It depends on the car...what are you building? so I don't have to look it up. Metal is good. Steel is good. Size depends on the engine's fuel requirements. Securing the line well, and routing it safely, are good.
I've been using aluminum 3/8" hardline more lately. Trick is it needs to be secured well. Hanging it out in space and expecting it to hold up like steel is asking for trouble.
Iv'e used 1/2" aluminum, which can easily be bent by hand as long as the bend isn't too sharp. I'm also using Teflon lined braided hose, which is super easy to work with. It's been on there for 4-5 years now with no problems, but I do use premium gas with no ethanol.
I would say 3/8" steel line is probably best for reliability & adequate flow. It can be a bit of a bear to form it to where you need it to go, but it is certainly doable. I try to stay away from rubber fuel lines these days because of the aggressiveness of modern fuels. I only use a short section of rubber line between the frame and the fuel pump (mechanical).
Been discussed a few times in the near past. Since we never know what the government is going to do with the fuel that we use, I made sure I was ready. I used stainless steel braided Teflon line in my current build, and will in my next. From the tank to the carburetor(s). A little more money, sure, but as safe as it gets in any case that you can throw it. As for period correct for an old car...paint it all black, or cover it in rubber..! Mike
PTFE lined with a stainless braid and a black pvc outer is available - looks like rubber with a bit of a shine. Or there's ptfe / stainless braid / woven nylon that looks like cotton over braid. The problems come at the ends though where you're stuck with AN type fittings. Doesn't bother me as I rather like that, and hate stainless braiding on anything where the ends can possibly escape! Totally pain averse I am! Chris
I use regular 5/16" brake / fuel line that already has the flare nuts and flares on it. Good enough for a 351 cu. in. engine. If I had to make up a really long length I would probably buy a length of the copper nickel material. I believe there are better and worse grades available, so do some research. Except for short lengths of flex hose at the tank and fuel pump, metal line should be used.
Tried and true steel lines are great, if you've got a good tubing bender and flaring tool. The NiCopp line is a dream to bend and flare, but because of how soft it is I have my reservations about running it the length of the car, along the frame, where a rock can kick up and nick, kink, tear, etc, without protecting it really well. You'd probably be fine with covering the line with that spiral? steel armor stuff, in the spots where you don't have it adel clamped in place.
3/8" fuel line, one continuous piece from tank to firewall. Just put this in last week on the shoptruck. It will run a short piece of nylon braided line to the in tank pump... down the frame rail (a bit tricky getting through the crossmember but I fabricated provisions for the line earlier in the build. I left room for a return line but I'm not using one this time. and to the firewall mounted filter. I am not a big fan of flex hose ran all over the underside of my cars and more joints mean more chance for leaks. Make sure you route away from heat sources to prevent heating the fuel in the line and away from moving parts obviously. Use a lot of clamps, these are just those rubber insolated clamps that are 3/8" so they fit snug.
Sorry for the hijack but, I was gonna use the original fuel line that runs from the tank to engine compartment as my pressure line then fab a smaller return line (FI) on my '54 Customline with 5.0/AOD. The original line is 65 years old and pretty crusty but no rust on the outside. Can I just blow it out really good, clean off the outside and use it?
Check for leaks after you blow it out. The ethanol in todays fuel causes lines to rust from inside out so there may be some weak points you can't see now.
I'm running 3/8" from the tank, I put a filter B/4 the electric pump, 3/8" to a regulator, then a glass bowl filter to a 4 port block. The 1st port has a fuel gauge then the other 3 go to the carbs. I'd include a pic but I'm told my image is too big...
I'm just wondering, are the glass sediment bowl filters okay under (low) pressure? Normally they are on the suction side of the pump, as I recall.
3/8 will allow sufficient fuel for most street driven engines. I would use steel because aluminum is more prone to cracking later. Check and see if you can actually snake a complete one piece line from the tank to the firewall. You may have to make two pieces. Jic fittings are just as good as AN fittings only less expensive.
