What should be the compression in a 16-valve Priors engine?

05 February 2016 Lada.Online 77 409 10
How to quickly and accurately determine the condition of the engine? Check the compression in the cylinders! Is the engine running rough, you feel a loss of power, the consumption of engine oil or fuel has increased and the car has become difficult to start in cold weather? All of these problems may be caused by low compression in one or more cylinders.

To ensure that the compression test gives accurate results

Compression depends not only on the technical condition of the engine, but also on the conditions under which it is measured. Make sure that during the check:

the compression gauge was working properly;
the engine has been warmed up to operating temperature (up to 90 degrees);
the throttle valve was fully open;
spark plugs in all cylinders must be turned out;
the starter was fully operational;
the battery was fully charged;
The engine air filter was clean.

What are the cylinder compression standards for VAZ engines?

Engine specifications must indicate “minimum cylinder compression values.” If you cannot find such data, determine the compression standards yourself using the formula:

Compression (kgf/cm2) = compression ratio (see technical specifications of internal combustion engine) * coefficient (for VAZ min 1.2, max 1.3)

The compression ratio of modern VAZ 21126 and VAZ 21127 engines installed on Granta, Kalina and Priora is 11. We multiply the values using the formula and get the compression standards: 13,2..14,3.
For the Vesta engine (VAZ-21129) the compression ratio is 10.45, the compression standards will be: 12,5..13,6.
For Niva (VAZ 21213, 21314) - 11,3..12,2.

If the compression gauge values in all cylinders are within the normal range, this does not mean that everything is fine. Different compression in the cylinders is also bad. It is important that the difference between all readings is minimal. Compare the minimum and maximum compression values in the cylinders. According to technical standards, the difference should be no more than 1 kgf/cm2 or 10% .

High compression in the engine

So, as mentioned above, compression in the power unit can be influenced by a number of factors. Let's start with increased compression. First of all, increased compression usually indicates that there is a problem with the engine. As a rule, the main symptom is unstable engine operation, discoloration of the exhaust and increased oil consumption.

Typically, in many cases, car enthusiasts are faced with so-called “oil” compression, when general engine coking and problems with oil scraper rings lead to excess oil and carbon deposits actually reducing the volume of the combustion chamber. The result is an increase in compression.

In other words, an increase in compression is caused by carbon deposits on the timing valves, the accumulation of coke in the combustion chamber and the occurrence of oil scraper rings. A common cause is also engine overheating, when oil loses its properties due to high temperatures and quickly contaminates the combustion chamber.

Other reasons include the use of additives in the lubrication system, pouring inappropriate or low-quality oil for the engine, constant operation of the engine on low-grade fuel, etc.

One way or another, the accumulation of coke and soot leads to a decrease in the volume of the combustion chamber in which the fuel-air mixture is compressed. Naturally, in this case, when taking measurements, the compression meter will show too high a compression.

Let us also add that deviations from the norm can be caused by incorrect installation of valve timing. Simply put, errors when aligning the pulleys when replacing a timing belt or chain will lead to the drive element jumping several teeth (on an internal combustion engine with a belt) or links (on chain engines) forward or backward.

To avoid possible problems, it is necessary to pay special attention to the location of the marks on the pulleys, engine housing, etc., that is, set the timing drive, and also correctly tension the chain or belt.

Also, the cause of high compression may be a combination of problems with valve stem seals and rings. If, after unscrewing the spark plugs in the cylinders, a clear excess of oil is visible in the form of a thick oil film on the cylinder walls, then this clearly indicates the need to replace the valve seals.

If we summarize the information why increased compression occurred in the engine, the reasons are as follows:

there is a lot of oil in the engine cylinders (rings are stuck, valve seals are worn, etc.);
change in the volume of the combustion chamber as a result of the accumulation of deposits and soot, as well as engine overheating and deposits of burnt oil;

Let us also add that compression is affected by air temperature and the condition of the air filter. When taking measurements, it is advisable to disconnect the air filter. It is also important to understand that at many service stations, compression gauges have a large error.

In practice, this requires several repeated measurements on a hot engine, preferably with different and pre-calibrated instruments. There have been cases when at one station the driver’s compression was determined after measurements, for example, 12.5-13, and at another service the readings for all cylinders were already about 16.

To solve the problem of high compression, you can use several available methods. The first is disassembling the engine, physically cleaning the pistons and combustion chamber from carbon deposits, replacing rings, valve stem seals, etc. A cheaper and less effective solution is to decarbonize the engine. In a nutshell, an active cleaner is poured into the combustion chamber for a certain time to remove carbon deposits and coke, after which the deposits washed off the walls and surfaces then burn out while the engine is running.

Reasons why there is no compression in the cylinder

Poor (small) compression in one or all cylinders indicates engine wear. There is an old and simple way to determine why compression has disappeared. You need to pour a tablespoon of engine oil into the spark plug hole and repeat the measurements:

if the pressure has increased noticeably, it means the piston rings have poor sealing;
if the pressure has not changed, then there may be several reasons (for example, leaking valves, broken gaskets under the cylinder head, there is a crack or burnout in the walls of the combustion chamber, in the piston bottom).

