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Fuel Lines

Posted: Wed Jun 25, 2014 12:27 pm
by jjmartin349571
Hi guys,

I've got a bit of a problem with my Golf - turns out the carby models like mine have different fuel lines to the fuel injected ones. I can't find any replacements and so I want to make my own. This is where I'm coming a little unstuck as it's not something I know much about as I've never had to replace fuel hoses on a fuel injected car, I've only replaced a couple of hoses prior to the mechanical fuel pump on the carb setup so pressure wasn't an issue.

Anyway, the fuel lines under the car are hard but flexible plastic, so my first question is can I obtain something similar and would it be suitable for running after the main fuel pump (digifant fuel injection uses 2 pumps - there is a lift pump on the fuel sender, then a second main pump under the car in front of the fuel tank which also incorporates a pressure accumulator and a fuel filter)? Would it be ok to use standard reinforced rubber fuel hose from the lift pump to the main fuel pump?

If anyone could point me in the direction of where I can get decent fuel hose that'd be suitable for my purposes then that'd be appreciated :)

Cheers,
Josh

Posted: Wed Jun 25, 2014 12:59 pm
by wurlycorner
Ordinary rubber fuel hose will be fine.
Or you could use cunifer metal pipes, or PTFE pipe (which you can buy in a roll from somewhere like RS) would be fine if you want to go plastic pipe route.
Nylon pipe (also from RS) might also be ok and would be cheaper than PTFE - check the data sheet for compatibility with petrol.

Posted: Wed Jun 25, 2014 3:00 pm
by jjmartin349571
Sorry if this is a really stupid question, but who/what is RS :?

Sounds like PTFE pipe may be the way forward from what you're saying, as I'd like to be able to use the existing clips under the car for holding the lines.Will it be able to take the fuel pressure though??

Posted: Wed Jun 25, 2014 3:34 pm
by wurlycorner
rswww.com

http://uk.rs-online.com/web/c/plumbing- ... 4294956312

I haven't looked through that in detail but on a quick glimpse, they don't list PTFE. It wasn't common back when I used it at work, but it was available. Completely inert and able to resist high temperatures, so ideal for all sorts of nasty stuff. Maybe people use an alternative material these days that's cheaper - notice there are quite a few brand names listed under the material section now, so I guess that's what's happened.

Anyway, have a look through that lot, using the filters on the left (suggest you filter by diameters you're interested in and then go from there).

EDIT: to correct Muppet typo mistakes

Posted: Wed Jun 25, 2014 3:46 pm
by wurlycorner
You need something that will cope with about 4bar pressure.

Posted: Wed Jun 25, 2014 5:27 pm
by Paul Phillipson
Plastic fuel pipe can be obtained usually by the meter from any commercial vehicle and most car parts suppliers, it comes on a roll in 4,5, 6, 8, 10 & 12mm so you will need to measure or take a sample with you. Rubber hose might react to the fuel causing it to swell and reduce or close the internal diameter altogether, flexi fuel pipe can also be purchased by the metre from the same outlets along with push-fit in-line connectors, T pieces, right angles etc. If using push-fit connectors stainless steel variety recommended for fuel use and you have to be very careful when cutting the plastic pipe to ensure a clean/square cut.

Posted: Wed Jun 25, 2014 5:29 pm
by Paul Phillipson

Posted: Wed Jun 25, 2014 5:31 pm
by Paul Phillipson

Posted: Wed Jun 25, 2014 5:35 pm
by wurlycorner
This kind of cutter for getting a perfectly square cut on plastic pipe/hose with no burrs etc.

Image


And there you go - other suppliers for the same stuff as RS, so see which is cheaper/most suitable for what you want. IME motor factors only ever stock the rubber fuel hose, but you might get lucky with one near you. Commercial vehicle motor factors is a good shout, I'm normally disappointed whenever I go into my local intertruck though, unless it's for a big drokk-off socket :twisted:

Posted: Wed Jun 25, 2014 7:00 pm
by jjmartin349571
Cheers guys, that's exactly the info I was hoping for 8-) I shall find out the dimensions I need and get some hose ordered.

Next question - I can't source a fuel pump anywhere. I know digifant injection needs about 3 bar of pressure, if I find out how many lph it needs can I just get a generic pump and fuel pressure regulator and wire them inline??