need advise from AN flarring experts!!!

[jmg222]

I posted this question in the "terminator EFI" build thread I have going , but this is distinct enough I think it warrants its own thread..

I have a 350 in my 88 cheorkee, originally went carb'd, now I'm installing a terminator efi. I've decided to go all stainless (304, .28 wall diameter) fuel lines rather than flexible.... using all an -6 fittings.

I'm having a hell of a time making the connections leak proof, making my own flares. After making all the flares, I pressurized the pump, and every single one of the connections leaked. I then realized that the @#$#@'n cheapo tool I was using was a 45 degree flaring tool, not a 37 degree flaring tool.

So, I bought rigid's awesome 37 degree tool and this (http://www.amazon.com/Ridgid-41162-...TF8&qid=1450024134&sr=8-2&keywords=ridgid+377) and this (http://www.amazon.com/Universal-Hydr...lic+flare+tool). both make perfect 37 degree flares.

I re-did each connection, making sure to prep each section meticulously before making the flare. reconnected everything, and each of my flares was still leaking. Each connection is stress-free (I.e., I'm not using the connection itself to pull the tube together).

What else can I look at? the only thing I can think of is that I'm using welded tube .... is it possible that the seam is interfering with the mating surface? will seamless tube make a difference (I don't mind spending the money on this, but if it's not going to work don't want to waste the time or $$).

I'v bought a few of the flare savers earl's sells -- these are basically 37degree "hats" you put on the male side of the connection, it's made out of aluminim, so it's kind of like a metal gasket. I've heard guys swear by these things... any experience with them?

I've started from zero knowledge or experience on this, I've managed to go from tank to tbi using all stainless... I'd hate to scrap now after all the time and $$ I've spent and go with braided stainless flexible line. There has to be something fundamental I'm missing.

 

[trippled]

Can you post a pic of a flare you've done?

 

[xcm]

Use tubing adapters that use a compression olive instead of a flare... good enough for fuel lines. No need to do flares unless your in high pressures, like brake lines. Been running the fuel lines on my 4.0/4.7's for 5 years.

 

[SleeperXJ]

I've seen copper or aluminum gaskets for AN flares. They were used for 500 psi hydraulic lines.
Cone shaped like the flar and fitting.

 

[jmg222]

Can you post a pic of a flare you've done?

I literally just out the truck up on the lift and parked my other car under it... Maybe ill make a flare out of scrap and post a pic.


Xcm: I'm aware if the compression fittings. If all else fails, I'll go that route. Was using this more as a learning experience ... If I really wanted to make it easy, I could have used nickel-plated steel ;-)

Sleeper: that's exactly what I was talking about in my original post. I've ordered a few of those, see if they work

 

[scramjet]

I've seen copper or aluminum gaskets for AN flares. They were used for 500 psi hydraulic lines.
Cone shaped like the flar and fitting.

Yes, conical seals (copper or alum) will result in more reliable joints. Common in aerospace, I think companies like Earl's sell them for automotive applications.

 

[Original_MudButt]

Though I have little experience in this arena, it kind of makes sense that if you are using welded tube, the weld will most likely crack at the flare... Did you take one apart and look at it? Use a magnifier. If there is even the slightest crack, I'm sure it will leak.

 

[stockerwithalocker]

You need to use seamless tubing, tube services is a good source. If you are using aluminum or copper tubing a seal is not necessarily needed. If you use stainless tubing I would recommend using a copper seal.

You also need to ensure you are getting a good flare. The b-nut should just clear the OD of the flare, and prep goes a long way. Make sure there are no burrs on the ID or OD before you flare. Lastly, if you are using aluminum fittings to aluminum B-nuts, use a little lube on the threads before assembling.

 

[Blazair]

http://www.gen-aircraft-hardware.com/images/pdf/as4824.pdf

 

[vetteboy]

I have that same flare tool, did all my brake stuff with it (-3AN). I used the copper-nickel stuff and so far have not had a single bummer joint on any of it.

Maybe a stupid question, but you're backing up all the connections with both tube nuts and tube sleeves, right?

 

[xcm]

Conical seals arent necessary, youve got other issues. As it says on the page linked "Use when component replacement is impractical or cost prohibitive".