There is another, more accurate way to find out why compression has disappeared. To do this, you will need to modify the spark plug. We remove the insulator from it, and weld the valve of the car camera to the metal body. Next, set the cylinder piston to the ignition timing position, remove the radiator caps and oil filler neck, screw in the manufactured adapter and pump air into the cylinder using a pump (create pressure in it):

if air enters the exhaust pipe, it means the exhaust valve is poorly sealed;
If air goes into the intake manifold, there is a problem with the intake valve.
if bubbles appear in the expansion tank, then check the cylinder head gasket;
If there is a hissing sound in the oil filler neck, it means that the piston rings are not properly sealed.

Engine diagnostics using compression measurements in the cylinders allows you to quickly and accurately determine its condition without disassembling, and in some cases will help avoid major repairs of the power unit. Have you ever experienced a lack of pressure in the cylinders? What was the cause of the malfunction? If engine problems persist, check the fuel rail pressure.

Source

What compression should the VAZ-2109 injector and carburetor have?

What is engine compression. How to check the compression of a VAZ 2109? Often, car owners are faced with vibration that unexpectedly occurs when driving at idle speed, and large fuel combustion. There are several reasons for this deficiency, for example, problems with spark plugs or malfunctions of the fuel system.

Poor engine compression can also lead to such consequences. If diagnostics of the fuel system shows that everything is in order, you need to check the compression in the cylinders.

Compression is the maximum pressure in the cylinder that occurs at the end of the compression stroke (at the moment the piston reaches top dead center). To measure compression there is a special device called a compression gauge (a pressure gauge with a hose and a fitting at the end).

What is engine compression. How to check the compression of a VAZ 2109?

Poor compression in the cylinders leads to the following consequences:

fuel consumption increases;
dynamics deteriorate (acceleration);
the accelerator responds poorly to the pedal;
poor “traction”;
black exhaust appears.

Checking the compression of the VAZ 2109 engine with your own hands

Before measuring compression, you need to check the valve clearances and adjust them.
Warm up the engine to 70-80 degrees.
Turn off the engine, remove the spark plugs (to do this, use a spark plug wrench).
Disconnect the fuel hose and clamp it to prevent fuel from leaking.
Remove the central drive from the ignition coil.
Use a compression gauge installed in the spark plug socket to determine the indicators.
Start checking from the first cylinder. Each cylinder must be checked separately.
At this time, the assistant must turn the starter so that the compression gauge can record the resulting pressure.
Record the device indicators.
The minimum permissible compression is 10 kg/sq. cm, and the spread between the cylinders should not exceed 1 kg/sq. see. If your readings differ greatly from each other, we can conclude that there is wear on the compression rings, valves that do not fit well on the seats, or problems with the tightness of the cylinder head gasket.

If the cylinder compression is less than the figure indicated above or is different in each cylinder, a major overhaul of the engine is required.

Most likely, you will have to change the cylinder head gasket, grind in and adjust the valves, and install new piston rings. It is possible that the piston rings are stuck, then the engine will have to be decarbonized.

To narrow down the range of possible problems, you need to do a few simple tests with an air compressor.

Set the piston of the cylinder being tested to the top dead center position.
Tighten the handbrake, turning on speed 4-5.
Start the compressor and supply air under pressure to the cylinder.

Monitor the air flow

If you hear a hissing sound in an adjacent cylinder, there is most likely damage to the gasket between the cylinders. To solve this problem, you need to replace the cylinder head gasket.
To make sure that there are no breakdowns in the engine cooling system, you need to remove the radiator cap or expansion tank and make sure that the coolant level does not increase when air is pumped. A breakdown may be indicated by air bubbles or a change in the color of the coolant, or the appearance of an exhaust odor.
If there is a hissing sound in the manifold or exhaust pipe area, it is most likely due to the intake or exhaust valve.

Source:

How to diagnose a VAZ 2108-21099 engine using a compressor

Only experienced specialists can visually clearly identify this or that engine problem; it is quite difficult, almost impossible, for an ordinary driver to do this. Of course, you can notice potential problems by the exhaust or sound, but this is only a small part of all possible malfunctions.

More accurate diagnostics are performed using serious instruments. This article will discuss engine diagnostics, which are more complex than visual, using simple, simple instruments.

Diagnosis of the VAZ 21099-2109-2108 engine using simple DIY tools

What is needed for diagnosis:

a compression meter that measures compression in the cylinders;
an oily rag that is used to determine the compression stroke of the engine. A tool made by combining a fitting for spark plug holes and a regular whistle will be convenient and effective;
adapter for spark plug holes, which is used in the process of checking the tightness of the combustion chamber, compressor for inflating wheels.

