Aeromotive and Fittings

[BRRT]

I had read some posts where guys had used something other than the recommended Fragola fittings on Aeromotive pumps and had leaks. I was ordering some items from Racetronix and threw a couple -6AN/-6ORB 90 degree swivels in my cart for the pump, thinking fittings are fittings. I had installed the Aeromotive 18638 in my tank, grabbed the Racetronix fittings, and was unpleasantly surprised when they would not screw all the way in. After receiving the recommended Fragola fittings and doing a bit of investigation I discovered the issue. The Racetronix fitting has threads 7/16" long under the hex. The Fragola fitting has threads 3/8" long under the hex, about 1/16" shorter.

Here's the Racetronix fitting:


So the Racetronix fitting is out of spec, right? No, not the case. I dug up both the SAE and MS spec. The spec calls for the port to have 12.7mm (1/2") of true threads, with some incomplete threads under that. This allows for the port to be tapped without using a bottoming tap. The Racetronix fitting should have worked, but the port is machined shallow on the Aeromotive pump.

OK, will the Racetronix fitting work on the Aeromotive fuel pressure regulator?
Nope, same issue. quite a gap between the fitting and regulator. It appears Aeromotive may machine their ports shallow.


So, does this mean only Fragola fittings will work? No, not necessarily. I checked some Parker steel -6ORB hydraulic fittings and they are 3/8" under the hex and would work. It's highly likely there are others. Just be aware of the issues before you pressurize your system. Not all fittings are the same, not all ports are the same.

[Mbufford]

The Evil Energy ORB fittings fit my Aeromotive parts perfectly, and cost way less than Frigola. Those are the only places I used the EE fittings, though, since I’m not using their PTFE hose and everyone says stick with the same manufacturer for hose and hose-attached fittings.IMG_0849.jpegIMG_0850.jpg

[michael everson]

Maybe that is done intentionally so as not to crush the O-ring?
Mike

[CraigS]

That looks like straight thread to me vs a tapered pipe thread. If it is straight thread shouldn't you use a brass or aluminum washer between the fitting and the body. A washer would fill in that gap.

[weendoggy]

That looks like straight thread to me vs a tapered pipe thread. If it is straight thread shouldn't you use a brass or aluminum washer between the fitting and the body. A washer would fill in that gap.

The regulator uses a straight ORB ("O" ring boss) fitting and is made that way and don't use a washer.

[BRRT]

Answers to questions:

1.) The port for an ORB fitting has a tapered area at the top that the O-ring is squeezed into providing the necessary seal. ORB fittings in hydraulic applications routinely seal 3000PSI systems.

2.) Yes, that is a straight thread. The Oring at the top provides the seal. No washer is used unless it is a high pressure hydraulic "positionable"(non-swivel) elbow that uses a nut and washer to compress the Oring.

When I threaded the Racetronix fitting into the Aeromotive pump the fitting bottomed out with enough of a gap it would not apply any compression to the Oring.

Here is a link to the SAE specification drawing:https://www.goodyearrubberproducts.c...n1.Page477.pdf

[BRRT]

The Evil Energy ORB fittings fit my Aeromotive parts perfectly, and cost way less than Frigola. Those are the only places I used the EE fittings, though, since I’m not using their PTFE hose and everyone says stick with the same manufacturer for hose and hose-attached fittings.IMG_0849.jpegIMG_0850.jpg

Thanks, that's good to know.

[Al_C]

BRRT, I give you a lot of credit for doing as much research as you did. I am one of those who commented that "other" fittings didn't work with an Aeromotive regulator. I just went with the advice of their customer service and used their part. Glad it's working out for you!

[BRRT]

BRRT, I give you a lot of credit for doing as much research as you did. I am one of those who commented that "other" fittings didn't work with an Aeromotive regulator. I just went with the advice of their customer service and used their part. Glad it's working out for you!

I should have taken your advice and I wouldn't have needed to investigate! Oh well, live and learn....

We got a lot of really smart guys on here. We all have knowledge and experience to share with each other. Its a good group.

[CraigS]

Ah, OK, an ORB fitting makes sense.

[CraigS]

I was just looking at an adapter to install an oil cooler. A nice block of CNCd aluminum also using ORB fittings. Apparently this length of fitting vs hole depth is a common problem. They go through why they recommend using the fittings that they sell for exactly the same reason.

[BRRT]

I was just looking at an adapter to install an oil cooler. A nice block of CNCd aluminum also using ORB fittings. Apparently this length of fitting vs hole depth is a common problem. They go through why they recommend using the fittings that they sell for exactly the same reason.

That's interesting. It's not a problem I have come across in industrial hydraulics.
I find it surprising, you would think everyone would adhere to the port spec.

What brand is the oil cooler adapter?

[CraigS]

I don't remember for sure as I looked at maybe 8 different brands.