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Posted by: matchpoint Jun 28 2016, 04:58 PM

I have my 76 - 914 engine and fuel tank out of my car during my frame off restoration. I want to replace the 2 plastic/nylon fuel lines in the tunnel with an OE product and not use the stainless or mild steal fuel line. I want to go back original and after 40 years of service I want to replace the plastic lines. Looks like everyone says go stainless but I want to go with the OE plastic.

Does anyone have a part number of a replacement plastic/nylon tubing of the same size as the OE plastic tubing. I think it is 7MM OD size. Auto Atlanta told me to just blow out the OE plastic lines and don't waste your time replacing. Looks like an easy replacement while the car is apart and all I need to know is a P/N of a plastic/nylon fuel tubing I can get @ NAPA.

Thanks

Posted by: napasteve Jun 28 2016, 05:19 PM

I'm having a hard time understanding why you wouldn't use SS lines. My OE plastic lines shrank and I had fuel leaking in the engine compartment. Not good. I'm not sure OE plastic lines were designed for today's fuel (Ethanol???).

Posted by: Jeff Bowlsby Jun 28 2016, 05:28 PM

OE fuel lines are NLA. The 1970-74 lines are nylon, but the 75-76 cars use a different material that is the best Porsche made at the time and they are very good quality. Unless yours are damaged they probably do not need replacement.

Nothing wrong with the stainless lines either.

Posted by: OU812 Jun 28 2016, 05:52 PM

Try the search function

There is mucho info on installing and folks that supply them.

Posted by: 914Sixer Jun 28 2016, 06:02 PM

Bel-Metric has the new version of the fuel line you are talking about called polyamide. Cohline is the manufacturer of the stuff. $9.01 a foot over 5 feet (8mm)

Posted by: mepstein Jun 28 2016, 06:10 PM

Makes sense not to use the best product available to carry gasoline into the engine compartment. Right? Especially a high dollar restoration.

Posted by: pete000 Jun 28 2016, 06:20 PM

This is the one part I would not want "Factory Correct" Those points deducted from the judge aren't worth it. Unless the car is not driven outside of the lawn of the show only...IMHO Go Stainless !

Posted by: green914 Jun 29 2016, 10:56 AM

Pelican Parts has the how to instructions for replacing the fuel lines with ss lines on their web-site.

Posted by: JawjaPorsche Jun 29 2016, 01:49 PM

If I was making an investment like you are, why take a chance on a fire. Go with stainless.

Posted by: Jeff Bowlsby Jun 29 2016, 01:54 PM

"Polyamide" is the larger family name for Nylon. Glad to see its also available in black for the 75-76 cars.

Posted by: matchpoint Jun 29 2016, 02:19 PM

Hi Jeff,
Thanks for your reply to my search for OE replacement plastic tunnel fuel line for my 914. I have the car apart and want to replace the 40 year old plastic fuel pressure and return line. Everyone seems to say use stainless tubing but I want to go back OE. I found Bel Metric on the internet has the hose. Looks like it is $8.25 per meter. I think it is a German MFG called Cohline. They say their hose is 8MM OD & 6MM ID which should work. From what I can tell I would need 32 feet. I want to use the plastic for 3 reasons. The OE has lasted 40 years. I want to go back to the OE black plastic look where the 2 hoses that come through the engine shelf are plastic and are one continuous stick all the way to the front firewall. The important reason is I want to keep hose clamp/rubber line joints to a min. and the 4 section stainless system that Tangerine offers would introduce 4 clamps to seam the sections together.

I will search the internet for another US mfg who offers polyamide. Let me know if you have a P/N for a US mfg or supplier. I think Imperial may make the hose also.
Thanks
Bob

Posted by: barefoot Jun 29 2016, 02:47 PM

http://www.parker.com/literature/Parflex/B-Parflex%20PDF%20and%20Images/CAT%204660.pdf

Go to page B20 look around
There are Parker stores to buy from
Barefoot

Posted by: Jeff Bowlsby Jun 29 2016, 03:01 PM

It will take some workmanship care and research to get these right using nylon. The nylon tubing can be bent with heat and a thick copper wire inserted into it to minimize ID collapse. OEM lines include a section of metal tubing up near the brake pedal area, you will probably just want to run the nylon full length through the tunnel.

Check the ID/OD...I believe you need a ~10mm OD for the supply.

Last I checked, McMaster carries the white nylon for a true OEM look for the 2 tubes the come through the engine shelf by the battery...its very cool to see new engine bay lines and watch the fuel flow through them. They are whitish translucent...but not opaque.

Give up on the idea of a single tube front to rear, it would be too complex. The fuel pump area disrupts the tubing continuity anyways and rubber hose/clamps are OEM.