Diagnostic procedure

The operating algorithm is as follows:

It's better to start with compression. First, you need to warm up the engine to operating temperature, and then turn off the fuel supply. In this case, the hose on a carburetor engine is removed, compressed and pinched with something, or simply lowered into some container.
For an injection engine, everything is much simpler - you just need to pull out the fuel pump fuse. Then you need to start the car (there should be some fuel left in the fuel rail) and wait until the engine stalls.
After this, the ignition system is turned off, for which the central wire is removed from the distributor, and the sensor on the injector that monitors the position of the crankshaft is turned off.
All debris that has accumulated there must be removed from the spark plug wells so that it does not get into the cylinders. After this, all the candles are unscrewed.
Next, the compression gauge fitting is screwed in or inserted—it all depends on the model—after which the assistant begins to start the engine. The starter must rotate the engine until the pressure gauge needle stops in one position. Such measurements are carried out on each cylinder, and their results are recorded.

There is a special formula with which the ideal compression can be calculated for any engine. Compression is 1.2* compression ratio.

For example, the VAZ 21083 engine has a compression ratio of 9.8. Thus, its compression will be equal to 1.2 * 9.8 = 11.76.

This means that a compression of 11-12 atmospheres is quite normal for this engine. But each measurement has its own errors.

What factors may influence measurements?

only a new or well-repaired car can have a compression of 12 atmospheres, for example, after an engine overhaul;
a cold engine that has not reached operating temperature will have significantly lower compression;
if the battery is weak or begins to “crumble”, then the engine will not turn so fast, so in this case the compression will be less;
compression increases due to the combustion of oil in the cylinders - as a result of its combustion, the connection is sealed.
Having recorded all the measurement data, it is necessary to analyze it. The spread of results for all cylinders should not exceed one atmosphere. For example, if in one cylinder the compression is 9 atmospheres, and in the other three – 11, then in this case you need to think about it. To more accurately determine the nature of the malfunction, it is necessary to carefully monitor the pressure gauge readings, or more precisely, how the pressure increases with each crankshaft revolution.

If at the first revolution there is low pressure (3-4 atm.), and with subsequent revolutions it increases, this indicates wear on the cylinders or problems with the rings. In this case, when about 10 cubes of engine oil are added to the cylinder, an increase in compression will be observed already with the first revolution.

When at the first revolution a compression of 5-8 atmospheres is observed, and with subsequent revolutions the picture practically does not change, this indicates possible valve deformation or a leaking cylinder head gasket

Important! A serviceable engine at the first revolution “produces” 6-8 atmospheres, and with subsequent revolutions it “pushes” up to 11-12 atmospheres.

After analyzing the overall results, we can draw the following conclusions:

compression of 0-4 atmospheres indicates a probable burnout of the piston, valve or cylinder head gasket;
compression 4-6 atm. usually indicates broken piston rings or partitions between these rings;
if the compression in each cylinder is approximately the same and amounts to 8-10 atmospheres, then this indicates wear of the cylinder-piston group, so it is necessary to prepare for the upcoming engine overhaul;
A new and run-in engine can have a compression of 12-12.5 atmospheres.

If a car with decent mileage produces results equal to or higher than normal, this indicates that oil may have gotten into the cylinders. The probable reason for this is wear of the cylinder-piston gear or valve guides.

Now it is necessary to compare the obtained data with the results of a visual inspection.

So, everything has been examined, an analysis has been carried out and the problematic cylinder has been found. But the overall picture still requires clarification. In this case, it is necessary to check the cylinder for leaks.

Leak test

You can check the tightness of the cylinder as follows:

Use an oiled rag or the previously described device with a whistle to close the hole in the problem cylinder.
It is also necessary to lift the car (it is enough to lift one drive wheel). Everything will be much simpler if there is a “crooked starter”.
When the top gear is engaged, you need to turn the drive wheel or turn the engine using a crooked starter in neutral gear. It is necessary to rotate the crankshaft until the oily rag flies out or the whistle begins to whistle. Using this simple method, you can determine the compression stroke in the required cylinder.
Next, the car is lowered, the handbrake and gear are engaged, after which the suspicious cylinder is inflated by a compressor (in extreme cases, air from the wheel can be used).

By the hiss of air you can get a more accurate picture:

air escaping from the adjacent spark plug hole indicates a burnt-out cylinder head gasket;
air escaping from the carburetor indicates a problem with the intake valve;
A hissing sound in the muffler indicates a burnt out exhaust valve. A side effect of this malfunction is the engine “triggering” and smoking. This problem is the most common;
Air coming out of the crankcase gas outlet indicates piston burnout or ring wear.

So, using the simple procedures described above, you can accurately determine whether this car is worth buying (if this was the purpose of the diagnosis), or find out whether your favorite car needs repairs.

Source:

Measuring compression in a VAZ 2109 engine

Compression in the cylinders of a VAZ 2109 engine is a very important indicator, on which not only power depends, but also the internal condition of the engine and its parts.

If the car engine is new and well run-in, then it is generally accepted that excellent compression will be 13 atmospheres.

Of course, you shouldn’t count on such indicators if your car’s mileage is already quite long and has exceeded 100,000 km, but it’s worth keeping in mind that a compression of at least 10 bar is considered the minimum acceptable.

To diagnose their VAZ 2109 engine, many people turn to specialized service stations for this procedure, although in fact this work can be done independently, having with you a special device called a compression meter.

I bought such a device for myself a few months ago, and now I measure compression on all my cars myself. The choice fell on a device from Jonnesway, since I have been using instruments from this company for quite some time and am very pleased with the quality.

