The device and repair of the exhaust system of the car VAZ 2107

It is not difficult to recognize problems with the exhaust system of a VAZ 2107 car - the noise of the engine is complemented by a roaring sound coming from under the bottom of the car. In 90% of cases, a motorist can solve the problem on their own by replacing or repairing a burnt muffler. You just need to understand the exhaust device, correctly diagnose the malfunction and change the worn element.

Purpose of the exhaust system

Before combustion in the engine cylinders, gasoline is mixed with air and fed through the intake manifold into the combustion chamber. There, the mixture is compressed eight times by the pistons and ignited by a spark from a spark plug. As a result of the process, 3 components are formed:

• heat and mechanical energy rotating the crankshaft;
• combustion products of gasoline - carbon dioxide and carbon monoxide, nitric oxide and water vapor;
• combustion under high pressure generates sound vibrations - the same exhaust sound.

Since the efficiency of internal combustion engines does not exceed 45%, about half of the energy released is converted into heat. One part of the heat is removed by the engine cooling system, the second is carried away by the exhaust gases to the outside through the exhaust tract.

The smoke at the exit from the tract is cooled to a safe temperature, you can safely raise your hand - it will not burn

The VAZ 2107 exhaust system performs several important functions:

1. Emission of combustion products from the chambers and ventilation of the cylinders after the next combustion cycle.
2. Reducing the amplitude of sound vibrations, that is, lowering the noise level of a running motor.
3. Removal and dissipation of part of the released heat in the atmosphere.

On the "sevens" with an injection power system, the exhaust tract solves another important task - it cleans the exhaust from toxic CO and NO gases by afterburning in a catalytic converter.

The device and operation of the exhaust tract

The exhaust system includes 3 main elements (starting from the power unit):

• double exhaust pipe, in driver's jargon - "pants";
• middle section, equipped with one or two resonator tanks;
• the last section is the main muffler.

3 sections of the exhaust system are connected with clamps

According to the car's factory manual, the exhaust manifold is a part of the engine and does not apply to the flue gas system.

The number of resonators in the middle part of the tract depends on the type of engine installed on the VAZ 2107. If the car was equipped with a 2105 engine with a working volume of 1,3 liters, 1 tank was provided for the section (modification of the VAZ 21072). Cars with power units of 1,5 and 1,6 liters (VAZ 2107-21074) were equipped with pipes for 2 resonators.

The length of the element is the same for all carburetor modifications of the VAZ 2107, but on machines with more powerful engines of 1,5 and 1,6 liters, 2 resonator banks are provided

More about the carburetor device: https://bumper.guru/klassicheskie-modeli-vaz/toplivnaya-sistema/karbyurator-ozon-2107-ustroystvo.html

On a VAZ 2107 with an engine 2105, it is undesirable to put a section on 2 tanks - this reduces the power of the power unit. Dreaming of the quiet operation of a 1,3 liter engine, I personally tried to change a 1-tank resonator to a 2-tank resonator. I did not notice a decrease in the sound of the exhaust, but I clearly felt the drop in traction under load.

The entire tract is attached at 5 points:

• the flange of the "pants" is screwed to the outlet manifold with 4 bronze nuts M8;
• the end of the downpipe is attached to the bracket on the gearbox;
• the flat muffler tank is hooked with 2 rubber hangers;
• the exhaust pipe of the muffler is fixed with a rubber cushion screwed to the metal bracket of the body.

The principle of operation of the path is quite simple: the gases pushed out by the pistons pass through the collector and the “trousers”, then enter the resonator section. There is a preliminary suppression of sound vibrations and a decrease in temperature, after which the combustion products enter the main muffler. The latter minimizes the noise level as much as possible and throws gases out. Heat transfer and smoke cooling occurs along the entire length of the exhaust elements.

On the injector "seven" gases undergo additional purification in the catalyst

On the "sevens" with an injector, the exhaust design is supplemented by a catalytic converter and oxygen sensors. The element is located between the receiving pipe and the second section, the connection method is flanged. The catalyst cleans flue gases from toxic compounds (nitrogen and carbon oxides), and lambda probes inform the electronic control unit about the completeness of fuel combustion by the content of free oxygen.

How to eliminate the smell of gasoline in the cabin: https://bumper.guru/klassicheskie-modeli-vaz/toplivnaya-sistema/zapah-benzina-v-salone-vaz-2107-inzhektor.html

Muffler and other malfunctions

The main noise reduction section of the VAZ 2107 serves for 10-50 thousand kilometers. Such a wide range is due to the different quality of products and operating conditions. The resource of the receiving pipe and the resonator lies within the same limits.

