This was definitely a boring day. I just figured out that Kubota ie Universal Diesels use British Standard Pipe Threads (BSPS) which are very close to our NPT threads - but mostly different. Their Oil Pressure Sender "looks" like an 1/8 -27 NPT but is actually a 1/8 - 28 BSPT. Close! You can Google BSPT and see the differences. It turns out that the 1/8, 1/4 & 3/8 are all off by one thread per inch but the 1/2 and 3/4 are the same as our NPT. There is also a "thread form" difference but that blew over my head. So what to do if you want to plumb in an oil pressure gage in a Universal M25? Being the dumb engineer I am, I didn't know they were different, and just forced them together tight with thread sealant and they are holding just fine. A much better approach would be to use thread adapters built for just this purpose, which I think are available from Swagelok. For a short discussion on this subject look at http://www.practicalmachinist.com/vb/showthread.php?p=899130. I didn't know I wanted to know all this, but today that was my chore. Off to the movies.
M25 Oil Pressure Sender Threads
Odd threads, spanners and positive ground.
David and all, Boy do I ever remember those days when I used to torture myself with Roots Group cars. I had three of them, all half drop head models, two Hillman's and a very cool right hand drive Sunbeam Rapier III with dual SU's (arrggh!!). See it here: http://en.wikipedia.org/wiki/Sunbeam_Rapier. Then I had to change it from positive to negative ground like the rest of the world by shorting the negative battery cable to ground,giving the entire electrical system a major heart attack and having to reverse the wires on the ammeter so everything read right, not to mention the grief with the rest of the electrical, "Lucas, Prince of Darkness" was oh so true. Glyn
David and all, Boy do I ever remember those days when I used to torture myself with Roots Group cars. I had three of them, all half drop head models, two Hillman's and a very cool right hand drive Sunbeam Rapier III with dual SU's (arrggh!!). See it here: http://en.wikipedia.org/wiki/Sunbeam_Rapier. Then I had to change it from positive to negative ground like the rest of the world by shorting the negative battery cable to ground,giving the entire electrical system a major heart attack and having to reverse the wires on the ammeter so everything read right, not to mention the grief with the rest of the electrical, "Lucas, Prince of Darkness" was oh so true. Glyn
Lucky Dog
Member III
Lucas Electrical???
Thanks for reminding me of bad electrical can get. I went through a series of Triumphs cars when I had more time to work on them than drive them. Remembering the previous hallmark, "the best of lucas always falls of before failing". Fun cars could pull off a adjust the two solex carbs during lunch.
ml
Thanks for reminding me of bad electrical can get. I went through a series of Triumphs cars when I had more time to work on them than drive them. Remembering the previous hallmark, "the best of lucas always falls of before failing". Fun cars could pull off a adjust the two solex carbs during lunch.
ml
Ah, my first set of wheels was a '67 Rover 2000TC with TC meaning twin carbs - a nice pair of SUs - just keep the oil in them topped up and they work great 
OK, having driven Rovers and ridden Nortons for many years
Q: Why do the English drink warm beer?
A: They have Lucas refrigerators.
OK, having driven Rovers and ridden Nortons for many years
Q: Why do the English drink warm beer?
A: They have Lucas refrigerators.