Permeation-resistant fuel line hose.
 

I was chasing what I thought was a slight fuel leak in the boot of the 540. My fuel tank, fuel pump, carbon canister, fuel filter and rubber fuel lines are all in the boot. After double checking all connections, resealing the level sender and pump the smell was still there. To cut a long story short I eventually found that rubber fuel line I was using was the problem. It was letting the unleaded fuel permeate up to 550g/sq mtr/day through the hose. I have approx 2.5 mtrs of 8mm fuel line in my boot. If you work it out that could be as much 34g of petrol permeating into the boot. No wonder there was a smell.
I went to, or rang most of major auto accessory, auto parts or hose suppliers around Brisbane and everyone told they had not heard of this problem.
I rang Speedflow looking for stainless braided telfon fuel line( expensive) to overcome the problem. This salesman was the first person to tell that they knew about the issuses with unleaded petrol permeation. They have two hoses only that can be used with unleaded fuel, stainless braided telfon fuel line and the new 444 series rubber EFI hose.
The 444 series is made to meet the standard SAE 30R9.
I checked my fuel hoses and the breather and vent lines where 30R6, 30R7, or 30R8. The pump and return line was a high performance EFI hose. None of these hoses are recommended for unleaded petrol due to the permeation.
So if anyone is buying any fuel hose for unleaded petrol make sure it has 30R9 on the hose or if you have a fuel smell in your car check to see if you are using the right fuel hose.
Below is a Gates Corporation "Automotive Techtip"

Warren

Avoid comebacks, install permeation-resistant fuel line hose Fuel line hoses carry gasoline from the tank to the fuel pump, to the fuel filter, and to the fuel injection system. While much of the fuel lines are rigid tube,sections of it are made of rubber hose, which absorb engine and road vibrations. There are two basic types of fuel hose: Fuel and oil hoses that meet the SAE 30R7 standard, and fuel injection hose that meets the requirements of SAE 30R9.
Standard fuel and oil (SAE 30R7) hose is rated for low-pressure applications at 50 psi working pressure up to 3/8" size, and 35 psi for sizes over 3/8". This general-purpose hose contains a light reinforcement, and the rubber materials can be any compound that is suitable for fuel, oil and vapors. However, Gates Corporation engineers warn installers that fuel formulations at many US refineries are constantly changing as proprietary blends are introduced according to government mandates and seasonal influences. At times, more aggressive fuels can extract the oils that give SAE 30R7 hose its flexibility. The result is a brittle, stiff tube that will greatly reduce the performance and service life of the hose. Fuel injection (SAE 30R9) hose or MPI (multi-port injection) hose is reinforced to handle higher pressures up to 180 psi. It can be used on all injection systems that use hose clamps. It is not designed to replace coupled assemblies on fuel injection systems.
Fuel injection hose is designed for low permeation contact with a wide variety of alcohols, alcohol fuel blends, and diesel fuel. It allows 15g/m2/day permeation whereas standard SAE 30R7 hose allows 550g/m2/day. (Gates fuel injection hose routinely performs at 1 to 2g/m2/day of fuel loss, well below the allowable standard.) Gates SAE 30R9 hose uses a laminated tube of Fluoroelastomer, as a thin wall inner layer backed by traditional compounds. This first layer protects the rest of the hose from attack, swelling or permeation from aromatics, oxidized gasoline (as can occur in fuel injection systems), ethanol or oxygenate additives and a wide range of petroleum based products.
The laminated tube will resist cracking caused by "sour gas," which forms when unused gas is returned to the fuel tank. As an added benefit, this hose construction reduces emissions because fuel can't evaporate through the hose walls.
SAE30R9 hose is also recommended for diesel fuel because its fluoroelastomer tube resists
deterioration caused by some diesel fuel additives. As refineries produce cleaner fuels and lower allowable permeation rates during the “vehicle at rest” condition, older hose specifications such as SAE 30R7 are becoming less reliable. This type of hose is no longer specified on OEM automotive fuel applications because of stringent permeation
standards.
Therefore, Gates engineers assert that the best choice for automotive fuel line hose applications today is fuel injection SAE30R9 hose. For installers, it is the best choice for reduced comebacks and for high performance, assured trouble free service in a changing fuel environment.
Finally, for submersible applications such as on the in-tank fuel pump, only SAE30R10 hose should be used, because when the hose fails, the pump will fail. Hose construction consists of low swell fluoroelastomer compounds in the tube and cover that resist gasoline and diesel fuel permeation and aging. Standard hoses have these fuel-resistant characteristics in the tube portion only. Contact your Gates jobber for information on Gates MPI/fuel injection hose and submersible fuel line hose.
Gates Corporation

Good info.... thanks for the post. mike

Sounds like well researched info. Thanks for that.

