Lapping valves with a screwdriver with your own hands

Why lapping is necessary

Manual lapping process for valves

When buying a car, most people look at the compression ratio in the cylinders. This parameter depends on a large number of factors, including the condition of the pistons, rings, and valves. The latter can simply poorly close the holes due to wear on the working surface or burnout. And a leaky combustion chamber is the reason for the low pressure in the cylinder. An external sign. performance deteriorates, acceleration becomes slow, the car simply “does not pull”, and under heavy load, even a small slope becomes an almost insurmountable obstacle.

And if you have carried out an overhaul of the engine, and the compression in the cylinders is far from ideal, then the first thing to do is look at the valves, how well they close the inlet and outlet openings. On some car models, a system is installed that performs grinding in the process. Everything is quite simple. the valve rotates around its axis, the excess metal is grinded away and, as a result, a perfectly flat surface is formed. When in contact with the block, no gaps are observed, the holes are closed as tightly as possible. But in most cars there are no such systems, so you have to do everything manually. There are only three ways, and we will consider them in detail.

How to grind the valve yourself

When repairing the engine, in particular, the cylinder head, it is necessary to do everything in such a way that there are no gaps between the parts. Therefore, it is important to know how to properly grind the valves on the car. The work is very time consuming, monotonous, even boring. But the further operation of the engine depends on how correctly it is carried out. And if you have ever dealt with this business, then you know what grinding methods exist, the time and labor costs for them, and most importantly. how well they allow you to carry out the work. But if you first heard about such a procedure, then you need to familiarize yourself with it in more detail.

Lapping with a hand drill

During lapping periodically you need to apply a new layer of paste.

This method will be much easier, and the quality will not suffer much. And an ordinary hand drill with a reverse will help you in carrying out the work (this condition is mandatory). You will also need to make a special tool. a simple drill bit, which is similar in shape to a flat screwdriver. And stock up on spots with a small gap under the nozzle tip in the center. When the whole tool is ready, you can start lapping.

Install the cylinder head upside down so that the slots are clearly visible from above. Lubricate the working surface of the valve to be machined with an abrasive paste. Now, using bitumen, glue the patch on the valve plate. Wait a little for the bitumen to dry and set. Now take a drill with a nozzle, install it in the patch and start rotating the valve. Add paste as needed. Try to do so that the rotation occurs in both directions at approximately equal intervals. To peel off the patch after lapping, just heat it up.

Manual lapping of valves

Such a device is used for manual lapping of valves.

The process can be broken down into several stages:

• The valve is being installed in a regular seat.
• The valve disc must be lubricated with a paste.
• Place the device on the rod axis.

Next, the valve lapping tool will help you rotate the valve in different directions using the handle. From time to time it is necessary to apply a layer of paste. And most importantly, try to press the working surface of the valve against the seat as much as possible in order to carry out the lapping as efficiently as possible.

Lapping with an electric drill

The fastest way is lapping with an electric drill.

But lapping with an electric drill will be much easier. After all, you will not waste energy on rotating the handle. The method is very similar to the one described earlier. But you need to make a simple device from a rubber hose and an old valve. The hose will act as a coupling, and you will clamp the stem of the old valve in the drill chuck. It is highly desirable that the inner diameter of the tube be equal to the diameter of the rod, so that the latter fits into it as tightly as possible. To get rid of twisting, you need to tighten all the joints between the tube and the rods using clamps.

It is imperative to have a reverse so that you can alternately rotate the valve in different directions, as well as adjust the speed. In this way, lapping the valves with your own hands will take a little time, and it will be carried out with high quality. But remember that each valve is rubbed under one socket; you cannot put it in another place. Lapping paste should also be used by number. First, which is intended for the initial, roughing, and only then the paste number 2, which is required for finishing the surface. When the width of the plane of contact of the valve disc with the seat is approximately 2 millimeters, it can be considered that the lapping was successful. And the most important thing in the work. do not let the paste get on the core. After work, be sure to rinse all surfaces with solvent or kerosene to remove traces of the paste.

