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Posted by: orangecrate Mar 17 2019, 09:30 AM

I've done a search here but can't seem to come up with anything.. Can anyone tell me what the thread is on the oil pressure sending unit? As in 8x1.5 , 10x1 , whatever.. I'm looking to run the typical T with mechanical gauge and the idiot light. But I'm not gonna run paint ball hose or a grease gun hose. Probably copper tubing. It will handle vibration and heat. Or stainless if I can find some around here.

Posted by: TheCabinetmaker Mar 17 2019, 10:50 AM

Can't remember which. ⅛ or ¼" npt threads

Posted by: BeatNavy Mar 17 2019, 10:55 AM

1/8 npt

Posted by: Mike Bellis Mar 17 2019, 11:18 AM

It's 10mm.

10mm and 1/8 NPT have almost the same thread pitch. The NPT is tapered, the 10mm is not.

1/8 NPT is used without trouble quite often. Just remember your pressure sending unit requires a ground, as you add T fittings and such. Braided grease gun hoses work great as an extension and are 1/9 NPT.

Posted by: Mark Henry Mar 18 2019, 04:10 AM

http://www.914world.com/bbs2/index.php?showtopic=208658&st=0

Posted by: Tbrown4x4 Mar 18 2019, 05:27 AM

Regular paintball hose is 1/8" pipe thread. Spyder hoses are metric and sealed with an o-ring. There is also a $5 adapter from metric to 1/8" NPT available.

The paintball hose can handle at least 850 PSI, but I don't know if hot oil would be OK.

I can check the thread size in the morning and thread one into my case to see if the adapter works, at least.

Posted by: Tbrown4x4 Mar 18 2019, 10:54 AM

Why did I get involved in this? I'm usually not so easily baited into posting, but here we go. The Spyder threads are metric, but will not thread into my case. I have a Snap-On Metric tap and die set, and it includes a 1/8-28BSP tap, which threads easily into my case using only finger pressure without cutting threads. 1/8 NPT is 27 tpi, so it may be close enough to thread in and seal.


I have a ton of new 1/8 NPT fittings, and they do not easily thread into the case. I get maybe 2 full threads until it wants to bind.

I don't have a sending unit to measure.

Posted by: BeatNavy Mar 18 2019, 11:18 AM

I posted too early. I remember researching this a few months ago and studied that thread that Mark posted above. I was planning for the Oil Pressure sensor I'm installing as part of an engine rebuild. I've used the stainless steel paintgun hose before, and I wanted to do it again on this engine.

Now I recall that threading the paintball hose (with the 1/8 NPT) directly into the case didn't feel 100% right at the time, and I was worried it was stripping a bit. For the engine rebuild I purchased a 10mm to 1/8 NPT adapter a few months ago. The 10mm threaded into the case perfectly.

Posted by: brant Mar 18 2019, 11:26 AM

yes technically it is metric

I bought a conversion fitting to make it into a grease hose SAE

you should not run rigid tubing
it will eventually crack
the leverage of standing up 5 inches, through the tin work, and then have a sender mounted on top... will cause vibration and eventually a crack

but hey.. .its only your motor oil pressure
why worry