-AN fittings for 5/16" hard fuel lines

[dadsbee]

He needs f to m.

THANKS, still sleep deprived from Cuba, missed the M and F. Back to the hangar.. LOL

 

[mopar67440]

Thanks all! The AN919-7-7d male to male black will work with an added 6an to 6an female to female coupler.

FYI...this is not a fuel injection system. This is for qty 2 Edelbrock AVS2 carbs being fed by Carter 4594 thru 3/8 hard line at 5-9 PSI.
The 5/16 return path will have a bleed of some orifice size to dial in a pressure of 5-5.5 PSI based on carb needle/seat size.
Should be easy to adjust PSI, will not dead head the pump, and eliminate the need for a bypass regulator that could fail down the road.

 

[OKDart]

Here's a chart for the F to M reducer

 

[RJ Squirrel]

https://www.ebay.com/itm/3579954961...7QlRvg-DMcB8TrhBUPSNzjvRPSZafqepNfHnEwGwwmpO0

AN6- 3/8
AN5- 5/16

 

[mopar67440]

Here's a chart for the F to M reducer

View attachment 1981320

View attachment 1981323

Awesome reference. Thanks!

 

[dadsbee]

https://www.ebay.com/itm/315024680269

AN894-6-5D Fitting | Aircraft Spruce ®

 

[Frankb]

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!

AN fittings don't work with double flare hard lines.
You cannot use a 5/16 double or single flare on a -6 fitting if the flare is on the large size. Size it correctly or it will not work.
Brass can work but its difficult to work with and its more prone to leak.
Seems your trying to mix and match different style fuel delivery systems.
AN is not required for carbs because they don't need much pressure.
Do not mix AN and NPT
Are you using an electric in tank pump or mechanical?
Most likely there is an adapter -6female to -5 male but why would you want to do this?
If not running an electric pump with regulator then use -6 supply and return.
Hard line is always better than flex but flex makes life much easier.

 

[Frankb]

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.

I install a larger line on return than pressure.
Fuel pressure to injectors (or carb) is controlled by return flow not pump pressure even though some pumps provide more pressure under more demand.
Up to about 650 HP I use -6 pressure and -8 return

 

[mopar67440]

AN fittings don't work with double flare hard lines.
You cannot use a 5/16 double or single flare on a -6 fitting if the flare is on the large size. Size it correctly or it will not work.
Brass can work but its difficult to work with and its more prone to leak.
Seems your trying to mix and match different style fuel delivery systems.
AN is not required for carbs because they don't need much pressure.
Do not mix AN and NPT
Are you using an electric in tank pump or mechanical?
Most likely there is an adapter -6female to -5 male but why would you want to do this?
If not running an electric pump with regulator then use -6 supply and return.
Hard line is always better than flex but flex makes life much easier.

I am not trying to mix 2 fuel delivery systems.
I know AN is not required for low pressure carb, but I selected the AN over brass because of aesthetics.
No NPT fittings or rubber lines are being used anywhere in the fuel system
The NiCopp hard lines will be single flared to mate with the appropriate AN fitting.
Carter 4594 external elec pump being used controlled by Bosch relay and inertia switch.
I will test the 6an to 5an reducer with the 5/16 return line that's already there. If this does not provide the control I want, I will either add a bypass reg or upsize the return to 3/8.

 

[Bird 426]

Sounds like you have an AN flaring tool.

 

[493 Mike]

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.
View attachment 1981288View attachment 1981289View attachment 1981290View attachment 1981291

That should flow enough fuel!
Mike

 

[dadsbee]

That should flow enough fuel!
Mike

-28, 1.75 inch ID.

 

[mopar67440]

Thanks for all the help everyone. Fuel log is all set. On to the tank and return.

I purchased a new sending unit (1967) with 3/8 out. There are no sending units for 66/67 with return line. My plan was to drill and add a 5/16 bulkhead with barbed nipple. I'm also replacing the original tank fuel filler and vent.
Few questions;
- Are the fuel fill kits/rubber elbows from the likes of Vans Auto or Classic Industries ethanol resistant?
- There is a coupler available to splice in line with the fill tube that has a return nipple on it. Anyone take this route vs a sending unit return?