Posted by: Catorse Jun 29 2016, 03:44 PM

They used asbestos for decades and lead for centuries. Just because it lasted doesn't mean it was the best material to use.

The plastic lines are a safety issue, plain and simple. Yes, I already replaced mine.

Posted by: Jeff Bowlsby Jun 29 2016, 04:04 PM

What basis do you have for that opinion other than anecdotal and is it a unilateral or conditional opinion?

Automotive engineers certainly had metal tubing available for fuel lines in the 1970s, they chose nylon intentionally and it met federal safety standards at the time of manufacture. Not saying they are not a maintenance item and may require replacement from time to time as good practice, but your unequivocal statement is not substantiated. I can think of a few disadvantages of metallic tubing over nonmetallic tubing for fuel lines, its not as slam-dunk as some think.

Posted by: mepstein Jun 29 2016, 05:01 PM

I would think the chance of it getting nicked by the shift mechanism inside the tunnel and sourounded by the 45 year old wire harness makes the ss lines the right choice. Might never happen but who knows. I know if it did it would be my car.

Posted by: Mueller Jun 29 2016, 05:08 PM

Nylon tubing for fuel is approved for aircraft use, not saying that is the end all to the discussion, just something to think about.

http://www.aircraftspruce.com/catalog/appages/nylaflow.php?clickkey=3011511

Posted by: napasteve Jun 29 2016, 05:11 PM

Jeff,

I just replaced my OE metal/plastic lines that run thru the tunnel and the plastic lines that run from the below the engine shelf to above with SS lines from Tangerine. The leak I experienced before the change was above the engine shelf where the clear plastic line was inserted into a rubber line to feed the injectors. Seems like that OE clear plastic line kept shrinking and I had to keep tightening the clamp to prevent leakage. I think I was really lucky that I didn't have a fire. My car is a '73; I'm not sure if lines in a 1976 are the same.

So my question is: do you think I made a mistake going to SS?

I have a chemistry background. There are a ton of different plastics out there, each with different characteristics and interactions with the various components in fuel. Lifespans will vary. SS, on the other hand, can sit in any fuel with any additive(s) for 1000 years and will not degrade one bit.

I can understand the desire for OE AMAP. It's kind of cool to have a timecapsule; I think it's one of the things that binds 914World members. It just seems to me that SS is WAY more durable (and therefore safer) than the OE lines and they are not that expensive or difficult to install.

Posted by: Catorse Jun 29 2016, 08:23 PM

Whoaa......are we saying the 914 has AIRCRAFT QUALITY NYLON in their for fuel hose? Yeah, I don't think so. Looks like old ass plastic to me. I am well aware of the advances made in polymers today, but we are talking about the stuff already IN the car.

Jeff,

You need to remember that the "automotive engineers" always did answer to automotive bean counters. The 914 was a budget model. Premium products were not used in its manufacture. I am guessing the 914 has plastic lines because they were cheaper, not better. Certainly cheaper than stainless.

My 911s of the same era have metal lines. What does that tell you about what Porsche thought???

Posted by: Amphicar770 Jun 29 2016, 08:26 PM

If you want to have original hoses because you think things like original motor oil are important, then that is your choice. Trying to argue that it is "better" because that is what came from the factory is nonsense.

Of course metal lines were available back in the 70's. So was gold wire. They did not choose plastic (or copper) because it was better but much more likely because Otto in accounting figured it would save $3 per car or Hans in manufacturing determined that it could be installed 3 seconds faster. Every cent counts in mass production.

Yes, some aircraft use plastic lines but they are also subject to a level of annual and other inspections that go far beyond what even the most anal car owner is accustomed to. Every part has a lifespan rating and is replaced regardless of condition.

If you do stick with plastic lines that is great. Just make sure to have a non-original fire extinguisher in your car.

Posted by: mepstein Jun 29 2016, 08:53 PM

Our shop works on 911's all day long. Porsche definitely built 911's to a higher standard with better materials. 914's were built cheap. I love 914's but it's easy to tell the difference in every part of the car.

Posted by: matchpoint Jun 29 2016, 09:09 PM

Three reasons Porsche may have used plastic fuel line in the tunnel. 1. Cost 2. Easy to handle at assembly 3. Porsche was able to eliminate 2 splices of rubber fuel line hose in the engine bay that would have been required to connect a metal line from the tunnel and a shorter metal line that runs up through the engine shelf at the battery tray. This would have required 4 rubber to metal connections in an engine bay. More risk of hose clamp fuel leak in an engine bay. By using plastic Porsche has a longer continuous plastic run without adding unnecessary splices after the firewall into the engine bay.

