8 cylinder front engine iconic vehicle
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By captainOCD
#89907
After monkeying with the cooling system some more I decided to wake up my tan 86.5 project car from it's winter hibernation.  It started up and ran for a bit then I heard liquid.  I realized quickly it was fuel and shut things down.  Fortunately everything was cold under the hood.

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This was the hose (supply?) that runs from near the 14 pin connector up to the hardline to the front damper.  Further inspection showed the line was cracking on the outer radius of the bend it makes, and and broken through right at the peak of the bend.  I suppose the bend could have been a bit more gradual, but this sure isn't something I expected to happen.

These fuel hoses were put on in summer 2018 after I got the car and did the timing belt job, and the car has run for all of 30 minutes maybe in the past 3 years and driven maybe 100 yards.  I put these same fuel lines on my blue car too, so figured I should check over it too.  Sure enough there are small cracks starting to form on the outer radius of the bend on that supply line.  Not nearly as large as the ones on the tan car, but concerning none the less.  I checked the "U" shaped line between the fuel pressure reg and the damper at the rear and found the same small cracks on the outer radius of that bend as well.

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After only 3 years and ~5k miles on the blue car I'm not happy with how these held up at all.  Could have easily caused a fire.  I looked on 928 motorsports' site and it looks like they're selling a different brand of hose now.  Wonder if that's why.

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By captainOCD
#90064
I'll say. So now I've got two cars that need new fuel lines.

I ordered some 99918115250 hose for the interim (it looks like that's bulk injection hose Porsche sells) from a local dealer to hopefully get things back together safely (I was planning to take the blue car to cars and coffee this weekend). Long term I suppose I need to get something more like Roger's or Greg's hoses.
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By worf
#90068
What was your source for the Cohline fuel hose?

I’ve got yards of Cohline hose running around, but, all but 6” of it for vapor lines (not liquid.)
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By captainOCD
#90069
I bought it from 928 motorsports in spring of 2018.
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By worf
#90077
captainOCD wrote: Wed Jul 07, 2021 2:58 pm I bought it from 928 motorsports in spring of 2018.
So, I went and checked my stock of bulk hose. The fuel hose I use is Flennor.

It is interesting that my Cohline coolant hose looks a lot like your fuel hose. But, my eyes are not mass spectrometers.

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By Sazerac
#90090
Safety of the fuel system is a very interesting topic to me.

In addition to the cracking at the bends, I wouldn't tolerate the split end on the end of the U-hose either. Are those barbed ends on the ends of those fittings with simply clamps? I think I vaguely remember Carl promoting a solution like that, and it sounded totally unconvincing to me.

Yup, looks like you need two sets of real fuel lines.
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By Crumpler
#90097
I have a nauseous feeling about this. I’m glad you were able to avoid disaster.
Is there a way to do post mortem analysis on this hose in question?
I wouldn’t expect a bend failure in any grade of fuel rated hose in that short amount of time and limited use.
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By worf
#90099
Crumpler wrote: Wed Jul 07, 2021 6:06 pm I wouldn’t expect a bend failure in any grade of fuel rated hose in that short amount of time and limited use.
Back in the day, when Roger put together his “fuel hose and clamp” kit, one of the *specific* problems was the bend radius of the “U” hose and why he actually commissioned a run of formed fuel hoses for that specific application.

Greg Brown’s PTFE hose does not have a small enough allowable bend radius to enable an identical replacement for the U hose (‘87+) either. His solution is a longer hose with a different route. Same deal for the supply hose.

So… bend radius of fuel lines is definitely “a thing.”
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By captainOCD
#90106
I do recall reading concerns about the barbs when I put these fuel lines together several years ago. I want to say I filed down the sharp edges of the barbs to prevent them from cutting the rubber, but I'm not 100% positive. Guess I'll find out when pulling the lines apart. And that split in the one line was there when I put the lines on. I can't remember the exact circumstances of it, but I think that was the last piece of the fuel line I had, and somehow had accidentally cut the end some.

This photo was from May 2018 when I put these lines on.
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Greg's lines do look fantastic, and no doubt would be a great solution, but I think they're quite pricey at $600 (x2) here, especially since this tan car is still in need of a more or less full restoration. Roger's new lines look like an attractive option. I haven't seen much mention of what the type of line still used is though. Not sure if they're plastic lined or rubber.


I won't argue with anyone that the rubber lines aren't the best solution here. At the time (and even now still) it seems like people have had generally good luck with rebuilding the fuel lines, I couldn't find another failure similar to this one. That said I plan to take a close look at how things have held up here, particularly surrounding the lines where they are clamped to the barbed fittings. I want to see if there are cuts being made in the lines by the barbs and clamps, if the clamps are failing to hold the lines to the fittings, etc. If this setup proves to be problematic, I'll see about getting a set of Roger's rebuilt lines.

