RB25 oil pressure sensor thread size

[Reignman]

Does anyone know the thread pitch of the oil pressure sensor on an RB25? My sensor is leaking oil out of it and I want to replace it with an aftermarket sensor and gauge

Thanks

[PorkChopExpress]

1/8th bpt

[cdorhout]

Isn't it 1/8 NPT?

[jdmser]

nope, bspt=British standard pipe thread

[gawdzilla]

confirm. it's female 1/8 bspt. it is close to 1/8 npt but smaller. if you try to tighten a 1/8 npt male fitting in, it may not seal correctly because it is too tight.

what gauge are you planning to get? greddy, hks, defi, and other jap gauges are 1/8 bspt senders.

autometer, stri, etc. are 1/8 npt. if you want to run a 1/8 npt sender in there, take a 1/8 bspt die and cut your sender down a bit with the die, then install.

[Darius]

Maybe this is why my sandwich adapter is leaking? Wondering if it is tapped for 1/8"bspt and it came with 1/8"npt plug fittings? Since it is such high pressure, it is harder than hell to keep oil from seeping past it.

[gawdzilla]

or could be the other way around. 1/8 npt female with 1/8 bspt male plug will be too loose and not seal right. home depot sells 1/8 npt plugs if you need it. what type of gauge sender are you using in your sandwich plate? that will tell you what female thread your sandwich plate has if your gauge sender seals fine

[Darius]

I have two Defi gauge sending units and they seal fine with just teflon tape. I haven't pinpointed the leak exactly because the plugged port is on the bottom so it always looks like it is the culprit because an oil droplet is hanging from it. Think I'm going to pull the filter this weekend and retighten the sandwich plate nut down to make sure it isn't leaking between the block and sandwich plate.

The leakage hasn't decreased so I'm assuming that it isn't the plug anymore or I would expect to see some kind of change from messing with teflon paste and tape and RTV.