Checking thermal valve clearances on engines of VAZ 2108, 2109, 21099 cars

The VAZ classic family cars: 2101, 2102, 2103, 2104, 2105, 2106, 2107, 2121, 2123, 2131, 21053, 21213, 21214 have a four-stroke engine.

The carburetor was installed on the engines of Zhiguli cars until 2000 and subsequently, after a simple modernization, an injector was used on cars 2105 and 2107. This is an in-line engine with vertically arranged cylinders in a block. The channels of the cooling system in the cylinder block are made along the entire height of the cylinders, effectively cooling the piston group, piston rings from “stagnation”, and also preventing deformation of the cylinder block from local heating.

The crankshaft is located at the bottom of the cylinder block on five main sliding bearings. Oil seals made of oil-resistant rubber are used as seals to prevent oil leakage.

An important engine component is the cylinder head. It is a complex cast aluminum alloy block with valve seats and guide bushings pressed into it. The cylinder head contains a cooling jacket and oil passages for supplying lubricant under pressure to the camshaft bearings and rockers that drive the valves.

Oil seals are installed on the valves to prevent oil from entering the combustion chamber. A total of 8 valves are used.

The camshaft is mounted on the cylinder head and is driven by a double-row chain from the crankshaft. Semi-automatic chain tensioning device, powered by a spring. It is possible to install a device for automatic chain tensioning, the rod of which adjusts its position based on the oil supply under pressure.

Unlike the UMZ engine installed on Gazelle, Volga, UAZ cars, the transmission of movement to the valves from the camshaft is carried out through levers (rockers), without the use of rods and rocker arms. The OHC rocker system ensures stable operation of the valves at idle and at high crankshaft speeds, reducing the ringing noise of their operation.

Adjusting valves of VAZ 2106, 2107, etc. According to the maintenance instructions, it is performed every 10,000 km and, due to the simple and compact layout of the engine, there are no difficulties in the procedure.

Getting started and disassembling

Before starting work related to adjusting the thermal clearances of the valves, it is necessary to prepare the engine, tools and related materials.

Secure the car with the handbrake and move the gearbox to neutral. For safety reasons and to prevent independent movement, additionally install shoes under the wheels. Open the hood and check the engine temperature, which should be approximately 20 degrees to carry out the valve adjustment process.

As an exception, there is a correction table for valve clearances depending on engine temperature, but given the unpredictable deformations of the metal structure, we recommend adjusting at the temperature specified in the manufacturer's instructions. It is at a temperature of 20 degrees that the metal structure is in a stable state, without noticeable thermal linear expansion or contraction (negative temperatures).

Before disassembling parts and assemblies to provide access to the valve regulation operation, turn off the power to the on-board electrical network of the machine by disconnecting the negative terminal of the battery.

Further operations for preparing the gas distribution mechanism of a carburetor engine differ from those of an injection engine.

On a carburetor engine:

• Unfasten the retaining spring latches of the air filter housing cover or unscrew the wing nut;

• Remove the cover and put the air filter element aside;

• Using an “8” socket or an open-end wrench, unscrew the four nuts holding the air filter housing on the top of the carburetor and move it to the side, separating it from the crankcase ventilation pipe;

• Remove the carburetor choke drive cable by partially unscrewing the half-clamp holding the cable sheath and the cable rod clamp;

• Using a slotted screwdriver, unfasten the plastic ends of the accelerator pedal drive on the carburetor and, by removing the locking ring from the drive axis mounted on the valve cover, remove the rod.

On an injection engine:

• Remove the limiter (in the form of a bracket) for spontaneous release of the cable from the throttle linkage groove.
• Turn the throttle linkage counterclockwise and pull the cable tip to the side;
• Unscrew the two bolts holding the accelerator cable assembly bracket with a 10mm head;
• If there is an adsorber, remove the connector on the purge valve;
• Loosen the clamps on the air duct and gas ventilation pipes, unscrew with a “10” head the bolt securing the plastic sleeve of the pipes on the valve cover and remove them;

Using a “10” socket, unscrew the eight bolts securing the valve cover and remove it from the block head. Inspect the parts of the gas distribution mechanism for damage and the condition of the springs.

