Valve grinding procedure is an accurate grinding operation, because of which tight joints are obtained. To do this, part of the metal of the mating surfaces remove with special abrasive powders and pastes. True, sometimes the chamfers of the valve seats are already polished, then grinding should not be done.
| Grit designation | Grain sizes |
| M40 | 28-40 |
| M28 | 28-20 |
| M20 | 20-14 |
| M14 | 14-10 |
| M10 | 10-7 |
| M7 | 7-5 |
| M5 | 5-3 |
Abrasive materials are distinguished by their granularity. Among the main abrasive materials: grinding powders, micropowders and grinding grains. Specifically, micropowders are used to grind the valves.
Powders and pastes for grinding in valves
To grind the valves, special powders and lapping pastes are used. During wiping, paste is applied to the edge of the valve. The task of lapping the valve is to lapping it to the valve seat. Manufacturers offer a wide selection of grinding pastes.
Depending on the surfaces of the mating surfaces, different micropowders are used (M14-M40). M 40 powder is mixed with gear oil, and M14 powder with engine oil. When mixing, a special paste is obtained, which is applied to the chamfer of the valve. Then produce grinding the valve for 1-2 minutes. Rub the valve very carefully.
The finer the abrasive material, the better the grinding is considered. Therefore, it is recommended to use GOI paste with kerosene for finishing grinding in the valves. For the initial processing of the valve, primary coarse paste is used; for fine finishing, fine grained paste is used.
Valve grinding tools:
1 – clamp; 2 – mandrel; 3 – valve.
