COMPRESSION DROPPED - WHAT TO DO? DOES THE ADDITIVE RESTORE COMPRESSION?
If the compression in the cylinder has fallen, the compression is restored to its nominal values and aligned with the cylinders at the beginning of the 2nd stage of processing (sometimes at the 1st stage) with the Atomium additive.
Atomium compositions getting into the zone of friction of the piston ring along the sleeve and along the surfaces of the piston groove creates conditions for the formation of a new structure. Simply put, this is the process of cleaning the friction surface to the "original" iron crystal lattice (this is minus 0.5-1 microns) and " building up a new layer of iron on it. The new layer consists mainly of iron, it is strongly bonded to the base and has a thin-porous structure, increased strength and microhardness. The thickness of this layer reaches only 5-15 microns (about one hundredth of a millimeter), but the oil-holding capacity of this layer is many times greater than the ability of a normal friction surface. It is this property that ensures the sealing of the cylinder – piston ring – piston groove nodes. Thus, if the compression in the cylinder has fallen, then during normal operation at the beginning of the 2nd stage of processing (sometimes at the 1st stage), the compression is restored to its nominal values and aligned with the cylinders. The created layer also has increased wear resistance, which increases the life of the nodes up to 2 times and increased anti-friction properties, which significantly reduces friction losses.
Let's now understand what compression is.
What is compression and how is it measured?
Compression is the value of the maximum pressure created in the cylinder when the piston moves from the lower dead point (LDP) to the upper dead point (UDP), when the engine is idled by the starter. The term "compression" should not be confused with the concept of "compression", which is a calculated value and represents the ratio of the volume above the piston space of the cylinder when the piston is at bottom dead center (BDC) (total cylinder volume) to the volume above the piston space of the cylinder when the piston is at top dead center (TDC), that is, the volume of the combustion chamber. Compression measurement is one of the easiest and most affordable ways to diagnose an engine. The apparent simplicity of the compression measurement procedure has earned the fame of a "universal" method that can not only determine the fault, but also generally assess the technical condition of the engine as a whole. But this universality is deceptive - the obtained measurement results often require special analysis, and it is not always correct to draw unambiguous conclusions from them, since the pressure in the cylinder at the end of the compression stroke, when the piston is at the upper dead point (UDP), depends on a number of factors.
HOW DO THEY CHECK ENGINE COMPRESSION?
The most common device for these purposes, which will help determine whether the compression has fallen into the engines - the compressometer. This device is a pressure gauge connected by a hose to a fitting and a check valve. When the engine crankshaft rotates, air is pumped into the hose until the pressure in the hose is equal to the maximum pressure in the cylinder. Its value will be recorded by the pressure gauge. In contrast to simple domestic designs, foreign analogues are produced with sets of adapters (adapters) that allow measurements to be made on cars of all brands and models. Easy to work with and compressoria. Their purpose is the same, but the results of measurements are recorded on paper or special plastic cards, which makes it possible to archive them for later comparison in different periods of operation of the car. The disadvantage of compressoria is the difficulty in assessing the dynamics of pressure rise when the scroll of the crankshaft.
Modern motor testers measure compression quickly and efficiently. These devices do not actually record the pressure, but the amplitude of the pulsation of the electric current consumed by the starter during scrolling - the higher the pressure in the cylinder, the greater the cost of the starter's power to rotate the crankshaft. Thus, if the engine compression has fallen, it is possible to simultaneously measure the compression in all cylinders in just a few turns, without resorting to turning out the candles, which is important for multi-cylinder engines. The disadvantage of the motor tester is that the results obtained are expressed in relative units, for example, as a percentage of the cylinder that works better. Only the most expensive motor testers are able to measure the absolute value of compression in each cylinder, but this is only possible on the basis of a large number of statistics on a specific engine model and their comparison with the actual pressure in the cylinder.
What affects the engine compression?
First of all, we note the position of the throttle valve: the more it is open, the more air entering the cylinder, the higher the compression and Vice versa-a closed valve will reduce the pressure in the cylinder. Of course, the amount of air entering the cylinder is affected by the degree of contamination of the air filter. Compression is also affected by a violation of the timing phases, for example, during installation or as a result of a belt or camshaft drive chain jumping. This leads to a change in the moment of closing the intake valve, shifting the beginning of compression in the cylinder in one direction or another. Then the compression values will also differ. Compression is strongly affected by gaps in the valve actuator (in the absence of hydraulic compensators or if they are faulty).
Thus, a small gap in the intake valve drive will lead to a later closure and, consequently, to a reduction in compression. At the same time, small gaps in the exhaust valves will increase the so - called valve overlap-the value of the angle of rotation of the crankshaft, during which both valves in the cylinder are open at the same time. The result is the same-the compression will decrease. The compression will also be affected by the engine temperature - the lower it is, the more the air compressed in the cylinder will be cooled, and the less its pressure will be. Engine temperature has an effect on the thermal clearances in the valve train, which in turn affects the results of measurements. But that's not all. Fuel equipment malfunctions; oil entering the combustion chamber through the valve guide bushings, piston rings, crankcase ventilation system and turbocharger seals; the degree of battery charge and starter failure can affect the amount of compression. As is clear from the above, if your engine has dropped compression in one cylinder, two cylinders, or 4 cylinders, there may be several reasons.
