The FT1741 Vacuum Tester can be used to check for leaks between the valve face and the seat on cylinder heads.
The vacuum tester can be used after the valves and seats are ground and the valve springs are assembled. To use the tester attach the correct adapter to the vacuum pump handle. With the vacuum pump on, place the adapter over the valve. Make sure that the adapter seal is in full contact with the combustion surface of the cylinder head. If the gauge shows less than 68 kPa (20 inches Hg) vacuum, the seal is not good. Tap the stem of the valve with a soft tip hammer and test again. If the gauge shows a wrong reading a second time regrind the valve face and seat.