Repair of the cylinder head (cylinder head) is an important process that determines the operation of the engine and the car. And tightening the cylinder head is one of the key points in the overall repair of the unit. Reliable, correct and economical operation of the engine depends on the high-quality and correct tightening of the cylinder head.

What does the tightening of the cylinder head affect?

A similar work (tightening) is done when the reverse process is carried out to assemble a car engine. And how correctly, reliably and tightly the cylinder head bolts are tightened can greatly affect the operation of the combustion chamber, the gas distribution mechanism and the engine as a whole.

In the event that the cylinder head is tightened incorrectly, or in the wrong sequence, or weakly, this can lead to a breakdown of the gasket, which is installed between the cylinder head and the cylinder block. After damaging the gasket, the consequences are difficult to predict correctly. Most often, after this, water from the cooling system enters the engine oil. It turns out an emulsion that lubricates engine parts much worse than engine oil, and therefore the engine can quickly "jam".

In addition to water entering the engine oil, the engine power may sharply decrease, the sound of the engine may sharply increase, etc. In any case, there will be nothing good after an incorrect tightening of the cylinder head.

To tighten the cylinder head bolts with sufficient force, be sure to use a special tool, in this case it is a torque wrench. It has a special scale that will allow you to determine the force with which you need to tighten the cylinder head bolts. Each motor has its own tightening parameters, you will learn them from the repair manual for the motor of this machine.

Next, we will try to explain in detail and demonstrate in the photo the key points of how to correctly and reliably tighten the cylinder head bolts in order to ensure reliable and correct operation of the car engine for a long time.

Tightening instructions for cylinder head bolts

As mentioned above, we only use a torque wrench to tighten the cylinder head. It is impossible to tighten the cylinder head with the required force with open-end wrenches or box wrenches, even if you use additional tools, a crowbar or a pipe.

The dynamometer located near the handle shows how much force was applied when tightening, and this requirement must be met accurately. A slight deviation from the requirements is allowed, of the order of 0.5 kg / m.

After taking the torque wrench, remember the second requirement - the order of tightening the bolts (nuts) of the cylinder head. The order is a certain scheme that must be strictly followed.

The central nuts (bolts) are tightened first, and then gradually move to the edge of the cylinder head.

There are several schemes for tightening the head, and they are all correct. The main thing is to observe the "iron" rule: tighten the bolts (nuts) in pairs from the center to the edges. And do not try to tighten completely at once, as this can distort the head. Tighten in three stages: first tighten the bolts (nuts) slightly, then tighten strongly, and then finally tighten strongly. For the first tightening, set the wrench dynamometer to the 3 kg / m position, then more. Intermediate puffs should be "sounded" by the characteristic crackling sound. This sound means the nut (bolt) has been tightened correctly. Experienced locksmiths recommend tightening bolts (nuts diagonally).

After that, tighten the cylinder head completely and the motor can be operated. The torque wrench is set to the maximum position required by the repair manual for this vehicle.

Important! After clicks, during the final tightening, pull the bolts (nuts) no further! This will break the threads.

After tightening the cylinder head, let it "settle". In order not to waste time, you can fasten the collector and other equipment removed during disassembly for now, tighten the chain, etc. After waiting 30-40 minutes, make a test puff.

The fact is that the gasket, which is placed between the cylinder head and the engine block itself, has the property of "shrinking", that is, filling irregularities and grooves that are on the surfaces of the cylinder head and the block, although they are not visible to the naked eye. If the control tightening is ignored, then in the near future the gasket will "push through", and the engine repair will have to be repeated.

The tightening torque of the VAZ 2112 cylinder head (16 valves) is very important, since deformation occurs with an uneven installation of the head. This leads to the fact that after disassembly, it will be necessary to grind at least 2 mm from the surface of the block head. If you observe all the tightening torques, then you will not have to sharpen the head, and if you need to do this, then no more than a quarter of a millimeter.

Head design

In order for the hydraulic pushers to work in normal mode, oil is supplied to them from the lubrication system. It is supplied through special channels in the engine block and cylinder head. Oil flows through these channels and to lubricate the journals on the camshafts. There is a valve in the channel, with which the oil is not drained from the top after the engine is turned off. This allows you to keep the system operating normally until it stops completely.

Camshafts

When repairing the head, it is imperative to check the condition of the camshafts. When assembling, follow the instructions and maintain the tightening torque of the VAZ-2112 cylinder head (16 valves). Such a motor is installed on the "Priora" - it is quite powerful, has excellent characteristics and does not require frequent maintenance. Two camshafts drive intake and exhaust valves.