How to check engine compression correctly?
If we take into account all the factors listed above, then the following simple rules should be followed when measuring compression:
- the engine must be "warm" or " warmed up»;
- the fuel supply must be turned off (you can turn off the fuel pump, injectors, or use other methods that prevent fuel from entering the cylinders);
- on petrol engines, you must turn out all the candles (selective removal of candles is not allowed, since it increases the resistance to rotation and arbitrarily reduces the speed when the engine is scrolled by the starter);
- the battery must be fully charged and the starter is working properly.
Compression is measured with both open and closed throttle valves. At the same time, each method gives its own results and allows you to determine your defects. So, when the flap is closed, little air will enter the cylinders, the compression will be low and will be about 0.6-0.8 MPa. Air leaks in this case are comparable to the flow of air into the cylinder. As a result, compression becomes particularly sensitive to leaks-even with small leaks, its value drops several times. This measurement allows you to make conclusions or assumptions about the following engine defects:
- poor fit of the valve to the seat;
- about the valve hanging, for example, due to incorrect Assembly of the mechanism with hydraulic pushers;
- defects in the Cam profile of the camshaft in designs with hydraulic pushers, and, in particular, uneven wear or runout of the rear side of the Cam
- lack of tightness caused by a burnout of the head gasket or a crack in the wall of the combustion chamber (these defects are accompanied by white smoke, the formation of an emulsion in the oil, and increased pressure in the cooling system)
When measuring compression with an open flap, the picture will be different. A large amount of incoming air and an increase in pressure in the cylinder, contribute to an increase in leaks. But the compression does not fall as much (approximately 0.8-0.9 MPa). Therefore, the method of measuring with an open flap is better suited for determining more "rough" engine defects, such as:
- piston breakdowns and burnouts;
- breakage or hanging (coking) of the rings in the piston grooves;
- valve deformations or burnouts;
- serious damage (teasing) to the cylinder surface.
In both methods of measurement, it is desirable to take into account the dynamics of pressure increase - this will help to establish the true reason why the compression in the engine fell, with a greater probability.
So, if the pressure measured by the compressometer is low (0.3-0.4 MPa) at the first compression stroke, and increases sharply at the subsequent cycles, this indirectly indicates the wear of the piston rings. In this case, filling the cylinder with a small amount of oil (3-5 cm2) will immediately increase the pressure on the first stroke and compression in General. On the other hand, when the pressure reaches 0.7-0.9 MPa on the first stroke, and almost does not increase on the subsequent cycles, most likely there is a leak in the valve or head gasket. More accurately determine the cause, you need to use other diagnostic tools or indirect signs.
How to use the measurement results in practice?
The main rule is to keep in mind: in most cases, the results of compression measurements are relative. This means that first of all it is necessary to rely on the difference in compression values for different cylinders, and not on its absolute value itself. Here are just two examples that confirm the validity of this statement. A relatively new engine cannot be started. Fell the compression in the engine. Compression in cylinders is 0.5-0.6 MPa (5-6 kg / cm2), which is about half the norm. The reasons may be mechanical failure or wear of parts of the cylinder-piston group. But the same compression drop can be observed due to a malfunction of the fuel supply system. The cylinders received excess fuel, it will wash away the oil from the cylinder walls, and the piston rings cease to properly seal the combustion chamber cavity. Another case: the old engine has a compression ratio of 1.1-1.2 MPa. Standard! However, the engine consumes more than 1 liter of oil per 1000 km. this is understandable if you take into account the wear of the rings, pistons and cylinders. What is it? The answer is simple: a large amount of oil entering the combustion chamber seals the gaps in the wear zones. As you can see, the results of measurements should be treated with caution. And, in order not to make a mistake in the conclusions during the repair, you should know in which cases you can rely on the measurement results with confidence, and when-only take note of them. Table 1 shows a list of faults and some compression measurements, if any. Of course, these data do not have specific values, but only make it easier to determine the direction of the fault search.
Table 1. Some defects and malfunctions of gasoline engines detected by compression measurement
|Fault||Fault symptom||Compression, MPа|
|Open valve||Closed valve|
|Fully functional engine
The crack in the lintel of the piston
|Blue exhaust smoke, high crankcase pressure||0,6-0,8||0,3-0,4|
The burnout of the piston
|The same, the cylinder does not work at low speeds||0,5-0,5||0-0,1|
Occurrence of rings in the piston grooves
Bullies of the piston and cylinder
|The same, unstable operation of the cylinder at idle is possible||0,2-0,8||0,1-0,5|
|The cylinder does not work at low rpm||0,3-0,7||0-0,2|
Cam Cam profile defect (for designs with hydraulic pushers)
Increasing the amount of carbon in the combustion chamber in combination with worn oil caps and rings
|Increased oil consumption with blue exhaust smoke||1,2-1,5||0,9-1,2|
Increased wear of the cylinder-piston group
|Increased fuel and oil consumption for fumes||0,2-0,4||0,6-0,8|
The compression in the engine has dropped - will the Atomium compositions increase the compression in my engine?