The occurrence of a muffler malfunction is characterized by the following symptoms:

• the appearance of a rumble from the exhaust system, in advanced cases turning into a loud roar;
• constant thud - the pipe touches the bottom of the car;
• a rarer malfunction is a complete engine failure, the power unit does not start and does not show signs of “life”.

On VAZ 2107 injection models, a malfunction of oxygen sensors causes increased fuel consumption, unstable operation of the power unit and loss of power.

The condensate accumulating in the tank provokes corrosion and the formation of through holes

Rumble and roar indicate burnout of the exhaust pipe or muffler tank, which occurs for the following reasons:

• natural wear of metal;
• through damage from a blow or a shot from the side of the engine;
• the effect of corrosion due to the large amount of condensate that accumulates at the bottom of the tank.

Usually, burnouts occur at welded joints of pipes with muffler or resonator tanks. If the body is leaky from corrosion or mechanical stress, the defect is visible on the bottom of the element. Often, the exhaust "cuts" - gases break through at the junction of two sections due to a loosening of the connecting clamp.

Loose pipe connections sometimes give out drips of condensate escaping along with smoke

While teaching his wife to drive a "seven", my friend unsuccessfully chose a platform with a low parapet instead of a curb. Passing back, the girl caught the road fence with a silencer. Since the part had already worked out for a decent period, the blow was enough to pierce the body through and through.

The grazing of a tank or pipe on the bottom of the car occurs due to stretched or torn rubber suspensions. Swinging and impacts cause a dull annoying knock, which is eliminated by replacing the rubber bands.

Stretching or breaking of rubber suspensions causes thuds from the side of the muffler

If the engine is absolutely “dead”, it is worth checking the catalyst of the injector “seven” or the tract itself for blockage. A completely blocked pipe section will not allow gases to be ejected from the cylinders and a new portion of the combustible mixture to be drawn in.

A clogged or clogged catalytic converter can be identified by a soft hiss of air coming from one of the pipe joints. When you repeatedly try to start the engine, the pistons pump air into a clogged exhaust system, which under pressure begins to escape through leaks. If you unscrew the "pants" from the manifold and repeat the start, the engine will probably start.

I personally had a chance to see a complete blockage of the pipe when a friend asked to start the car from the pusher (the battery was discharged from the long rotation of the starter). The attempt failed, we moved on to the diagnosis of ignition and fuel supply systems. A quiet hiss of air from the manifold was noticed when checking the carburetor. It turned out that the owner added a “good” additive to the fuel, which provoked the formation of soot, which completely clogged the exhaust tract.

Case rupture occurs with a strong impact or as a result of a shot from the side of the exhaust manifold

How to change the main muffler

Small fistulas on the body, located in accessible places, are usually eliminated using a gas welding machine or a semi-automatic device. Closing in another way will give a temporary result - gas pressure and high temperature will render any clamp or adhesive patch unusable. Welding a stainless steel muffler requires the right skill.

If you do not have the necessary equipment and skills, it is better to replace a worn part with a new one. The operation is not difficult, special devices are also not needed. For a beginner, the procedure will take no more than 3 hours.

Preparation of tools and workplace

Since the muffler is located under the car, disassembly requires an inspection ditch in the garage, an overpass in an open area, or a lift. It is extremely inconvenient to remove the part while lying on the ground under the car. The main difficulty is to separate 2 sections in this position, whose pipes are inserted one into the other and stick strongly during the period of operation. Therefore, it is not recommended to change the muffler without a pit.

To perform the work, you will need the usual tools:

• ring wrench or head with a knob size 13 mm;
• hammer with a comfortable handle;
• gas wrench No. 3, capturing pipes with a diameter of 20 to 63 mm;
• flat wide screwdriver, pliers;
• cloth work gloves.

With a pipe wrench and a powerful screwdriver, it is easier to separate the sections of the exhaust tract

To facilitate the unwinding of stuck threaded connections and the separation of pipes, it is worth purchasing a lubricant such as WD-40 in an aerosol can with a straw.

During operation, the rubber suspensions are stretched, which is why the case begins to hang out in a horizontal plane. Hence the advice: along with the final element, change rubber products, the kit is inexpensive (about 100 rubles).

Suspension rubber bands should always be changed along with a burnt pipe.

