140A wing tank drain valve

[8413]

Does anyone know which model wing tank drain valve the A models use? I’ve read here that some years had straight thread some years tapered thread. Mine are Curtis valves, just not sure which model.

[6183]

My 140A utilizes the Safe Air CAV-170 drain valve which is a 7/16 - 20 UNF thread.

Can you see the part number of the Curtis Valve on your tank?

According to the 140A parts book an AN814-4D plug which is a 7/16-20 thread was utilized originally.

[8413]

Mike, I won’t be with my plane for a week or so. I’ll take a look when I get back. I have the push and twist style Curtis.

The Saf-Air CAV-170 cross references to the Curtis CCA-2100. However that one appears to be a push type and not the push and twist. Maybe they changed the design or I may not have done enough research yet.

I like the ability to replace the o-ring in the Saf-Air. Maybe I’ll switch to that. I wonder if either are considered better than the other?
Josh

[6643]

If your fitting is drilled for safety wire then it should be straight thread. Pipe threaded drains were typically not.

[8413]

After inspecting my drain valves, I found that they are Curtis CCA-4300 which is straight thread.

I had one weeping a little and after exercising it a bit of lint came out. I think that was my problem. Seems to be dry now. I like easy fixes!
Josh