Repacement Fuel Line Advice

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May 19, 2010 | 07:36 PM

V8 Stingray

Thread Starter

Instructor

Joined: Apr 2009

Posts: 160

Likes: 5

From: Gorey Ireland

Repacement Fuel Line Advice

Hi Guys,

Have a leaky fuel line that I now need to replace, so looking to do a proper job on this - however never used AN connectors before - so looking for a bit of advice as to whether the below is correct.

Also, I am planning to use overbraid hose all the way from the pump to the carb feed lines - is this ok? Should I be considering a steel line?

I have a new Holley Street Avenger with dual feed.

So, to start I'll have a new dual feed kit from Fragola (-8 AN) http://www.summitracing.com/parts/FRA-920023/

into a russell -8AN hose connector http://www.summitracing.com/parts/RUS-610030/

then into an -8AN hose and again into a into a russell -8AN hose connector http://www.summitracing.com/parts/RUS-610030/

I then plan to put in a new -8AN fuel filter http://www.summitracing.com/parts/RUS-650100/ and back to a -8AN hose end http://www.summitracing.com/parts/RUS-610030/

more -8AN hose

-8an hose end http://www.summitracing.com/parts/RUS-610030/ to a 90 degree -8AN coupler http://www.summitracing.com/parts/EAR-982108ERL/ to a -8an hose end http://www.summitracing.com/parts/RUS-610030/

-8AN hose then to a final -8AN hose end http://www.summitracing.com/parts/RUS-610030/ before into the fuel pump.

No sure exactly what connector I need to attach to the fuel pump, and seems to be contradicting thoughts on this. From what I make out the thread coming out of the stock fuel pump is 5/8"-18 - so I just get a 5/8"-18 to -8AN adapter like this one? http://www.summitracing.com/parts/RUS-640630/?rtype=10

May 19, 2010 | 08:34 PM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

I wouldn't use flex hose on anything with pressurized fuel in it. Use solid line for such purposes. You can make your own with a tube-cutter, an inexpensive small tube-bender and a flaring tool.

I don't know where your leak is, but you can also put a splice in for a small damaged area of tubing. Just connect it with compression fittings for that same size of tubing. Measure carefully what you need to cut out and how long the replacement line needs to be. Tighten fittings to proper spec per manufacturer.

May 20, 2010 | 06:40 AM

aussiejohn

Drifting

Joined: Jul 2002

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From: The only Corvettes in Highett Victoria

Regards from Down Under

aussiejohn

May 20, 2010 | 07:40 AM

Aflac

Race Director

Joined: Oct 2002

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From: Smalltownville Michigan

Cruise-In 5, 6 & 10 Veteran

St. Jude Donor '09

you can use flex hose (aircraft consistently have used braided hosed in high vibe, high flex areas with 3-4000 psi for years) in those areas. They do require close inspection relatively frequently though. They use the flex lines in places where things have to move (brakes, landing gear components etc...) But, seeing that you are plumbing fuel lines (nothing should be moving unless something is horribly wrong), the safe bet is to use rigid lines.

*note: I am a USAF hydraulics craftsman. 1993-present.

May 20, 2010 | 08:24 AM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

Flex/braided hose is capable of handling fuel line pressures; and it is safer than non-braided hose because it has outer protection on the hose. But, when you put it in your car, you are not likely to check it as often [or ever, when you get it installed] as the airframe mechanics are required to do on an airplane. The choice is yours. I merely stated that I wouldn't do it.

May 20, 2010 | 08:43 AM

Gordonm

Race Director

Joined: Dec 1999

Posts: 19,610

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From: Forked River NJ

Your fuel line will be fine running braided line. The braided line will handle the low fuel pressure no problem. I have run this setup on mine and other cars for years without a problem. I would run the fuel filter coming off the fuel pump instead of up higher like yo uahve in your diagram, there is more room there then after your 90 degree fitting. The 8 AN line is way over kill for your application. A 6 AN line will feed 500+ HP with no problem at all. No need to run a 1/2 line from the fuel pump to the carb. I would also not run the 90 degree fitting you have shown. Run one with a gradual bend. Those hard 90 degree fittings are tougher on flow then a gradual bend 90 degree fitting.
Here is an old picture from a few years ago of the system I was running. This is all 6 AN lines and feed 409 RWHP just fine. Ran it on the dyno and it maintained 6 psi right up to 6500 rpm.

Last edited by Gordonm; May 20, 2010 at 08:48 AM.

May 20, 2010 | 12:18 PM

markdtn

Le Mans Master

Joined: Aug 2003

Posts: 7,720

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From: Chattanooga TN

If you choose to use compression fittings, consider getting some hydraulic ones. They are made for higher pressure use.

May 20, 2010 | 12:37 PM

81pilot

Drifting

Joined: Aug 2009

Posts: 1,635

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From: Enid Oklahoma

Quote:

Originally Posted by 7T1vette

I was a fuel systems specialist in the AF Reserve after active duty and actually we had a lot of fexible braided lines. Even in places that were only checked when there was a problem since you could not get to them without a lot of airframe dissassembly, especially in heavy lift airframes. The requirements were mostly on the pumps and related redundant equipment to do the inspection/periodic replacements. I wouldn't hesitate to use them in a car if properly installed, thats why they were designed, but everyone has thier own preference. So I understand your opinion...