DIY repair gas distribution mechanism uaz patriot

In detail: do-it-yourself repair of the UAZ patriot gas distribution mechanism from a real master for the site my.housecope.com.

The gas distribution mechanism (abbreviated as timing) is a mechanism used to ensure the timely admission of the combustible mixture into the engine cylinders and the release of exhaust gases. In short, the timing is a system for controlling gas flows in the cylinders of an internal combustion engine with variable valve timing. The operation of these functions is ensured by the timely opening or closing of the valves of the mechanism.
The most common are overhead valve timing systems. All gas distribution mechanisms can be classified into the following categories:
• By the location of the camshaft - upper or lower
• By the number of camshafts - one or two
• By the number of valves
• According to the configuration of the camshaft drive - chain, toothed-belt, gear

Automotive engines can be equipped with different types of gas flow control systems, which makes them flexible and simplifies their design.

The main functions of the timing belt are supplying the fuel-air mixture to the cylinder and removing the exhaust gases after it has ignited.

The gas distribution mechanism is formed from valves and the actuator and the camshaft. The valves are designed to open and close the outlet and inlet ports. Each of the cylinders has n-th number of valves (depending on the design features of the cylinder head). Depending on the complexity of the timing belt, there are several valve arrangements and their number in the block head, namely:
• Two-valve (one for the inlet, one for the outlet)
• Three-valve (two for inlet, one for outlet)
• Five-valve (three for inlet, two for outlet)
The valve consists of a rod and a disc, and the place with which it contacts in the cylinder head is called the seat.

Video (click to play).

The valve seat is a small ring with a beveled inner surface. The seats are installed in special holes in the cylinder head and ensure the tightness of the combustion chamber, transfer excess heat to the cylinder head and allow air to flow when the valve is open or closed.

The main work of the gas distribution mechanism is performed by the cylinder head. It is made of light metal, or rather from an aluminum alloy, and is attached to the block with special bolts. The cylinder head has a combustion chamber, holes and channels for coolant, holes for installing spark plugs or nozzles, channels for lubrication and a set of valves. The placement of the camshaft drives and the camshaft itself is due to the design features - mainly this is a cavity in the front of the cylinder head.

The valves are poppet-shaped at their base. Any valve opens or closes under the action of a mechanism that has an eccentric cam, the operation of which is synchronized with the period of rotation of the crankshaft and the position of the piston in the cylinder. The intake valve is always larger, and the exhaust valve is made of metal that is more resistant to temperature loads than the intake valve.

When the valve is closed, it is held in place by a spring force. The valve disc is located in the seat (the guide sleeve forms coaxiality between the working chamfer of the valve and the seat, ensuring tightness), and the upper surface with the help of the spring plate is held by a lock - crackers, which fit tightly into a special groove located at the end of the valve.

The spring is designed to close and hold the valve and return it to its original position, after passing the camshaft. Valve springs can be divided into the following types:
• Symmetric spring with different pitch of turns
• Asymmetric valve spring
• Dual valve springs

In a symmetric spring, the distance between the coils alternates (a large distance, then a small one), an asymmetric valve spring has a small distance between the coils at one end and a gradually increasing distance at the other. Twin springs are made up of two springs - an inner and an outer one.

Under the action of the force of pressing the spring, the valve disc is tightly pressed against the seat, ensuring the tightness of the combustion chamber and the correct operation of the gas distribution mechanism.

The valve cracks serve as a lock connecting the outer spring plate and the valve so that the spring returns the valve to its original required position.

The valves are made of heat-resistant, in the overwhelming majority of cases, chromium steel, which can withstand a temperature load of about 800-900Cº.
The valve poppets also use high quality steel or alloys of lighter and stronger metals such as titanium.

The engine valves open in the sequence in which the engine is running. The opening of the valve itself occurs at the time of transmission of the camshaft force by means of the drive.

In modern internal combustion engines, there are several valve drive schemes:
• Hydraulic pushers
• Roller arms
• Rocker arms

Hydraulic pushers or hydraulic backlash compensators are located in the guide holes of the cylinder head, on the same axis of the valve holes. When the engine is running, hydraulic tappets eliminate noise, and the valve timing itself works more smoothly and gently. In the presence of hydraulic lifters, it is not necessary to adjust the clearances in the valve mechanism. The pusher is made of a body, cylinder, plunger, spring and check valve.

