Fuel line failed

datsun dave

Club Member
WTF going on have fuel coming out and misting on all the main fuel lines going to and from the fuel rail.



Under the car on the floor was covered in fuel.



Just glad that i noticed a mist coming from the vent before i started the car it looks like all the fuel lines have failed.
 

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red baron

Well-Known Forum User
Hi Dave, the fuel pipe you used was it injection pipe? I ask this because I have seen a z32 with carburetter pipe fitted. This was leaking and misting the same as you described,it cannot take the pressure. You have fit a fuel injection pipe, but be careful as they both look the same. I recommend you did not use it as it could set the car on fire he was fortunate,we took all the pipes off and replaced them with proper pipes and the car was fine.
 

Mr.F

Inactive
The Aeroquip / Speedflow -06 braided hose has an operating pressure of 1000psi and a burst pressure of 6000psi. Also compatible with all fuels including alcohol and nitromethane. No way should genuine hose from either supplier be creating the effect you photographed.
Could that hose have been clamped for any reason which may have damaged the inner tubing?
 

richiep

Club Member
I talked to Dave earlier and he says it was all injection-rated pipe, which he spent a hell of a lot of money on. It does look like the high pressure has caused it to fail though.

Dave - how long had these hoses been fitted to the car? Could they have degraded while dry during the car's build if they had been fitted for several years?

All very unfortunate as I was looking forward to a trip out in it today!

edit: that's a hell of a high rating Mike for the hose - makes it seem crazy that they could fail in the way they have as they should clearly be able to take it.
 

Mr.F

Inactive
i'd never ever run braided covered lines

Best you never fly either then - this is aero quality stuff that delivers fuel to aircraft engines. If treated as directed, it does not fail in normal use.
Part of the problem is that, like any quality product, there are cheap imitations available which do not meet the rigorous standards provided by Aeroquip, Speedflow, Earls and other leading manufacturers. They look pretty but would be marginal under carb pressure.

Just look at the number of race cars plumbed in this way and you should appreciate that it has some significant advantages over rubber hose and Jubilee clips!
 

datsun dave

Club Member
The Aeroquip / Speedflow -06 braided hose has an operating pressure of 1000psi and a burst pressure of 6000psi. Also compatible with all fuels including alcohol and nitromethane. No way should genuine hose from either supplier be creating the effect you photographed.
Could that hose have been clamped for any reason which may have damaged the inner tubing?



All the hoses have failed they are all doing the same.
 

Dale

Club Member
I found an article talking about modern fuels containing more harmful and corrosive additives that can dissolve rubber, particularly when the fuel is sitting for a while.

If you use petrol for your family car, classic car, boat, motorcycle, Quad, lawnmower, strimmer, rotavator, chainsaw, generator, pump or any other type of equipment that has a petrol engine, you need to know about Ethanol in your fuel.

What is Ethanol?

Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colourless liquid. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a solvent and as an alcohol fuel. In common usage, it is often referred to simply as alcohol or spirits.

Where does it come from?

Ethanol is sustainable and domestically produced from renewable resources such as corn, grains and potatoes.

Why add Ethanol to Petrol?

Ethanol is good for our agricultural economy and helps us reduce our dependency on foreign petroleum products. On the “green” side they are aimed at improving air quality and reducing air pollution from fuel emissions.

What proportion of the fuel is Ethanol?

Permitted ethanol content in petrol is 5% which is to rise to 10% in 2013. However we are led to believe supermarket fuels may already have as much as 10% ethanol blended in. We hear a 15% mix is on its way in the USA.

While this is good for the domestic farmer and our environment, Ethanol can cause serious problems to your engine and fuel system. Generally vehicles built after 1996 have been designed with Biofuels in mind, but earlier cars and engines with carburettors are going to need help. What types of problems have been encountered?

1) Water accumulation in the fuel tank - ethanol absorbs water from the air. The water condenses in the fuel tank and will pull the ethanol out of suspension with the petrol. This is bad news because it strips the octane out of the petrol, leaving you with a layer of octane-poor fuel on top and a water-ethanol layer mixture on the bottom. If this gets sucked into the combustion chamber, you will have poor starting and very rough running with potentially engine damage.

