4-15. AUXILIARY POWER UNIT - Continued
Extract seat and clean out seat housing.
Press new seat in head using discarded
valve as arbor or using a pilot drift. Heat the
head if necessary in an oil bath to 320 - 360
deg. F (160 - 180 deg. C).
Cut valve seat using a 35 mm cutter for
either inlet or exhaust valves. Finished seat
diameter (A) should be 1.06 in. (27 mm) for
inlet valve, 0.91 in. (23 mm) for exhaust
valve. Seat width (B) should be between
0.055 - 0.063 in. (1.40 - 1.60 mm).
Lap valve and seat with valve grinding
compound (item 31, Appendix E).
Install cylinder head on engine as detailed in