Replacement procedure

Before starting work, you should put the "seven" in the pit and wait 20-40 minutes, depending on the air temperature at the workplace. The exhaust tract warmed up by the engine must cool down, otherwise you will get burns even through gloves.

Dismantling the old muffler is carried out in the following order:

1. Carefully treat threaded connections and joints with WD-40 grease from a can, wait 10 minutes.
2. Loosen and unscrew the nuts of the metal clamp that tightens the ends of the muffler and resonator pipes. Slide the mount to either side.
   

   If the bolt is stuck and unwinds with great difficulty, it is worth changing the clamp to a new one.
3. Unhook the 2 side hangers attached to the tank.
   

   Usually rubber hangers are easily removed by hand, but if necessary, you can use pliers
4. Remove the long screw securing the rear rubber pad.
   

   Drivers often change the long bolts of the pillow for ordinary nails
5. Swinging the section to the right and left, disconnect the muffler from the middle pipe and remove it from the car.

Many Zhiguli owners have not used a long screw for attaching the rear cushion for a long time, because the thread turns sour from rust and does not want to unwind. It is much easier to insert a nail or an electrode with a diameter of 3-4 mm instead of a screw and bend the ends.

The last section of the exhaust pipe is attached at 4 points - 3 hanging rubber bands and a joint with a resonator

If the exhaust system sections cannot be disassembled, use the suggested disassembly methods:

• unbend the outer end of the pipe (with slots) with a powerful screwdriver;
  

  Thanks to two slots, the edge of the stubborn pipe can be bent with a screwdriver
• having set a wooden gasket, hit the end of the pipe several times with a hammer;
  

  You can hit the muffler body with a hammer, but through a wooden tip
• turn the pipeline with a gas key;
• for convenience, cut off the old muffler with a grinder, then disassemble the connection.

Assembly is carried out in reverse order. Install rubber bands on a new spare part, grease the mating surfaces with grease and put the muffler pipe on top of the resonator. Make sure that the pipe sits all the way, then put on and tighten the clamp.

Video: replacing a VAZ 2107 muffler in a garage

REPLACEMENT OF THE MUFFLER VAZ 2101-2107

Repair of minor damage without welding

If small holes have formed on the pipe or muffler body due to corrosion, they can be temporarily repaired and extend the life of the part by 1-3 thousand km. Welding defects will not work - the metal surrounding the holes probably managed to rot.

For the work will need the following materials:

• high-temperature ceramic sealant;
• thin soft metal (tin) 0,2-0,4 mm;
• large sandpaper or a brush fixed in an electric drill chuck;
• scissors for metal;
• degreasing agent.
  

  With the help of ceramic sealant, small holes in the pipe can be temporarily sealed.

It is not necessary to remove the muffler, act as necessary. If the defect cannot otherwise be reached, carefully dismantle the element. Produce sealing according to the instructions:

1. Sand the damaged area with sandpaper to level the surface and reveal any imperfections hidden by rust.
2. From the tin, cut a clamp that covers the through holes.
   

   The tin clamp is easily cut from a thin metal profile
3. Degrease the area and apply a coat of sealant on the side of the damage.
   

   Ceramic sealant is applied to a surface well cleaned of rust.
4. Lay on a tin piece, wrap around the pipe and make a self-tightening collar.
   

   After tightening with pliers, the bandage should be tapped with a hammer

A tin clamp is made by double bending the ends of the workpiece. To avoid mistakes during the repair process, first practice on any pipe. When the sealant has hardened, start the engine and make sure that the clamp does not allow gases to pass through.

Usually, the bottom wall of the muffler tank rusts from the inside under the influence of aggressive condensate. There is an "old-fashioned" method for solving the problem - a hole with a diameter of 3-4 mm is specially drilled at the lowest point. The sound of the motor will practically not change, but the water will stop accumulating inside the tank.

The drain hole must be drilled at the lowest point of the body

Video: how to close the exhaust without welding

how to weld a muffler without welding

What muffler can be put on the "seven"

There are 4 replacement options:

1. Regular muffler VAZ 2101-2107 made of ordinary steel with anti-corrosion coating. Plus - low price of the product, minus - unpredictable duration of work. When buying, it is rather difficult to assess the quality of the metal and workmanship, except that the welds will be made quite carelessly.
2. Factory section in stainless steel. The option is not cheap, but durable. The main thing is not to buy a fake from cheap Chinese metal.
3. The so-called straight-through type sports muffler, manufactured in the factory.
4. Weld the outlet element of the desired design on your own.

