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Thread: Fuel Line Sizing

  1. #21

  2. #22
    The point I was making was that in our experience Cohline 2122 is NOT compatible with E10 fuel when used in the engine bay of a 911 and I am aware of the difference between E10 and E85.

    The hose shown on the above photographs is from a car used in the UK where the vast majority of fuel is still E5 - particularly premium grades which are 97 RON or above.

    E10 will not generally be introduced into the UK until 2020 and is some of the reason why we have been dissapointed with the performance of Cohline 2122.

    A fuel hose with a Max. Operating temperature of 50degC also seems too low for use in the engine bay of a 911 and Cohline stated this fact very clearly when we supplied them with samples of the failed hose from a UK based car.

    The E85 fuel used by the car we service annually, which lives in France, suffered a catastrophic failure rather then just an issue with percolation and subsequent deterioration. We had advised our client not to use E85 and fortunately he has followed this strategy since the failure.

    When we first encountered the problem we started changing fuel lines every year but this approach was less than successful and cars started to exhibit some issues after 6-8 months.

    We then bought samples of 4 x different hose and kept it filled with fuel for more than a year.


    Our first choice was Aeroquip Startlite 100 Series which is advertised an being compatible with E85 fuel and has a Black Nylon braid. It has a maximum operating temperature of 149 degC. It suvived a 12 month test without any sign of a problem.

    There are however, two issues. The first is cost at around $40 per metre, the second is the ID, which at 8.6mm, -06) makes it difficult to seal onto an 8mm hose barb. If I would buy this hose in 7.5mm ID I would use it without hesitation.

    We tested Codan 3106 and again results were good with no issues. The Codan is around 2 x the cost of Cohline and is quite difficult to source in the UK.

    We tested Gates 4324 Series which was also sound but again is only available in -Dash sizes.

    The control was Cohline 2122 which was, in our view, unsatisfactory with the braid becoming damp to the touch after about 6 months.

    Cohline did comment that the hose sample we supplied only exhibited external cracking and that the inside diameter was reasonably sound and this was due to temperature effects and that we had used the hose outside it's design limits.

    This clearly means that 2122 is unsuitable for use on a 911 as we only fitted this hose on SWB carburetted cars, with the hose fitted in the standard location. I find it confusing that 2122 was used for many years at engine bay temperatures in a 911 which have now become too high.

    I am not surprised that the damage that is evident is concentrated to the outside of the hose as the manner in which the braid is applied does not help.

    There is a good report issued by Transport Research Laboratory (TRL) in the UK where they clearly demonstrate that Ethanol increases the 'mass transport' of gasolene through an NBR hose and the escaping vapours wash out the synthetic binders from the rubber and that this causes embrittlement and cracking.

    The type of binders being used has a significant impact on the behaviour of individual hoses and I found Cohline's explanation regarding temperature unconvincing.

    Clearly to form a quantifiable conclusion would need much more work than we have carried out but we simply decided not to take the risk and use Codan.

  3. #23
    Senior Member
    Join Date
    Dec 2008
    Location
    Black Mountain, NC
    Posts
    539
    The Gates hose I mentioned is 4219 BG "Baricade" Green Shield, rated to 3.5 bar / 50 psi, will enquire on MM sizing. made for ethanol resistance.

    Regards

  4. #24
    The Gates 4219 is a very good hose but we didn't try it out as it doesn't have a textile 'overbraid' and we specifically wanted hose that maintained the original appearance if that were possible and we limited our search to hoses of 'original' appearance.

    4219 is available with a 5/16" ID which is 7.9mm and an OD of just over 14mm so is lightly larger than the original.

    There are also Cohline and Codan hoses that may be good that aren't braided and they are also slightly larger in outside diameter.

  5. #25
    Senior Member
    Join Date
    Dec 2008
    Location
    Black Mountain, NC
    Posts
    539
    Thanks Chris, I will try to source the braded cover version you posted, went to the rubber version after quick failure of the fabric covered from Stoddard & others failed too quickly. Appreciate the information.

    Best Regards

  6. #26
    I have 50metres of the Codan in 7.5mm dia if I can help.

  7. #27
    Senior Member
    Join Date
    Oct 2004
    Location
    SW Suburbs of Chicago
    Posts
    284
    Any thoughts on Continental? Same as Cohline? for example:
    https://www.ebay.com/itm/BMW-7mm-Clo...9UxUkl&vxp=mtr
    Mike O'Meara
    Reg #1043
    72 911T
    56,59 356s gone
    67,68 912s gone

  8. #28
    Senior Member
    Join Date
    Dec 2008
    Location
    Black Mountain, NC
    Posts
    539
    Thanks Chris, was able to order a roll of the 8mm 4324 -10053, fabric covered. Will now have it on hand, Sterling, Peter, feel free to stop by if you want some, I will be here by the time I get back from the Texas Hill Country Rally.

    Thanks again for the information and your research!!

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