Oil pressure sender thread pitch
 

The size is 1/8PT, not 1/8NPT, for those curious..

Also 1/8PT (Japanese) is 1/8 -28 BSPT.
:D

I am familar with NPT but what is PT?

BSPT = British Standard Pipe Thread

Not the same as our NPT, National Pipe Tread.

PT only comes in Cruisers. :D

PT is Japanese actually, but the same as BSPT. At least, in this case. Took me a little while to find the thread pattern.. :-/

I found an adapter for it to convert the stock oil press. sender hole to 1/8NPT so I can use my aftermarket gauge w/o tapping the stock location. It's about $15 from a local industrial supply place.

The adapter is available @ www.pegasusautoracing.com

Cool, thanks man.
http://www.pegasusautoracing.com/Pro...asp?RecId=3142
I didn't know the details of what was needed for this until today. I really didn't want to retap my iron for the NPT.. At any rate this is in the forum db now, so if anybody searches they'll be able to find it.

Trust me. You don't want to re-tap the iron for the 1/8" NPT. I just did this last week, engine is apart, and the cast iron is a pita to get the tap to start in.

I did the re-tap for the temp sender, since I am replacing all of the gaiges with Autometer gauges, except the tach and speedo.

Before I tapped the oil sender, I ran across a thread that said to cut the mushroom off of the oem sending unit and tap what's left for the 1/8" NPT. If your tap is sharp, you don't even need to redrill for the tap. Works like a charm and I had the satisfaction of sacrificing the oem sending unit to save time and money.

That's interesting. I'm a bit worried though because I think NPT threads are larger in diameter than BSP.

Not sure what you are asking. The BSP is a finer thread, not sure about the diameter.

It was the temp sensor I tapped. Below is a pic of the the stock temp sensor on the right. It is smaller in diameter than the op sensor. On the left is the cut oem op sensor and the 1/8" adapter screwed into it. This is for a mechanical gauge, not electrical.

https://www.rx7club.com/attachment.p...d=123970&stc=1

The one on the right is water temp sender, not oil pressure. I will see measure them since I have the thread gauge at home.

Dang, that is a really good idea, using the old sending unit.
Yeah, see if you can find the water temp sender thread pitch. It would be nice to have them both in the same convenient thread.
I would guess that it is metric and not pipethread, but who knows..

Read my post more carefully. Yes the water temp sensor is on the right in the previous pic. It was that hole that I tapped for the 1/8" NPT sender for my Autometer gauge.

You don't need to tap for the op sender, and I doubt if you can because the the diameters are nearly the same and I think it would simply strip out the threads and nothing would hold securely then.

Below is a pic with the oem op sender and the modified one of the left hand side. On the right hand side of the pic is the oem temp sender and the after market temp sender. If one wants to put an after market temp sender in the stock location, the hole will need to be tapped. The op sender hole does not need tapped if one sacrifices the oem op sender.

I may be confusing people because of the temp sensor.

Hope this clears up any confusion.




https://www.rx7club.com/attachment.p...d=123975&stc=1

I mentioned that to make it clear for others.

:bigthumb:

It's clear now. Thanks. Good idea too.

could someone bump this to the Archive.

zombie bump. I miss threads like this, they were informative.