Source: https://granta-service.ru/tyuning/kakaya-kompressiya-dolzhna-byt-na-vaz-2109-inzhektor-i-karbyurator.html

What should be the compression on a Lada Priora 16 valves

Car : Lada Priora. Asks : Ninja Turtle. The essence of the question : at what minimum compression does the engine still run well?

Hello. It feels like the engine has stopped pulling. There is practically no smoke from the exhaust. If there is, then after rain it’s mostly STEAM . We measured the compression - 11.6 , 14 , 12 , 14 . The master said that the first cylinder is not very good, but there should be traction.

Is this normal compression for the Priorovsky 16-valve engine?

Factory compression on Lada Priora

New engines after running in may show 16. This is quite normal.

It is believed that if the compression is less than 13 on a Priorov engine, then this will lead to immediate problems. The engine on the Priora is very high-torque, if the compression is less than 12, then the thrust will no longer be the same. That is, the minimum compression is about 12 atmospheres .

Compression check

Even for cars with a significant mileage, this parameter should not decrease less than 12 atmospheres . In your case there is a problem with the first cylinder, there could be many reasons. If I were you, I would get into the engine with capital only after a serious oil leak or the traction disappears completely.

To check compression on a Priora, the following tools are required:

To measure compression on a 16-valve engine:

Warm up the engine until it reaches operating temperatures.

You can inspect the condition of the spark plug wells with a flashlight.

Capital is close. But you can drive!

Simple gasket test

If there is insufficient compression, you need to pour a little oil into the cylinder. Then we check again. When increasing the parameters, the problem should be looked for in the piston rings. If nothing changes as a result of the addition, then the head gasket will have to be replaced.

We would recommend checking the compression of the first cylinder in this way.

Source

Arrangement of cylinders on the Prior

Let's see if this is as experienced car owners describe.

Work resource

The working life of the VAZ engine is 200 thousand km. Next, the car owner has to put the engine in for major repairs. The timing belt needs to be checked every 50 thousand kilometers. According to experienced car owners, it is because of a broken circuit that the valves bend.

The engine does not like overheating, which means it does not like the lack of oil. Car owners should carefully monitor the presence of lubricant inside the engine. Without oil, the VAZ21126 will overheat greatly, which means the engine’s already short lifespan will become even shorter.

The working life of the chain may be less than the life of the motor itself. But a broken timing belt takes valves and pistons with it. This disease was not present on VAZ 21124 engines. But such engines were installed only on Standard class Priors, that is, cheap modifications of domestically produced cars.

Similar article Engine temperature indicator and sensor on Lada Grant

Other reasons that affect the life resource:

fuel quality. The operating book indicates the brand of fuel that the engine requires. Do not underestimate the figure under any circumstances;
quantity and quality of oil. Experienced mechanics do not recommend pouring or adding lubricant if the car owner changes the oil himself. Do everything strictly according to the level. Such engines love semi-synthetic or fully synthetic lubricants.

Following the rules described above, the motor can last the stated 200 thousand kilometers.

Attention! Pour new oil strictly into the filler neck. You can use a funnel for the procedure.

What to do if the number is unreadable

If the number is not readable, then an examination is ordered. This procedure most often occurs at a post or during a technical inspection. When the inspector cannot read the engine number, he orders an examination.

The number cannot be read for some technical reasons or due to the large amount of rust that has eaten the metal. If the car was often driven in humid areas, in snow with increased salt deposits from ice, then the metal will be susceptible to corrosion. Of course, the embossed numbers cannot be determined.

Attention! During the examination, documents are confiscated. The vehicle is suspected of being stolen, and the code may have been broken. This cannot be avoided, so you just need to wait for the results of the examination and not rush things.

The car owner is invited to the procedure at the appointed time. The process consists of the following steps:

Experts remove all parts from the engine compartment, which, in their opinion, will interfere with a detailed examination of the VIN code.
Experts lubricate the remaining code with various means. It must be said right away that the examination is free, but the work of experts must be paid. Therefore, it is necessary to prepare money at the end of the procedure.
Then the result is photographed. Photos are taken from different angles.
They write off the vehicle coding from other parts of the car where they can be read.

Similar article VAZ 11186 engine, technical characteristics and service life

If after the procedure they were able to read the numbers, then the car owner can safely go to the MREO. If it fails, then the owner will have to wait half a month until the results are known.

During this time, it will be found out whether this car is listed as stolen, and whether the coding on it has been interrupted. If everything is in order, the documents will be returned to the car owner, and he will continue to drive the Lada Priora.

If the VIN code has rotted naturally, then this will be indicated in the documents. The car owner will be given documents, and the number will be additionally written in the technical passport

It is important to know that after painting with chemicals, the engine number can rot very quickly. Therefore, it needs to be lubricated with lithol. Painting is not recommended under any circumstances. Since the traffic police at the next check will suspect that the numbers have been interrupted. Then the car owner will have to undergo an examination again.