With a hand tool

This method is something like the process of making fire by primitive people. suckers are attached to a wooden stick, they fix the rod, and the stick itself rotates by hand. This so-called “old-fashioned” method was in use when there was no power tool. Its plus is the minimal risk of damaging the valve system. But it takes a lot of time. up to half an hour for each valve.

Why do you need to grind the valves

New valves are lapped for a better fit to the seat. During operation, carbon deposits form on the valve system, as a result of which the tightness of the adhesion of the valve disc to the seat is broken.

This leads to a malfunction of the fuel system. When the exhaust manifold loses its original characteristics, it provokes burnout of the valve system, a drop in engine power, wear of the guide sleeve, damage to the seat and other troubles. In order to establish a clear operation of the cylinder head and reduce the risk of carbon deposits, after cleaning the valves, they are lapped in. as a result, the valves and seats fit well one to one.

Standard Lapping Tool Set

The most important tool is abrasive or diamond paste. It must be applied to the edge of the valve. the paste will create a sandpaper effect and allow the plate to grind to the saddle faster.

By the type of processing, the pasty composition differs in the size of the abrasive elements. from coarse-grained to fine-grained. Coarse abrasive is used for initial lapping. Finish lapping is carried out using a fine-grained paste. then the component head will be tightly installed in the seat.

Pastes also vary in price. from inexpensive for personal use to branded formulations for professional lapping. You can carry out self-processing with a composition of average cost. It is important to monitor the condition of the valves themselves and the correctness of the lapping process.

The next step is to choose a tool for the job. Lapping can be done by:

• Electric drills.
• Wooden fixture with suction cups.
• Pneumatic tool.
• Special pneumatic machine for tapping.

An electric drill for grinding is most popular among amateur craftsmen. due to its availability and versatility. In repair shops, a special chamfer grinding machine can be used.

Saddle machining and refurbishment requires the use of special tools. This is a cutter for removing a working out. a device made in the shape of the valve seat. The cutter is put on the drill, since the drill is usually medium-sized.

The tool is used if the valve heads are damaged due to burnout.

You will also need a desiccant to remove the “crackers”. the parts that connect the spring plates to the valve.

Using a pneumatic machine (tapping method)

The difference between the pneumatic machine and the previous tool is the grinding technology. The tool does not work with rotary movements, but simulates the operation of valves in real conditions.

The tool is easy to use and makes lapping the most accurate and high quality.

Important! After lapping, the abrasive compound must be carefully removed. If it gets into the engine, it will damage the cylinders and other parts.

How to properly grind valves: basic methods

There are four main processing methods.

When is it time to think about lapping

To understand whether lapping is necessary, you can use different test methods. they can be used to clarify the degree of depressurization of the valve system.

How to check lapping:

• The cylinder head is being dismantled.
• The head is cleaned of soot, oily film and dirt.
• The head of the BC and bearings are being checked. They must be free of any deformation and mechanical damage.
• The camshaft bearings are checked. They should also be free from damage, burrs and metal sagging.
• To control the tightness of the valve system, it is necessary to install the cylinder head on a flat surface, pour a little kerosene or gasoline into the combustion chambers and leave it for a while. If the level of kerosene starts to decrease, it means that there is a leak and the tightness of the valve system is broken.

When a leak appears (that is, depressurization), the motor does not work evenly, so it is necessary to lapping.

Using a pneumatic tool (rotary method)

Lapping the valves with your own hands when using a pneumatic tool is quick, simple and with minimal effort. The device is a motor connected to a pin. A special suction cup is attached to the latter, which fixes the valve. The system is brought into working condition using compressed air.

The advantage of this method is that there is practically no risk of making a mistake, even if you are inexperienced. The tool controls the entire process. the angle of rotation, speed and speed. And all this happens even faster than when using an electric drill. one valve takes only a couple of minutes.

