Hardening Gas Hoses

[Jay Laifman]

It seems every few years I'm having gas hoses go brittle and break. I have long known about this, and heard it is caused by today's gas. But it seems to be accelerating. I had it happen about 5 years ago on my 911, and it just happened again! I shudder at the thought of the pictures I've seen of those 911s that have had engine compartment fires over the years.

Are there any hoses that we can use on our cars that are more resistant to this?

This is for my 1973 911.

[NYNick]

Jay,

I went to a Porsche Parade a few years ago and one of the Tech Sessions. The speaker was discussing high end restorations but stressed that when it comes to fuel lines, he throws originality to the wind and only uses expensive fuel injector hose. IIRC it was Goodyear or Continental. I bought 25 feet for my old BMW project, but when checking my 72 911 recently I noticed they had used the same stuff.

I'm not near my garage but a little searching on the interweb I'm sure you'll find it. Try Summitt Racing. Not sure what you've been using but this is the only stuff I would use.

[Jay Laifman]

Ha! FWIW, the last time I got hose I went to the Porsche dealer. I actually didn't do it for "originality" as much as I did it for quality.

I find that yes, Porsche charges a ton more than what other places charge for "OEM" or non-OEM. But, in many cases the difference in quality is noticeable. Sometimes it is just a little more care in filing edges. Sometimes it's hard to tell. But sometimes it is a big difference. So because I bought the car for its quality, I try to keep it that way.

But, here, it seems "quality" may not cover the change in gas.

[NYNick]

Sorry, maybe I put it the wrong way. It's not that my 72 had the 'original' lines in it that were the same as the fuel injector line I had purchased for my BMW. It was that someone had installed fuel injector lines on the 72 for standard fuel hose.

Point being, find the Continental Fuel Injector hose, and try that, unless that is what is already on your car....you don't say what that is other than Porsche OEM.

FWIW, I think it's like $75 for 25 feet.

[Jay Laifman]

I just came across this hose by Gates for modern fuels:

https://www.gates.com/us/en/fluid-power/engine-hose/fuel-line-hose/4219bf-barricade-greenshield-fuel-hose/p/4219-000000-000000

[QueWhy]

Can you get ethanol free gas, or is that illegal too in CA? I live in a fairly small town and have at lest 4 options for ethanol free and it’s not that much more expensive than normal premium.

[Jonny042]

If you'd like to use a more "correct" hose with outer braiding, Belmetric carries a flennor brand multi-fuel hose approved for use up to E85:

https://www.belmetric.com/multifuel-hoseethanol-approved-c-14_662/rhm10braid-flennor-multifuel-hose-10mm-braided-p-9906.html?zenid=u1ap2b4pbqc3lb7p9gn6nn7mf7

PS - Assume you still have MFI on the car, this is what I chose for all the fuel hose in my MFI system, it's rated for 150psi....

[Jay Laifman]

Awesome. But how do they not have 8mm?

[Quicksilver]

People are making this too complicated. You want a Teflon lined hose so it is resistant to everything and the rule of thump is stainless braid reinforcement...
BUT! If you want the visual excitement of stainless braided hose you MUST make sure that the stainless sheathing can't touch anything because vibration will make the stainless grind through anything.
- As far as I'm concerned a much better choice is a stainless braid reinforced hose with a rubber outer sheath that protects the hose and everything around it. Here is a picture of the manifold distribution lines on my Carrera showing hose with an outer sheath...


Just go to any good quality hose shop that makes up custom hydraulic hoses and whatnot. (I used Mesa Hose in Costa Mesa. They guy at the counter recognized the jumble of hoses by sight and said "80s Porsche?"!!!) Any good hose shop can identify the fittings and come up with a much better hose than you will get through an automotive supplier and I was surprised how cheap it was.

[Quicksilver]

Originally Posted by QueWhy

Can you get ethanol free gas, or is that illegal too in CA? I live in a fairly small town and have at lest 4 options for ethanol free and it’s not that much more expensive than normal premium.

Silly question. Everything is illegal in California.

[Jay Laifman]

I was hoping someone would give the right answer to that!

[Jay Laifman]

FWIW, I just contacted Porsche to see if they are supplying their hoses for classic cars that don't get messed up by new gas.

[Litle brother]

Originally Posted by Jay Laifman

FWIW, I just contacted Porsche to see if they are supplying their hoses for classic cars that don't get messed up by new gas.

It’s going to be interesting to hear what they have to say


Sent from my iPhone using Tapatalk

[Trackrash]

Originally Posted by Quicksilver

People are making this too complicated. You want a Teflon lined hose so it is resistant to everything and the rule of thump is stainless braid reinforcement...
BUT! If you want the visual excitement of stainless braided hose you MUST make sure that the stainless sheathing can't touch anything because vibration will make the stainless grind through anything.
- As far as I'm concerned a much better choice is a stainless braid reinforced hose with a rubber outer sheath that protects the hose and everything around it. Here is a picture of the manifold distribution lines on my Carrera showing hose with an outer sheath...


Just go to any good quality hose shop that makes up custom hydraulic hoses and whatnot. (I used Mesa Hose in Costa Mesa. They guy at the counter recognized the jumble of hoses by sight and said "80s Porsche?"!!!) Any good hose shop can identify the fittings and come up with a much better hose than you will get through an automotive supplier and I was surprised how cheap it was.

Aeroquip makes alcohol resistant hose. My last set lasted 20 years.

[Trackrash]

Like this.

[patkeefe]

I just drop a line to BoxsterGT.

[smarens]

Originally Posted by patkeefe

i just drop a line to boxstergt.

+1

[Jonny042]

Originally Posted by Jay Laifman

Awesome. But how do they not have 8mm?

Oops - is 7.5mm close enough? I thought I used 9 or 10. The Cohline hose is rated up to 50% Ethanol:

https://www.belmetric.com/braided-metric-hose-oem-c-14_138/?zenid=a0628d3g5jq9d3ch92bdkg6dg1

[RobTT]

Maybe your hoses are getting too hot?
If so some fibreglass/silicon fire sleeving may be the answer.

[Jonny042]

Originally Posted by Jay Laifman

Awesome. But how do they not have 8mm?

Installing my fuel hoses yesterday, pretty sure they are the Flennor hoses and they are indeed 8mm. So might be worth dropping them a line.