There are four ways to view the quality of the valve and seat sealing surface of the valve device: visual inspection, pencil line drawing, oil bearing blue view and seal tester view.

Intuitive viewing

     The valve seat can be slightly impacted by the valve, and the embossing investigation can be performed after taking out the valve, which is determined by the width of the embossing and the touch condition. When the touch is wide or the touch is poor, the valve and valve port should be trimmed from the beginning or the valve port should be replaced until the seal is outstandingly stopped.

     Use a pencil to evenly mark the valve working surface (each 3~4mm) with a certain number of lines and the valve seat working surface touch, roll 1/4~1/3 turn, take out the valve, and the surrounding seals are blocked or evenly, about 1.2 ~1.5mm wide. Explain that the seal is good, otherwise it should be ground from scratch.

Tu Hongdan Oil Method

Valve device

     Usually, the repairing unit adopts this method, applying a thin bearing blue or red dan oil to the valve cone surface, putting it into the valve seat, holding the valve disc by hand, and rolling the valve several times, and taking it out after investigation, if its bright ring is not Intermittent, indicating that the seal is outstanding, otherwise it should be ground from scratch.

Valve air tightness view

     Gas test method: use airtight tester, usually used in a larger repair shop, such as the pressure of the barometer does not decrease, indicating that the air tightness is excellent.

     Oil test method: In the usual small repair shop and car unit, put the valve into the valve port and pour the clean fire oil to the valve plate just over. Wait 10-15min to investigate whether the oil surface is lowered or not. Is there any oil oozing out? If it is confirmed that the airtightness of the air valve is not good, the sealing surface should be ground from the head; if not, the airtightness of the valve and the valve port is outstanding. For qualified valves, they should be clean and clean, coated with oil, and placed in the cylinder head valve seat in order to prevent corrosion, mistakes or loss.