The camshafts rotate in special sockets, which are located in the head itself. The difference between the camshafts is that there is a small belt on the intake. It is located near the very first support. To prevent axial movement, there are thrust collars - they are located on both sides of the support in front. There are self-tightening seals on both camshafts in front.

How to repair

1. Device for compressing valve springs. You can use both "store" and homemade. The main thing is that it is convenient to work.
2. Device for pressing out valve stem seals.
3. Tube-shaped mandrel for installing the caps.
4. Keys for "10", hexagons, tweezers and screwdrivers.

Perform the following manipulations:

1. Carry out all the steps to remove the head and camshafts.
2. Remove all valves using a special device.
3. Remove the valve stem seals.
4. Replace and lapping valves. It is necessary to change the valves if there is damage - burnouts, violation of geometry. Be sure to sign on which sockets you rub the valve - otherwise the tightness will be broken.
5. Collect all valve drive mechanisms - hydraulic pushers, springs, fix them with crackers.

All assembly steps are carried out in the reverse order, only one feature must be taken into account: adhere to the recommended tightening torque of the VAZ-2112 cylinder head (16 valves). The photo shows the tightening sequence.

How to tighten the cylinder head bolts

Be sure to tighten the tightening according to the scheme given in the article. In order to tighten the bolts, you need to follow a few simple steps:

1. Install a new head gasket, place it on the centering sleeves.
2. Install the head and screw on the bolts of its fastening.
3. Start tightening with a torque of 20 N * m. If the scale is in "kgf / m", then divide by 10.
4. In the second run, you need to turn all the bolts by 90 degrees according to the scheme.
5. For the third run, they turn another 90 degrees.

Do not use bolts with a length of 95 mm or more. In general, the procedure is quite simple, but a torque wrench is required - without it, it will not work to withstand the correct tightening torque of the VAZ-2112 cylinder head (16 valves).

The cylinder head or cylinder head is one of the most important parts of the engine. And during engine repairs, it is often necessary to replace its gasket. I believe that the correct replacement of this auto part involves the indispensable replacement of the cylinder head pins. About why you need to tighten, how to determine its moment, about the schemes for tightening the bolts of the cylinder head and about the general rules of tightening, I will tell you later in the article.

Before we get started, let's take a look at what this mechanism is. Materials for the production of cylinder head can be: alloyed cast iron or aluminum alloy. This is the cover that covers the cylinders. Performs the following functions:

1. Protective. It protects the cylinder block;
2. In the cylinder head, cavities are provided for: valve bushings, valve spring support washers, for fastening the intake and exhaust manifolds;
3. In its front part there is a hole for placing the chain tensioner and the camshaft drive;
4. Threaded spark plug holes are provided.

Tightening the cylinder head bolts must be carried out in order to prevent the formation of phlegm at the junction of the elements in question. This happens, as a rule, due to oil leakage.

How to determine the tightening torque

Alas, not all motorists are aware that today's car models do not need to tighten the cylinder head bolt. Previously, this operation was necessary for the successful passage of the first technical inspection. But these times have already sunk into oblivion and today, even on VAZ engines, tightening is not necessary. The only models that need tightening are Moskvich, UAZ and similar models.

As already mentioned, the tightening time is the appearance of phlegm at the junction of the head and cylinder block. This happens for several reasons:

1. due to a breakdown of the gasket, we need a mechanism;
2. its distortion due to engine overheating;
3. initially incorrectly tightened cylinder head screw.

Cylinder head bolt tightening diagram

Tightening the cylinder head bolts pass in two stages.

• The first stage: 1-10 is fixed with a moment of 3.5 - 4.1 kgf * m;
• The next stage involves the use of the same pins, but tightening with a torque of 10.5 - 11.5 kgf * m;
• The moment is 3.5 - 4.0 kgf * m. the last (eleventh) screw is tightened;
• Next, I will describe the schemes for securing the pins of the VAZ 2108 - 09, Samara and 16-valve VAZ engines.

In the first case, the order of work is similar to the classical one, but it takes place in four stages:

1. The screws are tightened with a torque of 2.0 kgf * m.
2. They are also fixed with a torque of 7.5 - 8.5 kgf * m.
3. Turn on 90 0.
4. They also turn to 90 0.

In the second, the course of work is carried out in three stages:

1. tightening torque - 2.0 kgf * m;
2. then turn the screws 90 0;
3. reception - once again turn the screws 90 0.