The roller lever, also known as the rocker, transmits the force from the camshaft cam to the valve stem during rotation - the rocker takes on the translational force of the pusher rod and transfers this movement to the valve stem.

The rocker arm is a double-arm lever - at one end there is a hardened firing pin that presses the valve, on the other there is a screw for adjusting the thermal gap.

The timing design, where roller levers are installed, has a number of advantages - friction between parts is reduced, the weight of the entire unit is less and its dimensions, respectively.

When the engine is running, all of its parts wear out. The valves, going through their cycle of work, heat up due to the frictional force, which makes them unusable. In order for the valves to serve for a long time, it is worth monitoring the thermal gap - if it is not observed, the tightness of the combustion chamber will be broken, which will lead to some problems, for example, the appearance of shock loading on the valves and a decrease in compression in the cylinders.
To prevent this from happening, you should set the required thermal gap between the valve and the pushing plane of the timing. When the motor heats up to operating temperature, all of its parts heats up, expands and deforms slightly.

Camshaft - Controls the opening and closing of valves and the timing of engine strokes.
The pre-shaft has a drive connecting it to the crankshaft with a chain or belt. The shaft itself is a multi-cam shaft, individually made for a separate valve.

Crankshaft - designed to transfer the translational movements of the connecting rods to the rotational movement of the flywheel. It is connected to the camshaft to synchronize the engine strokes.

The advantages are size, no slippage, high efficiency.
Disadvantages - rapid wear, high noise, the need for adjustment.

Advantages - smoothness, quiet operation, no need for lubrication.
Disadvantages - fragility, large size, slippage.

Advantages - dimensions, high efficiency, constancy of the gear ratio.
Disadvantages - noise, rigidity leading to failure.

The main purpose of the gas distribution mechanism on the UAZ Patriot SUV is to synchronize the crankshaft with the camshaft, but, in addition, also to be able to set the cycles for opening and closing the valves. The functionality of the gas distribution mechanism directly affects the efficiency of the car engine, therefore it is very important that the mechanism is in good working order. The main element of the connection between the crankshaft and the camshaft is the chain mechanism. But over time, during the operation of the car, wear of the working elements is characteristic, as a result of which various breakdowns occur. In particular, the timing chain mechanism stretches over time and loosens the chain tension, which can lead to a burst or slippage. Thus, the manufacturer UAZ Patriot established that the timing mechanism elements must be replaced every 80,000 km. Today we will pay attention to the process of replacing the timing chain on the UAZ Patriot Euro-3 SUV with our own hands.

Read also: DIY valve repair

Initially, it should be noted that the UAZ Patriot SUV, or rather, its ZMZ-409 engine in the timing mechanism has not one chain mechanism, but two. They are referred to as the upper and lower timing chains. Therefore, the design of the timing belt on the UAZ Patriot Euro-3 SUV is a complex mechanism that requires a qualified approach to repair work, in particular, to replace chain elements.

Often, SUV owners wonder when it is necessary to replace the timing chain so that there are no troubles on the road? Sometimes there are situations when an open timing chain occurs on a UAZ Patriot car, which entails a lot of negative consequences. The main and objective factor indicating that it is soon necessary to replace the element is its condition. If, while the engine is running, a metallic sound is heard from the engine compartment, then it is time to check the tension of the timing chains.

If the chain tensioners do not allow the mechanism to be tightened, and the vehicle's mileage reaches 80 thousand, then it is recommended to take time and money and replace the chain. How to do this with your own hands on the UAZ Patriot Euro-3 SUV, let us consider in more detail.

The ZMZ-409 Euro-4 engine from the factory has single-row timing chains. On this UAZ Patriot modification, the timing chain breaks earlier than in Euro-3 and unexpectedly! But if you really need to replace the product, then it is recommended to install only a two-row one. The double-row chain has a significant resource of work, which increases its efficiency, and long before a break, the engine begins to emit extraneous sounds, warning of wear.