Preparing for regulation

Allow the engine to cool before starting repair work.
The temperature for adjusting the valves should be no more than 20 degrees. To work you will need the following tools:

• set of wrenches;
• screwdriver;
• tweezers;
• puller;
• measuring probe;
• adjusting washers;
• gaskets for 8 valves.

Set the car to the handbrake, lift one of the front wheels with a jack - this will allow you to turn the crankshaft, and then engage 5th gear.

After this, follow the sequence of actions:

1. Disconnect the pipes from the valve covers and remove the air cleaner. Then disconnect the throttle drive cables from the carburetor.
2. Unscrew the two nuts, remove the cover and remove any remaining oil. Remove the timing belt cover.
3. Place the piston of cylinder No. 1 at TDC on the compression stroke.

Valve adjustment process

The procedure for adjusting valve thermal clearances is the same for carburetor and injection engines. The only difference is the thermal clearance of the valves. On a carburetor engine, the clearances on all valves are set to 0.15 mm when the engine is cold, and on an injection engine, 0.20 mm. Adjustment begins with setting marks on the crankshaft and camshaft.

By turning the nut securing the belt drive pulley (drive disc on an injection engine) with a special wrench to “38”, we align the mark in the form of a mark on the pulley with the protrusion on the front cover, while the mark on the camshaft sprocket should coincide.

In this position, the piston of the fourth cylinder is at TDC (00 kV) and the eighth and sixth valves are adjusted (numbering from 1st to 8th starts from the radiator).

For this:

• the dipstick is inserted between the camshaft cam and the working surface of the valve lever;
• use key 17 to loosen the locknut to allow free movement of the adjusting bolt;
• by rotating the adjusting bolt with wrench 13, achieve a gap value at which the feeler gauge will move with little effort;
• holding the wrench 13 against turning the adjusting bolt, tighten the locknut.

It must be borne in mind that when tightening the lock nut, the resulting gap may “move” to a larger or smaller direction, so it is important to re-check the thermal gap after fixing the adjusting bolt.

The next pair of valves is adjusted by turning the crankshaft by 1800, while the camshaft sprocket will rotate by 900. The mark on the sprocket will be located at the cut of the junction of the lower and upper camshaft beds.

In this position the fourth and seventh valves are adjusted.

By positioning the crankshaft 360 degrees, the first and third valves are adjusted. And in the position of the shaft set at 540 degrees, the fifth and second are subject to adjustment.

Specifics of the work

There is a category of drivers who strive to do all the maintenance and repair work on their car themselves.

This is especially true for owners of domestic cars, and this is commendable.

But such drivers need to realize that a number of works, especially those related to adjustments, require not only theoretical knowledge and experience, but also a kind of “feeling” that comes with time, through trial and error.

Especially such work includes all adjustments carried out on the carburetor, as well as valve adjustment and a number of other adjustments.

Therefore, if you are doing this for the first time, then call a person who has done such work on his car at least 3-5 times, and preferably on the same model as yours.

Also, before carrying out work, check the timing belt tension. It is important.

IMPORTANT: The engine should only be cold, but not lower than 30 - 400C, this is the ideal temperature.

If you have just arrived at the garage and want to adjust the valves on the same day, then it will take about 5-6 hours for the engine to cool down.

You can immediately begin removing the valve covers and other parts; this will reduce the engine cooling time to 1-2 hours, as the heat exchange between the hot engine and the environment will increase.

It’s better to proceed from the principle: arrive in the evening, carry out the work in the morning.

By the way, don’t forget about the gasket under the valve covers; in 90% of cases it has to be replaced, so you should have a new gasket on hand.

Counting cylinders and valves.

The valves are counted as follows. Stand to the left of the car in the direction it is moving, near the engine. Face the engine.

Cylinders and valves are counted from left to right of the timing chain.

The last will be the 4th cylinder and 7.8 valves, but the adjustment begins with valves No. 6 and 8.

Adjustment order table:

On a carburetor engine, to more accurately determine the position of the camshaft, it is possible to use a distributor, the slider of which is directed to the socket of the high-voltage wire of the corresponding cylinder. If the distributor cover is removed, then four screws on the housing that coincide with the sockets of the high-voltage wires can serve as a guide.

