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Copper gas line?

Discussion in 'The Hokey Ass Message Board' started by Cerberus, Aug 20, 2011.

  1. Cerberus
    Joined: May 24, 2010
    Posts: 1,370


    I noticed yesterday the previous owner installed 3/8" copper fuel line running from the tank all the way to the front crossmember. It's fastened high on the frame with insulated straps out of the way of road debri. Should I replace it with steel line ?
  2. Gearhead Graphics
    Joined: Oct 4, 2008
    Posts: 2,577

    Gearhead Graphics
    from Denver Co

    Supported it should be safe. I've seen it used on some drag cars back in the day. Personally I think I'd go to steel just for my own peace of mind.
  3. mustang6147
    Joined: Feb 26, 2010
    Posts: 1,848

    from Kent, Ohio

    Copper is fine for low pressure like fuel. I found copper used on my brake lines, and I stopped driving till I removed it.

    The big problem with copper line is, it is seamed which under high pressure could rupture. I use aluminum, however it is what ever you feel comfortable with.
  4. FIFTY2
    Joined: Apr 9, 2008
    Posts: 318


    I used it on my return line, havent had any problems.
    I know some people worry about copper work hardening, but Being in the HVAC business Ive yet to see a copper line work harden and break ( and they are under as much or more stress than ones in a car, air conditioners vibrate alot).
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  5. 69f100
    Joined: Dec 3, 2009
    Posts: 736

    from So-Cal

    there was copper line on an old firebird we had and we never had a problem till we removed the engine to rebuild it. the line got snagged on something and snapped pretty easy. it should be good as long as it isnt flexing alot though. but i would agree that it is best to just replace it with steel, just seems stronger
  6. 19Fordy
    Joined: May 17, 2003
    Posts: 5,290


    Put your mind and your insurance company at ease and install a steel line.
  7. It is illegal to use up here. I have seen it used before and have also seen a guy just barely touch it with a live 14g wire and it popped a hole in it so easy, he had a fire going in no time:eek:

  8. chopt top kid
    Joined: Oct 13, 2009
    Posts: 959

    chopt top kid

    The reason that copper is not the best choice for mobile equipment (in this case make that read automobiles) is because movement (vibration do to driving down the road) will cause it to work harded over time and it will eventually crack...
  9. noboD
    Joined: Jan 29, 2004
    Posts: 6,087


    I've had it happen on a car I bought that had it was installed before I bought it. Use steel. The "copper" line on brakes is cunifer, not the same thing. Cunifer has a good bursting pressure and doesn't work harden, is a nickel copper alloy. Totally safe and legal. This has been covered here many times, do a search.
  10. chopo
    Joined: Feb 20, 2006
    Posts: 1,177


    dont do it. not legal here. to soft. buy an abc exh. if you choose to run that.
  11. blue 49
    Joined: Dec 24, 2006
    Posts: 1,037

    blue 49
    from Iowa

    A friend of mine has several airplanes from the 40's and the factory used copper fuel lines. With FAA rules, when being rebuilt, they have to be replaced with the same. A lot more vibration in an old airplane than a car.
  12. slinginrods
    Joined: Oct 6, 2008
    Posts: 404

    from florida

    copper enables vapor lock and boils gas very easily ,toss it.
  13. dennis carpenter sells copper plated steel line in either 5/16 or 3/8's that MAY be whats on your car i bought some 5/16's it but im using it for the lines on my flatheads oilfilter canister it has a tendency to flatten if your bend it

    i saw a r*tr*d tonight that had plumber grade 3/8 copper lines running from his pump to both of the holleys on his tunnel ramed bigblock looked kinda decent except for the solder joint on the T fitting from the front to the rear carb
  14. finn
    Joined: Jan 25, 2006
    Posts: 448


    I seem to remember that (in a previous life) we had a lot of warranty claims on bosch Diesel injection pumps. The claims were traced to a black gum which formed in the fuel system on trucks and tractors plumbed with copper components, i.e. lines.

    I did a quick search and confirmed references to a black gum which forms when hydrocarbons react with copper lines, especially with ethanol. Also, it seems that fuel system manufacturers say to stay away from copper, and there is a rather strict limit as to the amount of copper allowed in gasoline to control the catalytic formation of "gum"

    On the other hand, stills use copper lines, don't they?
  15. Rob3865
    Joined: May 23, 2011
    Posts: 106


    My understanding has always been that copper does not support a double flare very well because it is too soft. That would not be very good in fuel applications.
  16. Chopp'd49
    Joined: Feb 20, 2011
    Posts: 128


    There are a ton of new car manufacturers using a copper ferrous alloy that is safe and very usable/flexible. It will not corrode and is super easy to work with. A little pricy,but I used it for my brake lines and fuel line cause it had that copper look. If yours is straight Home Depot copper line I would change it. if it is the new stuff then it is the best you can buy.