Thanks!

 

[493 Mike]

Thanks for all the help everyone. Fuel log is all set. On to the tank and return.

I purchased a new sending unit (1967) with 3/8 out. There are no sending units for 66/67 with return line. My plan was to drill and add a 5/16 bulkhead with barbed nipple. I'm also replacing the original tank fuel filler and vent.
Few questions;
- Are the fuel fill kits/rubber elbows from the likes of Vans Auto or Classic Industries ethanol resistant?
- There is a coupler available to splice in line with the fill tube that has a return nipple on it. Anyone take this route vs a sending unit return?

Thanks!

One can always poke a hole and solder a return anywhere that suits you. Drill your hole smaller than you need and drive a tapered punch in the hole to open it up. That will flare out the metal and give you a strong solder joint.
Mike

 

[mopar67440]

One can always poke a hole and solder a return anywhere that suits you. Drill your hole smaller than you need and drive a tapered punch in the hole to open it up. That will flare out the metal and give you a strong solder joint.
Mike

Good point. Will do.
One concern I have is the rubber elbows for the filler tube and vent tube from Vans and Classic. Are they resistant to ethanol? I'm in Mass which is E10
In my research I found Filler Neck Supply. Any experience?

 

[493 Mike]

Good point. Will do.
One concern I have is the rubber couplers for the filler tube and vent tube from Vans and Classic. Are they resistant to ethanol? I'm in Mass which is E10
In my research I found Filler Neck Supply. Any experience?

No. Ask your local auto parts supplier. They should have the correct hose in bulk in stock.
Mike

 

[Dan64]

Thanks all! The AN919-7-7d male to male black will work with an added 6an to 6an female to female coupler.

FYI...this is not a fuel injection system. This is for qty 2 Edelbrock AVS2 carbs being fed by Carter 4594 thru 3/8 hard line at 5-9 PSI.
The 5/16 return path will have a bleed of some orifice size to dial in a pressure of 5-5.5 PSI based on carb needle/seat size.
Should be easy to adjust PSI, will not dead head the pump, and eliminate the need for a bypass regulator that could fail down the road.

Are you using a Enderle style log regulator made for mech. injection?, it's the little log with the spring to regulate pressure past the point of the carb feeds. I tried this on my 64' with a large Clay Smith mech. fuel pump putting out around 12psi . Didn't work well, pressure fluctuated and wouldn't stay steady. I gave up and used a regulator and dead heading it. I do have that electric Carter fuel pump on a truck and it does not have a regulator and is dead headed, works great, holds a steady 5.5 psi. I'm curious to see if your set up will work well since you are using a lower pressure pump, maybe it won't fluctuate?. Please let us know.

 

[mopar67440]

No. Ask your local auto parts supplier. They should have the correct hose in bulk in stock.
Mike

Local parts store is not going to have the rubber elbows for the fuel filler on a 66/67, and I wouldn't trust their source anyways. Plus, I highly doubt anyone behind the counter would have a clue if it was ethanol resistant or not.

 

[mopar67440]

Are you using a Enderle style log regulator made for mech. injection?, it's the little log with the spring to regulate pressure past the point of the carb feeds. I tried this on my 64' with a large Clay Smith mech. fuel pump putting out around 12psi . Didn't work well, pressure fluctuated and wouldn't stay steady. I gave up and used a regulator and dead heading it. I do have that electric Carter fuel pump on a truck and it does not have a regulator and is dead headed, works great, holds a steady 5.5 psi. I'm curious to see if your set up will work well since you are using a lower pressure pump, maybe it won't fluctuate?. Please let us know.

I'm not using the log mentioned. It's a home made fuel log with -6an fittings. 3/8 supply, 5/16 return. Carter 4594 elec pump (6-9PSI).
The plan in order
1. Test with capped 5/16 return line (dead head) and measure PSI
2. Depending on test 1. results, add bleed orifice to 5/16 return line and size bleed accordingly for 5.5 PSI (similar to vapor return filter)
3. If 2. fails, upgrade 5/16 to 3/8 line w/ bleed or bypass regulator and adjust to 5.5PSI