If the replacement time has come or you find out that the chain on the SUV is worn out, then a process such as replacement will be required. Before proceeding with the repair activities on the UAZ Patriot Euro-3 SUV, you need to make sure that you have the following tool:

hex key 6 mm;

heads on the crank "12", "13", "14";

hammer and chisel.

In addition, you will also need accessories, such as a tank for draining coolant from the radiator, etc., but more on this later.So, replacing the chain on the ZMZ-409 engine of the UAZ Patriot Euro-3 SUV involves the following steps:First, unscrew two bolted connections numbered 2. After Image - DIY repair gas distribution mechanism UAZ Patriot

it is necessary to bend the plate 6, thereby freeing access for unscrewing the bolt 5. Now you can remove the gear, and then the chain mechanism itself, pulling it up. The bottom element is retrieved in the same way.

Replacing timing elements is a laborious process and requires care and adherence to the correct sequence of actions.After removing the chain and gears, they must be washed in gasoline, and then a visual inspection for damage should be performed. If the chain, gears or tensioners are visibly damaged, they must be replaced.

Let's briefly consider what the assembly process of this mechanism is.

The assembly process of the mechanism is carried out in the reverse order of removal. In this case, the installation of the crankshaft gear implies an operation to press on it. In this case, the shaft should be installed so that the mark on the crankshaft gear coincides with the mark on the cylinder block. In the photo below, these tags are designated by numbers 1 and 2, respectively.

After that, the chain damper is installed and the chain is put on the crankshaft gear. Before installing the chain, lubricate it thoroughly with engine oil.

Next, the element is put on the driven gear, installing the latter on the intermediate shaft until the dowel pin enters the hole. It should also be borne in mind that mark 4 must line up with mark 5. The bolt connections of the blast shaft gears are screwed on, fixing them with a lock plate. By pressing the tensioner, you need to tighten the element until the marks on the gears coincide. At the final stage, it is necessary to lubricate the elements with engine oil and install all the removed parts in the reverse order of removal.Summing up, it should be noted that replacing the timing elements on the UAZ Patriot SUV is possible at home only if you have free time, the ability and skills to repair a car. At the workshop, the work will be done much faster, and the engine will run like a clock.Do you still think that car diagnostics is difficult? If you are reading these lines, then you have an interest in doing something yourself in the car and really savebecause you already know that:

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The gas distribution mechanism on the engine of the UAZ Patriot car performs the function of synchronizing the crankshaft and camshaft, and also sets the cycles for opening the closing valves. The efficiency of the engine, its trouble-free and reliable operation depends on its work. That is why the operation of the timing system of the UAZ Patriot engine is very responsible. So to increase the reliability of the timing mechanism, a chain transmission is used, but it can also stretch or even break over time. As a result, individual parts and the timing chain itself must be replaced approximately every 80,000 km. The exact mileage cannot be said here, since it will depend on the operating conditions of the engine. If the engine is running for wear, then replacement of the chain may be required earlier. The wear of the chain will manifest itself in its "rattling" - a high-frequency sound like from valves.

In this article, we will just give information on replacing the chains and gears of the gas distribution mechanism. It is noteworthy that the timing mechanism of the UAZ Patriot uses 2 chains, conventionally the lower and the upper. Such a timing mechanism can be considered difficult to maintain, therefore replacing the chains will require advanced qualifications from the mechanic who will carry out the work.

The photo shows the UAZ Patriot timing mechanism and the catalog numbers of the mechanism

Before starting to work with the engine, it is necessary to remove the radiator ("Removing the UAZ Patriot radiator")

Loosen the clamp of the supply hose to the cooling system pump and remove the hose from the fitting.

Remove the cylinder head cover. Remove the four bolts and remove the front cover of the cylinder head assembly with the fan drive clutch and fan (viscous clutch with fan removed for clarity).

Remove the crankshaft speed sensor (synchronization sensor) (see "Crankshaft sensors for UAZ Patriot").

