Paul Turner
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| posted on 15/11/12 at 07:11 PM |
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Check your fuel pipes
A timely reminder for all you happy people out there not to forget your fuel pipes on your pride and joy. Might be a long post but bear with me.
Built my car in 1992, x-flow, carbs etc, just used rigid plastic fuel pipe with a small piece of reinforced petrol pipe at either end to connect to
carbs and pump etc. It ran like that until 2001 when I fitted a Zetec on carbs and did not touch the pipes or anything and I never had a problem.
During the winter of 2004/2005 I fitted injection to the car using an MBE ECU, Jenveys etc. Obviously I needed to put high pressure pipes in and a
return and after much investigation and discussion decided on Moquip TFE hose from Think Automotive. Its main selling point was the fittings which you
can fit without special tools plus if you get it wrong you can re-use them once. All went well but I quickly discovered it was not the easiest stuff
to work with, the hose is extremely high quality but the braid is lethal when you cut it and is can be difficult to work with in tight spaces i.e.
tank to LP pump and LP to swirl pot swirl. Because of this I decided to use a 8mm braided steel hose from another well known retailer of kit car parts
that they guaranteed was compatible with unleaded and was easy to work with. The pipe from the bottom of the swirl pot to the main filter and form the
main filter to the HP pump was always intended to be 12mm rubber and the bled from the top of the swirl pot to the tank 6mm rubber.
All went well and I had no problems but in July 2009, just over 4 years after first using the car with injection I got a terrible smell of petrol when
I went out one Sunday. When I stopped I spotted a drip from the swirl pot and immediately drove the 3 miles home. By then the smell was really bad and
the gauge was dropping like a stone. To get to bolts and the pipework I had to remove the interior trim and I found to my horror the carpet under my
seat was soaked in petrol, I had been sat in a bomb. On inspection all the Mocal TFE stuff was fine but the cheaper braided pipes simply disintegrated
when I tried to remove them as did the 12mm hose. However, the 6mm bleed pipe was fine but it flows very little fuel since there is a 1mm restrictor
in the pipe. I was not happy to say the least.
After much phoning round I was convinced to use 8mm and 12mm cotton braided fuel hose by another well known supplier of fuel system components, I was
guaranteed it was up to the job.
Just over 3 years on from that experience I decided to check the hoses and guess what, virtually the same again. The 12mm and 8mm have started to
crack but the 6mm is still fine, looking at them they would fail some time next year if they remained on the car.
So the 8mm is being changed to Mocal TFE which I should have done originally and the 6mm will be replaced with the best quality (hopefully R9) rubber
hose I can buy. The 12mm is a bit of a problem since no one appears to do 12mm R9 but I am prepared to live with a lower spec in the area (R7?)
because its easy to change and has to be removed to change the fuel filter anyway.
The problem with the R9 stuff appears to be its only available in imperial sizes and all my unions are metric plus there are loads of stories about
cheap Chinese stuff simply being marked as R9, got to think about that one since the air bleed union on the swirl pot is welded on.
So please check your fuel pipes
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rusty nuts
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| posted on 15/11/12 at 07:20 PM |
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Have a look at David Jenkins sticky at the top of the Engine and transmissions section of the forum
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splitrivet
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| posted on 15/11/12 at 07:23 PM |
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This was brought up some time ago re unleaded and fuel hose deterioration. Might be an idea to post a sticky for new members and others regarding this
safety subject.
Edit, Sorry there is one already.
Cheers,
Bob
[Edited on 15/11/12 by splitrivet]
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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splitrivet
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| posted on 15/11/12 at 07:28 PM |
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Just as an aside to Fozzie it might be worthwhile to have a heading for safety subjects such as this so they arent missed as is the case here.
Cheers,
Bob
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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jamesbond007ltk
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| posted on 16/11/12 at 11:18 AM |
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I've had a very similar experience with my car over the years and, having missed David Jenkins' sticky post, not ever found a satisfactory
solution.
What really gets me though is that I have a short length of fuel hose from a 1984 Mk3 escort (used as a donor for wiring and a few other bits) that,
desppite being subjected to the same fuel and standing periods as brand new "modern" hose shows no signs of perishing whatsoever.
A very timely post for me though as I am at this stage in my rebuild so I will be picking hose very carefully.
Thanks
Rich
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Paul Turner
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| posted on 24/11/12 at 05:15 PM |
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Short update, I have given up in my search for metric 6mm R9 hose for the return plus even though the existing 6mm pipe was fine 3 1/2 years ago and
looked fine now once off it was cracked and shot.
My last port of call was that well know high street shop called ***fords. They said they stocked the real R9 stuff on the phone but the Goodyear hose
they had in store was the usual DIN 73379-1 which is R6 and useless. It worries me that they are selling this to Joe Public as suitable for use with
unleaded fuel. How many people will be injured or worse when it cracks and fails.
So the return is also being done in the Moquip TFE hose after I have got the swirl pot modified to suit the JIC fittings.
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johnH20
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| posted on 26/11/12 at 10:12 PM |
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I am not a fuel chemist or indeed any sort of chemist except for a very ancient A level , but I do not see how the removal of lead from petrol can
induce the problems you describe. On the other hand alcohol in quite small concentrations can have a very serious adverse effect an elastomers and
indeed some metals. We don't see production cars failing in the way described because the industry undertook a major program more than 15 years
ago to make vehicles alcohol tolerant and E10 fuel is now quite widely available even if it is not advertised as such. I suspect this is the most
likely cause of the problems. How fuel pipes can exist in the aftermarket that fail in the way described I do not know but it is quite shocking.
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PSpirine
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| posted on 26/11/12 at 10:45 PM |
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Halfords actually stocked the high-quality fuel lines, at a freakin bargain price at that (£3.00 per metre!), but you'll be lucky to find a
store that still offers it.
Alcohols (as mentioned) and bio-diesel are the main problems affecting seals and fuel lines now. Up to about 10% is okay, but 30% ethanol or full
biodiesel will eat through most cars' fuel systems very quickly. There are a select few that use resistant fuel lines and seals, but there
aren't many of them.
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