Checking compression in cylinders

On new Lada Priora engines, the compression in each cylinder must be at least 16 atmospheres. And if, when replacing it, it turns out that in one or more cylinders these readings are very different from the maximum, then a more thorough diagnosis of the engine is necessary, and identification of the problems that caused such a decrease.

In order to check the compression on the Priora ourselves, we will need:

Compression measurement

A compression test is carried out for a general assessment of the technical condition of the parts of the cylinder-piston assembly and the engine valve mechanism. The check is carried out with the engine warmed up to operating temperature. We increase the pressure in the engine fuel system (see “Replacing the fuel filter”) and do not replace the fuel pump fuse. We unscrew the spark plugs from the cylinder head (see “Checking the condition and replacing the spark plugs”). Disconnect the engine management system wiring harness assembly from the ignition coil wiring harness assembly (see “Engine Removal and Installation”).

Install the compressor tip into the spark plug hole of the cylinder head. We connect the wire terminal to the negative terminal of the battery. We turn the crankshaft with the starter while the accelerator pedal is fully pressed for 2-4 seconds (the pressure gauge should stop rising). We record the pressure gauge readings and relieve the pressure in the compressor. To correctly assess compression, the battery must be fully charged - the crankshaft speed when cranking must be at least 180 min -1. Similarly, we check the compression in other engine cylinders. The compression of a running engine should be between 11.0 and 13.0 bar, and the difference in cylinder readings should not exceed 2.0 bar. To find out the reasons for low compression, pour 10-15 cm 3 of engine oil into the cylinder through the spark plug hole and repeat the measurement. If, upon repeated measurements, the compression increases by more than 2.0 bar, the most likely cause of the malfunction is severe wear, blockage or breakage of the piston rings. If after filling the oil the pressure gauge readings do not increase, the valve discs most likely will not fit into the cylinder head sockets. This can occur if the valve actuator is malfunctioning, or if the valve poppets or seats are severely worn, burned, or damaged. The cause of the malfunction can only be definitively determined after disassembling the engine.

On new Lada Priora engines, the compression in each cylinder must be at least 16 atmospheres. And if, when replacing it, it turns out that in one or more cylinders these readings differ greatly from the maximum, then more thorough diagnostics of the engine is required and identification of the problems that caused such a decrease.

To check the compression on the Priora yourself, we will need:

Candle head
Extension
Ratchet or crank
Compressor
Head 10 mm

Reasons why there is no compression in the cylinder

if the pressure has increased noticeably, it means the piston rings have poor sealing;
if the pressure has not changed, then there may be several reasons (for example, leaking valves, broken gaskets under the cylinder head, there is a crack or burnout in the walls of the combustion chamber, in the piston bottom).

if air enters the exhaust pipe, it means the exhaust valve is poorly sealed;
If air goes into the intake manifold, there is a problem with the intake valve.
if bubbles appear in the expansion tank, then check the cylinder head gasket;
If there is a hissing sound in the oil filler neck, it means that the piston rings are not properly sealed.

How to determine why the compression in the cylinder has dropped?

If it is determined that in one of the cylinders the compression is below normal, it is necessary to determine what exactly caused the problem.

To more accurately determine why the pressure in the cylinder dropped, you should carry out several simple procedures:

Pour 10-15 g into the cylinder with reduced compression. engine oil, then measure again. If the indicators have improved, it means that the reason for the fall lies in the rings (they are stuck or one of them has burst);
Remove the valve cover and check the valve clearances on the required cylinder;
Carefully inspect the engine at the junction of the head and the block. If there is a gasket breakdown leading outward, oil leaks will be visible;
Pull out the dipstick and assess the condition of the oil. If it is very blackened and a burning smell is clearly visible, then this may indicate a breakdown of the gasket, in which the cylinder is connected to the oil channel;
Assemble the engine and start it. Then you should inspect the expansion tank of the cooling system. If escaping air bubbles are visible in it, this will signal the connection of the cylinder with the channel of the cooling system. Additionally, you can put your hand on the exhaust pipe while the engine is running. If small sweet-tasting drops remain on the palm, this will indicate that coolant has entered the cylinder, that is, there is a breakdown.

If all the procedures carried out did not produce results, that is, after filling the oil, the compression did not increase, the thermal clearances are normal and there are no prerequisites for a breakdown of the cylinder head gasket, then the reason lies in the piston, valves or cylinder head.

But to make sure of this, you will have to remove the block head.

Reasons for a drop in compression in one cylinder

It also happens that a pressure drop occurs in one of the cylinders, and significantly (in some cases, compression can drop to 3-4 kgf/cm2).

And such diagnostic results are a reason to worry, because there are malfunctions in the power plant.

