Fuel fitting sizes

[Ncostello]

When considering fuel filter heads that come with various size ports. . which is larger? 1/2-20 UNF (SAE O-ring) or 3/8-18 NPTF? I think it takes a 37/64" drill bit when tapping for 3/8-18 NPTF... but I have no idea how the SAE fittings are measured.



Guess my point is which will flow more (bigger opening) when the fitting is installed. Stanadyne said the 3/8"x18 NPTF filter head they sell actually had larger ports than the 1/2"x20 SAE O-Ring one. I couldn't discuss it with them since I had no idea. Thanks TDR.

 

[illflem]

The flow area though an o-ring fitting is smaller than the equivalent fraction size of pipe thread. 1/2 SAE and 3/8 NPT will be real close to the same size. O-ring type fittings are more leak free than pipe thread in a vibrating environment and are easier to take apart/put together, no thread sealer involved.

 

[Ncostello]

How about this... Who makes a M12x1. 5 X 3/8" hose barb fitting. I couldn't find one anywhere on earth. The only place that came close is a place called Anver Corporation and I'm still not sure with them. They have such fittings that adapt 1/8" NPT x 3/8" hose barb... and they also claim to make the threads in metric but didn't list the sizes. They were closed when I called.



I checked a dozen places that supposedly specialize in metric stuff but they were stumped.



Anyone ever find a direct hose fitting that will tie right into a Carter OEM lift pump? The normal thing is the Weber fitting for -6AN but thats only good if your using AN type hose. I was thinking of using Marine SAE J1527 3/8" hose and smooth liner clamps. Its just that darn one fitting I cant find.



I suppose there is always custom machine shops but the cost could exceed just using Aeroquip fittings and hose. Thats what I'm looking into avoiding.

 

[Ncostello]

I dont know if anyones interested but Adaptall Inc. makes specialty fittings for adapting metric stuff to english sizes. They carry a steel fitting that is male M12x1. 5 X 3/8" NPT female. It uses the sealing washer just like the banjo fittings and is intended for port fittings. This would allow anyone wanting to adapt the OEM fuel pump to standard size fittings a choice. Then you could always install some inexpensive 3/8" fuel hose and barb fittings, clamps etc to upgrade the stock setup if you feel its too small. Just something I thought I'd pass along. Maybe some already knew this. The part is 9235-12-06 by Adaptall. They sell through most hyd. shops and wont sell direct to consumers. My price at the local hyd shop is $6. 60.

 

[jhurst]

Hey thanks for the heads up on the Adaptall fitting. Going to head to the local shop and see if I can get a couple.





Justin H

 

[Ncostello]

Actually a better choice would be a M12x1. 5 by 1/4" NPT female. You can still get a 3/8" hose barb X 1/4" NPT male to go along with this adapter and get the full benefit of 3/8" hose ID in the smaller barb fitting. 3/8" NPT is a little too large for what I wanted. They have about anything.