Fuel line plan?

[65er]

I'm probably all messed up here since I can't seem to find any info. I'm way off the beaten path, for sure.

 Planning out my new fuel line setup to replace my stock 5/16 line, I wanted to go with hard line as much as possible.  But with a couple connections so I don't have to bend and install one monstrous snakey thing.  Well I haven't seen a lot of hardline to hardline connections, so I figured I'd get some JIC two piece caps and some plugs, drill them to fit the tube and braze them on.  Should be nice and secure, easy to work with and reasonably cheap, yes?  Then I thought maybe the lines should all be flared and assembled with male/male unions between them.  But I had already placed the order by then for the brazed setup so I'm inclined to go with that unless it's a bad idea.  No high pressure, it's just going to be an engine mounted Carter pump.  I ordered Aeroquip AN-6 TFE braided hose with appropriate ends for making connections between the engine and frame.

[65er]

Oops, I guess I didn't present the question too well!

Are brazed end fittings acceptable for the hard lines?

[jayb]

The lines are steel, or stainless steel?  I can't imagine that you'd have any trouble with the brazed fittings on steel lines.  I'd just make sure you clamp the lines securely so they don't vibrate; that could potentially crack the brazing I suppose.  Probably not a big worry though...

[65er]

The lines are steel and will be well secured with plenty of rubber insulated adel clamps.  Thanks Jay!

[cjshaker]

Do you know anybody with a TIG welder? It would require MUCH less heat and be more secure than brazing. I have seen brazed fittings in HVAC situations release from an improperly prepared cleaning/bonding surface, and copper usually brazes better than steel. I would be inclined to go the TIG route, but then I have a friend who is a master TIG welder.

[LargeRickhead66]

I would silver solder it ( good silver solder 50%  or at least 35% silfoss ), if you don't have access to TIG. Good silver solder is very strong if done correctly.
Under no circumstances should you ever "butt braze or silver solder" a joint. Either use sweat on type fittings or swage one end to be coupled...And use the appropriate flux. Any refrigeration supply house can supply all necessary stuff.

[65er]

I was looking at some 56% stuff.  Looks high quality and easy to work with. Funny, we have a TIG welder here at the shop but we never use it. Went so long unused that last time we rearranged the shop we used the old wiring to hook up a new CNC machine instead.  Now we have a welder with no place to hook it up, lol.  But I do have a torch and some MAPP gas, I could heat the stuff up good for sure.  Or I could use propane if that's hot enough. No need to overheat anything.

[65er]

Other question about this idea... If you got working on a project and discovered silver soldered fuel lines, would you think "good job here" or "nut job was here" lol

[Drew Pojedinec]

Why not -10 SS braided line Wade?
Working where I do in an intensely high vibration environment....  where we aren't even allowed to use solid core wire, everything must be braided no matter how large.  Brazed fuel lines would worry me.  Not that it couldn't be done, but the potential for failure is much higher than other methods.

You can also run copper fuel line if ya want, but that doesn't mean you *should*

[65er]

...so Drew, you're of the "nut job" opinion, hehe! 

I had thought that going full length with the hose would be too expensive but after looking at the cost of the tooling for the hard line, and the extra fittings as well as the expensive silver solder or flaring tool the hose really is pretty economical.  Will also be nice to not have to fool with all the tube straightening, bending and either soldering or flaring.  I guess let's forget about all that hardline stuff, the hose is going in.  It'll be the Aeroquip PTFE stuff with the Aeroquip fittings to suit.  Shouldn't have to worry about that stuff breaking down in a few years.

Thanks!

[Drew Pojedinec]

I installed the Summit -8 PTFE SS hose.
fittings are $3-$10 instead of $30-$40 as well.
Did the whole job for under $200, with the hose, the ends, the rubber clamps, etc

http://www.summitracing.com/parts/sum-230820/overview/

I don't care whatcha do, Just offering another simpler option.  I appreciate your ingenuity always, but I find that you often try to make something simpler by making it 100times more complicated than it needs to be....   but that's what we love bout ya.

[My427stang]

I used 1/2 aluminum on the Mustang, one piece front to back with a bunch of Adel clamps and a second piece front to back for a return.  Flared each end, it was pretty easy and doesn't move.  The truck has 3/8 steel, a little tougher to shape but it wasn't a complicated set of bends.

I personally like hard line, but not nearly ambitious enough to sweat them all together

[65er]

Curious about the 1/2" lines.  I have the Carter M6905 pump on the way http://www.summitracing.com/parts/CRT-M6905
which seems to be more than adequate for 500 HP, yet it has 1/4" NPT inlet and outlet.  Those fittings are roughly 1/4" inside diameter.  If I have a 1/4" restriction at any point in the system, what would be the benefit of going with 1/2" lines instead of 3/8"?  I can see the potential restriction with 90 degree elbow fittings, but otherwise near as I can see the larger lines would flow the same unless I had a pump with larger fittings.  What am I missing here?

[KMcCullah]

I'm with Ross. I like hard line. Plus I think most drag strips only allow so much hose and the rest has to be hard line. Something to consider if you spend any time at the strip.
When I worked for Coors I became familiar with Swagelok fittings.

http://www.swagelok.com/

They were all stainless and had a double ferrule arrangement. No need to sweat/braze or flare. I've got several in the fuel system on my truck. More for you to think about Wade. 

[jayb]

Actually, running a #10 AN line from tank to engine is pretty standard practice, and not illegal at any tracks that I know of.  I actually run these lines on my Mach 1, my Shelby clone, and my Galaxie.  I like hard lines too, though, because you can use fewer clamps and the line just seems to stay in place better.

I have used the Swagelock products and they are excellent, but expensive.

Wade, if your pump has 1/4" pipe inlet fittings the ID of those holes is going to be too small for a 500 HP engine, IMO.  Somebody here posted an upgrade to larger fittings in a mechanical fuel pump a while ago, where he took the 1/4" pipe threads and bored them out to a larger size to eliminate that as a restriction.  I'd recommend doing the same thing to your pump.  However, if you are not going to do that, then I agree that going to a larger line than 3/8" wouldn't buy you anything.  At the same time, you have to realize that restrictions in a fuel line system are the sum of their components.  A 1/2" line is going to have less restriction than a 3/8" line, and the longer the line, the bigger that effect.  So there would definitely be a benefit to running the 1/2" lines, although again I think that the restriction of the ID of the 1/4" pipe fittings in the pump would dominate any other restrictions in the fuel system.