Lapping valves with a drill

A piece of hose is required to carry out the work. One of its “tail” is fixed on the valve stem, and the other. on the drill. A small amount of lapping compound should be applied to the valve itself and the seat, after which the part is installed on its workplace in the cylinder head.

The process has several features:

• Lapping is carried out at low speeds. it is recommended to use drills capable of working at such speeds, or screwdrivers.
• At the moment of contact between the plate and the saddle, it is necessary to reset. release the trigger of the electric drill.
• During the grinding process, no effort should be applied. this can provoke damage to the elements of the valve system.
• It is recommended that lapping be carried out in several stages. first with a coarse-grained paste, then with a medium, and at the end with a finishing treatment with a fine-grained composition.

Practice is important. if this kind of work is performed by an amateur, there is a risk that his unskilled actions will lead to the fact that the car will need expensive repairs.

Do-it-yourself lapping of valves. How to grind valves with your own hands without a tool?

When repairing an engine, valve grinding is often required. This is a demanding job, for which you need to have the right tool at hand. Of course, you can do without it. So, how do you grind valves yourself??

Are cutters always needed

Classification of pastes

Valve lapping paste is classified according to the degree of surface treatment: for initial treatment. coarse, for final. fine-grained. The latter option is very popular, since such products are recommended by masters who repair engines. Fine-grained paste allows quick and correct grinding of valves. At the same time, much depends not on the composition of the product, but on the condition of the chamfers and the details themselves. In addition, not everyone can grind valves with their own hands. For self-processing, it is recommended to use the usual composition, per tube.

Don’t buy the most expensive pasta. If there is a need for it, then you can purchase it in the process.

Features of lapping in both cases

If the shape of the chamfer is not broken, the usual lapping is carried out. If there are defects, the part is first processed using a lathe, and the valve seats are cleaned with conical cutters. In this case, the dimensions of the devices are of particular importance.

To begin with, the valve seats are machined with a roller cutter having an angle of 45 °, then the upper chord is cut off with a roller cutter with an angle of 15 °, and the lower part of the saddle is chamfered with an angle of 75 °. It is also allowed to process parts with abrasive wheels and a hand drill. In this case, the tools must have angles of 45 °, 15 ° and 75 °.

It is worth considering that lapping the valves with a hand drill or screwdriver takes a lot of time. To speed up the process, you can use an electric tool that can be turned in both directions, as well as gradually rotate around the circle.

“Grandfather’s” cutters

Lapping valves with your own hands is a simple process if you know how and what to do. Previously, there were cutters for cylinder head repair. This valve lapping tool was mainly used to re-seat parts. Some masters still use such a tool. Externally, the device is a socket attachment made in the form of a valve seat. The cutter is fixed in the drill. The device is small in size and resembles a kind of drill.

Lapping paste

Or maybe put in new valves?

When replacing parts, you should pay special attention to their quality. The height of the valves must be the same in any case. The presence of roughness and notches on the ends, rods and sealing working chamfers is not allowed. It is recommended to polish the parts to a high shine before installing a new kit. This process should be carried out not only on the valve stems, but also on the black valve neck and on the flat plate. Thanks to this processing, the parts will be less overgrown with carbon deposits and heat up. It is not recommended to touch the sealing chamfers during processing. They should only be rubbed onto the saddles.

Do-it-yourself lapping valves

Do-it-yourself valve lapping is our topic today. One of the stages of engine overhaul consists of a complex of work with the cylinder head. Some work can be done independently, which will save extra money and make the work better. One of the varieties of these works is valve lapping. The following is a self-lapping sequence for valves.

Manual lapping of valves

Technologically, this is a simple process, so almost everyone can grind the valves. First, paste is applied to the valve working surface or plate. After that, the valve must be placed inside the lapping device, installed in its original place and pressed against the cylinder head. Then you need to rotate it to the sides, periodically opening the valve.
After completing the initial lapping, you should remove the valve from the device, study the result of the work and do the same with paste
You need to be patient, since this process is quite long and tedious, because the engine has 16 valves and it will take a lot of time to grind them.