Years ago.......I ran 3/8" Aluminum tubing INSIDE a pneumatic hose from the tank to the fuel pump. Bent /formed real EZ and since it was inside the rubber air hose tighter turns were possible. Rubber hose was added protection against any flying rocks and crap from the road. Rubber hose also acted as a little more insulation from the heat of summer. Thicker size of the rubber hose worked great with common 'C-type" household electrical hangers. Big fuel line adds to the "macho/big boy" image of SBF engine! Alum. tubing came in a 25' roll and hose was free so very low cost install. (I liked that) 6sally6
Eng. choices are flathead, Y block, and Ford FE. Have a number of builds in progress. With steel line, what type of ends ???
Many O.E.M. vehicles used them before the carb. My 2 bbl. only needs about 4 p.s.i., so there's no problem at all. They are available from most any parts store, as are the replaceable filter elements. The ports in & out are 1/8" so if you need mega fuel flow, this wouldn't be ideal. I would never use one on a high pressure system.
I like using regular brake lines. They are readily available in different sizes and lengths from you local auto parts store, as are the various fittings to couple & connect to the system. Be sure to use "inverted flair" fittings for a leak proof installation. A simple tube bender, a tubing cutter and a double flair kit are all you need.
I use this style of tube fitting for aluminum fuel line. Easy to work with and has not leaked a drop since it's been on the car.
No matter what material used, put a good filter before the pump.i use the 90's Ford filter for my cars .
Great picture. The OP should be aware that the picture shows how to make a 37 degree fitting. Notice that the flare on the end of the tube is a "single flare". He will need a flaring tool that specifically makes 37 degree flares. Inline tube sells a nice one. Instead of simply pushing the tubing out all at once and maybe cracking the flare, it works as an eccentric in forming the flare. Might be able to find them a little cheaper somewhere on line, but try to get one that works similarly. Mine was about $100, but its really well made and works well. Again, I went on line and bought packages of JIC sleeves and nuts. Its cheaper to buy them maybe 25 at a time and put the extras in a drawer. Don't try to use 45 degree flares with 37 degree fittings. If the budget allows, I would buy or borrow a tubing straightener. Lets you uncoil the tubing and make it look nice and straight. Pics below show 37 degree flaring tool and a SET of flaring tools that do lots of different tubing types. The single tool is good for all 37 degree flaring whether you do it in a vice or already installed on the car. The SET only allows you to do the flares before you install the tubing. Both have their advantages. If anyone decides to buy a SET, note that some sets are less expensive because they contain fewer dies. If you are NEVER going to run fuel injection on your vehicles, you don't need the flares to form the GM push on type fittings. The set will make nice 45 degree, 37 degree, bubble flares.....lots of choices for brake lines as well as fuel lines. These type tubing benders give a tight professional looking bend. You can get them off Ebay used for about $30.
I used 3/8" stainless lines. Ran a short section of -6 nylon/rubber/black braided line from the tank to the 3/8" SS line and same from the front end of the SS line to the fuel pump. Used aluminum clamps to hold everything in place with a couple bulkhead fittings along the way to secure it, too. SPark
While I have used them over the years, I too never really liked them. They work great, probably just an irrational deciciency in my DNA. I like to "repurpose" (can I use that politically correct term on the HAMB)......actually I hate that "Fxxxxx" word. I simply "reuse" existing tubing clamps that I scrounge off cars at the junk yard. They have ones that deal with multiple lines when needed. Additionally I found some at the "Nationals" that are plastic and work really well. So there are a few other options out there.
5/16" line on the flatty and Y block should be fine, perhaps 3/8 on the FE if it's going to be making some power. Ford got away with 5/16 on those for the most part, too. Double flares on steel lines where they attach to a fitting, or a bubble (first half of the double flare process) if you are going to slip rubber hose over it, and clamp it.
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