General tightening rules

The beginning of the process should take place with the study of the manual for the operation and repair of the machine.

To work, you need to familiarize yourself with:

1. the algorithm for tightening the bolts of this device;
2. the required time of force to tighten the cylinder head bolt;
3. with the recommended pins for fastening.

General tightening rules exist in the presence of various parameters and are applied to work with all types of engines:

1. As for the control of the tightening torque of the screws of the mechanism in question, here you need to use a special torque wrench.
2. A simple wrench is not used in this case.
3. It is necessary to apply a time equal to the time of the beginning of the movement of the screw to the screw being tightened.
4. It should be remembered that the thread of the pins must be carefully checked before the process.
5. Do not reapply the spring screw as this will result in oil leakage through the gasket of the element in question.
6. TTY bolts should not be used for tightening or tightening the cylinder head, as this type of bolt is used for aluminum cylinder heads. All information on TTY screws can be found in the machine manufacturer's instructions.
7. The figures for the tightening time of the gasket and the tightening time of the engine should also be taken into account, and at the same time, do not allow discrepancies in them. For details, see the specifications for the head gasket.
8. When working with the screws securing the cylinder head with a dead-end hole, it is necessary to monitor the oil filling. It must be poured carefully so as not to overflow, as this will lead to the fact that the screw does not reach the end.
9. When working with pins with a through hole, the threads must be lubricated with a plastic sealant before screwing in.
10. The head bolts must be in perfect condition. Old, cut pins or pins that have already been used once are by no means suitable.

And to all those who decided to do the tension of the cylinder head screws, I want to give a couple of tips.

1. stretching in an engine with a cast iron cylinder head only needs to be done on a hot engine;
2. but in the cold state, the broaching is carried out in the engine, in which the aluminum head of this device is used.

So I introduced you to the rules and techniques for tightening the pins of this mechanism. Hope this information was helpful for you and your vehicle! And may the tightening of the cylinder head screws be successful with a minimum of effort!

Automotive Bolt Tightening Video

By watching the post, you will learn how you can tighten the cylinder head bolts.

A number of repairs to the power unit of the car are associated with the removal of the block head. Dismantling the cylinder head does not cause any particular difficulties, but planting the unit in place when assembling the motor requires full compliance with the installation technology, in particular, tightening the fasteners.

Consequences of improper installation of the cylinder head

Correct tightening of the block head is very important, since the performance of the motor directly depends on it. The cylinder head acts as a cylinder cover, and any violations in its fit affect the processes taking place inside the power unit.

Insufficient tightening of the head leads to a fall due to loss of tightness at the junction of the cylinder head with the cylinder block, burnout of the gasket, breakthrough of working gases from the cylinders and their ingress into the channels of lubrication or cooling systems, penetration of technical fluids into the combustion chambers, which in turn negatively affects on the functioning of the power unit and can cause very serious damage.

Excessive tightening also does not bring anything good, in this case, damage to the head often occurs - cracks appear, or fasteners collapse - bolt rupture, thread failure, etc.

Uneven or improper tightening often causes warping of the head, due to which gaps appear at its junction with the block, which leads to the same consequences as insufficient tightening.

Part features

The cylinder head is a structurally rather complex part. It is a massive plate in which channels are made for the circulation of liquids of the lubrication and cooling system, and technological holes - candlesticks, for injectors (in diesel engines), fastening.

Also on top of the cylinder head there is a so-called "bed" of the camshaft - a seat for its installation.

Despite its massiveness, the block head is a fragile part due to voids inside, so excessive tightening force often leads to cracks in the walls and bridges.

For the manufacture of cylinder head, two types of metals are used - aluminum (the most common) and cast iron.

To secure the latter, steel bolts or studs with nuts are used. For example, the head of the UAZ 31519 block is attached with pins.

The difference in the materials of manufacture of the head and its fasteners has one negative factor - the different thermal expansion of the components during heating, especially with regard to the aluminum cylinder head.

Uneven tightening of fasteners (nuts, pins, etc.) during thermal expansion leads to the appearance of excessive stresses in the metal structure, as a result of which the head warps.

Bolt Tightening Conditions

When installing the block head, it is important to adhere to the tightening technology, which includes a number of criteria:

• Tightening order;
• An effort;
• Condition of fasteners (for example, studs with nuts);

Each motor has its own tightening order, which must be followed to ensure that the head is evenly attracted to the block and to eliminate the occurrence of stresses on any parts of the surface. For example, on a VAZ 2105 it looks like this.