Very interesting. I'm happy to see that they specifically mention that alcohols are compatible with SAE 30R9, as I'm just about to buy the remaining parts for an E85 fuel system. I've always used regular braided hose in the past, but it looks like the 444 series rubber line is the best cost effective option this time. Thanks.

trevor w
 

Warren
Thanks for the info I also have been chasing a smell in the boot of my Harrison Cobra replaced the 2'' hose clamps with the super smooth bolt type compression clamp to no avail. I also have about 1.5 meter of 5/16'' EFi hose but with boot closed over night it is smelly next morning.
I am on the Sunny Coast Qld do you have any contact details for resellers in Brisbane for the MMM product.
Regards
Trevor w

Trevor,
My boot is exactly the same, boot up the smell dissapated, but with boot shut overnight the smell returned.
I found Repco sold the 30r9 hose(the salesman was like the other places I tried, didn't know a thing about standards used to identify the type of hose).
Performance Wholesale at Springwood sell the Speedflow version(444 series). The price difference between the Gates hose(Repco) and Speedflow is the shocker. Repco want about $30 a mtr and Speedflow quoted me $11 mtr for the 444 series hose.
This hose is stiff compared to the hose I am removing. Putting the hose onto the fitting on the outlet of the fuel pump is an ongoing saga. Boiling water, rubber grease and liquid soap only have minimum effect when trying to push the hose onto the fitting.


Warren

Warren,
Thanks for the post, I am in the process of hooking up my tank and fuel lines and didn't have a clue about these issues.
I haven' spent a lot of time on this forum, but I learn something new every time.

Thanks to all

Dennis

I'd never heard of such an issue - brilliant info thanks Warren!

Me too! You learn something new everyday!

one of the shops i do woprk for knows of 2 cars that have caught alight
due to unleaded fuel eating fuel lines

look at nearly every new model car
they have plastic fuel lines
holden and ford all use plastic click on fuel lines

shows how **** the automotive industry is that they sell efi fuel hose
even though they can cause so much damage
and all of us use it because no one wants to pay two arms and a leg
for the proper stuff when i work on their cars
if there were more incidents then the normal efi hose u get a repco
or auto shops would all be banned from sale

i know a gtr with this smell problem but its major job to redo hoses
so they fitted an oil cooler thermo fan in the boot to suck the fumes out
heheheheh
works a treat

I have heard of this from a few places down here.

None of my braided hoses are in an enclosed area, so I did not feel the need to change.

Cheers,

Ben

In the US you can buy the fittings and plastic fuel line to replace or repair the fuel line like the type Ford and Holden use.

Here is a bit of reading if anyone is interested. It is the SAE Standard for fuel and oil hoses.

http://doc.isiri.org.ir/c/document_l...DLFE-23609.pdf

Warren

I have never had any issues with aeroquip hose and i have now used it on 4 cars for feed and return lines. However, i have heard of some of their competitors hoses allowing seepage as you described.

My older ERA runs classic fuel line available over the counter from any parts house and doesn't have this problem. Sounds like the trouble comes from selecting an improper EFI type tubing? So, if it's not an EFI application (thus, low pressure) why wouldn't you just use standard hose in the first place?

Warren
Thanks for the info Price etc.
I have used a Green high temp. EFI hose in the engine bay and that was real difficult to expand over the pipe ferrul so I finished up using a copper pipe swaging tool hammering same into the end of the pipe up and over the swage portion leave for awhile hoping it losses memory long enough for you get off and fight a little easier to get onto where want to be.
Just a thought
Trevor w

"was real difficult to expand over the pipe ferrul...."

I have been using super duper extra heavy duty hose suitable for mining type environments with push-lok fittings (ie, JIC, barbed, no clamps). It is very thick wall hose and the best way I have found to fit them is to use a smear of Molykote O-ring grease. I have tested this up to 150psi with no clamps and had no issues.
Some brands of push-lok fittings recommend using no clamps as it can cause damage to the hose, will be interesting to see what they say about that at rego, I will be armed with manufacturers recommendations at the time.

Mystery Gas/Fuel Odor Problem- SOLVED !! Hey everyone- I had to share regardless...
I am the proud owner of CSX-4970 427 S/C (also own 05 Ford GT). Since buying my wonderful machine last summer I began noticing a mystery odor of gas in the garage, even after a few hours of storage. I did all the research I could, checked all connections possible etc and no sign of a fuel leak anywhere. I brought the car to the local "high-end exotics dealer/mechanic" for some advice/repairs and was given a misguided diagnosis and grossly ripped off. Smell and obvious fire/explosion hazard still very much there- not even an improvement.
I then luckily heard through my car-guy network that there is a MAJOR problem with the ethanol infused pump gas being forced down our throats... Especially in metropolitan areas of the country.. It seems the ethanol alcohol being put into our gas literally eats through the rubber fuel lines of our cars, causing no actual "leaks", but allowing fuel vapors to permeate the rubber and accumulate in any confined area- like a garage... And obviously the stainless steel braiding around the rubber does not help the problem. Unfortunately, nor does the TEFLON insulated fuel lines.. They keep the problem at bay a few weeks longer but they too succumb to the ethanol eating through them...
I called the good folks at Aeroquip and they honestly and confirmed all of the above.. I asked the Aeroquip rep,
".. then what do I do to solve this potentially dangerous problem?".. He said, ".. Replace the SS braided fuel lines with Aluminum hard lines, preferably 1/2". ... I did so and PROBLEM SOLVED... what a relief... Hope this is useful.. Best to all.. Cobra Kurt...