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, problems of a very different nature periodically occur. One of these problems is the unsatisfactory level of compression 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 level of compression, but also on factors such as reduced fuel economy, as well as engine oil waste.
Need for measurements
It is only necessary to start installing piston rings when the driver is sure that the problem is in them. To do this, you should find out the level of compression in the cylinders. You can give an example of how this is done on VAZ cars.
It is immediately worth noting that for measuring workthe engine must be warm. Measurements are not taken on a cold engine. The work itself will require the use of a special pressure gauge, which is equipped with a threaded tip. You can buy it at any auto shop.
How to measure?
Before such a large-scale work as installing rings on a piston, you should make sure that the problem is in them.
First you need to unscrew all the available candles from their places. Next, you need to disconnect the central cable from the ignition coil. The vehicle must be in neutral and its throttle must be fully open. After all these manipulations, you can begin to screw the tip of the compression gauge into one of the holes where the candles were previously located. You will need an assistant to work, since at this time it is necessary to turn the starter handle. Two or three turns are enough to carry out the work.
Readings in the region of 12-13 kg/cm are considered normal data2.
Norm when measuring compression
Some models will not require piston rings even if the reading is between 10 and 12. But if the numerical value is less than 10, then this is an indicator of too low a compression level. There is a small nuance. If, over time, the compression returns to normal, then the fault lies not with the piston rings, but with the valves.
To be 100% sure, you need to pour about 20 ml of oil into the controversial chamber, then turn the starter handle again and measure. If the compression returns to normal andstops at about 12 kg/cm2, then the reason is in the rings. In this case, the installation of piston rings on the piston cannot be avoided.
First step in changing rings
To replace these parts, you will have to disassemble the engine. This stage is considered preparatory.
- First, you must completely drain the old oil, since after installing new elements, you will need to fill in new lubricant.
- Secondly, it is necessary to loosen the exhaust pipe of the muffler.
- After that, the valve cover is removed, and the motor is set according to the existing marks.
- Next, the camshaft star is dismantled, and if the work is with a front-wheel drive VAZ, then you need to remove the bolt securing the belt pulley. After that, the timing belt itself is removed directly along with the pulley.
- In the classics, it is necessary to loosen the tensioner, after which both the chain and the star that are installed on the camshaft are removed.
- The next step is to dismantle the rocker with springs, while putting all the parts in the correct order, so that later they can be returned to their places without any problems.
- It is necessary to disconnect the manifold, after which the head of the block is removed.
- Next 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 up to make it possible to remove them along with the piston.
Test work
The procedure for installing rings on the piston requires that the old parts be checked first. For thisyou need to 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 carrying out 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 understand whether it is necessary to install oil scraper rings on a new type of piston, you can attach it at the same stage. If the gap difference is too great, then replacement is necessary.
Gap measurements
Most often, gap measurements are taken in the upper part of the block, since in these places the wear of parts is minimal. In addition, you can check the distance using special gauges. 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 to check, and if the readings are less than required, then filing can be done.
When you need to measure the diameter of the piston, then you need to do this in its lower part - the skirt. A micrometer is used for this, and after receiving reliable data, they must be compared with the table, which indicates the permissible parameters. Usually they are in the technical documentation for the car.
Another important point that comes next in the list of the order of installing rings on the piston is checking the clearance between the piston groove and the ring. If the allowable limit is exceeded, then this indicates that the rings must be replaced. Limit value - 0,15 mm. In addition, a routine visual check for cracks and other defects is also recommended. If any rings have passed all the stages of verification, then after washing they can be put back.
Piston ring installation
Firstly, most of the purchased rings have the inscription TOP on one side, which means top in English. It is logical that this side should look up after mounting.
There are two ways for the installation itself. The first is safer, while 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. It is necessary to lower them to the level of the slot. The piston ring mandrel can then be removed 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 bottom line is simple and lies in the fact that you need to spread the gap with your fingers, increasing the inner diameter of the ring until the piston passes through it so that the part is in the desired groove. The main disadvantage is that in the absence of experience, many people simply tear the rings, as they apply too much force.
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 the place of their installation, 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. Installation order - from the bottom ring to the top. When installing them, there is no need to stretch or bend them, the whole process is carried out very carefully.
The grooves for these spare parts have locks, the task of which is to prevent the element from rotating during operation. Therefore, the clearance for fastening should be exactly in them. The piston ring cannot be put anywhere else.