My car 76 - 914 and has 2 long runs of OE Black Nylon/Plastic Polyamide that is 8mm OD and 6mm that are about equal length. Does anyone out there have a P/N and source where I could purchase 25'? The one supplier so far that I have found is Bel-Metric. They offer a German product mfg by Cohline that they sell for $8.25 per Meter.
Thank You

Posted by: Jeff Bowlsby Jun 29 2016, 10:30 PM

We should not advocate for either the nylon or SS fuel lines, both can serve their function well and one is not necessarily better than the other. The lines are located in protected areas of the chassis so impact damage is not likely.

Nylon lines don't corrode, are seamless, and may insulate the fuel from heat soak better than metallic lines. OE nylon should be replaced if obviously embrittled or cracked - they are maintenance items. But it is not correct to generalize that all OE nylon lines are bad or unconditionally safety hazards, even at 40 yrs old. I would not go so far as to universally rip these out without careful examination of your specific lines. The original lines in my car, and many cars I see, are perfectly serviceable.

Which is more durable against battery acid - I don't know - the original issue causing the recall?

SS lines if of lower quality SS material can corrode, may be seamed and therefore subject to splitting especially when radiused, and may transfer heat better than non-metallic. Can you say vapor lock? We don't know the quality of materials of the aftermarket SS available on the market - could be good, or bad, we just do not know, but it is a concern.

Nylon lines can melt but not the SS lines, but consider that the system using either material includes rubber lines which are not fireproof so its a moot point.

Posted by: mbseto Jun 30 2016, 08:46 AM

Nylon is VERY susceptible to battery acid. The rock climbing equipment industry has tested this extensively.

Posted by: John Jentz Jun 30 2016, 09:35 AM

The lines are made from Nylon 12, 70-74, and Nylon 13, 75-76. This is an excellent choice as they are both usable with gas and alcohol. My 96 Audi A4 and 90 964 use nylon fuel lines (so do most cars) so do you really think it's just "old ass plastic" or maybe the best practice?

Posted by: matchpoint Jun 30 2016, 10:14 AM

Can anyone expand on Nylon 12, 70-74 & Nylon 13, 75-76 as the fuel line tubing used to replace OE Nylon fuel line tubing on 914's.

Posted by: oakdalecurtis Jul 26 2016, 12:22 PM

Sorry to those who might have read this story in previous fuel line threads, but I often read here about tunnel fuel lines holding up well. I have a 76 2.0, had it's original fuel lines, here's what happened:
As a newly elected Councilman in a small rural central California city, I was asked by to bring my '76 teener to drive in the annual city Christmas parade through town. I pulled into the parade line and began slowly idling down the main street route with another Councilman in the passenger seat. We hadn't gone far when a man on the sidewalk approached the side of our little yellow ride and told us we were "leaking water under the car real bad". That's an interesting comment since there is no water onboard a 914 to leak! I opened my door and leaned out to look under the car, only to see gasoline spraying down mid tunnel and rapidly pooling under the car! I quickly told my Council colleague to get out of the car fast! Then I franticly waved to onlookers to create an opening among the sidewalk crowd of people, and drove the still running 914 into a dirt field and shut it off. I left a trail of gasoline on the ground behind the car at least a foot wide as I went toward the field. After having my 914 towed to my mechanic, as you probably already guessed, the fuel line, under pressure from tank in front to the engine in the rear, decided to split after 30 years, at that opportune moment during the parade. I had the fuel line repaired and all was fine. I was invited to the city Christmas parade again the following year. When I pulled up in my teener to get in the parade line this time, my Council colleagues were standing nearby on the curb with lighters, flicking them repeatedly and saying they were "ready for me this year!" That's how you know who your friends are in politics!!!!

Posted by: porschetub Jul 26 2016, 11:26 PM

never seen an issue,thats why I replaced mine with late model VW Golf hose ,insert the correct brass inner pieces on the rubber joints and use fuel hose clamps,job done.

Posted by: 914_teener Jul 26 2016, 11:40 PM

The failure was the battery placement which caused the early failures.

The 914 was a transition model and the decision to move the fuel pump was an easier decision logistically form an engineering prospective than moving the battery in my opinion.

I never moved my pump for that reason and my lines are in good shape and not on the pressure side of the pump.

Now the connections and rubber hoses in the injection loop in the engine compartment. I check those all the time.

I sleep at night and drive my car alot....in really hot weather.

Posted by: veekry9 Jul 27 2016, 03:16 AM

Old lines have ruined a few 914s,so,a rigorous r-n-r of the entire fuel system is vital.
Wet spots on the floor,a whiff of fuel,and soggy rubber are the clues.

https://www.aircraftspruce.ca/menus/ap/fuel_line.html
http://www.westmarine.com/fuel-lines
You wouldn't want your 914 to burn.

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