Why do you need to grind the valves

As you know, a certain working pressure is created in the cylinders of the engine, which pushes the piston down. If the pressure is not strong enough, the engine power drops. This phenomenon occurs on machines that have recently undergone a major overhaul and the reason lies in poor quality lapping of the valves. This is why pressure loss occurs.

Therefore, it is recommended to independently carry out the lapping in order to obtain the highest quality result and prevent re-disassembly of the engine.

Do-it-yourself lapping valves

What is needed in order to grind the valves

If you decide to self-lapping the valves, you should prepare the necessary tools and tools. To work, you need to prepare a special paste for grinding the valves, which on the package has index 1 and 2, which shows the granularity of the granules that it contains. You will need both of these. You will also need
valve lapping tool, with which this procedure will be performed.

Before lapping, you should evaluate the condition of the valves. If the valve is bent, you do not need to restore it yourself, since without the use of high-precision instruments, it will not be possible to achieve perfectly accurate geometry. Easier to get a new valve.

Lapping valves with a drill

To speed up the grinding process, you can use an electric drill. The principle of operation is similar, it just goes much faster. You should definitely check the presence of a reverse mode on the drill and the possibility of adjusting the rotation speed.
When using a drill for lapping, a valve adapter must be purchased. As in other cases, rotation occurs in both directions, using pastes No. 1 and.

It is necessary to avoid getting the paste on the valve stem, because then kerosene will be required to remove it. The seats for the valve poppets must be the same size, therefore regular checking of their sizes is required.

Lapping valves with your own hands is no longer a problem.

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Do-it-yourself lapping valves

An operation such as lapping the valves is included in the list of engine overhaul works. It is aimed at ensuring as tight fit of the valve disc to the seat as possible, thereby minimizing the possibility of fuel passing into the cylinders or the breakthrough of exhaust gases.

After long-term operation of the car, carbon deposits settle on the surfaces of the chamfer of the valve and seat, micro-shells appear, scuffs.

As a result, the contact patch between the surfaces decreases, the valve does not fit tightly to the seat, because of which it starts to leak and the compression of the engine decreases.

To remove carbon deposits, cavities, scuffs, and valve lapping is used, as a result of which the contact patch between the valve and the seat is restored.

In addition to performing this operation as part of a major overhaul, the grinding of valves is carried out in a number of cases.

So, these works are carried out:

• When a valve or saddle burns;
• When the valve disc burns out;
• When replacing them in case of damage, in general, always when there are problems with these elements.

Valve Lapping Process

First, remove the head from the engine. Next, the camshaft, adjusting washers or hydraulic lifters are removed from the head.

The next step is to dry out the valves. For this, either a device is used, or they are knocked out by a spacer.

After that, the mounting plates and springs are removed. The valve itself is removed from the head to assess its condition and the condition of the seat.

If it has no traces of burning and its rod is not bent, then it is not necessary to change it, it will be suitable for further use.

The saddle should also be inspected for signs of burning. If there are traces of burning of the seat, its surface is first processed with a cutter.

After making sure that there is no burning on the surfaces, the grinding process begins.

To do this, a little paste is applied to the valve chamfer for initial processing.

Then it is put in place, and a grinding device is put on its rod. If it is homemade, then the rubber tube on the rod must be clamped with a clamp.

Then the device pushes the valve against the seat and lapping begins.

To do this, the valve is turned by 180 degrees by the knob, and then it is turned in the opposite direction. With such movements, lapping is performed.

It takes about 5-7 minutes to process the surface with one type of paste. time.

The position of the valve changes periodically. That is, it needs to be rotated about 90 degrees. from the extreme position when lapping, after which the process continues again with turning it by 180 degrees. and return back.

It is not advisable to mechanize the process by using a drill with an attachment on the valve stem.

Drills usually have high speeds, so when lapping with it, there is a possibility of overheating of the seat and valve chamfer.

In this case, a screwdriver is better suited. But the circular movement, which will be provided by a drill or screwdriver, is not recommended when lapping, this operation is best done by half-turning the valve, followed by turning in the opposite direction, that is, manual lapping.

