When repairing the engine often requires grindingvalves. This is a responsible job, for which you need to have an appropriate tool at hand. Of course, you can do without it. So, how is the valve lapping done by hand?
When lapping is required
Many apply special tools, pasteand suction cup for valve lapping. However, not everyone knows how to properly carry out such a procedure. Seats and valves have only a few types of defects:
- chamfers are covered with shells or soot, but their shape is not changed;
- chamfers are covered with soot and shells, while their shape is changed.
In the latter case, something like steps may form on the surface of the part. In addition, the conical shape of the chamfer may change and become rounded.
Features of grinding in both cases
Если форма фаски не нарушена, проводится обычная grinding in If there are defects, the part is first machined with a lathe, and the valve seats are trimmed with conical shaped cones. At the same time, the dimensions of fixtures are of particular importance.
To start the valve seats are processedwith a roller cutter having an angle of 45 °, then the upper corbel is cut with a roller cutter with an angle of 15 °, and in the lower part of the saddle a bevel is removed with an angle of 75 °. The processing of parts with abrasive wheels and a hand drill is also allowed. The instruments should have angles of 45 °, 15 ° and 75 °.
It is worth considering that the grinding of valves with a hand drillor a screwdriver takes a lot of time. To speed up the process, you can use an electric tool that can be turned in both directions, and also gradually rotate around the circumference.
Lapping paste
First, you will need paste for grindingvalves. This is the first thing worth buying in a specialty store. In the process of processing paste is applied to the edge of the valve. Such a composition serves as a kind of small skin. Thanks to the paste, you can easily grind the valve to the socket. There are several main varieties of such tools. All of them have certain differences, which are reflected in the cost of production.
Paste classification
Valve lapping paste is classified bydegree of surface treatment: for the initial treatment - large, for the final - fine-grained. The latter option is very popular, since such products are recommended by masters involved in engine repair. Fine-grained paste allows you to quickly and properly grind the valves. In this case, much depends not on the composition of the tool, but on the state of the chamfers and the parts themselves. In addition, lapping the valves with their own hands does not work for everyone. When self-processing is recommended to use the usual composition, which costs 100 rubles per tube.
Do not buy the most expensive pasta. If there is a need for it, you can purchase it in the process.
Grandfathers
Lapping valves with their own hands - simpleprocess if you know how and what to do. Previously there were cones for the repair of the cylinder head. Such a device for lapping valves was mainly used to restore the seat parts. Some masters use this tool so far. Externally, the device is a nozzle for the socket, made in the form of landing valve. The roller cutter is fixed in the drill. The device has a small size and resembles a kind of drill.
Always need cones
Do I need such a tool?To answer the question, you need to look at the seat, pressed in the heads. If their integrity is not broken, you can proceed to the grinding. If they are damaged, for example by burnout, then they are recommended to be treated with special cones. The technology in this case is quite simple. Initially, it is recommended to change the guides, and then perform grinding. In each case requires an individual approach. You can purchase special fittings for grinding valves in almost any specialty store.
Or maybe put new valves?
New valves are not always required.Of course, if the parts are slightly bent, then you should not try to align them. The process will not produce results, and you only spend time and energy. In this case, it is better to visit the store with spare parts for vehicles and purchase a new set.
When replacing parts should pay special attentiontheir quality. The height of the valves in any case should be the same. Roughness and scratches on the ends, rods and sealing chamfers are not allowed. It is recommended to polish the parts to shine before installing a new set. This process should be carried out not only on the valve stems, but also on the black neck of the valve, and on the flat plate. Thanks to this treatment, parts will be less overgrown with carbon and heated. When machining, sealing chamfers are not recommended. They should only be ground to the saddles.
Valve lapping machine
Many for lapping valves are madespecial adaptations. This may require a rubber hose and a conventional drill. Grinding in of the valves with their own hands in this case is carried out as follows:
- The rubber hose is put on the drill. This may require a drill and several clamps.
- A lapping paste is applied to the end of the hose.
- One of the engine valves is inserted into this hose. For reliable fixation, you can use clamps.
- The valve is inserted into the socket, and its lapping begins.
При таком методе очень важно не включать maximum revolutions on the drill. The process should proceed slowly and carefully. As for revolutions, they should be from 400 to 500 per minute. When the speed increases, the seat and valve belts become very hot. In the process of lapping is not recommended to make circular motions. It is necessary to simulate the operation of the engine valve, while moving forward and then back.
It is worth considering that the grinding of valves with a drill and a hose is a painstaking process that takes a lot of time.