The reasons for a drop in compression in one of the cylinders above normal may be:

COMPRESSION RINGS. These elements play one of the most important roles, since their task is to ensure tightness in the piston-cylinder pair. If the rings are damaged (burst) or stuck, they will begin to leak working gases into the sub-piston space, which is why a significant drop in compression occurs;

VALVES. Through these elements, the components of the combustible mixture are admitted and exhaust gases are removed. But during the compression stroke, the valves are closed, which seals the combustion chamber. But if, due to a violation of the combustion processes, the edge of the valve plate and seat are burnt, or the thermal gap is broken, and it turns out to be slightly pressed, then the tightness of the chamber is not maintained, which affects the compression;

PISTON. This element is rarely to blame for a drop in pressure in the cylinder, but there are still situations when the reason lies precisely in it. As a result of the same process changes, the piston crown may burn out. This usually happens due to a violation of the ignition angle. And if the piston burns out, then there will be no tightness;

BLOCK HEAD. Although rare, it does happen that cracks and other defects appear in the combustion chamber, affecting the loss of compression. Also, the head can cause a loss of pressure in some cylinder if it fails due to overheating. Due to changes in geometry, the head in some places simply does not fit tightly to the gasket. Even a simple insufficient tightening of the cylinder head bolts can affect compression;

cylinder head gasket. Due to internal defects or overheating, a breakdown of this gasket may occur. As a result, one of the cylinders is connected to a channel of the cooling or lubrication system, another cylinder (in this case, a strong drop in compression is observed in two cylinders), and the breakdown can also lead out of the engine. Read more about the signs of a broken cylinder head lining.

Also read why the car engine does not pull.

Compression - what is it and what should it be?

Compression is a measure of the maximum pressure in the combustion chamber that the piston can create when it reaches TDC during the compression stroke.

Measuring this indicator gives an idea of the tightness of the chamber, which in turn depends on the condition of a number of elements - the piston and compression rings, valves with seats, head gasket, and the installed thermal gap in the timing belt.

Since the compression measurement technology itself is simple, and the data obtained as a result of its implementation makes it possible to estimate the remaining life of the power plant and identify a number of malfunctions, this diagnostic operation is quite common.

Although car power plants have a common design principle, they are structurally different, which also affects compression indicators.

Each engine has its own specific maximum pressure values in the combustion chambers, which must be indicated in the technical specifications. documentation for the car.

For example, for a VAZ-2106 a compression of 11 kgf/cm2 is considered normal, but for a VAZ-2110 this figure is already 13 kgf/cm2.

Note that when measuring, it is not necessary that the device should show values that correspond to the norm. As engine components wear, compression readings will drop.

Moreover, if they drop below a certain value, this will be a signal of extreme wear of the power plant’s CPG, and the need for major repairs.

Some variation in readings between cylinders is also allowed. However, it should not exceed 1 kgf/cm. sq.

That is, if measurements on a VAZ-2115 showed that the compression in the cylinders was 12 kgf in the 1st, 11 kgf in the 2nd, 12 kgf in the 3rd, 12 kgf in the 4th, then the power plant of the car will be considered to be in working order.

Read more about compression and compression ratio of a diesel engine.

Procedure for checking compression on a 16-valve Priora engine

We will immediately show how to perform this procedure on a 16-valve engine, since on an 8-valve engine everything is done much simpler, and there certainly won’t be any questions.

The first step is to warm up the engine to operating temperature.
Remove the top plastic casing
Unscrew the bolts securing the ignition coils and remove them
Remove all 4 spark plugs

Now you need to disconnect the power from the coils by disconnecting the wiring harness block, as shown in the photo below in more detail.

Now you can screw the compression gauge fitting into the spark plug hole of the first cylinder, as is clearly shown below.

Now you need to turn the starter while pressing the gas pedal all the way to the floor. At this time, you must either fix the device so that it is securely fastened, or ask an assistant to hold it. It is necessary to turn the starter until the pressure stops increasing.

What and how to measure compression?

As noted above, measuring compression is a simple operation, and it can easily be performed in a garage.

But for this you need a special measuring device - a compression meter.

In fact, this is a regular pressure gauge, equipped with a check valve, as well as an extension cord for ease of diagnostics (the kit may also include attachments for working with different power plants).

In addition to this, the device will also require a spark plug wrench. You won’t be able to diagnose it yourself, so you also need an assistant.

Let's look at how compression measurements are made using the example of a VAZ Kalina car.

The sequence of actions for diagnostics is as follows:

Warm up the engine to operating temperature;
We relieve the pressure in the fuel rail (pull out the fuel pump fuse, and then start the engine again so that it produces the remaining gasoline in the rail);
We remove the tips of the spark plugs, as well as from the ignition module;
We unscrew all the spark plugs;
We install a compression gauge in the spark plug hole of the cylinder;
We ask the assistant to press the gas pedal all the way (this will ensure maximum air supply to the cylinder, which will make the readings more accurate), and then turn on the starter. In this case, to obtain correct data, it is necessary that all 4 strokes have passed in the cylinder being measured, that is, you need to turn the crankshaft at least 2 turns;
Since the compression meter has a check valve, the device will record the maximum pressure value in the cylinder;
We write down or remember the obtained pressure value, reset the readings and move on to the next cylinder.

After taking measurements in all cylinders, we compare the data. If the difference in readings does not exceed 1 kgf/cm2, put the spark plugs in place and continue operating the car.

Motor 126 and 127: working life, differences

These engines on Priora had a displacement of 1.6 liters (or 1596 cm3). Optimal for city sedans, the engine size of the Lada Priora gave a good combination of dynamics and consumption: along with very decent acceleration, fuel consumption does not exceed sky-high numbers. Both engines received good marks, because the car behaved perfectly in the city and on the highway.