After lapping with rough paste, the surfaces are thoroughly cleaned with a rag to remove residual paste.

Then a finishing paste is applied to the valve chamfer and the lapping process is repeated.

A successful lapping result will be a uniform gray matte color of the lapped surfaces without any traces of pits or scratches.

So, one by one, all the valves, both inlet and outlet, are rubbed in. There is no particular difference in which engine of the car this operation is performed on.

The valve grinding process is the same for both the VAZ-2106 and the VAZ-2109 and later models.

The difference in the complexity of the work of these cars can only be the process of removing the cylinder head, preparing for lapping, and of the convenience of access with a device to the valves due to slightly different shapes of the cylinder head.

Required valve lapping tool

Lapping the valves is not particularly difficult, but it takes a long time to complete them, especially if you do it yourself.

It is impossible to perform them on a car, you will have to partially disassemble the power plant, namely, remove the cylinder head.

Therefore, when deciding to grind the valves, you should immediately take care of the presence of a new cylinder head gasket.

Of the tools to perform this operation you will need:

• A set of keys and heads;
• Valve dehydration device;
• Lapping device;
• Lapping pastes;
• Rags;
• Kerosene.

Work attachments, lapping paste

Let’s go through the valve attachments.

There are special devices for pulling out the crackers that hold the valve head in the landing plate.

There are many of them, we will not describe all of them. We only note that they all act according to the same principle.

With this device, the valve springs are compressed, the valve mounting plate is lowered down, releasing the crackers, and they are removed.

But you can do it with a simple method. A piece of tube is required, slightly smaller in diameter than the mounting plate.

This tube is placed on a plate and is hit hard with a hammer. Due to the impact, the springs are compressed, the plate sags and the crackers pop out.

In this case, it is better to close the hole on the side on which the blow will be struck, so that crackers do not fly out through it.

Now about the lapping device.

It can be purchased, usually such a device consists of a nut clamp, a rod and a wrench.

But you can do it yourself. To do this, you need a rod with a diameter equal to that of the valve. A knob is welded to it so that a T-shaped structure is obtained.

On the other side of the side knob, a piece of rubber tube is put on the rod.

metal rod with a diameter of 5. 8 mm, depending on the diameter of the valve stem, 2. rubber tube, 3. clamping clamps.

The inner diameter of the tube must be chosen so that it fits snugly on the rod.

You will also need another clamp, it will clamp the edge of the rubber tube, which will be put on the valve stem.

For lapping valves with your own hands, some devices are not enough, since this operation is performed using special pastes.

It is not difficult to find them, you can purchase both cheap lapping pastes and very expensive ones.

For lapping, it is better to purchase kits consisting of two pastes or just two pastes. for primary roughing and for secondary finishing.

It may also be necessary to use a cone cutter. It is a cone head for a drill with metal cutters inserted into it.

Use it to treat damaged saddle surfaces.

Checking the quality of lapping

After lapping all the valves, it is recommended to check the tightness of their fit to the seats.

To do this, first you need to reinstall all the valves in place, install the springs with mounting plates and dry them out.

Here, one cannot do without a device for drying.

Next, the head is installed on a flat surface with the valve plates up.

Kerosene is poured into the combustion chambers, since it has a high fluidity. Its level is measured and the cylinder head is left for a day.

If, over time, the kerosene level has not decreased or decreased very slightly, the lapping is done well and the engine can be assembled.

If a kerosene leak is noticed, the valve grinding operation is performed again, but only those on which a leak is noted.

As usual, to consolidate our material, we suggest you watch a video about the current, how to grind the valves with your own hands using improvised means.

Tools.

For lapping, you will need to prepare a metal rod.

On this rod, you need to put on a rubber hose with a diameter equal to the diameter of the valve. This will be your main and only tool.

True, if you want to speed up the repair process, then you can replace it with a drill.

Do-it-yourself lapping valves.

