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MG MGB Technical - Use of Copper in Fuel Pipes

I'm interested to know if BBS members know of any downfalls with copper used for transporting petrol. I've read that copper deteriorates over time when in contact with petrol.

Many thanks,
Brian
Brian McIlvenna

Brian-
Copper tubing for the fuel system is illegal in many countries. Why? Because it can develop cracks from vibration and ultimately fracture. Nothing like having a fire in the engine compartment at highway speed! Why is it advertised and sold for fuel systems in countries where its use for that purpose is illegal? Because people will buy it, of course! Use stainless steel tubing instead.
Steve S.

Many of the original fuel and brake pipes are made from a copper/nickle alloy and are fine for fuel. As Steve stated, plain coppor will harden and crack.
John H

When I was working at an EXXON Mobil Laboratory we used to routinely do a
'copper strip corrosion test'
We would place a copper strip in petrol (or LPG, Diesel and Jet Fuel) and warm it to 50 degrees for two to four hours. A very colourful range of copper sulphides and oxides would appear on the surface if you left it too long or it was a bad batch and failed the test. Purples mauves blues blacks. Yes, copper is subject to chemical attack. Since we had to do this test on every batch of fuel it must have been common place at one time to use allot of copper in the fuel system. Now the gauge sender and parts of the carb's would be the only bits left. The test has been retained because now days we use allot more of catalytically cracked petrol , misleadingly called 'stabilized gasoline' or commonly "Stab gaso". This is the component of petrol that really attacks copper. Straight run petrol (distilled direct from crude) or Light alkylate (used in avgas) would never fail a copper strip test.
Catalytically cracked petrol produced from relatively valueless heavy black "leftovers" is one of the main reasons why we haven't run out of petrol despite all those predictions in the 60's
Peter

When you can buy specifically manufactured pipe for fuel why would you waste time looking at anything else?

Pete.
Peter Thomas

Plain copper will work fine if it's properly supported, as long as it can't vibrate it won't work harden.
Ron
R. Algie

Thanks everyone for your input. The reason I'm posing this question is that copper is the material offered for a new fuel line by a British MG component supplier.

The information about the cracked petrol is very interesting? Is this common practice in Europe too? I think petrol should be cheaper then if this can be produced along side the straight refined type.

Thanks,
Brian
Brian McIlvenna

Most refineries have a cat' cracker.
Its a simple concept. Just flow the oil residue (under heat and pressure) through a zeolite catalyst. That's just a variety of clay doped with aluminium to create super acid sites in the clay matrix that cleave hydrocarbon bonds.
BLACK goo gos in and out comes petrol.
However the catalyst does get gummed up and you need to regenerate it with lots of heat in something that looks like a gigantic Dyson centrifugal vacuum cleaner. Each of these literally costs billions to build and maintain.

The stab' gaso' petrol is lower octane, not as stable as straight run, has more impurities and will form gums etc more readily. It is usually a less than 40% proportion of the petrol blend.
The residue from the cat' cracker tends to find its way into fuel oil for ships or industry boilers etc.
Peter Sherman

Brian, are the lines offered pure copper or cupro-nickel and look like copper? Cupro-nickel is a material that's been used very succesfully in OEM manufacturer brake and fuel lines in vehicles such as Volvo and Subaru (I believe) for decades. They show a longer fatigue-life than steel. Somewhere in the archives there's an article about it from a few years ago!
Jeff Schlemmer

Jeff has a good point there about alloys. The iron in stainless reacts very differently from pure. Our coperstriptests used pure copper
Peter Sherman

This thread was discussed between 19/11/2007 and 01/12/2007

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