TR2/3/3A Oil Sump Thread size TR3A

[houleyh]

What is the thread size of the plug on the sump pump. 1/2 NPT I guess?

Please advise

 

[TR3driver]

My recollection is that it's smaller than 1/2; maybe 3/8 NPT (which is actually close to 1/2" in diameter, as NPT threads are sized by nominal inside diameter of the pipe, rather than outside diameter).

 

[TexasKnucklehead]

If thread doesn't match one of the taps or dies I have, I don't know how to tell what it is. But here's some more information from the plug that seems to fit in my TR3 oil pan -I think it's correct. I think pipe thread is tapered, as this is.

 

[TR3driver]

That's a 3/8 NPT.

1/2 NPT would be 14 tpi, and measure .836" in the middle of the taper.

And your photos show exactly why I prefer to use "hex socket" plugs. MMC will sell you a nice magnetic, hex socket plug (turns with a 5/16" Allen wrench) that will never round off, for under $2.

 

[TR3driver]

If thread doesn't match one of the taps or dies I have, I don't know how to tell what it is.

You've got everything you need, except for this chart: https://mdmetric.com/tech/tict.htm