Unscrew the two bolts and remove the upper chain tensioner cover with gasket. Remove the cover carefully, as the spring of the hydraulic tensioner acts on it. Then remove the hydraulic tensioner (see "Removing and disassembling the hydraulic tensioners of the UAZ Patriot timing chains").

Also remove the lower chain tensioner.

Unscrew the 7 bolts and remove the chain cover. Remove the cover carefully so as not to damage the front crankshaft oil seal installed in it, the cover gaskets and the cylinder head gasket.
Unscrew 1 bolt of the upper tensioner and remove the tensioner arm together with the sprocket.
Also remove the lower tensioner arm. Also together with an asterisk.
Unscrew the 2 bolts and remove the plastic chain guide.

Remove the gears from the camshafts by unscrewing the bolts securing the gears to the camshaft flanges (see "Removal, Troubleshooting and Installation of Camshafts"). You will need a puller here.

Unscrew bolts 2 and pull out the guide 1 of the chain up. Bend the ends of the lock plate 6 and unscrew the bolt 5, to do this, keep the intermediate shaft from turning by inserting a screwdriver into the hole of the gear 3. Remove the gear 4 by inserting a screwdriver between it and the gear 3 and resting the screwdriver as a lever on the gear 3. Remove the gear 4 from the upper chain and remove the chain by pulling it up. Remove gear 3 from the intermediate shaft and remove it from the lower chain. Remove the lower chain from the crankshaft gear.

If it is necessary to remove gear 2 from the crankshaft, first remove the bushing 1 and the rubber O-ring between the bushing and the gear. Then press on gear 2. The gears are removed with a puller.

After removal, wash the chains and gears in gasoline, wipe and dry them.
Examine the chains. If cracks, chips or significant wear are found on the chain bushings, replace the chains.
Replace gears that have chipped or chipped teeth.
Replace damaged chain guides.
The tensioner sprockets must rotate freely on the axles. If the sprocket teeth are chipped or chipped, replace the tensioners.

If you removed the gear from the crankshaft, press it onto the crankshaft, install the o-ring and bushing.
Turn the crankshaft so that mark 1 on the crankshaft gear is aligned with mark 2 on the cylinder block. In this case, the piston of the 1st cylinder will take the TDC position. Install the chain damper 4 without tightening the damper mounting bolts 3. Put chain 5 on the crankshaft gear, having previously lubricated it with engine oil.

Put the chain on the driven gear 1 and install the gear on the intermediate shaft 2 so that the gear dowel pin goes into the hole of the intermediate shaft. In this case, the mark 4 on the gear must coincide with the mark 5 on the cylinder block, and the chain branch passing through the damper 3 must be tightened.

Install the countershaft drive gear so that its dowel pin fits into the hole on the driven gear.
Install the two countershaft gear bolts with a lock plate under them. Tighten the bolts to a torque of 22–25 N • m (2.2–2.5 kgf • m) and fix them by bending the edges of the lock plate on the edge of the bolt heads.
Pressing the tensioner lever, tighten the chain and check the alignment of the marks on the gears and the cylinder block.

Tighten the chain guide mounting bolts.

Install the previously removed belts and the cooling system radiator.

The timing mechanism on the UAZ Patriot engine synchronizes the operation of the camshaft and crankshaft. Also, its functions include the establishment of valve system opening cycles. The high-quality functioning of the engine directly depends on the work of this node. In view of this, this node should be given special attention. Of course, the chain is practical and reliable, but it also stretches. In some cases, the chain may even break. The timing chain on the UAZ Patriot must be changed after 80,000 km. But this is only the recommended interval. In fact, the chain drive may deteriorate earlier. Factors such as weather conditions, driving style and others can affect its premature wear. If you notice that the chain has begun to "blur", this is a reason to inquire about its condition.

Here we will talk about how you can replace the chain yourself at home. Of course, you can turn to specialists, but this will cost money and, moreover, will not contribute to the addition of experience, but it is so necessary for motorists who want to learn how to understand technology. The timing mechanism of the UAZ Patriot has 2 chains, which makes replacing a consumable difficult. But you shouldn't think that only professionals can do it. Each motorist will be able to replace the chain with his own hands, you just need to make every effort for this.

