While the truck is under reconstruction I would like to remove the temperature sensor and plug the hole in the head. I tried several pipe threads. None fit. No bolt will fit. What plug size am I looking for?:
Easiest way would be to use a rubber stopper. Did you use a thread pitch gauge on the fitting? I’m thinking it should be a standard bolt diameter and pitch (coarse or fine.)
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
I did some checking in your Project Journal. Is the head in question the "8385913" one you have posted pics of previously? If so it should have the smaller temp sensor port which is 3/8" NPT (National Pipe Thread). A brass one from a FLAPS should fill the need. Others will chime in and confirm or correct my info.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
You know I to thought it was 3/8”. I questioned my 3/8” brass fitting after dry fitting it. The reason was it screwed in 1 1/2 threads by hand then it stopped. If memory serves me right pipe fittings are tappered. So I applied my go to threads sealant Permatex 300 and tightened with an open end wrench.
That one's a straight bolt thread, not a tapered pipe thread. I believe it's a 5/8" coarse thread. I've seen people plug the hole by putting a copper penny into it and installing a shortened Allen bolt on top of it. You might have to file or grind the OD of the penny a little to make it drop into the hole. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