You can also use the distributor with the cover removed: connect a control light to the low-voltage circuit and turn the crankshaft with the ignition on. The moment the light turns on indicates the exact position of the camshaft at which the corresponding pair of valves is adjusted.

Freeing up work space

You need to understand that you won’t immediately remove the valve cover, you need to get to it.

Using a size 8 wrench, unscrew the three bolts and remove the air filter cover, and then remove the filter element.

Disconnect all the hoses that go to the air filter.

Using a size 8 wrench, unscrew the four bolts securing the air filter housing to the carburetor and finally remove the air filter.

Go ahead.

Using the same key number 8, disconnect the choke cable.

Disconnect the washer spring, and then the gas pedal linkage itself.

Then we remove the distributor cover and move the high-voltage wire harnesses to the side so that it is convenient to work.

We take out the oil dipstick, while inserting a clean rag into the hole to prevent dirt from getting in.

Now we can freely make the adjustments we need.

Also read - Do-it-yourself valve lapping, videos, photos, devices and tools used.

Two-step technique

There is a simplified method for adjusting valves in two steps.

1. Set the crankshaft to top dead center.
2. We combine the marks on the camshaft and the shaft bed.
3. We adjust the 4th, 6th, 7th, and 8th valves.
4. Immediately after this, turn the crankshaft a full turn.
5. We adjust the 1st, 2nd, 3rd and 5th valves.

The two-turn adjustment technique allows you to reduce the time for servicing the gas distribution mechanism, and is also convenient for beginners to carry out this procedure with their own hands.

On a Chevrolet Niva car and a number of Niva cars, the thermal valve clearances are adjusted automatically by hydraulic compensators.

Why do you need to adjust valves?

The metal valve stem tends to expand and contract as it moves. The seats in the cylinder head bend, which changes the thermal clearance. And physically it needs a certain cost due to the design features of the engine. The consequences of untimely adaptation are irreversible. A jammed valve during operation of an eight-valve engine loses its seal, and the avalanche flow after ignition burns its edges and the cylinder head seat, which goes back into the head housing. Such repairs are expensive and are not covered by the warranty. It’s better to adjust it in time, especially since the price of adjusting an 8-valve engine at 600-800 rubles per 30,000 km is not that significant.

With the gap set correctly, the car will move freely, without loss of traction, consuming less fuel. The heating cannot be adjusted under any circumstances. Just cool the engine to 30-40 degrees. Otherwise, you can make a mistake and tighten the valves.

There are times when the valves have been adjusted, but the knocking still remains. The reason may not be the gaps. On a cold engine, the piston heads and pusher bushings in the head housing may knock. There can be many reasons, so you shouldn’t rush to conclusions and check everything carefully. There is a special device - a stethoscope, with which you can easily listen to the sounds of a running engine.

Adjustment Tools

The adjustment procedure begins with disassembling the valve cover and parts that prevent access to it.

Necessary tools for preparing the gas distribution mechanism for adjustment:

• 1/2 inch ratchet wrench with extension and socket for “10” and “8”;
• universal screwdriver;
• pliers.

To adjust the thermal clearances of the valves, the following tool is required:

• Ratchet key to “38”;
• Open-end wrench 17;
• Open-end wrench 13;
• The probe is 0.15 mm thick (for an injection engine - 0.20 mm).

Valve shims

Valve clearances are selected using adjusting washers. The washers come in different sizes, most often found in increments of 0.05 mm. You need to select a washer of the required size.

The washer is installed between the cylindrical side of the cam and the pusher.

Adjustment with a micrometer

The most accurate method for regulating valve thermal clearances is to use a device with a dial indicator - a micrometer. A micrometer is a very sensitive device that responds to changes in the translational movement of its measuring rod every hundredth of a millimeter.

The procedure is similar to the order of adjustment using a feeler gauge. The peculiarity of this method is to install a rail on the studs of the camshaft bed, onto which a micrometer is attached. The rack contains information on the angles of the crankshaft position to the valves corresponding to adjustment.

Before starting work, the micrometer is mounted on a device that has a lever in the form of a rocker arm. One side of the lever rests on the micrometer rod with a light touch, and the other on the extreme part of the rocker. By lifting the rocker without force with a special “spade” until it touches the back side of the camshaft cam, note how many divisions the arrow has deviated from the zero position. For a carburetor engine, the needle should deviate by 52 divisions.