Over time, the chain pivots will wear out and the chain will stretch. It is necessary to change the chain in the case when it is already not possible to adjust its tension, when there is a mismatch of the marks on the shafts. If chips or any other damage appear on the chain, this also means that the consumable has served its purpose, and it is time to replace it with a new one. With a stretched chain, the engine runs unevenly, a grinding grinding is constantly heard. In this case, the car will not start the first time. Also, a stretched chain is the reason that the car begins to "eat" more fuel. The stretched chain can slide over the sprocket. In the end, it can simply break off, and this will cause the piston to hit the valves. The latter will bend from this, and the car will need to be overhauled.

The chain, of course, is somewhat more practical than a belt, but its resource is also used up sometime, and it needs to be replaced. If you decide that you will carry out this procedure yourself, then exactly follow the instructions below, and you will definitely succeed.

Work must be carried out only with a cooled engine. Before carrying out the main work, the radiator should be dismantled. Remove the hose supplying cooling to the pump by loosening the clamp that secures it. Dismantle the cover that covers the cylinder block by unscrewing the 4 mounting bolts. We remove the water pump. Now you need to dismantle the crankshaft timing sensor and its pulley. Remove the chain tensioner cover. It is removed together with the gasket. Care should be taken when removing the cover as the tensioner spring is pressing on it. We remove the tensioner. In the same way, we remove the tensioner acting on the lower chain.

The chain cover can now be removed. To do this, you will have to unscrew 7 bolts. You need to remove it carefully, you must try not to damage the gaskets. Now remove the upper and lower tensioner arms together with the gears. We remove the chain damper, which is attached with two bolts. We dismantle the camshaft gears, which are bolted to the flanges.

Perceiving the following information, be guided by the photo below, since here the numbering of the necessary parts will be given. Unscrew the bolts (2) and raise the upper chain damper. Fold back the stop plate (6) and unscrew the bolts (5). The intermediate shaft must be secured so that it does not rotate. To do this, insert a screwdriver into the hole (3).Now we remove the gear (4) by inserting a thin screwdriver between it and the gear (4). Now we take out the gear (4) and take out the chain, which for this should be pulled up. Now remove the gear (3) and remove the bottom chain.

Now focusing on the next shot below. Remove the bushing (1) and then remove the gear (2). You will also have to remove the rubber seal. Now we press the gear (2) and remove the gear wheels. A special puller can be used for this purpose.

After dismantling, the gears should be washed in gasoline and wiped with a rag. It is possible that the gears will also need to be replaced. This will be necessary if chips or cracks are noticed on them. Most likely, the dampers will also need to be changed, since plastics are fragile material. Also check the condition of the tensioners. They have to be changed if the sprocket teeth are chipped.

If you removed the crankshaft gear, then, when assembling the mechanism, it will have to be pressed onto the crankshaft. After that, we put the seal and the bushing. Pay attention to the alignment of the marks. The crankshaft should be turned so that the mark (1) (see photo below) on the crankshaft aligns with the mark (2) located on the cylinder block. In this case, the piston of the master cylinder should take the TDC position. Install the damper (4). Do not tighten the bolts (3) too much yet. Now we take the chain (5), lubricate it and put it on the crankshaft gear.

We put the chain on the main gear (1) (photo below) and on the intermediate shaft (2). Pay particular attention to align the mark (4) with the mark (5). At this time, the section of the chain located on the damper (3) must be tensioned.

Now we tighten all the unscrewed bolts and check the alignment of the marks again. To do this, tension the chain by pushing on the tensioner.

Having previously lubricated the upper chain, we put it on the main gear of the intermediate shaft. It will have to be pushed into the hole located in the cylinder head. We insert the main gear and, turning the crankshaft to the right, put the chain on it. We tighten the chain by turning the camshaft counterclockwise. All other nodes must be reassembled in the order in which they were disassembled.

As you can see, there is nothing particularly complicated here, you will definitely succeed.

