision spraying without further processing. But if in mass production they cannot ensure a stable quality and service life of such a coating, then when using repair technologies, the resource may turn out to be even less, it all depends on the contractor.

There are chances for a quality repair, the technology is widely used for small-scale racing engine building, and there the highest requirements for coverage. That's just the price of work and the testing procedure will be appropriate. From the glorious Soviet past, many factories have inherited recovery technologies from this series. It is possible that know-how is applied somewhere that allows such restoration to be carried out reliably and inexpensively, but I personally do not know such places. Who knows, share!

An additional advantage of using such technologies is the ability to restore only a damaged cylinder, which makes this option beneficial when returning to life exactly a damaged, but not worn-out block.

Cast iron sleeves are much cheaper, they are not made for a specific motor, but are selected according to size. As a result, a motor sleeve using this technology is noticeably cheaper and is used much more often. In contrast to the fitting of a cast iron sleeve, only a "hot" fit is used in cast iron or with the use of liquid nitrogen to cool the sleeve and reduce its diameter.

When using high-quality liners and precise machining, the resource of the piston group may turn out to be even higher than that of the original coating, but again, errors in the work of the workshop are possible, which means that local overheating of the cylinders and thermal deformations may appear.

The disadvantages of cast iron sleeve technology are traditionally the already mentioned deterioration in heat dissipation, the need to use high heating of the "shrink fit" block, nitrogen cooling of the material or high-tech spin welding technology and a higher probability of error than with aluminum sleeves.

More often than not, this will be the only intelligent motor rebuild technology available. There are many reasons for this: for example, there are no specialized aluminum sleeves, technologies for boring and processing Alusil and applying Nikasil, which is typical for Russia. If the cylinder block was overheated and its geometry was broken, then a liner is needed, the working surface of which can be bored out for the new geometry of the block, and here the choice of recovery technologies narrows down to cast iron or bored aluminum liners.

Pistons for sleeved motors are selected from among the original ones according to the already described technology or special custom-made ones are made, as well as for motors with a standard cast iron cylinder working surface.

What is the result?

99% of all engines are produced according to the described technologies, which means that there are always chances for restoration. The main thing is to find a good performer with a run-in recovery technology, a supplier of high-quality spare parts and take a responsible attitude to checking the engine that has received a new life.

In our previous article, we wrote that due to the economic crisis and the rise in the price of imported spare parts, the overhaul of internal combustion engines (ICE repair) is once again becoming relevant and economically feasible. In this article, we will talk about the main methods and technologies that are used in the restoration of damaged and worn engine parts.

Before carrying out a major overhaul of a car engine, it is completely disassembled, after which all parts are washed and defective. This is a prerequisite for ensuring a high quality result of the ICE repair, since wear products and parts of damaged parts can get into the cooling jacket or block the oil channel, which will lead to repeated failure of the repaired engine.

Cylinder block before starting repairs, they are checked in a special pressure bath for hidden cracks. Identified shallow damage to the repaired car engine is first drilled to the base with a cutter, and then boiled with metal. With the help of welding, the holes punched by the connecting rod in the block of the repaired internal combustion engine are also closed, as well as the damaged partitions between the cylinders are restored. It should be noted that blocks made of aluminum and aluminum alloys are easier to cook than cast iron, as they have a lower melting point. Holes in cast iron blocks are eliminated with cast iron patches.

Cylinder block boring

Worn or damaged cylinder walls are bored to repair size and larger diameter pistons and piston rings are used. But this method of repairing an internal combustion engine is applicable only to engines whose manufacturer, during the design, made a margin that allows the cylinder block to be bored.

In lined cylinder blocks, the liners are pressed out and new ones are installed. Repair of internal combustion engines, for which the manufacturer did not provide for this, is carried out as follows: first, it is necessary to bore the cylinder, and then press in a cast-iron sleeve with a diameter for a standard piston for each compartment. If the cylinder block of the car engine being repaired is made of aluminum alloy and has a small wall thickness between the cylinders, then the cast-iron sleeve also strengthens the structure.

The surfaces of the block and head deformed during overheating are ground on the machine, while the gasket is selected in such a thickness that the degree of compression does not change.

Crankshaft and grinding

Damaged crankshaft beds of a car engine being repaired are restored by processing on a horizontal honing machine. At the same time, a very thin layer of metal is removed and a perfectly even axis of rotation is provided, which is a very important condition, since otherwise uneven loads will act on the shaft, which can lead to jamming or breakage and complete failure of the repaired internal combustion engine.

Troubleshooting of the crankshaft is carried out both by visual inspection and measurements, and with the help of various technical means. A rather interesting method for checking the crankshaft is magnetic flaw detection:

1. the crankshaft is mounted on two supports with windings of different polarities;
2. a special oil is applied to the surface;
3. after the crankshaft is sprinkled with metal powder.

The magnetic field that is created when current passes through the shaft makes it possible to detect hidden cracks in the shaft, since powder particles characteristically line up above them.

The detected shallow damages on the necks are eliminated by grinding the crankshaft, while the liners of the required sizes are selected for the repaired internal combustion engine. If there are no original repair parts, then they are replaced with non-original ones, and sometimes they are made independently to the required size.

When repairing a car engine, the bends of the crankshaft are corrected on special press equipment. With a large wear of the necks, a tape made of a high-strength alloy is welded onto them, after which the crankshaft is ground to fit the bearings. In the same way, the surfaces damaged from wear under the seals are restored. During the repair of the internal combustion engine, broken key connections are also subject to restoration.

The described method is not used for diesel crankshafts, because they work at higher loads that fall on the parts of the crank mechanism. You will have to buy a new crankshaft only if there are large cracks on it.

Piston group - piston replacement?

When overhauling a car engine, replacing pistons may not be necessary if the residual thickness of their walls and bottom allows for restoration. However, piston manufacturers do not provide repair dimensions and companies that specialize in repairing internal combustion engines can only rely on their personal experience.

On the piston bottom damaged from impact on the valve, counterbores are made. If it is not possible to find rings of a suitable size for the piston of a car engine being repaired, then grooves are slightly bored under them.

Without replacing the pistons, the connecting rods themselves are aligned on the press machine, and a new bushing is installed under the piston pin.

The cylinder head (cylinder head) is checked in the same way as the block itself - in a pressure bath. In order to expand hidden cracks, hot water is poured into it, after which all technological openings are closed and air is supplied under excess pressure to the cooling jacket. If there are cracks, air bubbles will be visible in the corresponding place.

The restoration of the cylinder head, as well as the cylinder block, is performed by welding. After that, the head of the block of the repaired internal combustion engine is again checked in the pressure bath.

Other possible technological operations during the overhaul of a car engine:

1. The valve guides are replaced with repair ones (if any) or made independently.
2. Excessively worn valve seats are bored out, and new ones are pressed in their place.
3. Bent camshafts are aligned on a press machine. As a rule, there are no cracks on them.
4. Beds, as in the cylinder block, are bored on a special machine. After that, metal strips are welded onto the bearing surfaces of the shafts and polished.

Repair technologies developed over a long period of time make it possible to restore almost any engine with damage of varying complexity. But do not forget that major repairs are not cheap, and before starting work, it is necessary to carry out economic calculations, because it will probably be much cheaper to purchase a new power unit.