Variable valve timing - what is it? What is the dynamics of the engine?

If you want to easily find out if a car has a variable valve timing system, you should look at the engine designation. It is known that it is almost impossible to remember them all. What markings are worth knowing? The most popular are V-TEC, Vanos, CVVT, VVT-i and Multiair. Each of them in the name implies either an increase in the amount of air, or a change in the position of the valves. Learn what motor timing is and how variability affects the drive. will you come with us

What are engine timing phases?

How would you say it in a simple way? This system controls the opening of the intake and exhaust valves. This will improve the flow of gases between the combustion chamber and the intake and exhaust manifolds. This, in turn, allows you to get more engine power without using, for example, a turbocharger. Variable valve timing is implemented in several ways. However, their role is always to regulate the opening times of the valves in a certain range of engine speeds.

The mechanism for changing the valve timing is a key element

CPFR, as this element is briefly called, is a key piece of a complex puzzle. The variable valve timing mechanism is also called a phaser, variator, phase shifter, or phase shifter. This element is mainly responsible for controlling the camshaft and changing its angular position. In many cases it is integrated with the distribution mechanism. This translates into a simplification of the mechanism itself and a smaller drive size.

The mechanism for changing the valve timing - signs of a malfunction

Like many other car parts, KZFR is also susceptible to damage. How can you recognize them? They are not always unambiguous, and often the symptoms of the problem coincide with other possible malfunctions. However, there are characteristic symptoms. If your engine's variable valve timing system is not working properly, you are likely experiencing:

• fluctuations in idle speed;
• knocking in the engine;
• no change in engine performance in the low speed range;
• dimming the engine when stopped, for example, at a traffic light;
• problem with starting the engine;
• noisy operation of a cold drive.

Driving with a damaged valve timing wheel - what are the risks?

In addition to the fact that you will feel the problems we have listed while driving, the mechanical consequences can be dire. Incorrect operation of the valve timing mechanism affects the valve shaft itself. Do not neglect timing drive maintenance. There is nothing to wait for, because the result may be irreversible damage to the roller itself. And then the variable valve timing system will not work properly and there will be another part (expensive!), Which will need to be replaced.

How long does the variable valve timing mechanism work?

On the example of a mechanism from BMW, i.e. Vanos, we can say that for a long time. In properly operated and maintained engines, problems do not appear until after exceeding 200 kilometers. This means that in new vehicles, the owner is unlikely to have to replace this element. What matters is how the engine works. Any carelessness will be visible in the way the mechanism works. And what can really go wrong in a variable phase system?

Damaged valve timing sensor - symptoms

How to know if the variable valve timing solenoid valve is defective? Symptoms of damage are similar to the failure of a stepper motor. It is designed to maintain a constant idle speed. When there is a problem with the sensor (solenoid valve), then the engine at idle will probably have a tendency to stall. It doesn't matter if you drive cold, or a hot engine. The cause of the problem may be a malfunction in the control system or a mechanical failure. Therefore, it is best to first measure the voltage at the solenoid valve, and then replace the elements.

Changing the valve timing and replacing the entire drive

You probably guessed that the valve control mechanism could fail. And this shows that KZFR is not eternal. Therefore, from time to time (usually with every second timing change), the wheel itself should be replaced. Unfortunately, the variable valve timing system is not the cheapest to operate. In some cars, the purchase price of all parts of the drive, together with a water pump, should not exceed 700-80 euros, however, there are models for which only one timing belt costs at least 1500-200 euros, so this is a huge amount. Price.

How to care for the variable valve timing system? For the correct functioning of the variable valve timing system, it is important to properly maintain the power unit. Crucial are the oil change intervals, which should take place every year or every 12-15 thousand kilometers. Also remember that after a long period of inactivity, you should not spin the engine above 4500 rpm, because the oil that controls the operation of the mechanism will not yet flow there from the oil pan.