Lift valve detent issue
Lift valve detent issue
Working on cleaning up and using a later model TCV with integrated holding to replace my TCV on very early 80s 446. I bought a kit from NE Ingersoll so I plan on using those parts to refresh. While disassembling the late model TCV I found the lift control detent screws and and cover to have slightly bunged up threads so they are difficult to remove and install. I think they can be cleaned up with with some tap and die work but the thread size is alluding me. Anyone have a definitive idea about what thread size these small things are? They appear to be the common part to almost every TCV valve diagram I have seen with screw(18) and cover(17). Also the seat(26) in the main relief valve that requires a hex(allen) wrench to remove is stuck tight and cannot yet be removed. Is that going to be a problem when I put the TCV back together with new rings and ball bearings if I don't loosen it?
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Harry
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Re: Lift valve detent issue
I was thinking the thread size was 1/4-20, but I’m not sure if all tcv are the same size. That’s what I seem to remember from the three I’ve worked on. What gave you tried to remive the allen head machine screw?SpartyGuy wrote: ↑Sun Sep 06, 2026 9:05 am Working on cleaning up and using a later model TCV with integrated holding to replace my TCV on very early 80s 446. I bought a kit from NE Ingersoll so I plan on using those parts to refresh. While disassembling the late model TCV I found the lift control detent screws and and cover to have slightly bunged up threads so they are difficult to remove and install. I think they can be cleaned up with with some tap and die work but the thread size is alluding me. Anyone have a definitive idea about what thread size these small things are? They appear to be the common part to almost every TCV valve diagram I have seen with screw(18) and cover(17). Also the seat(26) in the main relief valve that requires a hex(allen) wrench to remove is stuck tight and cannot yet be removed. Is that going to be a problem when I put the TCV back together with new rings and ball bearings if I don't loosen it?
1973 444, 1974 644, 1976 446, 1977 646, 1986 226
