Topic: oil pressure switch thread size

[neil10]

Anyone know what type of thread on switch? and what pressure the switch runs on?

[754]

I think it is 1/8 NPT

 The pressure it cuts it at, on a running motor is best described as;

 "Engine DEATH  too late Buddy!! "

[bryanj]

Thats why in maniacs, sorry mechanics, circles its known as "The Its  Too Late Light"

[Klark Kent]

7psi i think?

-KK

[mark]

There are 2 different thread pitches used on 1/8" pipe fittings - 27 tpi(U.S. standard) and 28 tpi(Brit. standard) - and I'm darned if I can remember which one Honda used.

7psi. sounds about right.


Happy trails.

[Bodi]

Every one I've seen has a US 1/8 NPT pipe thread (tapered thread). There was one thread here where someone found a straight British oil line connector thread in his motor, I suspect that one was rethreaded by a PO.

[neil10]

Yep went down to local car spares
found a 1/8 gas thread oil switch which has 40 k.p.a pressure put it on works fine.

[lordmoonpie]

Just replaced mine for a capillary action smiths oil gauge - it used a straight 1/8 BSP fitting straight out of the box and it's an American K3 donor CB750...BSP is British Standard Pipe fitting.

[750essess]

I tried 1/8 NPT and 1/8 BST, they are very close to the same thing. The angle of the threads is slightly different. They both work for this application in aluminum.

[Kevin400F]

[quote ]
>>I tried 1/8 NPT and 1/8 BST, they are very close to the same thing. The angle of the threads is slightly different. They both work for this application in aluminum.<<
[/quote]

"close enough for aluminum"......gotta love it.    The original was 1/8" BSPT 28tpi.  While its true you can jam in a 27tpi 1/8" NPT fitting if that's all you have, you may as well use the correct thread pitch to help prevent leakage.

[750essess]

I used 1/8th bspt, but alot of people have used 1/8 npt with no problems and they are easier to find.

[lordmoonpie]

...not in Britain they're not, BSP rules! 

[750essess]

Alright, fair enough 

[tinyrobot]

Does anyone know what size line they used?  Autometer has some kits in either -3AN or -4AN.

Also Side note. I noticed during a search that the only other "oil pressure switch thread size" was a thread exactly 1 year to the day before this one    weird

[tinyrobot]

bump

[bradweingartner]

For what it's worth, BSPT is used on a lot of Jap cars too for their oil pressure switches. So if you need one, that's where to look!