Xcm: I'm aware if the compression fittings. If all else fails, I'll go that route. Was using this more as a learning experience ... If I really wanted to make it easy, I could have used nickel-plated steel ;-)

If you wanted to take the easy route, youd be done by now with the compression fittings, youd also be leak free... Your spending for AN plumbing, theres no reason to fight leaks... this is as easy as installing the lines, and snugging them up if they leak. Done and done.

 

[jmg222]

Conical seals arent necessary, youve got other issues. As it says on the page linked "Use when component replacement is impractical or cost prohibitive".


If you wanted to take the easy route, youd be done by now with the compression fittings, youd also be leak free... Your spending for AN plumbing, theres no reason to fight leaks... this is as easy as installing the lines, and snugging them up if they leak. Done and done.

you're missing the point. I'm trying to learn something new. I agree, I could throw on compression fittings and Nickle-coated tubing and be done with it. I'm not knocking that in any way (and if I can't get this leak free, I may end up doing that). I intend on using all stainless tubing lines on my '67 'vette and when I add a supercharger to my '02-- I'd like to figure it out on the Cherokee where if I make a mistake, no big deal. Worst case, even if I make a stupendous error and somehow wreck the motor, I part it out. I make a mistake on the 'vette... well, I probably wouldn't be happy.

Please, let's not turn this into a debate over stainless/an vs. nickel/compression fittings. I'm sure the latter work fine. I don't care. IF I did, I would have made the title of this thread "should I use nickel/compression for my FI?"

 

[jmg222]

I have that same flare tool, did all my brake stuff with it (-3AN). I used the copper-nickel stuff and so far have not had a single bummer joint on any of it.

Maybe a stupid question, but you're backing up all the connections with both tube nuts and tube sleeves, right?

yup. all earl's.

 

[jmg222]

You need to use seamless tubing, tube services is a good source. If you are using aluminum or copper tubing a seal is not necessarily needed. If you use stainless tubing I would recommend using a copper seal.

You also need to ensure you are getting a good flare. The b-nut should just clear the OD of the flare, and prep goes a long way. Make sure there are no burrs on the ID or OD before you flare. Lastly, if you are using aluminum fittings to aluminum B-nuts, use a little lube on the threads before assembling.

Thanks. The longest run I can find of seamless stainless is 6' -- anywhere else I can get slightly longer runs? I need about 8' to go from tank to front w/ bends.

Also, if I did use the 6' length, any issues if I joined it somewhere with another length of tube with a male/male coupler to make the full run?

 

[jmg222]

Though I have little experience in this arena, it kind of makes sense that if you are using welded tube, the weld will most likely crack at the flare... Did you take one apart and look at it? Use a magnifier. If there is even the slightest crack, I'm sure it will leak.

That was my first thought. No crack at all on the flare, but I'm wondering now if the weld is creating a bump in the flare that's preventing a good seal.

 

[jmg222]

I got a length of seamless tubing and did some flares on that and the welded tube I've been using, pics for comparison-- if the seam really is the issue (and I'm starting to think that it is), anyone have leads on where I can get 5/8's seamless stainless tube in lengths greater than 6'? I haven't seen them anywhere in coils (assuming they don't do this), but need at least 8' to get from tank to intake, or need to add another junction.

Anyway, here's a flare using the welded tube -- you can see the seam clearly on the inside of the tube:

Flare using same tool, on seamless stainless:

 

[trippled]

No double flare? I haven't seen one of those in years! Try a double and see if that seals.

 

[jmg222]

No double flare? I haven't seen one of those in years! Try a double and see if that seals.

I thought you weren't supposed to use double flares for 37degree AN fittings?
I'll try anything at this point ...

 

[trippled]

Hmm im not exactly sure. But usually the double flare is considered better. Plus with the seam inside the tube im not surprised its not sealing.

 

[jmg222]

Hmm im not exactly sure. But usually the double flare is considered better. Plus with the seam inside the tube im not surprised its not sealing.

thinking about it, if I did double-flare it, that would make the outside of the tube the mating part of the flare, and the outside is polished smooth...

I may just pick up some lengths of seamless stainless --- the longest length I can find is 6', need about 8' for the run from the tank to the EFI, anyone know where I can get that?