So, we know what compression is, how and what to measure, know the factors influencing the measurement results, and now we can talk about the possibility of partial or complete recovery of compression with the lubricating composition Atomium.
The Atomium lubricant composition is not an additive or additive to the lubricant, since it does not improve its characteristics, but interacts directly with the metal surfaces of contact zones (friction surfaces) of parts of assemblies and mechanisms.
Atomium tribo-compounds help the "friction pair" system (for example, the piston ring – sleeve, the shaft neck – bearing liner, etc.) to reach a new qualitative level of energy balance (more optimal contact conditions for friction parts), they are a catalyst and initiate the process of adaptation of the "friction pair" system.
Atomium tribo-compounds have the effect of restoring friction surfaces (forming a protective layer up to 15 microns thick) and optimizing the geometry of friction surfaces. In addition, the created metal structures (protective layers) have an increased oil – holding capacity-the protective layer holds the oil on the surface much stronger than the usual surface, which shifts the friction mode to the area of semi-liquid or hydrodynamic friction (the "oil wedge" operation).
Picture #1 shows all the parts and mechanisms of the engine that are directly related to the amount of compression, all of them are more or less subject to friction processes, and, accordingly, the "Atomium" tribo-compounds can affect them (only the cylinder liner is not shown).
Friction parts such as the cylinder-piston group, crank mechanism, and gas distribution mechanism primarily determine the condition and life of the engine and are also the most expensive spare parts.
Atomium tribo-compounds in the process of regular operation of the engine on the "base metal" layer by layer forms a new structure, which is based on a crystal lattice of iron.
However, this occurs only in areas of direct contact of rubbing surfaces, and the load and temperature in the contact zone must be significant.
Now let's look at which faults indicated in table 1 "Atomium" tribo-compounds will solve the problem, and which ones will not.
Failures associated with friction No. 2, 3, 6, 7 and 8, of course, in-place recovery technology, the company "Atomium" not be. But according to statistics, this happens quite rarely. Whereas, malfunctions associated with natural wear or increased wear due to insufficiently favorable lubrication conditions (teasing), and these are malfunctions # 4, 5, 9, 10 are the most characteristic and are subject to non-selective restoration by the technology of the company "Atomium".
The occurrence of rings in the grooves of the piston (No. 4) when the rings are completely stationary (which is extremely rare), of course, "Atomium" tribo-compounds "are not treated". In case of complete loss of mobility of the rings-it is necessary to make de-coking by special means.
When the rings are partially mobile, the "Atomium" tribo-compounds allows you to first clean the contact surfaces of the rings and the piston grooves, and then, at the second stage, form a new structure.
In case # 5 of a non-catastrophic surface bully (the bully groove does not exceed 1 mm, and the total area of the bully does not exceed 10% of the total area of the working surface), Atomium tribo-compounds "smoothes" the bully. And if it does not completely "close" them, it still levels their influence by improving the properties of the rest of the friction surface. Malfunction # 9-an increased amount of carbon in the combustion chamber is "treated" with the Atomium tribo-compounds, in some cases-after replacing the oil-removing caps in combination with special means for removing carbon. In this case, it is important to control the degree of oil contamination and replace it if necessary. Otherwise, the process of preparing the surface for restoration with the Atomium tribo-compounds will be neutralized by abrasive wear due to the increased content of washed off carbon (dispersed carbons).
Fault # 10-increased wear of the cylinder-piston group – the most typical case for engines with long, but normal operation. In this case, as in others that can be "treated", the Atomium tribo-compounds at the first stage (500 – 1000 km before the oil change) prepares the surface for restoration; removes the lacquer films, the distorted surface layer of metal, polishes the surface and then contributes to the creation of a new protective structure. The thickness of the layer increases gradually, and reaches from 3 to 15 microns, depending on the operating conditions of the specific friction unit. The main restorative effect in the sense of restoring compression is not related to the thickness of this layer, but to the significant oil-holding capacity of this layer. That is, it attracts and firmly holds the higher amount of oil and different fine sub-micron particles and Atomium tribo-compounds. This "thick" layer allows you to restore the gas density in the ring - piston groove – cylinder liner node.
The result of restoring compression leads to improved fuel combustion conditions (by improving the filling of the cylinder with air and reducing the loss of working gas in the crankcase), and this leads to an increase (recovery) of power and pickup, reducing unburned products, reducing carbon deposits, and improving environmental performance.
In addition, there is a decrease in oil consumption for carbon monoxide (due to an increase in the oil density in the piston grooves). The protective layer not only increases (preserves) the engine life, but also has better anti-friction properties (increasing mechanical efficiency), and this allows you to reduce fuel consumption, increase power and throttle response even for a new engine.