2) Deposit is like to build up - Ethanol when mixed with water readily forms Gums in the fuel system much quicker than fuel without Ethanol. These Gums coat fuel system components including filters, carburettors, injectors, throttle plates and will then form varnish and carbon deposits in the intake, on valves, and in the combustion chamber.

3) Lower fuel mileage, Decreased performance and acceleration. Ethanol contains less chemical energy than petrol does, and this means less mileage for the driver. 3-5% drops in mileage are expected.

4) Corrosion of internal engine components - Water contamination may cause fuel system corrosion and severe deterioration.

5) Contaminants in fuel system – water, degraded rubber, plastic, fibreglass and rust may get drawn in.

6) It could encourage microbial growth in fuel. Ethanol being organic and hygroscopic may allow the growth of fungus.

7) Short shelf life - as short as 90 days

8) Corrodes plastic and rubber - Ethanol is a strong, aggressive solvent and will cause problems with rubber hoses, o-rings, seals, and gaskets. These problems are worse during extended storage when significant deterioration could take place. Hoses may delaminate, o-rings soften and break down, and fuel system components made from certain types of plastics could either soften or become hard and brittle, eventually failing. Fuel system components made from brass, copper, and aluminium may oxidize. The dissolved plastics and resins now in the fuel could end up in blocked fuel filters or gummy deposits.

9) Melts Fibreglass - bikes and boats with fibreglass fuel tanks can have structural failure as the Ethanol will break down and pick-up some of the materials the tanks are made from. Again this material, dissolved from the tank, can be carried through the fuel system and can cause damage to carburettors, fuel injectors and can actually get into the combustion chambers.

And then I found some chap that has researched it and the different grades of rubber used to make the hoses and which once are more resistant to modern fuels.

Background

* Since getting my car on the road 7 or 8 years ago I have had to replace rotted flexible fuel hoses 3 times. Each time the hose has cracked and was dripping fuel everywhere.
* I have always used decent quality hose (Gates, or similar).
* It seemed to happen randomly but especially after a long spell in the garage, whether due to bad weather or whatever. (significant point #1)
* Some other people had similar problems.
* More people were using similar hose and having no problems (significant point #2)

Results of research

* Petrol has changed significantly over past few years - it now contains more alcohol-based substances, which are very corrosive to normal rubber.
* Hoses in the USA are marked with an SAE code, e.g. SAE J30R9, according to its ability to resist modern fuels. As much of the hose bought in the UK is made (or sold) in the USA then these markings may appear here.
* There are 4 significant groups of SAE codes:
Unmarked hose - will probably be for the original petrol formula, without modern additives (but see later comments).
30R6 - This is the standard for the petrol formula of 5 - 10 years ago, for fuel injection. The bore may or may not be lined with Nitrile.
30R7 - This is the standard for the petrol formula of 2 or 3 years ago, for fuel injection. The bore is lined with Nitrile.
30R9 / 30R10 - This is the current standard. The bore is lined with Fluoroelastomer/Nitrile. 30R9 has Fluoroelastomer/Nitrile on the inside, while 30R10 has it inside and out, which allows it to be used immersed in petrol (e.g. in a fuel tank).
* There is also a marine grade for use in boats - ISO 7480 A1 - that is roughly equivalent to 30R7-and-a-bit, with added fire resistance.
* One of the causes of fuel pipe failure described in the USA literature is stale modern fuel, not so much the fuel itself. These fuels become extra-corrosive when they get old.
* The USA seem to use a higher percentage of alcohol in their regular fuel - but we're not far behind in Europe.

What got me angry...

