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Discussion Starter #1
I am completely new to the AN-6 fittings and I am looking to run Nylon lines on my 41 buick. I have a Tuned Port SBC in it and I was looking to relocate the route of the fuel lines using AN-6 fittings. Every kit I fond has braided nylon hose with it, but I was looking to use the non braided lines I already have. Is this possible to do? DO the AN-6 fittings work both with/without the braided covering? This is the only thing holding my up from getting my car started here soon. Thanks in advance for any info. Im currently at work, but will try to respond as soon as possible.
 

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If you're talking about solid nylon tubing, the only fittings I've seen used with it in industrial applications are compression type fittings and push fit fittings. The only AN fittings I'm aware of that use compression connections for the tube are for Teflon hoses with braiding. I'm not sure these would be the correct dimensions for the internal diameter of the nylon tube.

Even though the fuel system is fairly low pressure compared to some industrial applications, make sure the connections are absolutely correct mechanically. You sure don't want a fuel hose to blow off with 40 lbs of pressure.

Also, I would want some type of braided shield on the tube. The tube isn't very good at abrasion resistance.
 

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AN-6 makes a small fuel line, is this from the pump too carb or from tank too pump.

AN fittings are designed for the wall thickness of the braided line. Building a fuel system; tank too pump AN-10, pump too carb; AN-8, you want fuel volume.


41 buick, I can tell you this, it not having 40 psi as fuel pressure unless we are talking FI


Greg
 

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I have a Tuned Port SBC
This would indicate approx. 40 psi.

BTW - There are compression AN fittings made for metal lines, but if you use them on nylon they will most likely crush the tubing when setting the compression ring. The compression fittings I have used with nylon tube in critical systems have always had a metal tube that is inserted inside the tubing to prevent it from crushing. These were on 18 wheeler brake air lines. I wouldn't want anything less on a relatively high pressure fuel line. The AN to metal fitting don't have this.
 

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-6 is 3/8" line. Plenty for the application at 40lbs.

For nylon without the braided covering you'll need fittings for the compression(nylon) to 37 degree(AN style) flare connections. Pretty much any AN company makes them.

It's not cheap but the your safest bet is reusable AN fittings and braided line although the nylon will work if you must. The push lock style are rated high enough for 40lbs but I personally wouldn't do it that way.
 

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This would indicate approx. 40 psi.

BTW - There are compression AN fittings made for metal lines, but if you use them on nylon they will most likely crush the tubing when setting the compression ring. The compression fittings I have used with nylon tube in critical systems have always had a metal tube that is inserted inside the tubing to prevent it from crushing. These were on 18 wheeler brake air lines. I wouldn't want anything less on a relatively high pressure fuel line. The AN to metal fitting don't have this.

Missed the tune port thing thanks for saying.

Greg
 

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I recently replumbed a car using Nickel Copper 3/8" lines with 6AN fittings. Very easy stuff to work with. Just have to make sure you use 37* flaring tool. If you know any aircraft mechanics, they should be able to help with the right tool.
 

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Fuel lines

I converted my fuel lines to the nylon style used in the new cars and really like using it. Just about all my fittings are the GM style that takes a special tool to put the line on with altho there are videos on line where homemade tools worked just fine. A 25 foot roll of 3/8" nylon hose is about $30 at O'riellys.
 

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Discussion Starter #9
Thanks for all the replies and info guys. I got hung up yesterday and was unable to get on here and respond. Ok, I might not have included important details in here. Lol. I have TPI SBC out of a Camaro going into this Buick. The Fuel lines come out from the front of the intake manifold area at about a 45 degree angle downwards. From there, the lines look as if they would 90 and go down behind the water pump and to the frame. I do not want to run the nylon lines I am using to be close to the header in any way of course. So I want to change the direction of the fuel lines to run down the intake beside the driver side valve cover and down the back of the motor to the frame. I attached a photo (not mine) of what I want to do, but I don't have the braided lines, I have just the plain black nylon lines. I'm looking for the best way to bring the Nylon lines to the up just like the ones in the pic and connecting them just like that. I thought about 2 of the quick disconnect (plastic) fittings, but the lower of the two lines makes me have to bend the nylon to where it almost kinks. These lines will of course run back to the tank (filter first). Any ideas would be great. I think I have a solution, but if someone has a better idea, I am open. Thanks again guys.
 

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Fuel lines

On several TPIs I have drilled and tapped the fuel rail for the supply and bent the return coming from the regulator back so that both lines come up the trans tunnel. You can go to a junkyard and find GM quick disconnect lines that can be adapted to what you need for the nylon lines to connect to with GM fittings.
 

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Discussion Starter #11
On several TPIs I have drilled and tapped the fuel rail for the supply and bent the return coming from the regulator back so that both lines come up the trans tunnel. You can go to a junkyard and find GM quick disconnect lines that can be adapted to what you need for the nylon lines to connect to with GM fittings.
Thanks for the info. I'll look into that. I know this isn't the hardest of tasks, I just want to make sure I do it once and not have to come back to it later.
 

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Fuel lines

Those fuel lines are extra hard and difficult to bend. You can loosen the line at the regulator and rotate it to get some of the direction you would like to go in. Make sure the lines clear the distributor. If the lines are done this way they will be hardly noticeable. Do you know if your TPI was for a 305 or 350?
 

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Those fuel lines are extra hard and difficult to bend. You can loosen the line at the regulator and rotate it to get some of the direction you would like to go in. Make sure the lines clear the distributor. If the lines are done this way they will be hardly noticeable. Do you know if your TPI was for a 305 or 350?
Its for a 305. I haven't ran the numbers to be sure, but thats what it says on the back of the motor. It came out of an S-10 that was used for racing from what I was told. I got it from my father as something to throw in that was fuel injected. We're working on getting it up and runnin here soon, but this fuel line thing has been holding me up. I was thinking I could bend/move the lines just enought to get the angles I want and not have to worry about anything. The upper line I can get a 90 on easily without any problems. The lower one though I might have to do some bending. Only other thing i have to find is something that screws into the fuel line on the rail and have the Male Quick disconnect flare on it. I think I have a tool that can make them , but I have to double check.
 

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Fuel lines

If it was for a 305 and you are putting on a 350 there is a slight mismatch. First, you can do away with the 9th (cold start) injector and use a later program that lengthens the pulse of the 8 injectors to richen the mixture during cold operations. Next is to make the 350 happy and that is to give it more fuel than the original 305 wanted. Easy way is to up the fuel pressure to about 47 lbs with an adjustable regulator. Adjustable regulators cost money so just take the top off the regulator, drill a hold thru it, braze a 1/4- 20 nut on, then drop a quarter in the regulator over the diaphram, put the top on and insert a 1/4-20 bolt. As you tighten the bolt it will add pressure to the diaphram and up the fuel pressure. The program will not know the difference in pressure so the added pressure will compensate for the 350 vs 305.
 

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The program will not know the difference in pressure so the added pressure will compensate for the 350 vs 305.
This is accurate for a MAF setup, but not for a MAP (I believe).

OP - are you going to use the stock ECM? If yes, then what is the part number of it? Do you have a 9th injector?

There is a cheap way around your lines as well. The lines on most every TBI truck use the same fitting and will fit with a minor tweak on the return line. Then you can use the GM fuel filter (NAPA 3481). Then you can grab a repair line section that goes into the other end of the filter and pipe that into your pump (if not in the tank) via rubber fuel injection hose. The whole mess including a Walbro 255 pump is well under $200. If you already have a pump, then less than $100 and you'll be using factory parts that are cheap and easy to find.
 
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