Effort is another important factor for the correct attachment of this engine element. The plate is pulled in several approaches (on different motors their number is different), each of which is performed with its own effort.

The block head fasteners are tightened with a sufficiently large force, which leads to their pulling. Therefore, on many motors, bolts are not allowed to be reused, they must be replaced. But there are also motors in which replacement of fasteners is not needed and their re-installation is possible.

All information regarding the cylinder head tightening technology is indicated in those. documentation for the car, it is also often indicated on the packaging of the head gasket and fasteners.

General rules for performing work, methods used

There are a number of general rules that must be followed when installing the block head:

Despite the fact that each engine has its own characteristics of tightening the block head, the general technology of this operation is the same. In general, two methods are used to tighten fasteners:

• In several approaches, bringing the tightening force to the required value;
• Tightening the fasteners to a certain force (in one or more approaches), and then twisting the bolts at a certain angle.

The tightening method is selected based on the type of bolt.

The first method is used when using non-stretching bolts (these are not used now, but they can be found on old cars). But often this type of fastener requires tightening after a certain period of engine operation in order to compensate for the shrinkage of the cylinder head gasket. But such fasteners are allowed for reuse, and more than once.

The second method of tightening the block is relevant for most modern cars. And all because of the use of tension bolts (the so-called TTY type).

Due to elastic deformation, such fasteners are able to compensate for thermal expansion of the head and shrinkage of the gasket, but for this they must be brought into deformation mode (in fact, just stretch a little).

For this, it is necessary to turn the bolts twice at a certain angle. On some cars this angle is 45 degrees, on others - 90 degrees.

But after the elements are brought into the elastic deformation mode, they will no longer be able to return to their original state, therefore, their reuse is not allowed due to the high probability of destruction.

General order of work

Although the tightening of the block head has many nuances and features, the general technology of the operation is not complicated, it is only important to comply with the conditions.

The general work algorithm is as follows:

On some cars, it is additionally required to re-tighten the fasteners after a certain period of operation of the car. This information must be indicated in the technical documentation.

Some nuances

Tightening torque is one of the main factors for the proper seating of the block head. But this criterion is influenced not only by the applied force, but also by the fasteners themselves:

• The general condition of the bolts - new or used;
• The presence of grease on the threaded part;
• Thread condition.

The type of power plant (gasoline, diesel), as well as the number of valves, does not affect the cylinder head tightening technology. But this does not mean that the force and tightening order for all motors is identical and before planting the head, it is imperative to study the conditions for performing the operation and all its features.

Common mistakes

Despite the fact that automakers clearly indicate the order and nuances of tightening the cylinder head, many motorists make mistakes when assembling the motor. The most common ones are:

To avoid further problems, you should use only fasteners designed for a specific engine and fully comply with the working conditions.

Features of the performance of work on the example of some cars

As proof of the judgment that each power plant has its own characteristics of cylinder head tightening, we will consider the nuances of performing work on specific models.

VAZ-2112 16 valves

A number of modifications of the VAZ-2112 were completed with two types of 16-valve power plants (factory indices - 21120 and 21124). These two motors, despite some design features, have the same head tightening technology.

These units use 93 mm tension bolts. In this case, the reuse of fasteners is allowed, but on one condition - if their length does not exceed 95 mm (if it is more, they should be replaced). 10 bolts are used to secure the head.

Tightening is carried out in three approaches:

1. Bolts are tightened according to the order with a force of 2 kg / m;
2. Turning over 90 degrees;
3. Repeated extension by 90 degrees.

The drive pattern is shown below.

Between the 2nd and 3rd sets, you need to take a 20-minute break.

Since tensile bolts are used on these engines, additional suspension is not required during operation of the car.

VAZ-2107

On the VAZ-2107, all installed modifications of power units are 8-valve.

The head of the block is attached to them with 11 bolts, 10 of which are the main ones, and 1 - the auxiliary side bolts (installed in the side ledge).

On this car, tightening the fasteners is also performed in three approaches:

1. 10 main bolts are tightened according to the order with a force of 3.5-4.0 kg / m;
2. The same bolts reach with a torque of 11.5-12.0 kg / m;
3. The auxiliary one is tightened with a force of 3.5-4.0 kg / m.

Additional tightening of the cylinder head during operation of the VAZ-2107 is not required.

