What is compression?This pressure in the combustion chamber at the end of the compression stroke.It may be bled through the piston rings or the valve mechanism.In the first case, the repair involves only the replacement, and the second - it is possible to do without it.Consider the example of such a situation the engine VAZ.
First of all, it should be said that this procedure is called "lapping valves."During operation, the valve seats formed a deposit, which prevents them from fully closed.Thus, lapping valve avoids this problem.How to determine what they need lapping?The answer is simple.If you dropped the compression in the cylinders, such an operation is a must.The fact that the grinding valves need such an engine, a resource which is a little exhausted and the unit is far from being full of energy.
initially between the seat belt and the valve gap is formed due to wear of the latter.Since the "Cotton" at the close of a fairly strong, with time slips and broken edge geometry fit.Then, the gap falls unburned mixture that simply coke on the girdle of valves, making the gap even more.Generally, such problems occur mainly with the exhaust valves as inlet "polished" incoming stream.In addition, there are no obstacles to the flow of air, and when the temperature is as high as possible, the valves are closed.
now directly about how to produce grinding valves.WHA prohibits owners of these vehicles to carry out grinding drill.According to them, so it is impossible to make the necessary effort.But the fact is that the effort is just what is not required.If you put it, the saddle Stoch uneven.In this case, the valve will not accurately align, resulting in the appearance of the gap from one side.It is fraught with the above consequences.Yet lapping valve drill can not be as efficient as possible using a special set.
It is made in three stages.This order depends on the grain lapping compound, which changes in the process.If lapping valve is made with a drill, then it is clamped in pin of the same diameter as the rod.One end of the hose wear to the pin, and the other - to the valve.Then, the seat belt and lubricated paste and then exhibited minor rotational momentum.If they are too small, it is not terrible - just a little longer to work.
If they are large, there is a risk of overheating and saddles and valves.Then they will be the characteristic blue stripe.This is a sure sign of overheating.After the initial processing is erased paste, then rubbed the following, less grainy.After application of the paste of the third surfaces thoroughly cleaned with kerosene.Then you need to be lubricated with engine oil and repeat the lapping procedure, following "speed mode".This will ensure maximum tight closure.
Well, after that the compression in the cylinders will increase significantly.It should be remembered that the engines, the compression ratio is less than 8, are highly sensitive to it.This greatly affects the ease of use, so the grinding valves can be carried out even between repairs, for example, 20 000 km.
