stock oil pressure gauge question

[oldtrux]

anyone know what size and kind of thread on back of stock oil pressure gauge?i'm trying to get fittings to convert to -an fitting to use braided line instead of copper line.thx dan

[davbowen]

1/8" npt with 1/8" compression fitting. i think you"ll need some sort of adapter.

[ray_mcavoy]

The GM oil pressure gauges use a special type of compression fitting where the ferrule is built into the nut.
Weatherhead calls them "threaded sleeve" fittings and their 6100x2 nut will connect 1/8" tubing to the back of the stock gauge.



Edelmann calls them "double compression" fittings and their part number for the nut is 111200. The Everco equivalent is 11A.

I don't think anyone makes an adapter to go from the port on the stock gauge directly to AN.

[oldtrux]

great,thanks!sounds like i need 1/8''npt to -3-an adapter and i'm good.

[oldtrux]

posted same time as ray.so it's not 1/8'' npt??

[ray_mcavoy]

Originally Posted by oldtrux

posted same time as ray.so it's not 1/8'' npt??

1/8" NPT is pretty common on aftermarket gauges. And I have seen a few stock (mostly mid-70's medium duty truck) oil pressure gauges with NPT threads.

But the fitting I posted above is what I've seen on the vast majority of GM oil pressure gauges. If I remember correctly, they have straight 5/16"-24 threads (like a bolt). The seal is formed by the special tapered end of the nut which acts like a built-in compression ferrule when it's tightened down into the port on the back of the gauge.

[oldtrux]

ok thanks ray.so i guess there would not be a fitting to convert to even npt.hhhmmm??

[ray_mcavoy]

Originally Posted by oldtrux

ok thanks ray.so i guess there would not be a fitting to convert to even npt.hhhmmm??

If such a fitting exists, I'm not aware of one.

Weatherhead, Edelmann, etc. all make connectors that adapt NPT to the "threaded sleeve" / "double compression" type connection used on the gauge. But they're the opposite of what you need. They have a female port (just like the back of the gauge) and male NPT threads.

[1963c-10]

I have all the part #'s to convert to a -an braided line, give me a few minutes to get them out of my build thread.

[1963c-10]

Ordered the stainless oil pressure gauge / block kit through Summit. Its an Auto Meter kit #3235. This kit is a 4' length, but they have a longer one also.

The hose is -3 AN which is 1/8" inside, so same as the plastic line kits, but looks much better.

[1963c-10]

Couple more pics and the fitting for the back of the gauge

[oldtrux]

Thanks very much for the info 1963c10!i will order that up today!

[1963c-10]

No problem. I keep all my part numbers just for these reasons.

[MikeN]

Originally Posted by 1963c-10

Ordered the stainless oil pressure gauge / block kit through Summit. Its an Auto Meter kit #3235. This kit is a 4' length, but they have a longer one also.

The hose is -3 AN which is 1/8" inside, so same as the plastic line kits, but looks much better.

Both ends of the hose are female. I see the fitting in the photo that inserts to the back of the gauge, but I don't see another fitting in the photo to screw into the engine block that also has a male end to connect to the hose?

[1963c-10]

Post 11, 1st pic...it has the plastic cap on it to protect the threads.

Also pictured in the kit on post 10.

[1963c-10]

Originally Posted by MikeN

Both ends of the hose are female. I see the fitting in the photo that inserts to the back of the gauge, but I don't see another fitting in the photo to screw into the engine block that also has a male end to connect to the hose?

Thought about this last night and your correct. Not in the pics....but already installed on the my engine is a 5/8" adapter to connect to the line kit fittings (at least on the big blocks, I imagine the small blocks are the same). On the big blocks, the port is centered over top of the oil filter. I can get pics tonight if needed. The oil pressure switch which I'm not using that normally screws in the block is a 5/8" thread fitting. Easily found part at most auto parts stores.

Few pics of the install I did. PO had an existing hole drilled here, so I used that hole, but it widens to 3/4" for the grommet and stainless line to pass through.

The kit says to slit the grommet, but I didn't have any issues getting it over the fittings...just take your time and it'll work on.

[MikeN]

Cool, thanks!

[Crazy Rusty]

Originally Posted by 1963c-10

Couple more pics and the fitting for the back of the gauge

Just to confirm, the auto meter kit didn't come with the fitting to connect to the pressure gauge, you got a 5/16-24 x 3AN fitting separately correct?

Is this the correct one?

Edelbrock 76525 Flare Fitting Adapter, Straight, -3AN x 5/16-24 Stainless

[1963c-10]

That's correct. The fitting to the gauge was not included in the kit.

[1963c-10]

Summit racing #16150 was the fitting I used.

Heres the link: http://www.summitracing.com/parts/nex-16150

[Crazy Rusty]

Originally Posted by 1963c-10

Summit racing #16150 was the fitting I used.

Heres the link: http://www.summitracing.com/parts/nex-16150

Thanks, should be picking up one today so I can finally have a working oil gauge