    You can see the brake line in the attached photo

    Attached Files:

  17. KillerKustom
    Joined: Aug 28, 2007
    Posts: 286


    I'm with you. Nothings worse than driving your car and constantly worrying about something like a fuel line.
  18. 26 roadster
    Joined: Apr 21, 2008
    Posts: 1,999

    26 roadster

    really have no personal input, never used copper, always used steel, could see no advantages.
  19. mammyjammer
    Joined: May 23, 2009
    Posts: 456

    from Area 51

    Saw a beauftiful 63 427 Galaxie on a roll back today. Entire front end was burnt like it had a engine fire.
    I doubt it had copper line, but it got me thinking about a REAL serious evaluation of all my under hood plumbing!!!!!
  20. Copper brake lines are perfectly legal in the UK. Lots of people use them, and I've never heard of anybody bursting one, or having one break because it 'work hardened' from vibration.

    Or if they do claim that, they eventually admit it was only supported every 18" or some other such stupidity.

    It is not just plain soft copper, it is heat treated seamless tube, And no, it is not cunifer, that is something else.

    Cunifer is far better, costs about 25% more, and I don't understand why people don't use it instead of copper.

    Steel just plain rusts.

    Stainless costs a fair bit more, harder to work, but should last a lifetime.
  21. pcterm2
    Joined: Aug 25, 2009
    Posts: 553


    dude go with steel.
  22. I couldn't word any better. This was told to me by a head fleet superviser years back.
  23. carbking
    Joined: Dec 20, 2008
    Posts: 1,968


    In alphabetical order: aluminum, brass, copper, and steel have ALL been used at one time or another as material for fuel lines by various US manufacturers on production automobiles.

    Both aluminum and copper were used by G.M. as late (possibly later, don't know) as 1966 IN THE ENGINE COMPARTMENT. (Aluminum - Pontiac, copper - both Oldsmobile and Pontiac).

    The above not withstanding, I would personally be uncomfortable with anything except steel UNDER the car (of course, we still have gravel roads in rural central Missouri). I would not be afraid of cracking (assuming the line is well suspended) rather rock damage from rocks hitting the line.

    Hand-held tubing benders are relatively inexpensive, and steel tubing is available at your FLAPS.

  24. DaddyO's..Deuce
    Joined: Jul 31, 2011
    Posts: 780

    from Missery

    I bought a 25ft roll of 3/8 aluminum fuel line from summit for $18.95 bends easy and a small price to pay for peace of mind.
  25. Jimm56
    Joined: Aug 27, 2010
    Posts: 170


    Use steel or aluminum. Copper WILL affect the octane of your gasoline, and not in a good way.
  26. reefer
    Joined: Oct 17, 2001
    Posts: 691


    Copper/kunifer is fine.....if it is fixed to the frame as it should be (steel or copper ) it is not subject to is terminated at a bracket and the flexi hoses take the movements.Ciopper is drawn and not seamed as previuosly stated.

    Steel/Bundy ,tube is seamed and zinc is very susceptable to rusting through when the zinc coating wears off due to salt on the roads.One of the main failures at M.O.T test time is corroded brake lines.

    I work with copper lines every day in the Refrigeration industry...they are subject to vibration virtually 24/7, year in year out...the main problem these days is from thieving Pikeys who keep swiping it to weigh in as scrap...

    If it`s a choice at installation time, I`d opt for the Kunifer over a rolled and solded steel tube that is going to rust and be subject to high hydraulic pressures, every time.

    Believe me..if copper was deemed a safety issue...over here in the Nanny State that this once great country once would be outlawed over night.

    I can`t say one way or another about that Ethanol fuel that you guys use, but seeing as it is Alcahol based, I can`t see where it is a problem, as old moon shine stills had to use copper.
  27. Wise words. There are too many experts spouting/repeating the usual 'copper will work harden and break' when none have ever had a properly mounted copper line break on them.
  28. 19Fordy
    Joined: May 17, 2003
    Posts: 5,290


    What is a properly " mounted copper line break?" Thanks for the info.
  29. Truckedup
    Joined: Jul 25, 2006
    Posts: 3,772


    I used to work on air brake trucks from time to time.A lot of them had what appeared to be copper air lines.Truck air brakes operate in the 120 PSI range and dump trucks do vibrate just a bit :D
  30. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,145

    from MI

    Steel can work harden and fracture too, but copper is much more likely to do it than steel.

    I have wondered myself why more people and manufacturers don't use it. The SAE suggested switching to Cunifer some time ago. It seems most people don't know about it, and there is the higher cost. The way things are today you would think lawyers would be all over rusty brake line incidents.

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