Today, almost every family has a car at their disposal. Since this technique is assembled from a huge number of parts that work with each other, periodically malfunctions of a very different nature occur. One of these problems is an unsatisfactory compression level in the fuel combustion chambers. To eliminate it, it is necessary to install the rings on the piston.
To make sure that the breakdown can be eliminated by replacing the piston rings with new ones, you need to focus not only on the compression level, but also on factors such as reduced fuel economy, as well as engine oil fumes.
The need for measurements
Proceed with the installation of the piston rings only if the driver is sure that the problem is in them. To do this, find out the level of compression in the cylinders. You can give an example of how this is done on VAZ cars.
It should be noted right away that the engine must be warm for measuring work. On a cold engine, measurements are not taken. The work itself will require the use of a special pressure gauge, which is equipped with a threaded type tip. You can buy it at any car shop.
How to measure?
Before such a large-scale work as installing rings on the piston, you should make sure that the problem is in them.
First you need to unscrew all the candles from their places. Next, you must disconnect the central cable from the ignition coil. The car must be in neutral gear, and its throttle should be maximally turned to open. After all these manipulations, you can begin to screw the tip of the compressor into one of the holes where the candles were before. An assistant will be required for work, since at this time it is necessary to turn the starter knob. Two to three turns are enough to carry out the work.
Normal data are readings in the region of 12-13 kg / cm 2 .
The norm for measuring compression
In some models, it is not necessary to install rings on the piston even if the readings are from 10 to 12. But if the numerical value is less than 10, then this is an indicator of too low a compression level. There is a slight nuance. If over time the compression returns to normal, then the fault lies not with the piston rings, but with the valves.
To make sure 100%, it is necessary to add about 20 ml of oil to the disputed chamber, then again turn the starter knob and take a measurement. If the compression returns to normal and stops at about 12 kg / cm 2 , then the reason is in the rings. In this case, the installation of the piston rings on the piston cannot be avoided.
The first step in replacing rings
To replace these parts, you will have to disassemble the engine. This stage is considered preparatory.
- Firstly, it is necessary to completely drain the old oil, since after installing new elements, it will be necessary to fill in a new lubricating fluid.
- Secondly, it is necessary to weaken the exhaust pipe of the muffler.
- After that, the valve cover is removed, and the motor is set according to the available marks.
- Next, the camshaft star is dismantled, and if the work is with front-wheel drive VAZ, then you need to remove the bolt securing the belt pulley. After that, the timing belt itself is removed directly with the pulley.
- In the classic, it is necessary to loosen the tensioner, after which both the chain and the star, which are mounted on the camshaft, are removed.
- The next stage is the dismantling of the rocker with springs, while stacking all the parts in the correct order, so that later they can easily return to their places.
- It is necessary to disconnect the collector, after which the block head is removed.
- The following is the dismantling of both the sump and the oil pump.
- The connecting rod caps are removed, after which the connecting rods themselves are pushed upwards so that it becomes possible to remove them together with the piston.
Verification work
The procedure for installing the rings on the piston requires that old parts be checked first. To do this, remove each ring in turn from the piston and check them in your cylinder. In order not to get confused, it is strongly recommended to immediately lay them out in the right order. When conducting inspection work, the old rings should not create a gap between the outer diameter of the part and the cylinder wall of more than 1 mm. To compare the difference and to understand whether it is necessary to install oil scraper rings on a new type of piston, you can also apply it at the same stage. If the gap difference is too large, a replacement is necessary.
Clearance Measurements
Most often, measurements of gaps are taken at the top of the block, since in these places the wear of parts is minimal. In addition, you can check the distance using special calibers. It is worth paying attention to the thermal gap, which should be in the range from 0.25 to 0.45 mm. A probe is used for verification, and if the readings are less than required, then it is possible to file.
When you need to measure the diameter of the piston, you need to do this in its lower part - the skirt. A micrometer is used for this, and after obtaining reliable data, they must be compared with a table where the permissible parameters are indicated. Usually they are in the technical documentation for the car.
Another important point that comes next in the list of order to install the rings on the piston is checking the clearance between the piston groove and the ring. If the permissible limit is exceeded, then this indicates that the rings should be replaced. The limit value is 0.15 mm. In addition, it is recommended that a routine visual inspection be performed for cracks and other defects. If any rings have passed all stages of the test, then after washing they can be put back.
Installing piston rings
Firstly, most of the rings purchased on one side have the inscription TOP, which in translation from English means the top. It is logical that this side should look up after installation.
There are two methods for the installation itself. The first is more secure, and the second can be used by both professionals and beginners.
The first method involves cutting several flat pieces of tin with a thickness of 0.3 to 0.5 mm. Three or four such sheets are located along the diameter of the piston, and rings are put on top. Lower them to the level of the slot. After that, you can remove the mandrel for the piston rings from the plates. After that, the ring will be in the desired groove. The method is great for independent work.
The correct installation of the rings on the piston is carried out by another method, however, it will require certain skills.
The essence is simple and that you need to part the gap with your fingers, increasing the inner diameter of the ring until a piston passes through it so that the part is in the right groove. The main disadvantage is that in the absence of experience, many people simply break the rings, as they put too much effort.
Installing rings on the scooter piston
Here it is worth starting with the fact that these rings can have a different cross section depending on their installation location, it is very important to pay attention to this. In addition, the scooter rings also have a special letter that indicates the top layer of the part. The installation procedure is from the lower ring to the upper. When installing them, there is no need to stretch or bend them, the whole process is carried out very carefully.
There are locks in the grooves for these parts, the purpose of which is to prevent the element from turning during operation. Therefore, the clearance for fastening must be located in them. Nowhere else can I put the piston ring.