Copper fuel line (using gas fittings)

[SvenglishTommy]

I was replacing the primary fuel filter last week, and decided that while I was at I would replace the rather dodgy looking unmarked old fuel lines and the fuel cock at the tank(which had a slight leak) while I was at it.

I discovered that the dodgy looking fuel lines were actually solid copper pipe covered ina protective sheath. Despite an extensive search I can find very little info on solid copper fuel lines, and inparticular what kind of connections to use.

I eventually ended up at a gas shop who had all the right size connections and compression fittings (including a mini ball valve to replace the fuel cock). They would not commit to it's suitability for use with diesel though, but they couldn't see a problem with it.

What is the panels opinion on keeping the copper fuel lines, and the use of fittings designed for gas with diesel?

Thanks,

Tommy

 

[asj1]

A marine engineer did some work on my boat last year including replacing the old fuel lines and installing a primary filter and fuel stop cock. The copper lines used appear to be the same as the gas lines. However a flexible line needs to be installed at strategic points in particular where the fuel first reaches the engine (usually at another filter) otherwise engine vibration would immediately break the copper lines.

Regards

Andrew

 

[sunquest]

Should not cause a problem. 10mm poly sheathed copper pipe is used for connecting heating oil tanks to oil burning domestic boilers.

Geoff

 

[Guest]

I think Wade looks at a lot more applications than just gas. They even supply the covered pipe.

http://www.indanc.com/products_wade.htm#

 

[VicS]

I'd say that was right. Very important about the flexible hose to the engine of course.
There is nothing special about the compression fittings, either for gas or diesel. Make sure the flexible bits are suitable for diesel though.

You might need a larger diameter pipe than you would for gas but it depends on the size of the engine. Don't reduce the size from that used in the present installation and make sure the pipe is properly clipped in place just as you would for gas.

You might find This website useful and the prices very attractive. I am assured that the quality is good despite the low prices.

 

[rjp]

As far as I'm aware copper compression fittings are used for both gas and diesel (often 1/4 inch bsp or 8mm if metric - I have a mixture of both on my boat which is a bit of a nightmare inherited from previous owners) but as asj1 said you have to watch vibration where copper pipe is concerned. I recently had to replace some flexible fuel line as the previous owner had used metal braided gas pipe! Unfortunately over time this turned out not to be diesel resistant. It had reached a point where it didn't leak fuel out, but did let air in which took some finding. You can buy ISO 7840 flexible fuel line which will take standard compression fittings at the ends.

John

 

[Talbot]

First time I have seen those PVC covered pipes. look like a great idea for marine fitting. Do you know if you have to remove the PVC before making the compression fitting?

 

[SimonA]

Standard copper pipes with compression fittings pass the BSS requirements for inland boats.

 

[Talbot]

I have standard copper, and was hopeing that the pvc covering would provide some protection from corrosion.

 

[savageseadog]

Copper is OK Cunifer (Kunifer =) is better. Got mine from a truck parts supplier as brake pipe. The place I went to had imperial and metric sizes.

 

[boatbuilder]

Pvc covered is now the norm in CORGI instalations , just cut back about 1" for the fitting.

 

[SvenglishTommy]

Thanks all for the reassurance, the copper pipe is 30 years old now, but is showing no sign of corrosion or damage, only problem was the old compression fittings leaking a little. All the flexible pipe is 6mm internal diameter A1 graded 10 bar fuel line so that should be ok as the fuel system is just gravity feeding a 10hp engine.

 

[Tomkat17]

I fitted a small gas valve as a stop cock on the flexible rubber fuel line just prior to the primary fuel filter. This allows me to shut off the fuel to change filters without having to get to the awkward valve under the fuel tank. I was advised the the gas valve was suitable for diesel use. Haven't had any problems.

 

[pappaecho]

As the density of air/gas in considerably less than a liquid like diesel, then it will be more prone to leak at lower density ( eg gas) than in a liquid - which is why water fittings such as 15mm copper tube is used to connact gas supplies as well

 

[Talbot]

[ QUOTE ]
Pvc covered is now the norm in CORGI instalations , just cut back about 1" for the fitting.

[/ QUOTE ]

VMT

 

[alan8376]

You might want to check the build of the gas cock! It may consist of some rubber as a seal/materials which is ok with gas! However, diesel has a nasty habit of attacking seals not designed to with stand it! An HGV truck specialist would stock a tap fitted with compression joints which can cope with diesel.They are often used where 2 fuel tanks are used for
long journeys! Another souce is a firm that manufactures metal fuel tanks for home or business central heating.

 

[sailorman]

dont use copper through bulkheads / matrix below sole in the bilge i done this as recomended by purchace survey to replace high pressure plastic stuff.
2 seasons corroded through ( where it passed through ribs/ matrix ) now have fire retardent hose from engine compartment to HP plastic in bilge problem cured.