Plastic Tunnel Fuel Lines, I want to replace the 2 tunnel fuel lines in my 76 - 914 Options

[mepstein]

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???

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.

[matchpoint]

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

[JeffBowlsby]

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.

[mbseto]

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

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

[JFJ914]

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???

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?

[matchpoint]

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???

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?

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.

[oakdalecurtis]

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!!!!

[porschetub]

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???

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?

(IMG:style_emoticons/default/agree.gif) 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.

[914_teener]

(IMG:style_emoticons/default/agree.gif)

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.

[veekry9]

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. (IMG:style_emoticons/default/blink.gif) (IMG:style_emoticons/default/unsure.gif)

https://www.aircraftspruce.ca/menus/ap/fuel_line.html
http://www.westmarine.com/fuel-lines
You wouldn't want your 914 to burn.
(IMG:style_emoticons/default/dry.gif)
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