"Samara", 10th family, Priora

On models of the Samara family (2108-21099), as well as VAZ 2110-2112 with 8-valve units, tightening is already performed in 4 approaches:

1. Tightening with a force of 2.0 kg / m;
2. Reaching with a moment of 7.5-8.5 kg / m;
3. Turn around 90 degrees;
4. Re-turning 90 degrees.

The break between points 3.4 is 20 minutes.

As for the VAZ "tenth" family, which are equipped with 16-valve motors, their tightening technology is the same as that of the VAZ-2112 (described above).

The same applies to Lada Priora, on 8-valve units a method with 4 approaches (VAZ 2108-21099) is used, and on 16-valve units - 3 approaches (VAZ 2112 with a 16-valve motor).

Volga

On the ZMZ-406 engines installed on the Volga, according to the technical documentation of the automaker, the bolts of the engine block head are tightened in two approaches:

Subsequent tightening of the bolts during operation on this engine is not required.

Operation without a torque wrench

Since the force is precisely indicated on all these vehicles, it is impossible to do without a torque wrench when landing the cylinder head. But on some cars it is quite possible to do without it and use ordinary wrenches and an extension nozzle for tightening.

Immediately, we note that the performance of work without special. the tool is allowed only on "old" engines ("Moskvich", VAZ of the first models).

The peculiarity of tightening the block head without a torque wrench is the need to "feel" the applied force. For the rest, the general method of work is the same as with the use of specials. tool:

One of the options for tightening without a torque wrench is to double-tighten the fasteners after completing the 2nd approach.

The cylinder head (or cylinder head for short) is one of the most important components of the entire engine system of your car. The tightening process itself is quite simple, as is flushing the engine cooling system. To do the job well, you only need a special set of tools and the cylinder head bolts themselves.

When is cylinder head tightening necessary?

The need to periodically tighten the cylinder head is characteristic only of car brands that were produced until 2010 inclusive. All other models of modern cars have a completely different engine structure, as a result of which this stage of work is not carried out. However, for those who own the same VAZ-2106 or 2107, this problem is primarily relevant during the annual maintenance of the car.

• Pay particular attention to the selection of the correct tool, in particular the torque wrench. The more accurately you select it according to the size of the head, the less likely it is to knock off the thread. The most accurate torque values ​​are obtained using wrenches equipped with a dial force indicator.

To successfully tighten the cylinder head with your own hands, adhere to the following recommendations:

• Use the vehicle manufacturer's instructions. It specifies the exact values ​​of force and torque, and also sets the specific procedure for installing the cylinder head when repairing the engine.
• Check the original condition of the bolts. If you notice a breakage or distortion of the thread, then buy new samples.
• The surface of the hole and the threads of the bolt must be absolutely clean. The cylinders can be quickly cleaned with a wire brush, which is used when painting stamped discs.
• If you find "blind" holes for the cylinder head bolts, carefully use oil for lubrication. If there is more lubricant than necessary, you will not be able to install the bolt completely.

Advice: after tightening, be sure to lubricate the threads with plastic sealant.

• If TTY bolts are used in the cylinder head block, it is strictly forbidden to retighten them. With maximum force, they can simply rupture and lead to destruction of the gasket.
• When installing a new gasket under the bolt, it is imperative to clarify the information on the amount of force and torque when tightening.
• When tightening bolts of a special type TTY, it will be necessary to set and tighten them to a clear degree. To do this, you need an appropriate tool with an angle indicator in the body.

What is cylinder head bolt pulling used for?

If all the bolts of the cylinder block are in order and do not require replacement, but the torque is much lower than the values ​​specified by the manufacturer, it is necessary to pull the bolts. To do this, you need the following tool:

• Special torque wrench with torque indicator;
• A caliper or any small ruler.

Pulling the cylinder block bolts takes place in 4 main stages:

1. First, using a torque wrench, tighten the bolts in the order shown in the figure below to a force of 2.0 kg / cm.

1. Further, in the same order, you need to go through the second circle and hold out the value of the moment to 8 kgf / m.
2. At the end of the work, it will be necessary to turn the bolts to 90 degrees in the 3rd circle.

Important: If you have a 16-valve power unit in your car, then any type of bolts on it can be reused. The only limitation is bolts that do not exceed the standard size of 95 mm.

Replacing the cylinder head bolts and tightening them is a simple process that only requires the use of special tools and skill. If you are performing this type of work for the first time, then be sure to monitor the accuracy of the torque and setting the correct tightening angle.

Video: tightening the cylinder head