11 replies to this topic

[Steve-O 2014]

The previous owner has used rubber hose from the tank then to copper brake pipe for under the car then back to rubber hose for engine bay to electronic fuel pump.

Is that going to flow enough?

[cal844]

no, i use microbore (combi boiler pipe), works a treat

[tiger99]

I agree, brake line is 3/16", and fuel line is 1/4", for a good reason. BMC would never have used 1/4" pipe originally if 3/16" would have sufficed.

 

Also, copper is allegedly very bad in the fuel system, due to the ever-increasing amount of alcohol in the fuel, now at up to 10%, as well as being prone to fatigue failure due to vibration if not really well supported.

 

By the way, there is no such thing as "copper brake pipe", and the stuff sold as that is not fit for use in a brake system. Sadly, it continues to be sold and used in the UK, although it is illegal in Australia, the US, and most of Europe, for very good reasons. The only stuff that is safe for use in the brake system, apart from "bundy" pipe, with its corrosion problem, is cupro-nickel, aka Kunifer, which is made for that purpose and conforms to the relevant specifications, being legal just about everywhere. But Kunifer is not suitable for fuel containing alcohol either.

 

Flexible pipes used in the fuel system legally need to be of the proper approved material, and marked accordingly, however I can't find any information to say that rigid pipes need to be marked.

 

See here for some info, and be aware that some supermarket fuel is now E10:

 

http://www.v8registe... R14 281111.pdf

[Steve-O 2014]

Could this be why when i rev the car i can see the fuel filter slowly emptying?

[Steve-O 2014]

Like the pump is finding it hard to suck fuel through the brake line?

[Cooperman]

The cross-sectional area of 3/16" bore pipe is 0.0276 sq. ins.

The cross sectional area of 1/4" bore pipe is 0.0490 sq. ins.

 

So a 3/16" pipe can only flow just over 50% of a 1/4" pipe.

 

There is your answer. Simple engineering calculation gives the answer.

[Steve-O 2014]

Thanks

[Pete649]

and be aware that some supermarket fuel is now E10:

 

 

Am I right in thinking that E10 has to be displayed on the pump.

[coopdog]

I need to put a fuel return in my car, what pipe shall I use for that?!

[tiger99]

No, the change in law means that they can sell up to E10 without any notice at all. Above that, they do have to say so on the pump.

 

Actually, this is of most concern to owners of injection Minis, as a standard carburettor system can reasonably easily have all its troublesome materials replaced. I am not sure about the Viton-tipped needle valves, but I think the most problematic part, easily swapped, is the O ring on the float chamber to main jet flexible tube on many SUs. There are pumps available which are ok on E10, and plenty of choice of legal, approved flexible pipework.

[Pete649]

I thought EN228 allows petrol containing 5% ethanol to be sold un-notified but over 5% and up to 10% ethanol only if appropriately labelled. Has this changed?

Edited by Pete649, 27 February 2014 - 06:35 PM.

[tiger99]

Yes, I do believe there was a recent change. I saw mention of it somewhere, possibly in Practical Performance Car, within the last couple of months.