Apply a thin film of whitewash on a valve facet. Slightly press a working facet of the valve to a saddle, but do not rotate the valve. Then take out the valve and examine a saddle and a facet of the valve.

If paint remains on all circle (360 °) valve facets, then the valve концентричен. Otherwise replace the valve.

If paint is shown on all circle (360 °) valve saddles, directing (plug) of the valve and a saddle of the valve of a kontsentrichna. Otherwise to a pereshlifuyta facet.

Fig. 2.83. Admissible thickness of a spot of contact of a saddle of the valve

Make sure that the spot of contact is in a middle part of a working facet of the valve and has width of 1,0-1,4 mm (fig. 2.83).

Fig. 2.84. Check of spots of contacts of facets of saddles of valves

If the spot of contact is located too highly, correct a facet by means of mills with a corner of a cone 30 ° and 45 °. If the spot of contact is located too low, correct a facet by means of mills with a corner of a cone 75 ° and 45 ° (fig. 2.84).