Standard mufflers are made of ordinary metal with an anti-corrosion coating.

If you do not have welding skills, the fourth option is automatically eliminated. It remains to choose between stock and sports detail.

The straight-through muffler differs from the regular one in the following ways:

• shape - round, outlet of larger diameter;
• construction - inside a straight perforated pipe lined with fireproof sound-absorbing material;
• the sound of operation is low-frequency, louder.

Factory-made forward flow is painted on the outside with heat-resistant paint, the pipe outlet is equipped with a decorative nozzle

The forward flow resistance is much less than the factory muffler model. The design allows you to more effectively ventilate the cylinders and increase engine power within 5 liters. With. A side effect is a higher noise level, which is a pleasure for extreme riders.

The stock design muffles noise due to several internal baffles and additional perforated pipes, forcing gases to change direction and repeatedly bounce off obstacles. Hence the high resistance of the element and a small drop in power.

In a conventional element, sound and gases change direction several times, in a cocurrent element they dissipate through the perforation of the pipe

Tuning enthusiasts install forward flow in combination with other means - zero-resistance filters, turbines, and so on. Replacing a regular muffler with a straight-through one without performing other measures will give one result - a loud roar, you will not feel an increase in engine power.

It is not difficult for a motorist who owns a welding machine to make a forward flow on their own:

1. Make a round tank out of sheet metal (you will need rollers) or pick up a ready-made can from another brand of car, for example, Tavria.
2. Place a perforated pipe inside, having previously drilled many holes with a diameter of 5-6 mm.
   

   Slots in the pipe are easier to make, but it is better to spend more time and make holes
3. Fill the cavity between the straight channel and the walls tightly with non-combustible basalt fiber.
4. Weld the end walls and supply pipes. A curved element of an old muffler is perfect as an inlet pipe.
   

   If desired, forward flow can be made double - then the noise level will decrease
5. At the required points, attach 3 fasteners corresponding to the standard hangers.

You can ennoble the outlet pipe with a nickel-plated decorative nozzle. The choice of products in size and shape is extremely wide, the prices are quite affordable.

Video: do-it-yourself forward flow

Forward flow to the VAZ With Your Hands

What is important to know about the resonator

Structurally, the preliminary silencer is identical to the forward flow described above - a straight perforated pipe passes through the cylindrical body. The only difference is a partition that divides the space of the tank into 2 chambers.

Tasks of the resonator:

• extinguish primary sound vibrations of large amplitude;
• facilitate the work of the main muffler and extend its life;
• remove part of the heat from the flue gases.

The resonator bank resembles a forward flow, only the size of the part is smaller

The principle of operation of the element is based on the physical phenomenon of resonance - repeatedly reflected from the partition and the inner walls of the can, sound waves cancel each other out.

The VAZ 2107 car is equipped with 3 types of resonators:

1. The classic version for carburetor engines, used in the first models with an injector, is a long pipe with one or two banks (depending on engine size).
2. Injector models that comply with Euro 2 exhaust standards were equipped with a shortened resonator section with a flange at the front end of the pipe. A catalytic converter was bolted to it.
   

   The latest VAZ 2107 models were equipped with a converter that took away part of the length of the resonator tube
3. After the introduction of Euro 3 standards, the length of the catalyst increased, and the resonator decreased. The section for the injector version of the "seven" that meets these requirements is equipped with a 3-bolt front flange.
   

   Euro 2 and Euro 3 resonators differ in the shape of the mounting flange and length

During the operation of the resonators, the malfunctions described above occur - burnouts, rust and mechanical damage. Troubleshooting methods are similar to muffler repair - welding or temporary sealing with a bandage. It is not difficult to remove the resonator section - you need to unscrew the mount to the gearbox, then disconnect the muffler and "pants" pipes. On the VAZ 2107 with an injector, instead of the front clamp, the flange is disconnected.

Find out how you can control fuel consumption: https://bumper.guru/klassicheskie-modeli-vaz/toplivnaya-sistema/rashod-fupliva-vaz-2107.html

Video: how to remove the resonator VAZ 2101-2107

Replacement Silencer resonator VAZ classic

Since the classic Zhiguli models, including the VAZ 2107, have been discontinued, the problem of purchasing high-quality spare parts arises. The market is flooded with cheap mufflers that burn out after 10-15 thousand km. Hence the final conclusion: sometimes it is easier to turn to an intelligent welder and eliminate the defect at low cost than to purchase a new part of dubious origin.