Oil sending unit thread size

[Wickedtuna]

Afternoon All,
Does anyone know of hand the stud size on the oil sending unit? I joist replaced it a month or so ago and got oil in so didn't really want to pull it just yet. I am going electric fuel pump route and want to place a tee so that I can attach an oil pressure cut off switch for the pump. Better yet if anyone has done this and has part numbers that would be awesome too.

[Big John]

Oil pressure and fuel pump are two different things. I run an electric fuel pump in line with the stock fuel pump. Electric pump is close to the fuel tank. I have a switch on the dash to run the electric pump. I use the electric to load or prime the fuel system up to the carb. Turn it off and fire the engine. If the stock fuel pump fails I can run the electric until I replace the stock fuel pump.
Oil pressure thread is 1/8 fine I think?

[Big Ed]

John, he's talking about teeing into the oil pressure to create a fail safe to keep from ruining the engine. A pressure loss would kill the fuel pump. Good idea really.

[Big Ed]

Let's see, 1/8" pipe is R drill.


R drill is .339"


Calipers set at .339"


Looks right to me.

[Wickedtuna]

Thank you Ed, that is exactly what i was thinking. Thank you so much. I really appreciate it. Sorry John if i was not very clear.

[scoutsniper]

look for a hobbs switch either fix or adjustable, one example
http://www.jegs.com/i/JEGS-Performance- ... 0/10002/-1
i would upgrade to a relay for power and use this switch to interrupt the relay trigger or ground.
that how the nitrous fuel system is step up on my truck,it kills the pump if fuel pressure gets too low.
and my preferred method for adding relays
http://www.ebay.com/itm/Waterproof-Fuse ... q1&vxp=mtr

[Big Ed]

Thank you Ed, that is exactly what i was thinking. Thank you so much. I really appreciate it. Sorry John if i was not very clear.

I followed what you were saying.

No problem on checking thread size, my truck engine is apart right now. the sending unit was laying loose on the wagon.

[Tim Potter]

Afternoon All,
Does anyone know of hand the stud size on the oil sending unit? I joist replaced it a month or so ago and got oil in so didn't really want to pull it just yet. I am going electric fuel pump route and want to place a tee so that I can attach an oil pressure cut off switch for the pump. Better yet if anyone has done this and has part numbers that would be awesome too.

You don't need to be too concerned about removing the pressure sending unit with oil in the engine unless you do it while the engine is running. If it isn't, there won't be any pressure on the oil passages. There might be a small amount of drip, but no gusher to worry about. There's 3 ports to the oil galley on the driver side of the block, no need for a Tee, just pick one of the other two ports that aren't being used. Theoretically, best representation of OP would be at the #3 main bearing, middle of the block, but I've not noticed much of a difference using the outer two port for pressure senders. However, if I had to choose, I'd run the center to the dash gauge and either of the other two to the safety switch.

[Wickedtuna]

Oh nice!! The kit came with the tee already. I haven even crawled under to see, i thought there was another port i could use. Thank you Tim. Haven really looked into too much just getting everything ready. My brain will start 3 projects before I'm done with what I'm actually working on. But I file everything away till that day then bust it out. Thanks again.