Back when I removed the road draft tube I just removed the long screw and popped it off leaving the screw shaft in the valley pan. Then installed the grommet and inserted the PCV valve. If the PCV valve is fully seated up to the collar the screw shaft in the valley pan will insert itself into the PCV valve preventing it from closing. I taped a piece of aluminum foil to the base of the valve and inserted it approximately 4/5 of the way into the grommet. When I removed it I could see a clean impression of the valve base with an indentation where the screw shaft had pressed the foil against the valve base. I then replaced the valve leaving an approximately 3/8 inch reveal before the collar, that should leave enough room for it to close.
My understanding is the valve is to be open only under high vacuum conditions ie when idling. My question is with the valve always open can the additional air be causing a lean fuel mixture condition?



1955 312 T-Bird Warwick, NY