Until recently, both the ZMZ-40906 gasoline engine and the ZMZ-51432 diesel engine were installed on the car. In October 2016, the manufacturer announced that, due to low demand for the diesel version, only the ZMZ-40906 gasoline engine (Euro-4, 2.7 l, 128 hp) will remain in the factory line.The presence of two chains, upper and lower in the gas distribution mechanism, makes the process of repairing the gas distribution mechanism quite laborious. Replacing the UAZ Patriot timing belt can be done by hand only if there is an equipped room for repairs and the skills of a mechanic.

Timing repair kit: levers, sprockets, chains, dampers, gaskets.

Thread lock and gasket sealant

Some fresh engine oil

Allen key 6 mm

Wrench set (10 to 17)

Collar and heads for 12, 13, 14

Hammer, screwdriver, chisel

Camshaft timing tool

Additional accessories (container for draining antifreeze from the cooling system, jack, gear remover, etc.)

Before the actual replacement, install the car so that you have access to the engine compartment from all sides, including the bottom. Turn off the ignition and remove the “negative” wire from the battery terminal.
In order to gain access directly to the gas distribution mechanism of the ZMZ-409 engine, you will first have to dismantle several units located on or near the engine.First of all, you need to drain the engine oil and antifreeze into suitable containers, after which you can remove the radiator.Partially unscrew the oil sump bolts or completely dismantle the crankcase - this will further facilitate the installation of the gas distribution mechanism. Next, remove the power steering pump drive belt, and also dismantle the fan pulley. Next, remove the drive belt of the generator and water pump (pump). After disconnecting the supply hose from the pump, it is necessary to dismantle the cylinder head cover. Disconnect the high-voltage wires, remove the four bolts and remove the front cylinder head cover together with the fan. Then, after unscrewing the three bolts, disconnect the pump. Remove the crankshaft position sensor from its seat in the cylinder block by unscrewing the bolt securing it. Remove the crankshaft pulley. Experienced mechanics recommend jacking up the motor to facilitate removal of this part.After installing all the timing parts and the cylinder head cover, it remains to mount the previously removed assemblies: the crankshaft sensor, pump, generator belt, power steering belt, fan pulley, oil sump and radiator. Fill with oil and antifreeze after assembly is complete. Connect the high-voltage wires and connect the "negative" wire to the battery terminal.You will need: a "6" hex wrench, "12", "13", "14" heads, a small chisel, a hammer.1. Drain the cooling system (see "Replacing the coolant").2. Remove the radiator of the cooling system (see "Removal and installation of the radiator").4. Remove the alternator and water pump drive belt (see "Replacing the alternator and water pump drive belt").5. Loosen the clamp of the supply hose and remove the hose.7. Remove the four bolts and remove the front cover of the cylinder head assembly with the fan drive clutch and fan (viscous clutch with fan removed for clarity).9. Remove the crankshaft speed sensor (timing sensor) (see "Sensors of the engine management system").12. Unscrew the two bolts and remove the upper chain tensioner cover with gasket. Remove the cover carefully, as the spring of the hydraulic tensioner acts on it. Then remove the hydraulic chain tensioner (see "Removal and disassembly of hydraulic chain tensioners").13. Remove the lower chain hydraulic tensioner in the same way.14. Remove the seven bolts and chain cover. Remove the cover carefully so as not to damage the front crankshaft oil seal installed in it, the cover gaskets and the cylinder head gasket.15. Remove the top tensioner bolt and remove the tensioner arm with sprocket.16. Remove the lower tensioner arm with sprocket in the same way.17. Remove the two bolts and remove the plastic chain guide.18. Remove the gears from the camshafts by unscrewing the bolts securing the gears to the camshaft flanges (see "Removal, Troubleshooting and Installation of Camshafts").19. Unscrew the bolts 2 and take out the guide 1 of the chain upwards. Bend the ends of the lock plate 6 and unscrew the bolt 5, to do this, keep the intermediate shaft from turning by inserting a screwdriver into the hole of the gear 3. Remove the gear 4 by inserting a screwdriver between it and the gear 3 and resting the screwdriver as a lever on the gear 3. Remove the gear 4 from the upper chain and remove the chain by pulling it up. Remove gear 3 from the intermediate shaft and remove it from the lower chain. Remove the lower chain from the crankshaft gear.