In fact, the 126 Priora engine became the first sixteen-valve engine for this model, and the 127 is a modified version, “overclocked” by AvtoVAZ designers. In addition to the same engine displacement, they have other identical characteristics. The in-line type of arrangement of four cylinders provides a simplified design that can be repaired on your own.

The distributed multipoint injection system is involved in creating a good, rich fuel-air mixture (a lean mixture can lead to breakdowns). The cylinder diameter is 82 mm, the piston stroke is 75.6 mm, the compression ratio is 11. The “engines” fall under the Euro 4 standard, they are powered by gasoline with an octane rating of 95.

The 126 engine for the Priora received the following characteristics: 98 hp. (72 kW at 5600 rpm), acceleration to 100 km/h in 11.5 seconds (with manual transmission), city consumption 9.1 l - 100 km (manual transmission), maximum torque - 145 Nm.

The 127 engine for the Priora was upgraded to the following figures: 106 hp. (78 kW at 5800 rpm), acceleration to 100 km/h in 11.5 seconds (with manual transmission), city consumption 8.9 liters per 100 km (with manual transmission), maximum torque – 148 Nm.

The difference may not seem so noticeable, but this is a very small but strong step in design on the part of AvtoVAZ (this is where the change to sixteen-valve “engines” with a volume of 1.6 liters ended). For a car of the Lada Priora class, the engine power was sufficient.

In the same block it is necessary to say about the operating temperature. An absolutely normal operating temperature is considered to be between 90 and 95 degrees Celsius. Further, when the car is being pushed in a traffic jam, is basking in the sun, or for some other reason, but can still work - from 97 to 110 degrees. The engine is slow in places and wears out a lot, but you can still get to your destination. A temperature below 90 degrees is a direct sign indicating that the car has not yet warmed up, and it is better to wait in place until the arrow points to the coveted 80-90 mark.

Operating a car at temperatures above 110 degrees is dangerous because the service life of the engine is noticeably reduced - hot parts undergo very severe wear, overcoming the force of friction.

In general, the service life of the Lada Priora engine with a normal driving style and careful treatment is 200,000 km - after this mark the time comes when the “engine” requires major repairs. AvtoVAZ mentioned the timing belt separately as a recommendation, saying that it needs to be checked every 100,000 km (many car enthusiasts talk about the figure of 50,000 km).

All Lada engines have a problem, and it is related to the valves, which will be discussed further.

Signs of the need for internal combustion engine repair

The reasons why the operation of the engine is disrupted are arranged in a small list, starting with refusal to start and ending with floating idle speed (this problem was removed on the 127 “engine”). Not all breakdowns end in capital damage - sometimes it’s enough to add oil, sometimes it’s enough to adjust the ECU settings.

Compression reduction

A decrease in cylinder compression below 16 atmospheres is a bad sign. Such a high limit corresponds to a compression ratio of 11.

If the compression decreases (or vice versa increases), then the “engine” will have to be rebuilt.

Knocks in the engine

Engine knocks can come from several points. These could be hydraulic compressors, timing belt rollers or pins. The knocking noise could also be caused by low oil level. The answer to the question will be given by a thorough detailed inspection of all parts of the unit and checking the oil level.

Blue smoke from the exhaust pipe

The blue smoke that comes from the exhaust pipe appears when oil enters the combustion chamber. It can leak either from the valves or from under the piston. The result is the same: the oil is eaten up and blue smoke pours out of the chimney. Once the leak is located, half the problem will already be solved.

Troit motor

Sometimes in the cold the engine may stall - don’t be alarmed by this, because it may simply be one of the spark plugs that fails. In this case, we advise you to simply restart the engine and it will stop running.

How much does it cost to overhaul a Priora engine - average price

Self-repair of a Priora engine with 16 valves costs an average of 16-20 thousand rubles. The cost depends on the severity of the breakdown and may be lower or higher than this average range. Repairing a Priora engine can be entrusted to the wrong hands, but then you will have to pay for the work - sometimes the cost of repairs reaches as much as 40 thousand rubles.

This is an unreasonably inflated figure, because, as practice shows, you can rebuild the engine on a Priora, working at a moderate pace, in just three days - and three days of work is definitely not worth that kind of money. Don’t be afraid of not being able to cope - your Lada is easy to repair, and using the advice and “tutorials”, you will conquer even such a task that is impossible at first glance.

Video review of compression measurements on a Priora 16-cl.

In this case, a review is shown using the example of the 11194th engine, but there is absolutely no difference when performing this procedure.

I think that from the presented video review everything became more or less clear.

How to quickly and accurately determine the condition of the engine? Check the compression in the cylinders! Is the engine running rough, you feel a loss of power, the consumption of engine oil or fuel has increased and the car has become difficult to start in cold weather? All of these problems may be caused by low compression in one or more cylinders.

Low compression in the engine

Let us immediately note that both high and low compression are a bad indicator for the engine. As for low compression, in this case the engine starts poorly when cold, smokes, does not pull, noticeably overuses oil, fuel, etc. In gasoline engines, when trying to start a unit with low compression, the spark plugs are additionally flooded, which further complicates the situation.

