With shut-off valve and 0 - 150 psi (0 - 1035 kPa) gage attached to air line, secure air line to inlet fitting.
Apply 80 - 100 psi (550 - 690 kPa) air pressure to head.
Close shut-off valve and watch gage for pressure drop.
Discard head if there is any pressure drop within 15 seconds after applied.
c. Magnetic particle inspection.
ST-1166 magnetic crack detector is
used to check valve seats and
injector ports for cracks.
(1) Place magnet on area being inspected.
Hold thumb partially over spray cap
of bulb to keep from blowing off.
(2) Spread moderate amount of powder with spray bulb on valve seats and injector ports.
COMPRESSED AIR USED FOR CLEANING PURPOSES WILL NOT EXCEED 30 PSI
(207 KPA). USE ONLY WITH EFFECTIVE CHIP GUARDING AND PERSONAL
PROTECTIVE EQUIPMENT (GOGGLES, SHIELD, GLOVES, ETC).
Blow off excess powder with low air pressure.
If crack exists, powder will fall into it and will show as a white line.
If valve seat insert(s) is cracked, mark for replacement.
Discard head if injector port is cracked or head area around valve seat is cracked.