Car chain tensioners: overview, features and replacement
In modern cars there are two types of transmission of torque from the distribution mechanism on This is a belt and chain design. The second option is more reliable and durable, however, late service and repair can lead to too noisy operation of the device. Adjust the state of the transmission allow chain tensioners, which are equipped with all sets of timing.
The considered mechanism ensures the normal operation of the circuit and the entire drive. The unit is easy to maintain and simple in design. The tension is performed under the influence of a spring or oil in the working rod of the device. The engine chain tensioner is a fairly reliable element, rarely fails. However, if there are extraneous noises, it is necessary to check its condition and, if necessary, replace it.
Ignoring this problem leads to the weakening and jumping of the chain, which is fraught with more serious breakdowns in the power unit.Cleaning and replacing parts is quite realistic to implement on their own. Next, we consider the features and principle of operation of these devices.
Mechanical chain tensioner
In this case, the required amount of tension is achieved using a plunger spring. Under its influence, the work item comes out of the landing compartment and contacts with a special shoe. The load on it continues until the resistance of the chain. This helps to prevent its sagging and fix the desired position by means of a stopper.
With long-term operation, the chain is stretched and requires re-adjustment. After unscrewing the plunger retainer nut, the spring will again adjust the degree of slack. Such chain tensioners have a significant minus. They are prone to clogging by small particles, which increases the likelihood of plunger jamming. You can solve this problem simply by tapping an element. In case of damage to the device case, it must be replaced.
Due to the relatively time-consuming maintenance of the drive with mechanical tension of the chain, many car owners switch to an automatic type, which automatically adjusts the tension of the chain, eliminates jamming of the device.
The timing chain tensioner of this type has a ratchet that automatically controls the sagging and stretching of the transmission element. The node consists of a body and a spring-loaded dog located in it, as well as a toothed bar. The teeth are made with a bias in one direction in increments of one millimeter.
The principle of operation of this design is as follows:
- the spring of the device acts on the toothed bar with force, depending on the slack of the chain;
- the strap transmits the force to the tensioner boot;
- reverse movement is eliminated due to the ratchet locking pawl;
- the stopper falls between the teeth, preventing the plank from moving backwards.
Such a principle of operation consists in the constant action of a spring on a bar with a chain tension, and the ratchet device prevents it from loosening.
Possible faults and their causes
If there is a clearly noticeable increase in noise during operation of the gas distribution unit, you should remove and check the chain tensioner of ZMZ or another engine. It is located on the right side of the power plant. A similar mechanism works with the help of a spring and oil pressure in the body, which depends on the same indicator in the motor itself.
The reasons leading to the appearance of extraneous sounds when operating the timing chain:
- poor purge plunger devices;
- clogging of air vents;
- excessive plunger wear;
- incorrect adjustment of the spring;
- ball valve failure.
Consider the order of disassembly and installation of this device.
Replacing the chain tensioner
In order to remove the mechanism, it is necessary to unscrew the plunger fixing bolt. This should be done carefully, because the screw is under great pressure, which gives the spring. Then you want to dismantle the spring-plunger filling. The spring length in the unloaded condition should be 155.5 millimeters.
In the next step, check the device. To do this, the plunger is shaken, while the ball (work item) must move freely. Then check the functionality of the valve. When blowing in compressed air, it should open, and after repeating the manipulation on the other hand, it should close. If this does not happen, you need to remove the valve from the mounting bushing and clean both elements. You also need to pay attention to the purity of the slit.
Installation and adjustment
Mechanical-type chain tensioners are installed after filling the working chamber with the required amount of oil. The plunger with a spring and a new gasket is placed in the seat, after which the fixing screw is rotated. The edge of the spring in the form of a cone should be turned towards the closing bolt.
After installation, it is necessary to unscrew the fastening bolts of the cylinder head, after which its cover and cover of the camshaft gear are removed. The tensioner should be moved in both directions until the oil appears near the fixing screw and a feeling of real resistance to movement of the part. At the final stage, the locking bolt is tightened with a force of 35 Nm, the cylinder head covers and camshaft gears are put in place.
Installation of an automatic device
The tensioners of the automatic type timing chain are similar in design to most vehicles. They are sold with a working rod placed in the housing, which is fixed by a check from the end. Removal and installation of this device is identical to the mechanical version.
After installation of the device, it is necessary to remove the fixing check with nippers or pliers. After that, the spring will push the bar. Then the control bolt must be screwed into the end part of the body. It serves to prevent the spring from falling out and comes complete with the main assembly. In fact, the process of replacing the engine tensioners is similar, regardless of the modification and type of device. Knowing the sequence of operations, you can easily perform this work yourself.
Features of the tensioners on domestic cars
The tensioner of the VAZ chain of early modifications is a structure with a spring. Modern models (after the seventh series) are equipped with hydraulic devices. The plunger rod is driven by the pressure generated by the oil. This type is fully automatic and does not require additional intervention to adjust the chain tension.
This part, like any other, is subject to wear and deformation. If damaged or clogged, the tensioner should be replaced or repaired. Removed the device according to the standard version.In earlier versions of "Zhiguli", it is additionally required to disassemble the oil supply tube located at the end of the body of the assembly. To prevent the fluid from leaking during the operation, the hole must be blocked with a bolt of a suitable diameter or rag.
Check for suitability
After removing the parts you need to check the item for clogging. Oil can carry fine particles and other contaminants that adversely affect the operation of the device in question. Excessive accumulation causes unstable operation of the plunger rod and its wedging.
You can clean the tensioner yourself without much effort. Place the item in a tank with gasoline for several hours, rinse and dry it thoroughly. When inspecting the hull, pay attention to the presence of dents, cracks and scratches. Similarly checked plunger mechanism. If no visible damage is found, a check is made on the performance of the device.
The device is taken in one hand, and the other is trying to move the plunger rod in the frame. It should move freely, without sticking. In case of difficulty moving, it is necessary to repeat the washing process.If this does not help, the part must be replaced. Installation of the element is performed in the reverse order of removal.
What do users advise?
Motorists give different tips on how to improve or choose a chain tensioner. "Mercedes" and other foreign cars from well-known manufacturers are often equipped with a timing chain. As a rule, the device for stretching the chain in modern cars is made with the possibility of automatic adjustment. This allows for easy maintenance and repair of the site, ensuring the reliability of its work.
In addition, when replacing the tensioner, users recommend setting the stock of the new device to the minimum position. This makes it possible to maximize the working chamber, avoiding jamming and excessive noise. This, in turn, contributes to the correct adjustment of the degree of chain tension.
Such a small, but important detail, as an engine chain tensioner, is a kind of fuse against loosening of the transmitting element and its jumping off. Such things can lead to serious malfunctions of the power unit.If the old version of the car is equipped with a mechanical version, it is easy to improve it by replacing the automatic version.
It is more convenient because it stretches the chain without additional human intervention, eliminates stem seizure, and is easier to disassemble and assemble. In its principle of operation, all variations of timing chain tensioners have a similar sequence. The same applies to the replacement and repair parts.