-AN fittings for 5/16" hard fuel lines

[mopar67440]

Good morning all,

Question for those familiar with the AN fittings.

I'm in the process of updating my 5/16 fuel line to 3/8 for dual AVS2 carbs on a 440, and looking to use the 5/16 as a return line.
I created a fuel log with -6an (3/8) 37* double flare hard line coming in, and would like the 5/16 37* double flare return at the other end of the log with a gauge.
The problem I ran into was downsizing from 3/8 (-6AN) to 5/16 (-5AN) without converting to NPT first. There are is no straight forward way of going from -6AN female to -5AN male.

I would prefer not to use so many fittings to accomplish this. Converting to brass fittings brings me to 45* brake line flares which could leak.

Can a use a 5/16 double or single flare on a -6an fitting if the flare is on the large side?
If not, any suggestions?

Thanks all!

 

[Frank Mopar]

Run 6an back or add a fitting or two. IMHO that is.

 

[BSB67]

Run 6an back

This

 

[gkent]

Why two different size lines ? Use 3/8 for both.

 

[mopar67440]

Run 6an back or add a fitting or two. IMHO that is.

What do you mean by run 6an back?

 

[mopar67440]

Why two different size lines ? Use 3/8 for both.

I'm using the existing 5/16 as a return and adding the 3/8 supply.

 

[gkent]

What do you mean by run 6an back?

The same as you're running to the front !!!

 

[dadsbee]

You can get AN unions with a size change. I have boxes full. Will look after I blow snow.

 

[mopar67440]

The same as you're running to the front !!!

So are you saying a 5/16 flared line with fit the -6an which is for 3/8 line?

 

[mopar67440]

You can get AN unions with a size change. I have boxes full. Will look after I blow snow.

5an is for 5/16 line. 6an for 3/8. I could not find a union or adaptor to change from 3/8 to 5/16.

 

[pnora]

5AN is a bastard size. As said above better to go 6AN.

 

[Frank Mopar]

You can run 6an with 5/16 barb to hook to tank if that’s the problem.

I would run 8an to front for two carbs but that’s another issue.

 

[dsd1967]

Try an aeroquip 2027-6-5s fitting and see if that will do what you want.

 

[mopar67440]

You can run 6an with 5/16 barb to hook to tank if that’s the problem.

I would run 8an to front for two carbs but that’s another i

No problem at the sending unit with the 5/16 return. I am referring to the fuel rail/log at the carbs.
Also not worried about running 3/8 vs 1/2 too the two carbs. This is street driven with occasional blasts.

 

[Bird 426]

Fragolia makes fittings that have a compression fitting on one end. Just slip it over the clean cut tubing and tighten it. It's a pushlock fitting, so rubber hose is involved. I have used it on two of my cars between a fuel pressure regulator on the frame over to a mechanical fuel pump or metal line at the engine. Maybe something like that would work for you.

 

[gkent]

This is street driven with occasional blasts.

Then no need for 1/2" !!!

 

[dadsbee]

5an is for 5/16 line. 6an for 3/8. I could not find a union or adaptor to change from 3/8 to 5/16.

Oh I'm well versed in AN fittings. Dug thru them all and someone seems to have taken my -7's. You are looking for an AN919-7. Steel is -7, Aluminum -7D and Stainless -7S.

 

[dadsbee]

Here ya go...
AN919-7, AN919-7S, Aircraft Steel Nipple / Union Reducer Fitting | eBay

 

[kiwigtx]

In any fuel injection system with a "Flow and Return", both lines should be the same size, otherwise you will discover all about restriction.

Don't even think about "Dead-heading" the supply line.

 

[Frank Mopar]

Here ya go...
AN919-7, AN919-7S, Aircraft Steel Nipple / Union Reducer Fitting | eBay

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