Which engine is cheaper to repair - Behind the Wheel magazine

When to overhaul an engine?

Let's look at how much it will cost to overhaul the most common types of engine with a displacement of up to 2 liters.
Typically, a 1.4–1.8 liter engine that has been properly looked after: timely oil and coolant changes, not overheated or causing water hammer, lasts for about 200,000–250,000 km. This is if we talk about foreign-developed engines. Domestic ones usually run noticeably less, but there are exceptions: some copies of VAZ engines “run” up to 200,000 km or more.

Stages of engine repair

Rebuilding the engine involves performing the following actions:

Removing the motor.
Complete disassembly and removal of accumulated dirt by washing and cleaning.
Identification of defective spare parts of the block that need to be replaced: inspection of the engine block for cracks, measurement of possible gaps formed, assessment of the condition of the crankshaft, identification of worn parts.
Overhaul of the cylinder head.
Restoration of the cylinder block.
Assembly of the unit and installation on the car.

Disassembly and dismantling of the engine

The process of removing the unit from the car may vary depending on the car model. Dismantling a carburetor engine is much simpler than an injection engine. There are fewer electronics that have to be removed first. Also, the disassembly process will be different for brands with front and rear wheel drive.

The preparatory stage preceding dismantling will be the removal of interfering mechanisms and unscrewing the retaining bolts. The removal of a heavy unit from the car body occurs using a special lift or winch. If there is no such device, then to reduce weight, all possible parts and spare parts of the engine are removed, and it is pulled out manually. This will require the help of several people.

Disassembly follows. The work should be done sequentially, carefully inspecting the parts for wear and placing them in order.

It is worth knowing that a VAZ engine can be disassembled in about 3 hours; disassembling a foreign-made engine takes more time: about 10 hours.

Washing engine parts

Washing is an important step that many people skip.

It is not right. Each detail has a specific meaning. If the spare parts are not washed and deposits are not removed, then the degree of wear can be incorrectly determined, which can cause rapid failure of the entire motor. You should also wash the block and cylinder head with special care to examine for possible cracks.

Diagnosis of damage and defects

Defects are identified visually and using measuring instruments. All spare 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, special attention is paid to cracks and chips.
The crankshaft is inspected and measured to check whether wear has appeared, and is also checked for alignment and bends.
Parts of the connecting rod and crank mechanism: the general condition and the presence of play are determined.
Gas distribution mechanism.

Cylinder head repair

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

Camshafts.
valves.
Guide bushings.
Valve stem seals.

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

Cylinder block repair

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

Crankshaft repair and restoration

A car's crankshaft can be repaired and bored a certain number of times, depending on the model. For example, the crankshaft on a VAZ needs to be repaired 4 times and is bored to fit different sizes of liners with their subsequent enlargement. Having dismantled the spare part, the first thing you need to check is whether it can be restored. If yes, then you can buy larger earbuds and get started.

The second thing you need to pay attention to is the crankshaft journals. If, upon inspection, wavy 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 liners without grinding is unacceptable. Repairing a car engine with your own hands will be in vain, the result will be zero.

Assembly and installation of internal combustion engines

Having prepared the head, cylinder block and crankshaft, we proceed to assembling the engine. For engine capitalization, you may need to purchase the following spare parts from a car store:

Valves, guide bushings and seats for them;
Connecting rod and main bearings;
Connecting rod pins and bushings for them;
Piston rings;
Repair kit for pump;
Oil filter;
Gasket set.

Engine assembly occurs in the following order:

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

When installing the liners and piston group, lubricate the parts and cylinder walls with a special lubricant. Its further performance and service life depend 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 design of the motor.

We install the unit in its original place using a lifting device. After successful installation, it is fastened, then the removed equipment and electrics are installed in reverse order. Before starting the engine, it is additionally recommended to center the clutch and test the engine.

Running in the engine

Having capitalized the engine, you definitely need to break it in properly.

Otherwise, the motor will quickly fail without using up even half its service life. During the break-in period, parts are ground in, and excessive load will harm them. According to existing standards, a car needs to be run in for about 2-3 thousand km. In this case, the speed should not exceed 60 km/h.

VAZ motor

With proper overhaul, the VAZ eight-valve engine must be disassembled to this condition.

Its design has long been known to auto repairmen, there is a sea of spare parts on the market, and almost every barn will take on the job. At the same time, work from “would-be-masters” who do not bother with instrumental measurements can cost about 30,000 rubles - even including spare parts. But the quality will be appropriate. Proper restoration of a VAZ engine can cost about 50,000 rubles.

, but nothing more. After all, the price of a new engine starts at 59,000 rubles. Plus installation cost.

Car maintenance after major repairs

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

After overhauling the engine yourself, with proper operation, the car will delight the owner for many years. The main thing is to change consumables on time and use high-quality, proven products.

You can see how the overhaul of a VAZ engine takes place in the video.

Diesel engines

Almost everything said in the previous section can be applied to diesel engines of the same displacement. But the repair will be a little more expensive - about 220,000–230,000 rubles.

The reason is that the piston elements of such engines are more expensive, and working with the cylinder head is more difficult. Sometimes removing injectors and glow plugs takes a lot of time. And they may get hurt in the process. Motors are less common, and therefore waiting times and component costs are somewhat higher. And all this does not take into account the repair or replacement of the turbocharger - an integral part of any modern diesel engine.

Engine overhaul - what is it?

With this article we begin a series of publications on the topic of engine repair of modern cars. We will analyze the repair features and problems of engines of popular cars. But first, let's define what it is: Overhaul.

