Help with Mechanical Oil Pressure Fittings Please.

[81GrandPrix383]

Hi,

I bought a car with aftermarket gauges already in it.
The oil pressure gauge is mechanical with the oil tube running from the gauge, through the firewall and needs to be hooked to the motor.
I want to hook it to what I think is the usual place at the top back of the block where the 1/8" Pipe thread hole is.
The problem is that I can't seem to figure out what size thread fits into the collar at the end of the tube from the gauge.
The 1/8" pipe thread is very close and goes together but will not seal properly.
The thread I am looking for is a hair larger than the 1/8" pipe.

Anyone have any suggestions?
I can't take the tube to the store with me.
I'm almost ready to go buy one of everything to make it work. lol

Thanks for any help you can offer.

 

[pontiacgp]

try an adapter with 1/8 npt on one side and g 1/8 on the other

 

[81GrandPrix383]

try an adapter with 1/8 npt on one side and g 1/8 on the other

It's worth a shot, thanks.

 

[pontiacgp]

opps my mistake to suggest a g thread....it does take an adapter tho, is it an an 3 thread?

 

[81GrandPrix383]

opps my mistake to suggest a g thread....it does take an adapter tho, is it an an 3 thread?

I'm not sure, I don't have any AN fittings to test it with.

 

[pontiacgp]

who makes the oil pressure gauge, try their web site to see what they can tell you about the fitting

 

[username]

If its a bit bigger than 1/8 its probably a 1/4-18, a -3 AN is 3/8-24.

 

[RockSS]

Go to the hardware store and buy a 90 degree fitting they have all kinds of adapter in the plumming section ... What your looking for is a 90 degree 1/8 pipe tread on one end and 1/8 compression fitting on the other ... you just slip the nut over your tubing then the compression ring then tighten the ring is tapered so when you tighten it it crimps on to the tube making it not leak ... that being said you do not have to crank it as tight as you can ... 😀

 

[RITTER]

Go to the hardware store and buy a 90 degree fitting they have all kinds of adapter in the plumming section ... What your looking for is a 90 degree 1/8 pipe tread on one end and 1/8 compression fitting on the other ... you just slip the nut over your tubing then the compression ring then tighten the ring is tapered so when you tighten it it crimps on to the tube making it not leak ... that being said you do not have to crank it as tight as you can ... 😀

NAPA also offers these in our brass fitting bin. If there is already a compression sleeve smashed on the nylon oil line, you are going to want to cut that off and put a new one on. Its not really a good idea to reuse those after their original seal has been broken. They cost like $0.05, so its completely worth it to just replace it, instead of leaking oil all over and then replacing it.
So, cut off that section. Take the piece to NAPA (or whichever store you go to) to be 100% certain that you have the correct size. Just let them know that you need a compression union to 1/8 male NPT fitting

 

[81GrandPrix383]

Go to the hardware store and buy a 90 degree fitting they have all kinds of adapter in the plumming section ... What your looking for is a 90 degree 1/8 pipe tread on one end and 1/8 compression fitting on the other ... you just slip the nut over your tubing then the compression ring then tighten the ring is tapered so when you tighten it it crimps on to the tube making it not leak ... that being said you do not have to crank it as tight as you can ... 😀

A compression fitting doesn't really work for me.
There is a threaded end on the tube right now. I don't want to cut the tube to take the end off and use a compression fitting when all i need to do is match the size and thread.
Also, with a compression fitting I would need to know the size of the tube to get the right size fitting. I guess with calipers I could figure that out but I still don't want to get rid of a perfectly good threaded line end.