Do not overtighten vice. Valve head damage may occur.
Clean all components in mineral spirits. Metallic components may also be cleaned in lacquer thinner.
Remove all carbon deposits.
wear and damage. Plates and seats should be free from pits, corrosion, carbon and excessive wear.
Springs should be free from worn spots. Always replace valve plates and seats in assemblies.
(10) Lapping of plate and seat surface is necessary even on new valve parts. Using a lapping compound,
grit #2-A or equivalent. Lapping surface should have a smooth uniform surface free from scratches,
(12) Assemble intake valve as shown (4, Fig. D-6)
(13) Place valve head upside down in vice. Using valve tool, Fig. D-15), screw valve assembly into head
being careful not to tighten down on valve plate (7, Fig. D-6). Tighten down tight with valve tool.
(14) Center punch two places on edge of threads to secure inlet valve cover (16, Fig. D-6) in valve head.
(15) Assemble outlet valve assembly as shown (3, Fig. D-6).
(18) Screw plug (12, Fig. D-6) and valve assembly (3, Fig. D-6) into valve head. Torque plug down to 18 ft
lbs (25 NM).
(19) Install stud (13, Fig. D-6) into plug (12, Fig. D-6) pull down (by hand) tight with allen wrench. Install
gasket (14, Fig. D-6) on stud and screw acorn nut (15, Fig. D-6) down on gasket. Check for free
(20) Align valve head on top of cylinder with inlet and outlet tubes. Install 6 socket head screws (18, Fig. D-
6) and torque to 18 ft-lbs (25 NM).
(21) Connect inlet and outlet lines and tighten securely.
Do not readjust safety valve.
Third Stage Valve Replacement. Third stage valves are replaced as assemblies only.