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Oil pressure union

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Rut

Rut

Obi Wan
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What size is the oil pressure union on a 1275? The PO put a smaller line of the plastic type to go with the plastic gauge (SunPro) in the block and I would like to find out if my original gauge works. The temp side works fine and I do use the cheap gauge to verify temp and would like to do the same with oil pressure. If I know the thread size in the block, the thread size of the original pressure gauge nut, and the thread size of the SunPro gauge nut, I should be golden, no?
Thanks, Rut
 
I bet someone has done this before, placed a T in the block and run 2 oil pressure gauges. Any ideas about the thread size of the block and the original oil pressure gauge nut?
Thanks, Rut
 
Pretty sure the block is 1/8" BSP. A 1/8" NPT will fit pretty well. I like to use "Form-a-Gasket" #1 on the threads to help seal. Just a little wipe of sealant, not very much at all. #1 hardens. I use it on most of the fluid fittings that infrequently get removed. BSP is British Straight Pipe, which seals with a copper crush washer under the head of the stock oil adapter fitting.

What you will likely have to do is to cobble up something from some 1/8" NPT stuff from the hardware store and figure out how to mate the 1/8" BSP adapter onto the "T" contraption. That's the hard part. You might have to epoxy or solder the stock fitting into the "T". If you want a replacement stock fitting, I can supply as many as you want. I don't use them on the race engines and have plenty in parts buckets and coffee cans.

Mike
 
McMaster-Carr (mcmaster.com) has some BSPP and BSPT fittings. Search on their site for p/n 4860K151 and you will see a 1/8" BSPP male to 1/8" NPT female fitting. From this you can use a 1/8' NPT to 1/8" tube union and use 1/8" copper to go to the gauge. Put a 1/8" tube T in the line if you want. I would lose the plastic tubing and go with copper all the way. I learned this the hard way.
Marv J
 
Why not? looks good from here.
 
While the hole in the block is almost certainly 1/8BSP, I have never had any problem using 1/8NPT fittings. Like others above, I have used Teflon tape on some threads, form-a-gasket on others (depending on which was at hand).

Most local auto stores will carry the 1/8" copper tube oil line kits. They will work fine if you loop the tubing to form a "spring" between the block and the firewall to absorb some of the vibrations and movement from the engine rocking. Those kits will be 1/8NPT and will include a female threaded fitting that can be attached to the back of the Smiths gauge with a bit of Teflon tape.

You can also order oil gauge lines from Summit that are made from AN4 braided hose (Longacre brand).
 
I guess my only concern is connecting the original gauge nut to the npt fitting. The way it seals may require a washer of some type?
Thanks, Rut
 
Come on Rut, try Ace for washers and such.
 
When I clicked on the link it gave me all of the brass fittings...number 4860k441 is the one in question. Sorry about that!
Thanks, Rut
 
Rut said:
I guess my only concern is connecting the original gauge nut to the npt fitting. The way it seals may require a washer of some type?
Thanks, Rut
Click to expand...

Yes, the original Smiths fitting uses a fiber washer crushed between the back of the gauge and the nut on the line. However, as I mentioned in my last post, you can wrap some Teflon tape on the post on the back of the gauge and run the 1/8NPT fitting up on it. It will seal fine. I have done this on several gauge installations where the Smiths hose and hose end fitting were not available.
 
Ahh yes, shade tree mechanics at its finest. lol
 
Shade tree indeed! I found a local machine shop/parts store and the owner has a B and an A in parts and understood exactly what I was trying to do. Bought a 1/8" npt Tee, male x female x female ans a 1/8" nipple and it all went together in 5 min. Only had to tighten one time to stop a leak and now both gauges work and read the same.
Thanks all, Rut
 
Well done.

Hay nothing wrong with shade tree. That fits me to a T and I get er done.
 
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