A micrometer for adjusting valves is supplied with a description and all necessary accessories.

A homemade rail can be made according to a factory design. With the help of such a rack, the actions when independently adjusting the valves are more confident and there is no need to remember the routine or sequence of operations.

Features of timing belt

For example, the timing belt is with the valves up and the camshaft. The engine's timing mechanism was a chain mechanism, which was present on all models.

A special feature of the timing system is the use of pressure levers, also known as rocker arms. They are located between the camshaft and the end of the valve stem. This means that the cam does not act directly on the valve, but through the rocker arm. The pendulum also allows you to adjust the thermal gap.

This clearance is required to accommodate changes in valve component geometry due to heat causing metal expansion. If such a gap did not exist, the valve timing would be shifted due to heating of the drive system. Simply put, when heated, due to the expansion of the metal, the valves do not close completely, which leads to a loss of compression and, as a result, a drop in power.

The list of work associated with servicing the drive units of these models includes such an event as valve adjustment. This is due to the design features of the valve mechanism. During operation, the working surfaces of valve heads, valve levers and camshaft cams wear out, which leads to a violation of the thermal clearance.

Fortunately, the same design is quite simple, so the adjustment work is quite simple and can be done with your own hands. It is only important to know the sequence of operation and the sequence of valve adjustment in the “Classic”. It is worth noting that the work is identical for almost all models, therefore the sequence of adjusting the valves of the VAZ-2101 and, for example, the VAZ-2105 is the same, only on the VAZ-2107 it is slightly different.

Since for most models the operating principle is identical, all Zhiguli models related to the “Classics” will be presented below.

The first and main principle of operation is to perform only on a cooled engine. This is due to the same expansion of the metal. If the valve adjustment on a VAZ-2102 or any other model is performed on a warm unit, the operation does not give a positive result, since when it cools, the metal will return to its original form and the gap will not match. normal, then just increase it.

It is also important to know when to adjust the VAZ-2105 valves. A real sign that the valve train is out of adjustment is a metallic clanging sound coming from under the hood when the engine is running. Moreover, its intensity changes in proportion to the increase or decrease in trade turnover.

The valves on the VAZ-2104 should also be adjusted during any repair of the cylinder head associated with the removal of the camshaft.

Consequences of untimely adjustment

Untimely maintenance of the gas distribution mechanism negatively affects engine performance, causing unbalanced operation. The engine runs rough, there is no traction performance, and fuel consumption increases. It is known that the injection phase is directly dependent on the thermal clearance of the valves. Correct and correct adjustment allows the valves to open and close in a timely manner. If the gap is set less than the permissible value, then the valve begins its operation with some advance, and vice versa, if the gap is large, it opens late. Reduced clearance on exhaust (hot) valves increases the time they remain open, which can cause the edges to slowly burn out, leading to loss of compression in the cylinder.

When operating the engine on gas (propane or methane), the thermal clearances must be adjusted with the same gaps, the value of which is determined by the instructions for operating the engine on gasoline. Adjusting the valves for gas does not have scientific and technical validity and can lead to unstable engine operation.

Purpose of VAZ 2106 engine valves

One of the most important systems that require adjustment during operation is the gas distribution mechanism (GDM). The design of this mechanism allows the fuel-air mixture to be supplied to the combustion chamber in a timely manner and exhaust gases to be removed from the engine cylinders.

The timing belt includes the camshaft and crankshaft and the chain connecting them. Due to the timing mechanism, synchronous rotation of two shafts occurs, which, in turn, makes it possible to strictly observe the sequence of opening and closing valves in all cylinders.

The timing chain ensures synchronous rotation of the two shafts

The camshaft lobes act on special levers that push the valve stems. As a result, the valves open. As the camshaft rotates further, the cams return to their original position and the valves close.

The camshaft is the main element of the gas distribution mechanism

Thus, the result of the operation of the gas distribution mechanism is the consistent and timely opening and closing of the valves.

There are two types of valves:

1. Intake (open the fuel supply to the combustion chamber).
2. Exhaust (provide removal of exhaust gases).

   
   Each cylinder of the VAZ 2106 engine has its own inlet and outlet valve