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A Replacement for a NLA Fuel Line

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Old 04-05-2007, 02:52 PM
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Imo000
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Originally Posted by the flyin' scotsman
The steel braid protects the outside of the hose; can't see how there's any prevention of interior collapse......

That’s not necessarily true. The braiding also guides and keeps the hose from internally collapsing. For the hose to collapse internally, the outside would have to also deform and the braiding keeps the outside from deforming.
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Old 04-05-2007, 03:23 PM
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Originally Posted by Bill Ball
The loop that goes between the dampner and FPR is high-pressure. That's the main piece at issue in this thread. The original S4+ version appears to be a semi-rigid molded core.
One idea we're working is forming the S4+ 'U' with EFI line using an internal flexible form then solidifying the shape using a coating. The form is removed once the coating sets, the ends can be inserted and the clamps applied.

WIP
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Old 04-05-2007, 03:42 PM
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Originally Posted by Imo000
That’s not necessarily true. The braiding also guides and keeps the hose from internally collapsing. For the hose to collapse internally, the outside would have to also deform and the braiding keeps the outside from deforming.
An engineer could verify, but I'm pretty sure that Imo000 is correct. Makes total sense.
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Old 04-05-2007, 03:50 PM
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Originally Posted by H2
An engineer could verify, but I'm pretty sure that Imo000 is correct. Makes total sense.
Knew I should have opted for those rubber structural courses..........damn electronics/telecom stuff got in the way

There's enough interest and folks involved Harvey I'm sure we'll get it figured.

Has anyone cut the U shaped hose open and examained it for structural make up?
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Old 04-05-2007, 03:53 PM
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Originally Posted by the flyin' scotsman
...solidifying the shape using a coating
What type of coating it is?
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Old 04-05-2007, 04:35 PM
  #66  
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And why is circumventing the idiotic engineering to route the hoses this way in the first place not a good idea?
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Old 04-05-2007, 05:15 PM
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Originally Posted by Sterling
Why coudnt we just have the material analyzed... for the factory construction, it looks to have a bit of a bend/shallow kink when new. I personally think the reasoning for the hose and the bend is for installation and removal. If it was a solid line, you would have to crack the bolts for the mounts to the dampners and move them outward.... it appears to be the same plastic type compound for the return line that goes over the passenger cam cover...... if we knew exactly what it was, then like everything else I bet there is a source for it. the bugger of it going to be shaping it and getting it onto the metal fittings. (sorry for the bugger reference... been hanging out with roger too much lately.... at least we have him saying Ya'll now which is humorous with an english accent)
The core appears to be the same as the passenger side line (that is the feed line, not return, BTW). That line needs flexibility to allow for engine movement. The rear loop appears to allow for some movement to make assembly easier. Since the fuel rails have rigid ends and the FPR and dampner are rigid mounted, you need to be able to move that U line around to get the connectors into the dampner and FPR fittings. They used hose on the front crossover, but not these loops probably because they needed to be molded to make the small radius. And they needed to be more than just a short hose to allow for the amount of movement they needed to accomidate engine motion and connector alignment.
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Old 04-05-2007, 05:19 PM
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The orginal fuel hose, as Rog100 and others have pointed out, is a "hose within a hose"....perhaps the outer hose is to give some leeway support for bending....similar to the outer SS covering shown above?

Also, I suspect that the brass "crimp" fitting on the old hoses appears to be loose on dissection because the hose has shunk with age. I have a new hose and it's tight.

H2
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Old 04-05-2007, 05:52 PM
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I just wanted to make sure of something before I responded - so it has taken me a moment to find another of the "U" lines and cut it up. There is no plastic reinforcement substrate within as has been said on this post. I did not think so (I have rebuilt a coule) but just wanted to look again to be sure.

Again - there is no plastic inner liner in that U-shaped hose in any of the ones I have cut up.
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Old 04-05-2007, 05:58 PM
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Originally Posted by Dr. Phil
Buddy, sumthin's goin' on here ... You godda look DEEP inside your fuel hoses ... and ask yourself .... I mean what, what ... what is it exactly that we're lookin' at here .... I mean ... there's just no two ways aboudit .... You know whaddamsayin? Cause ... cause change comes from within ... I can sit here and redesign your fuel hoses for you all day ... and .... and in the end ... the answer lies with you .... It's up to YOU to become less rigid ... It's up to YOU to take the first step and become more flexible ... to GIVE a liddle ....
Yep, the man said it all
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Old 04-05-2007, 06:08 PM
  #71  
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Originally Posted by Carl Fausett
I just wanted to make sure of something before I responded - so it has taken me a moment to find another of the "U" lines and cut it up. There is no plastic reinforcement substrate within as has been said on this post. I did not think so (I have rebuilt a coule) but just wanted to look again to be sure.

Again - there is no plastic inner liner in that U-shaped hose in any of the ones I have cut up.
Thanks, Carl. Perhaps my memory is bad...but I'm sure I remember someone saying that about the U-shaped hose. I have one that I've not cut up yet. However, I KNOW that one of the fuel hoses on my 968 had a hose within a hose covering. Debate as to the function of the second hose covering. Protection for the inner hose or?

Either way, it doesn't matter to me as long as a suitable substitution is found.

Harvey
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Old 04-05-2007, 08:11 PM
  #72  
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Originally Posted by Carl Fausett
I just wanted to make sure of something before I responded - so it has taken me a moment to find another of the "U" lines and cut it up. There is no plastic reinforcement substrate within as has been said on this post. I did not think so (I have rebuilt a coule) but just wanted to look again to be sure.

Again - there is no plastic inner liner in that U-shaped hose in any of the ones I have cut up.
Carl...........with all due respect the U fuel line pictures in your web site is of an older model of car. The S4 and up cars have a similar U shaped line but its a tighter U hence much of this discussion.

Perhaps for absolute clarity Roger or Heinrich who have multiple models could post some pics.
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Old 04-05-2007, 08:24 PM
  #73  
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85-86 on left, 87-up on right
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Old 04-05-2007, 08:26 PM
  #74  
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Thx Dave...........now how do we build the version on the right?


Or.......can we use the 85-86 version on newer cars; seems like they'd be easier to replicate.
Last edited by the flyin' scotsman; 04-05-2007 at 08:30 PM. Reason: another thought?
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Old 04-05-2007, 08:35 PM
  #75  
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Originally Posted by Carl Fausett
Again - there is no plastic inner liner in that U-shaped hose in any of the ones I have cut up.
That may be the case. The one that came off of my '85 has a plastic inner liner. Well, unless its something else.
Glenn
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