NH TC30 - add oil pressure gauge

PAProbe · Aug 4, 2015

Has anyone on here added an aftermarket oil pressure gauge to their New Holland TC tractor? I need to know what thread size the oil pressure switch is. I screwed out the factory oil pressure switch and tried to screw in my 1/8 NPT oil line and found that it is not NPT.

Anyone done this before?

PAProbe · Aug 4, 2015

Update - I found info here - http://www.tractorbynet.com/forums/new-holland-owning-operating/235218-new-gauges-1900-a.html
Someone installed a temp and oil gauge and did not need metric to NPT adapters. One user mentioned that his Ford 1700 was NPT and that the japanese tap shallower than US so the threads tighten up after 1 turn usually.
I had a test gauge I was trying to turn in and it did start but was immediately tight in the threads so I assumed it was different. I may try to turn it in slowly and back it to to check for any thread damage for permanently installing something.

RickB · Aug 4, 2015

Most Shibaura (Ford/new Holland compact) engine oil pressure senders are 1/8" BSPT which is one pitch per inch different than 1/8" NPT. Some guys notice the difference, some don't.

PAProbe · Aug 5, 2015

RickB said:
Most Shibaura (Ford/new Holland compact) engine oil pressure senders are 1/8" BSPT which is one pitch per inch different than 1/8" NPT. Some guys notice the difference, some don't.

OK Thanks.
I guess the Honda car guys run into this alot.
Here is a picture of the thread difference. The NPT has a sharp edge on the thread while the BSPT is more rounded. Most of those guys run a NPT tap over the BSPT threads and it works fine.
http://honda-tech.com/attachments/forced-induction-16/307934d1359360052-1-8-pt-will-thread-into-1-8-npt-seal-dsc05550.jpg

barbqranch · Aug 5, 2015

You can get BSPT fittings at McMaster Carr

McMaster.com

RickB · Aug 5, 2015

PAProbe said:
OK Thanks.
I guess the Honda car guys run into this alot.
Here is a picture of the thread difference. The NPT has a sharp edge on the thread while the BSPT is more rounded. Most of those guys run a NPT tap over the BSPT threads and it works fine.
http://honda-tech.com/attachments/forced-induction-16/307934d1359360052-1-8-pt-will-thread-into-1-8-npt-seal-dsc05550.jpg

Running a -28 tap or die over a -27 fitting is a lousy way to get around buying the right fitting. it is your dime.