Typically, low compression is actually a leak in the combustion chamber and an increase in the gaps between the elements of the CPG. More precisely, we are talking about the wear of the cylinder walls, the occurrence or destruction of compression and oil scraper rings, piston defects, damage to the cylinder head gasket, burnt out valves, etc.

As a rule, a decrease in compression in the cylinders is indicated by high oil consumption, bluish oil smoke from the exhaust pipe, loss of power and a number of other signs. Serious problems are observed when trying to start a cold engine, since before warming up the gaps between the parts are greatly increased.

In most cases, the engine in such a situation needs to be disassembled, after which the cylinder block is bored or lined, rings or pistons are changed along with rings, etc. If the engine is badly worn, then it is often absolutely appropriate to talk about a complete overhaul of the engine.

We also recommend reading the article about engine additives so that the engine does not consume oil and does not smoke. From this article you will learn about the types of these additives, the features of their operation, as well as the advantages and disadvantages of using such products.

As for various restorative additives to increase compression, this solution is very controversial. Let’s not deny that in some cases, decoking the engine, switching to a more viscous lubricant (for example, from 5W30 to 10W40) and the subsequent use of oil additives to increase compression allows you to increase the indicator, reduce lubricant consumption and continue to operate the unit for tens of thousands of kilometers. However, such methods do not always work.

If the unit is severely worn out, then often the use of thick oil and additives can be considered just a temporary measure that will allow the vehicle to continue to be used for a relatively short time.

Then you will still need to do a major overhaul, and the use of oil additives for some internal combustion engines also does not work without additional negative consequences. In other words, sometimes it is better to start repairing the engine right away than to delay repairs by pouring oil into the unit that is not recommended by the manufacturer, as well as various additives and additives.

What compression should be on Priore

Priora what should be the compression

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2 Compression measurement on 16-valve Kalina and Priora

Compression on Prior

During the previous measurement (1000 km ago) on a cold engine, I measured 18 bar in each cylinder. When completely...

Compression measurement on 16-valve Kalina and Priora

We measure compression

There are 11194 cylinders in the engine that is installed on Kalina, taken for disassembly.

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What should be the compression on a Lada Priora 16 valves

Car : Lada Priora. Asks : Ninja Turtle. The essence of the question : at what minimum compression does the engine still run well? Hello. It feels like the engine has stopped pulling. There is practically no smoke from the exhaust. If there is, then after rain it’s mostly STEAM . We measured the compression - 11.6 , 14 , 12 , 14 .
The master said that the first cylinder is not very good, but there should be traction. Is this normal compression for the Priorovsky 16-valve engine?

To ensure that the compression test gives accurate results

Compression depends not only on the technical condition of the engine, but also on the conditions under which it is measured. Make sure that during the check:

the compression gauge was working properly;
the engine has been warmed up to operating temperature (up to 90 degrees);
the throttle valve was fully open;
spark plugs in all cylinders must be turned out;
the starter was fully operational;
the battery was fully charged;
The engine air filter was clean.

What are the cylinder compression standards for VAZ engines?

Engine specifications must indicate “minimum cylinder compression values.” If you cannot find such data, determine the compression standards yourself using the formula:

Compression (kgf/cm2) = compression ratio (see technical specifications of internal combustion engine) * coefficient (for VAZ min 1.2, max 1.3)

Source

To ensure that the compression test gives accurate results

What are the cylinder compression standards for VAZ engines?

High compression in the engine

Reasons why there is no compression in the cylinder

What compression should the VAZ-2109 injector and carburetor have?

What is engine compression. How to check the compression of a VAZ 2109?

Checking the compression of the VAZ 2109 engine with your own hands

Monitor the air flow

How to diagnose a VAZ 2108-21099 engine using a compressor

Diagnosis of the VAZ 21099-2109-2108 engine using simple DIY tools

Diagnostic procedure

What factors may influence measurements?

Leak test

Measuring compression in a VAZ 2109 engine

What should be the compression on a Lada Priora 16 valves

Factory compression on Lada Priora

Compression check

Simple gasket test

Arrangement of cylinders on the Prior

Work resource

What to do if the number is unreadable

Checking compression in cylinders

Compression measurement

Reasons why there is no compression in the cylinder

How to determine why the compression in the cylinder has dropped?

Reasons for a drop in compression in one cylinder

Compression - what is it and what should it be?

Procedure for checking compression on a 16-valve Priora engine

What and how to measure compression?

see also

Comments 29

Motor 126 and 127: working life, differences

Signs of the need for internal combustion engine repair

Compression reduction

Knocks in the engine

Blue smoke from the exhaust pipe

Troit motor

How much does it cost to overhaul a Priora engine - average price

Video review of compression measurements on a Priora 16-cl.

Low compression in the engine

What compression should be on Priore

Compression on Prior

Compression measurement on 16-valve Kalina and Priora

What should be the compression on a Lada Priora 16 valves

To ensure that the compression test gives accurate results

What are the cylinder compression standards for VAZ engines?