At the time of overhaul of the engine of any vehicle, it is imperative to wipe the valves. The latter is necessary in order to provide the valve mechanism with tightness and improve the compression ratio. At first glance, it may seem to you that this is not an easy job, but this is not so, because lapping the valves with your own hands will not require you to use any special technical equipment and the qualifications of the repairman, so everyone can cope with it.

Lapping valves with your own hands: procedure.

We disassemble the power unit.

• First of all, we remove the attachments, which serve as a hindrance when working with the cylinder head. Then we attach the piston of the first cylinder to the top dead center, drain the coolant. Then we dismantle the exhaust and intake manifolds. Having gained access to the head, we immediately dismantle the air filter, and then the valve cover, just do not forget to pre-fix the camshaft pulley. To do this, you can take a screwdriver and rest it against a special pin. Next, we remove the timing belt from the pulley, that is, we unscrew the bolt and washer of the pulley and remove the latter from the camshaft. Now we unscrew the mounting bolts and remove the cylinder head. But this must be done in such a way that one of the ends of the camshaft must go beyond the boundaries of the timing belt cover.

We carry out dismantling of valves.

We wash the valves and their seats with gasoline.

We apply lapping (aka diamond) paste to the washed seats and install the valve in its place. We do it as follows.

We put a prepared metal tool on the valve (if lapping is done using a drill, then the valve is placed in its cartridge) and, very carefully turning it in all directions, we press it to the saddle.

At the same time, it is very important during this work to monitor the color of the valve edge and its seat. By the end of lapping, it should turn evenly gray.

Before completing the work, the valve should be flushed again with gasoline, completely removing the remaining lapping paste. Otherwise, the tightness of the valve will fail very quickly.

By the way, checking the tightness of the valve is the last step in the work of lapping the valves with your own hands. For this test, pour kerosene into the combustion chamber. If, for three minutes, no liquid oozes from the latter, then the valve is tight. Well, if the kerosene still shows through, therefore, lapping must be continued.

Why grind valves

During operation, carbon deposits form on the valve discs and also on the seats. It prevents the inlet and outlet valve from closing tightly. This is very important for normal engine operation. After all, after the fuel-air mixture has been drawn into the combustion chamber at the intake stroke, the piston compresses it, rising to its top dead center. The inlet and outlet valves must be closed. The stronger the compression ratio, the more efficient and economical the engine will run. Of course, with a loose fit of the intake valve in the seat, the maximum compression and effective combustion of the mixture will no longer be with all the ensuing consequences.

However, in order to rectify the situation, there are no particular difficulties. time and effort has to be spent on removing the cylinder head and the valves themselves. In addition, there is a high probability that there is no need to grind each of them.

Do-it-yourself lapping valves

Almost every owner of an old car of domestic or foreign production prefers to repair it on their own. Including sorting out the engine. In this regard, quite often it is necessary to grind valves in a home-garage environment. And many ask a natural question about what this procedure is required for and how to properly grind the valves.

What lapping paste to use

In addition to the aforementioned paste, there is ABRO Grinding Paste GP-201 on sale. In this case, in one package there will be two options at once: coarse-grained and fine-grained. Much cheaper than FABO. In addition, this paste is also suitable for removing rust from any metal surface, as well as for dressing cutting tools. In short, such a paste is multifunctional. Medium and fine paste in one package can be obtained by purchasing Done Deal. The basis here is silicon carbide powder. Also a universal remedy, useful on the farm. And if there is a likelihood and need to work with chrome surfaces, then you should pay attention to the PERMATEX paste. In any case, before buying, it is recommended to carefully study the instructions and only then make a choice.

Now let’s answer the question of what to do when there is no pasta. Sometimes there are situations when you need to grind the valves if there is no paste. Well, in this case, you will have to remember the old-fashioned ways, as already mentioned above, or diversify them a little. So, if there is no dust from the diamond wheel, then you need the finest sandpaper. You need to remove the abrasive from it and mix it with engine oil or grease. GOI paste mixed with the same lubricants is used as a finishing paste. Of course, the quality of processing by such means will be much lower. Especially when there is no relevant experience.

