Oil pump reduction valve: principle of operation. Adjusting the oil pump pressure reduction valve

The lubrication system of the internal combustion engine is possible only if all its structural elements are in good order and well-coordinated. The failure of at least one of its parts will inevitably lead to malfunctions in the power unit.

In the article, we will talk about what the oil pump reduction valve is and what its functions are. We also consider the operation principle of this lubrication system node, we will tell you how to properly repair and adjust it.

What is the oil pump pressure reducing valve ?

As is known, oil is supplied to the moving parts of the engine under a certain pressure created by the operating pump. Without this, the lubricant would simply have the glass in the crankcase, subjecting the elements of the crank-connecting rod and gas distribution mechanisms to the effect of increased friction and overheating. But too high a pressure is dangerous for the engine. Gaskets, seals, seals are unable to withstand the excess of its normal performance. Because of this, the oil begins to ooze out from under them, and can also get into the power and cooling system of the power unit.

It is to reduce the pressure of lubrication in the system and is intended to reduce the oil pump valve. The very word "reduction" is often used in engineering, denoting the reduction, reduction, easing of something. In our case, this refers to the oil pressure.

Where is he located?

The oil pump pressure reducer is most often located on the cover of this unit, which is located in the lower front of the engine block behind the generator drive pulley. Sometimes it can be installed on the body of the oil filter.

There are two types of valves: built-in and demountable. In the first case, the oil pump and the pressure relief valve are a single structure that can not be disassembled. In the second, the pressure control mechanism with the help of the tool is extracted from the pump and can be repaired separately.

The design of the reduction valve

How is the oil pump pressure relief valve arranged ? Its construction is quite simple. It consists of the following elements:

• Housing with internal central channel;
• A valve in the form of a small piston or ball;
• spring;
• Thrust screw (bolt).

How the reducing valve works

Oil pressure in the system may depend on several factors, but the main one is the number of revolutions of the crankshaft. In other words, the stronger we press the gas pedal, the faster the gears of the oil pump rotate. And the faster the gears rotate, the more oil the pump takes from the crankcase, and the higher its head is at the output.

When the pressure reaches a certain value, the serviceable valve opens slightly, passing oil into the spare channel, through which the lubricant gets back into the crankcase.

The operation of the oil pump reduction valve is as follows. A piston or a metal ball is pressed against the inlet of the housing by a spring, which in turn is supported by a stop screw. The oil, under the influence of increasing pressure, begins to press on the valve surface, damping it inside the housing and compressing the spring. Thus, an opening is opened, along which the lubricant flows into the reserve channel.

When the pressure is lowered, its value is no longer sufficient to keep the valve in the open position, and the ball or piston under the action of the spring again closes the inlet. As you can see, the scheme is fairly simple and reliable, however, it sometimes fails.

Malfunction of the pressure relief valve

The pressure relief valve, the oil pump and the oil filter are the main elements of the lubrication system, but if the latter, due to its design features, almost never breaks down, but only clogs, the first two parts can fail quite often. The reason for this is usually the use of poor quality oil, lubricant that does not match the type of engine and the conditions of its operation, as well as its untimely replacement. In this case, particles of dirt, metal shavings or combustion products, which are in the lubricant, settle on the working surfaces of the valve, which, in fact, leads to clogging and jamming.

Also, the cause of the failure can serve as a spring, if it eventually stretched or, conversely, contracted, twisted, burst.

At once it is necessary to designate that repair of the oil pump reduction valve is possible only if it has a collapsible design. For non-separable models, the entire pump cover must be replaced.

A defective valve is considered if it is not able to maintain the required pressure in the system, and when its mechanism does not work when the pressure reaches the maximum value. In the first case, it will not be difficult to determine the breakdown - you will be notified about this by a control lamp on the car's instrument panel. But you can learn about the increase in pressure only by the oil leaks on the engine.

At what pressure should the pressure relief valve

But how can one understand that the pressure has increased or, conversely, decreased? And how should it be? The optimum oil pressure in the system can be found by looking in the user manual. For different brands and models of cars it will be different. For example, the pressure relief valve of the oil pump "Tavria" is activated at 0.55 MPa. Approximately the same indicators are relevant for most Lada cars.

It is possible to measure the oil pressure by connecting a special liquid manometer to the system in the seat of the pressure sensor. Before this, the engine must be warmed to operating temperature. All measurements are made with the engine running.

Repair and adjustment of the oil pump pressure relief valve

To understand if the pressure relief valve is suitable for further operation, it is possible, only dismantling it and disassembling it. So it will be possible to diagnose all its elements. If there are deposits on the valve body, they must be cleaned with gasoline, kerosene or carburetor cleaning fluid . Also, you should carefully inspect the spring. If it has traces of stretching, compression, or deformation, it must be replaced.

When you completely move the valve, check its operation by simply pressing on the ball (piston). If it is pressed with effort and comes back, locking the channel of the hull, most likely, the mechanism is working.

The oil pump pressure relief valve is adjusted after the pressure relief valve is installed in the housing of the device. The process is performed by compressing or releasing the spring by unscrewing (tightening) the thrust screw. In parallel, the oil pressure in the system is measured with a liquid manometer. The adjustment is, of course, carried out with the engine stopped, and the pressure measurement - with the engine running.

Helpful Tips

Finally, we give some useful tips that, perhaps, will help to avoid problems with the oil pump pressure reducer, or enable us to detect its failure in time:

1. Fill in the engine only high-quality engine oil of a suitable type and viscosity class. Requirements for lubrication can be found in the recommendations of the manufacturer of the car.
2. Never mix different brands of oils, even if they are of the same grade.
3. In time, change the oil and the oil filter. The procedure for this procedure is also specified in the user manual of the car.
4. Do not allow dirt, moisture, process fluids to enter the lubrication system.
5. Watch for oil pressure. If you turn on the appropriate warning light on the device, do not hesitate to go to the diagnostics.
6. Pay attention to the operating temperature of the engine. Its overheating can cause the cooling liquid to enter the lubrication system.
7. If you decide to replace or adjust the oil pump pressure reducer without the necessary skills and tools, it is better to use the services of specialists.