For the time being though I do have some new rubber line that'll hopefully be here this week so I can at least make the blue car safe to drive around town again. Given that even this possibly questionable line lasted 3 years I think these will at least last long enough to evaluate and get some better replacements.
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By SeanR
#90117
I saw this on a couple of cars many years ago and stopped using rubber hose for these applications and do not remember what the hose brand was. The good news was when I cut the lines off there was no damage inside the hose on the barbed fittings. None. Had a car at the beginning of the year that I had put some on a decade past, figured it was a good time to swap them at my own cost for what I've been doing for a real long time and check the condition after all those years. They were just fine and would have been fine for a longer time for sure.

The hoses that Roger is selling as his rebuilds are what I've been using for 8-9 years and only on customers cars that I would be able to check on over time. I've been very happy with it and after Roger/Greg had their fall out Roger begged me to supply him with an option that was affordable and I had confidence in. Actually he was asking me for a good many years to do so but I never wanted them to come to market. I also made told him that if Porsche had hoses in stock that the customer should use those instead. I had been supplying them to other shops who I knew the owner for a good number of years though.

So details on the hose used. Braided nylon, very flexable etc.
https://www.summitracing.com/parts/sum-240603b

Using the factory connections and making them as close to the actual length as I can. Making the hose longer allows the U hose to work in the factory location instead of looping it around by the fuel cooler, but you can if you want to. Rogers got them on his site.

https://928srus.com/products/110-00-rb- ... a057&_ss=r
Bertrand Daoust liked this
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By captainOCD
#90118
Good to know about you and Roger's hoses. I think that's the route I'll end up going ultimately.
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By Landseer
#90163
Thanks for sharing a solution Sean.
I've got cohline circa 2018 from Carl on brown car. Will check them later today and report back.
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By captainOCD
#90388
Ok, so here's some more pictures and dissection of the hose that failed.  The bend was definitely pretty tight, so that definitely was a screw up on my part, and is probably why this one failed already instead of just being cracked already like the rest.

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For comparison here is the same line on my blue car.  This line is cracking, but not failed completely yet.

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One bit of good news is that the crimp on oetiker clamps were still securely on there, and there was no sign of damage to the hose where it was clamped onto the fittings.

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(the one small tear here was from cutting the hose open with a knife)
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Closer look at the failed spot.
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Split the hose down the middle to take a look at the inside.
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There was only one small tear on the inside.
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From what I can tell this hose isn't multiple layers of different materials, just rubber throughought with some cord.  It appears that the outer "layer" of rubber started pulling away from the cord.
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I still think this hose was of poor quality which is the main culprit here.  The sharper bend definitely doesn't help though.






As far as getting counterfeit hose, I suppose you could get counterfeit anything anymore (there are counterfeit headlight bulbs and spark plugs for crying out loud), so you just have to trust who you're buying from has a reputable supplier.  Ideally the manufacturer.  I had asked 928 motorsports who was supplying the hose in 2018.  All I got back from there was that cohline doesn't provide a lifespan on the hose, and that they now supply cohline 2240 (with a link to belmetric).  I'm not making any accusations there, but make of it what you will.  My honest guess is they don't know with the recent change of hands.
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By captainOCD
#90392
By the way, the hose I was hoping to pick up this week wasn't going to arrive until next week now most likely. I was poking around and found mention of the gates barricade hose.

https://www.gates.com/us/en/fluid-power ... 05652.html

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This hose appear to be closer to the original hose as far as construction goes. It's got a plastic liner with several other layers. Better temperature range than the cohline hose I had too. And the local napa happened to have some in stock, so I got the last 7 feet they had of the 5/16". That works out at 7.9mm instead of the 7.5 of the cohline, but it seems like it'll be quite snug still. I'm getting some more oetiker clamps tomorrow.

They do publish a minimum bend radius of 3" for this stuff. That should leave enough room for the supply line up front, but the "U" at the back will be too tight to run as the factory line was. I'll have to do as sean suggested there and run it longer to make sure the bend radius isn't too tight.

Again, planning for this to be a temporary repair, but at least it should be a better one than the cohline was.
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By captainOCD
#90652
SeanR wrote:Another link for the hose I'm using.


http://www.russellperformance.com/mc/ho ... ic-2.shtml


Someone doesn't like that I'm using it.
Ok, I was wondering who made it for summit. I've got some russel performance brake lines on my charger, that's been my only experience with them so far. That hose looks like some good stuff. The crimps you use look like they spread out the pressure across more of the barb, so I'd figure if the oetiker clamps didn't cause the hose to get torn on the barbs, yours sure wouldn't either.

Greg's hoses are certainly fantastic looking and would certainly hold up great, I just have a hard time justifying $600 on them if there are other solutions that will do the job safely.




I did replace all the hoses on my blue car yesterday. I cut open the feed and U hose and although they showed cracks on the outside, there was nothing on the inside (makes sense since they weren't leaking). I did notice that even the straight piece of hose between the fuel rails at the front had some cracking on it. I think whoever said ethanol may have been right. This car has never sat more than a week or two at a time, so maybe that's why it wasn't as badly damaged.

The gates hose does have a minimum bend radius of about 3". I had to make the U hose quite a bit longer, as you said sean, to achieve this. I've seen nothing but good things about this gates hose online. I wonder if it might hold up anyway. Still contemplating just getting your hoses from Roger for the U and supply at least though.

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