* Gates in the USA only make and sell fuel pipe of grade 30R9 or better (they even have brand-new super-grades). Gates in the UK distribute unmarked hose to motor factors that, if you are lucky, is only 30R6. Why don't we get the same? Are they dumping their surplus stock on the UK?
* The Gates sales rep for the UK and Europe didn't know that the USA grades were far higher than his offerings - he didn't even know the trade names for the USA products (shown in every USA Gates catalogue).
* 30R9 is freely available on the USA ebay, at sensible prices, made by big-name manufacturers such as Gates and Goodyear. It is never (or maybe rarely) available on the UK ebay. Only the excessive postage stopped me from buying it there.
* One on-line supplier (Think Auto) advertised that their hose is 30R9, but when it turned up it was unmarked. I recognised that it was stuff that I'd used previously and told them so. To their credit they apologised, refunded my money AND paid for the return postage.
* There is a general ignorance about this whole issue - when I asked for a specific grade of hose many suppliers didn't comprehend, while others were almost abusive ("Our stuff is good enough...!).
* The one who did supply the correct hose, Hose World, advertised it as 30R10 on their website, the bloke on the phone didn't think it was any special grade when I asked, and when it turned up it was 30R9, which is what I was after in the first place!
* If you search on any USA car forum about fuel pipe you will see that most people are fully aware of this issue, and the need to use modern hose. There seems to be a general ignorance in the UK.

Last thoughts and recommendations

It was almost certainly stale fuel that rotted my fuel pipe(s).

1. Don't buy general-purpose hose from a motor factor, unless it has at least 30R9 printed on it. Even stuff off the Gates stand isn't good enough.
2. If you are getting it via the internet or mail order, don't be fobbed off by excuses. Only the proper stuff is safe for long-term use.
3. If you are going to leave your car unused for a month or so, consider draining the petrol, especially if you are unsure of your fuel pipe grade.
4. If you really can't get 30R9, consider getting ISO 7480 - this is easily available from marine suppliers in the UK (but see point 3). All proper fuel pipe in this grade has to be marked, to meet regulations.

Additional thought

Re-reading some of the websites I found during this research reminded me of an important indication of fuel pipe decay - smell.

If you go into your garage and there is a stink of petrol, but you can't find a leak, then it is very likely that vapour is permeating through the fuel hose. If this is the case then it is a fair bet that the hose will fail sometime in the near future... maybe not immediately, but sometime.

All very interesting...
 
Best you never fly either then - this is aero quality stuff that delivers fuel to aircraft engines. If treated as directed, it does not fail in normal use.
Part of the problem is that, like any quality product, there are cheap imitations available which do not meet the rigorous standards provided by Aeroquip, Speedflow, Earls and other leading manufacturers. They look pretty but would be marginal under carb pressure.

Just look at the number of race cars plumbed in this way and you should appreciate that it has some significant advantages over rubber hose and Jubilee clips!

For what its worth when I use to build helicopters we didn't use it, 99% of race cars don't use it either, just for the very reason you can't see under the braid.:thumbs:
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Yet more bad luck Dave, you must have walked under a few ladders in your time!

Seriously do you carry a fire extinguisher in the car?

I'm not going to comment on the spec of the pipe etc because I'm not qualified to do so - but I am surprised about what has happened.
 

datsun dave

Club Member
Yet more bad luck Dave, you must have walked under a few ladders in your time!

Seriously do you carry a fire extinguisher in the car?

I'm not going to comment on the spec of the pipe etc because I'm not qualified to do so - but I am surprised about what has happened.



Always have a fire extinguisher in the car would have been bad luck if it went up.
 

pmac

Well-Known Forum User
Just been looking at the PTFE fuel lines.
FYI you will need new fittings for it.

Always have a fire extinguisher in the car

On a car like yours a plumbed in system would be a minimum requirement.IMO

I have hand held and plumbed in in my rally S30 build...for £200 its cheap insurance.

And I am only putting in a modest "Samuri spec " engine in;)
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Dave, do you think the internal pipe is 'breaking down' or perhaps the end fittings are not sealing and fuel leaking between the pipe and braiding and spraying out of the braiding?
 

datsun dave

Club Member
Dave, do you think the internal pipe is 'breaking down' or perhaps the end fittings are not sealing and fuel leaking between the pipe and braiding and spraying out of the braiding?



It's the fuel line 100% as it's all leaking both main fuel feeds the return and the hose from the FPR.
 
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