An engine overhaul involves completely disassembling the engine and replacing parts of its two main parts: the cylinder head and the cylinder block itself. In the cylinder head during a major overhaul, the following must be changed: cylinder head bolts, valve stem seals, cylinder head gaskets and cylinder head covers, spark plug ring seals, camshaft seals, timing belt or chain and everything connected with it. Valves and camshafts are changed depending on their condition and the reason for repair. In the internal combustion engine block the following must be replaced: main and connecting rod bearings, pistons and piston rings, thrust half-rings. All non-replaceable parts must undergo pressure testing and, if necessary, refurbishment. In the cylinder head, it is important to check the plane of contact with the block, the condition of the valve seats, and the tightness of the cooling system channels. In the cylinder block, it is also important to check the plane of contact of the cylinder head, the condition of the crankshaft and the surfaces of the cylinders. Based on the results of checking the condition of the cylinders, a decision is made to install piston group parts of standard or repair sizes. Currently, most manufacturers do not provide for the repair of internal combustion engines with cylinder boring and, as a result, do not produce piston parts of repair sizes. In this case, the manufacturer recommends replacing the cylinder block assembly. But there is another option - boring the cylinder block and installing a liner to fit the standard size of the piston group. Taking into account the difference in the cost of repairs and the cylinder block assembly, as well as difficulties with re-issuing documents (the block is a numbered unit), a block liner is the preferred option for engine overhauls. When overhauling an engine, it is very important to check the condition of the oil pump. If the major repair is a consequence of wear of the piston group and the car arrived at the service center under its own power, before disassembling the engine it is necessary to measure the oil pressure in the system. If the cause of a major overhaul is engine overheating, operation without oil or with a low oil level, replacing the oil pump is mandatory.

We have come to an important point: the reason for the overhaul. Everything described above mainly relates to engine repair due to wear of the piston group. That is, during normal operation of the car, in any case, parts wear out and over time they need to be replaced. Indications for major repairs are: oil consumption, reduced dynamics, increased oil consumption, extraneous sounds during engine operation, increased amount of crankcase gases in the air supply system. In this case, after a series of checks (measuring compression, checking oil pump pressure), a major engine overhaul will most likely be recommended. In addition, the cause of engine overhaul may be overheating of the engine due to a lack of coolant or malfunctions in the cooling system, low oil level in the engine and, as a consequence, oil starvation, which leads to increased wear of parts and the formation of chips in the lubrication channels. Sometimes, due to long-term operation of a car with a faulty cooling system or lack of oil in the internal combustion engine, it is more advisable to replace the entire engine or the cylinder block assembly, because oil channels clogged with chips and damaged cooling system channels due to overheating will not allow the engine to be operated even after a major overhaul. Therefore, when contacting a car service with a problem in the internal combustion engine, it is necessary to provide as much information as possible about the operation of the car.

Well, at the end of this part, let’s try to answer the question: what is better: a major overhaul of the engine or replacement of the entire unit. Let's say right away that there is no clear answer. If we are considering replacing it with a completely new unit, then of course yes, it is better to do just that. But the engine, and even the assembled cylinder block, are quite expensive. Therefore, most often the choice is between a major overhaul and a used unit. Here our opinion is entirely on the side of repair, although this option is often more expensive. Because when buying a used engine you are buying a pig in a poke. The condition and resource of such a unit is unknown to anyone. There is no guarantee for it either, since the 14-day guarantee that sellers of such goods promise cannot be called a guarantee. But, as they say, everyone decides for themselves, and due to experience, we can only recommend not to prioritize the cost of restoring the functionality of your car. You may have to pay twice: first for the internal combustion engine from the secondary market, and then for its repair.

What does engine overhaul include?

Such a serious repair of the power unit may include repair of the cylinder head or repair of the cylinder block itself. Sometimes crankshaft restoration also occurs. Engine overhaul can be complete or partial. To understand which one should be performed in your situation, it is necessary to conduct a thorough examination and diagnosis .

When contacting a service station, service center specialists will inspect the condition of the cylinders of your power unit. A mandatory measurement of the diameter of the crankshaft journals is also carried out and checked for play in the pistons and pins.

Timely computer diagnostics and maintenance of a gasoline engine will cost much less than its complete replacement

Sometimes an engine overhaul may only include replacing the piston rings, but if their wear is high, this will definitely not help.

Also, when the engine is overhauled, the cylinders are bored, the cylinder head is polished, and the crankshaft is restored.

What are the consequences of poor quality repairs:

What is needed for a major overhaul

When performing engine overhauls, attention must be paid to each engine component. To do this you will need a whole list of spare parts:

repair half rings;
generator and timing belts;
air and oil filter;
spark plugs in the required kit;
vacuum hose;
rings, pistons and pins included;
liners (connecting rod and main);
antifreeze, gearbox oil;
oil seals.

The list of spare parts may be expanded or shortened. This depends on the amount of work being done, the complexity of the engine repair, and the need to replace a specific spare part. In certain situations, you can avoid repairing a specific unit due to the excellent quality of the parts. It all depends on the degree of wear. This will all tell you what equipment you need to use in your work.

It is impossible to talk about the specific cost of the spare part. It will vary depending on the manufacturer, supplier and distributor. In addition, prices fluctuate depending on the market rate. For foreign cars, it is best to purchase used spare parts that will be of decent quality. The price will be almost halved.

It is worth paying attention that when carrying out repairs at a service station, craftsmen can recommend their own spare parts for installation, having their own supply network, offering a complete list. This will avoid expenses in case of necessary refurbishment. But the cost of spare parts will be slightly higher than on the market. If you purchase them yourself, there will be cases of waiting for delivery. This will also lead to payment for storing the car at the service station.

Important! Before purchasing any spare part for major repairs, you should consult with a specialist who will carry out the repair work. Since he encounters this every day, he will be able to suggest what and how best to choose. This will help avoid overfitting.