Lotus Elan

fuel hose deterioration

PostPost by: bob_rich » Tue Jun 11, 2019 5:38 pm

HI Folks

Gave the +2 it annual service to day and am getting a bit concerned about the state of the hoses use for the fuel injection ( car has a Emerald system wasted spark, with jenny throttle bodies and ford 36 tooth trigger wheel). The hoses are only around 4 years old. I have attached a picture of a section of hose that is in good order with a clear description of what its spec is. The OD of the hose is 14.5mm. I have looked for a similar hose on the web and I found one with a part number incorporating R7 rather than R10. Anyone know what this means? Could this cracking be related the use of modern fuel with added bio fuel ( usually fill up with 97 grade at local BP garage.)

I have attached a picture of the cracking. from what I can tell the bend radius of the hose seems with spec and I used springs to keep it in place and contain it so it does not put any stress of the fuel rail fittings.

Any opinions or advice would be helpful


hose-cracking1.png and
p6110539.jpg and
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PostPost by: Grizzly » Tue Jun 11, 2019 5:51 pm

Not seen one as bad as that but there is allot of rubbish no make hose about at the moment, i'd suggest only using quality fuel hose (Gates is my go to make) after all you don't want fuel spraying all over the place.
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PostPost by: mbell » Tue Jun 11, 2019 6:04 pm

The R7 v R10 is difference is the fuel types that the hose is rated to handle. You should carefully consider/research it when purchasing replacement hose. I suspect UK Super probably has something like 5-10% ethanol, so you need a hose capable of handling that, with fuel hose generally better safe than sorry. So over spec and buy good quality hose as suggested.
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PostPost by: pharriso » Tue Jun 11, 2019 8:20 pm

From http://www.underhoodservice.com/correct-fuel-hose-installation/ :

The Society of Automotive Engineers (SAE) is an industry group that creates standards for the automotive industry. When it develops a standard, it applies to all manufacturers in hopes of reducing engineering and testing costs.

SAE has more than 16 active and inactive J30 standards for fuel and oil hoses. If you look at the side of a fuel, oil or emissions hose you will see the letters “SAE” followed by the number 30 (some will have a J first). Next in the sequence will be the letter “R” followed by a number. The number after the “R” refers to the section of the performance standard it pertains to. The criteria are typically permeation, chemical resistance, construction, temperature range and kink resistance. The higher the standards go, the more criteria that must be met.

“R” numbers in some cases do not determine the pressure rating for the hose. Hose manufacturers typically print on the hose if it is intended for use on fuel injection systems. Also, you should check with the manufacturer of the hose to see if it is compatible with fuels like E85 or biodiesel. NOTE: IF A HOSE DOESN’T HAVE A SAE J30- STANDARD ON THE SIDE, DON’T INSTALL IT IN A FUEL SYSTEM.

SAE 30R6 hoses are designed for low-pressure applications like carburetors. These can also be used as an emissions hose.

SAE 30R7 hoses are designed for fuel. These can go under the hood and are typically used for low-pressure applications.

SAE 30R9 hoses are designed for high-pressure applications like fuel injection and oil. These are designed to stand up to the environment under the hood.

SAE 30R10 includes hoses that are submerged in fuel. This type of hose is used inside the fuel tank and typically on the fuel pump module. This type of hose uses a special layer on the inside and outside to prevent the core layers from being saturated in fuel. But, don’t use it under the hood. R10 hoses can’t stand the heat.

SAE J30R12 includes low-permeation fuel feed and return hoses.

SAE J30R14T1 is the standard for ultra-low permeation properties. This type of hose is typically approved for use with leaded and unleaded gasoline, diesel, biodiesel, E85, methanol, ethanol and gasohol fuels. These are typically used for low-pressure applications.
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PostPost by: elanman999 » Tue Jun 11, 2019 8:49 pm

That's not very good if it's for injection pressures.
After a quick search I cannot find R10 but found some R9 here:- https://www.advancedfluidsolutions.co.u ... e-95-c.asp

I had a similar problem when I went to EFI. I did find some OEM quality tubing but the suppliers had large (1000m) minimum orders so ended up using braided PTFE tube. Far from the cheapest and not the most convinient to install (large bend radius) but is a nice secure job. See here:- https://www.ebay.co.uk/str/torquesuk
For running through the cockpit I used copper/nickel tube on one of my cars.
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PostPost by: bob_rich » Sat Jun 15, 2019 7:25 pm

Hi All

Thanks for the useful info and the explanation of the R numbers. I obtained and fitted some R9 hose from Advanced Fluid Solutions which it transpired was located just down the road from where I live and so I could have saved the postage! I will keep a careful eye on this hose to see how it works out. The new hose had the full SAE code on it together in an embossed date code of 2019 01.

There is still some of the older R7 hose on the rear of the car around the fuel tank and pump but being in the boot the environment is not as severe and so this seems to be surviving OK.

thanks for all the help

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