How to determine if the valve needs to be lapped

Typically, the valves are lapped after an engine overhaul. Or, for example, after replacing the piston rings. In order not to disassemble the second time. The necessity of the procedure is checked on the removed cylinder head. It is installed on a flat surface with the valve plates facing up. Then kerosene is poured into the combustion chambers, and if it is not there, then gasoline will come off. The level is noticed, after which the cylinder head is left in this position for twelve hours.

If the liquid has not left during this time, then everything is in order. If it leaves, then it means that there is work to be done. To determine which of the two valves in the cylinder is leaking, the presence of dampness in the exhaust or in the intake manifold helps a lot. You can check in another way. The principle will be the same, but the difference is that liquid (gasoline or kerosene) is poured into the collectors. The head is on its side. Naturally, the flow is evaluated already from the side of the plates.

Lapping valves

In order to grind the valve to the head at home, you will need a drill (preferably with a reverse) and a special paste. To carry out this procedure, the valve will have to be dried and removed. By the way, at the same time, you can replace the valve stem seals, if necessary.

• It is recommended to degrease the valve and seat with a solvent prior to work. A small amount of lapping paste is evenly applied to the flange of the valve. It is very important to ensure that it does not get on the valve stem, because the paste is the strongest abrasive (usually diamond). If damage remains on the stem, the valve stem seals will fail much faster and oil consumption will significantly increase. To prevent this, a piece of felt can be put on the stock.

• Pressing occurs when pulling the drill towards you. Rotation should be done both clockwise and in the opposite direction. Usually, everything takes no more than two minutes to complete. To understand that the process is over, you need to know what a lapped valve looks like. Its chamfer forms a characteristic matte strip a couple of millimeters wide. Exactly the same strip, by the way, will be on the chamfer of the saddle. Sometimes, after the described procedure, finishing is also carried out. It is no different from the lapping process, except that instead of lapping paste, GOI paste is used, diluted with engine oil. Before applying with a cloth, carefully remove the previous lapping agent.
• It is necessary to check the quality of lapping not only by the strip mentioned above, but also by pouring kerosene or gasoline into the combustion chamber or manifolds. Before assembling the cylinder head, all parts must be thoroughly rinsed with gasoline. After all, if in the process of work the abrasive from the paste gets on other surfaces, then the consequences can be very sad. diamond powder will cause defects.

You should also know in what cases the lapping of the valves may not work. In the event that there are significant flaws on the working chamfers (shells) or when the saddles were crookedly bored (cut), it will not work to grind the valve. The first sure sign of this is the irregular or even intermittent matte strip on the chamfer. Here the solution is simple, although not entirely pleasant. buying new parts. Although, you can try and grind them on the machine.

Little materiel

For those who are not in the know, it is worth explaining that the valves are located in the cylinder head. There are at least two valves for each cylinder (in most cars). One valve allows the air-fuel mixture to enter the cylinder (combustion chamber) from the intake manifold, and the other releases exhaust gases to the exhaust manifold.

Of course, the valves are opened alternately. Valves look like a nail. The head, which is also called a plate, they are facing inside the cylinder. When closed, the valve head is in the seat and seals the combustion chamber hermetically, pressing against the seat with a working chamfer.

Let’s summarize

So, as can be seen from all of the above, lapping is a responsible, time-consuming procedure, but extremely necessary for good engine operation, not only after repairs, but also after over 60,000 kilometers. Only the question remained unclear: is it necessary to grind the valves on the new head.

As for such a case, there are two options: if the head is completely new and was purchased fully equipped, then you can not grind it. In any case, experts say that it is not necessary to do this. However, if the head was purchased separately from the valves, then lapping will be needed. Again, in any case, before installing it, the tightness of the fit of the plates can always be checked by an already known method, that is, by pouring gasoline or kerosene into the cylinder head or collectors.

