Hey guys, Im going to be installing a water temp gauge pretty soon. I need a spot to tap into, and my father told me to just T off the factory location with a brass fitting, as it will be the most accurate, and easy way to do it. My question is what size thread pitch is the port? Im guessing 1/8th NPT, but am unsure?

Any suggestions? I do not feel like cutting a hose, and then Ting into it there as the point of the gauge is to measure water temp inside head, not in the hoses before or after the radiator. Thanks!

 

One of the temperature sending units uses a 1/8" BSPT port. Close enough to 1/8" NPT.

I drilled and tapped the upper radiator hose housing to install a temperature sending unit one time.

It was on a P72 GS-R head with the upper radiator hose housing placed closer to the exhaust side of the head. You probably won't have room to do it on a PR3 head because there's too much stuff back there for it to be a practical place to put it.

 

Its going on a b20--
hopefully home depot will have a T