Do-it-yourself lapping valves

Dismantling the cylinder head and lapping the valves. The necessary tool and features of the work. Also watch the video.

In the process of overhauling the power unit, a mandatory grinding in of the valves is carried out. This is necessary to ensure the tightness of the valve train and improve the compression ratio. Despite the apparent complexity, lapping valves does not require special equipment and special qualifications of the master.

Before carrying out work, you must stock up on the necessary tools. To speed up the process, you can use a drill, in the absence of it, a hand tool is made.

For it you need a metal rod, on which you need to put on a rubber hose that matches the diameter of the valves.

All procedures were carried out on a VAZ 2110 car. On other models, the procedure is no different.

Procedure for lapping valves:

Upon completion of the preparation, you can begin to disassemble the power unit. First of all, all attachments that interfere with the work with the cylinder head are removed. The piston of the first cylinder is set to top dead center and the coolant is drained. The intake and exhaust manifolds are dismantled.

After gaining access to the head, the air filter and valve cover are removed. Now you can dismantle the cylinder head itself, but before that you need to fix the camshaft pulley. To do this, it is enough to rest the screwdriver against a special pin. After that, the timing belt is removed from the pulley. The bolt and the pulley washer are unscrewed and it is removed from the camshaft. After that, the mounting bolts are unscrewed and the head is dismantled. It must be moved so that one end of the camshaft extends beyond the timing belt cover.

After removing the block head, the valves are dismantled. Valves and their seats must be thoroughly flushed with gasoline.

After that, lapping (diamond) paste is applied to the seats and the valves are installed in place.

A prepared tool is put on the valve stem. If lapping is carried out using a drill, then the valve is installed in its cartridge. During lapping, the rod should gently turn in all directions and be pressed against the seat.

During operation, pay attention to the color of the seat and the valve itself. The end of lapping can be judged by the uniform gray color on the edge of the valve and its seat.

Upon completion of the work, the valves are flushed again with gasoline. It is necessary to completely remove the remnants of the lapping paste, otherwise the tightness of the valve mechanism will be quickly broken.

Now it is necessary to check the tightness of the valves. To do this, pour kerosene into the combustion chambers. If kerosene does not leak out of the combustion chambers for 3 minutes, then the tightness is in order. If the liquid has passed, then we continue to grind the valves further.

Lapping valves

After replacing the valves, it is imperative to grind them in. If you install valves without lapping, there is a risk that they will leak air or gasoline into a closed combustion chamber. In addition, sometimes lapping of old valves may be required: the main sign that the valves require lapping is different compression in the cylinders, in which the car jerks at idle.

Please note: before you start lapping old valves, they must be cleaned of carbon deposits with a metal brush, and then checked for runout using a special device.

The following tools and materials are required for lapping the valves:

Valve Lapping Tool. If you do not have a special tool, you can make a valve grinding device with your own hands using a drill and a rubber hose.

“Roller cutter” for the valve seat. It will be needed if the valve seat is damaged or burned out. in this case, before grinding the valve, you need to process the seat with a “roller cutter”.

The valves should be lapped on the disassembled cylinder head. It is performed as follows:

Lapping paste is applied to the valve chamfer in a circle.

A spring is put on the valve stem, the valve is inserted into the guide sleeve from the side of the combustion chamber.

To prevent lapping grease from getting into the guide sleeve, the valve stem must first be lubricated with graphite grease.

A lapping tool is put on the valve stem. If we are talking about a homemade tool from a drill, pull on a rubber hose.

Grind the valve, alternately pressing it against the seat, and then weakening the forces. If we are talking about lapping with a drill, turn it on at minimum speed in reverse mode, if about a hand tool, rotate it in turn in both directions by half a turn.

The valve should be lapped in until a 1.5 mm wide gray “band” appears on the chamfer. At the same time, a shiny “belt” of the same width should appear on the valve seat. about 1.5 mm.

After lapping, the valve and valve seat should be wiped with a clean rag and rinsed with gasoline to remove any residual lapping paste.

The lapping procedure must be repeated for each valve.