Rubber Fuel Hose

[RWebb]

I thought this might be a subject of general applicability, so I'm putting it in OT.

Flexible Fuel Hoses need to be replaced periodically in old cars (just like rubber brake hoses), but I'm not sure how often...

Other factors are whether the fuel hose is rated for the newer fuels (which contain Et-OH, ethanol) and the pressure they have to withstand. All these factors are things that the guys who work in auto parts houses seem NOT to understand (along with what clamps to use, but I'll get to that later).

I bought a VW Vanagon a couple of years ago (Slow Going), and this vehicle seems unusually susceptible to engine fires. I'm not sure if the risk of an engine fire in an old 911 is just as high, but my '73 DOES have the stupid design of putting the fuel lines near all the electronics -- like the high voltage sparkin' machine to make the spark plugs explode the fuel...

So, I've been trying to figure out what fuel lines to put on der Vanergon. One thing seems consistently and insistently mentioned on VW Vanagon forums is to use a rubber hose that is rated for Et-OH fuels. SAE has a spec for that: SAE J30R9.

AutoZone claims that they have FI hose from Goodyear rated J30R9, so I went there (actually I went there 3 times, and also went all over this town to every LAPS - and now believe that none of them is my FLAPS). I finally got the robotized humanoids at Autozone to find their hose, and it was not Goodyear.

Their hose DOES have SAE J30R9 stamped on it, but says the brand is "ArmorMark" and that it is made in Thailand. It also says WP 6.9 bar (not sure what WP means, but I assume it is rated to 6.9 bar, which just happens to be approximately
5,175 torr {or a tad over 100 psi fer y'all Anglais system folks}).

Now, people have posted on der Samba Vanagon forum about the Et-OH compatible hose having an internal liner (which used to be blue then changed to a black color). I cut this hose open and it does NOT have a liner, even a black one.

So, I thought I would post this to see what people here thought. Maybe someone on here is an expert in fuel hoses...

[EarlyPorsche]

I've been thinking about putting fresh lines on my 03 cub cadet since it looks cracked. I think I will look at a supply house like grainier for made in USA line. It will be expensive but I'd feel safer with an American made fuel line over Thailand and the like.

[RWebb]

ArmorMark also makes fan belts and coolant hoses. Not clear on who really owns this brand, or if I can trust the quality, as I don't find it in the Thomas Registry, in Wiki or by just a plain ol' Goggle search.

[A930Rocket]

Good question. I replaced every bit of rubber hose on my 318is after I bought last spring, spending $450-500 fir all. A lot of it was cracked, but I feel better driving it now.

[Dan J]

Randy,
This is a big problem in the auto service and motorsport world
(I own a shop in Ct) Bottom line is if it doesn't have a teflon liner I wouldn't use it
it will rot. No OEM is using rubber hose most haven't since the mid 90's
Try the biggest LAP in town or see if Goodyear can direct you to a dealer
I wouldn't trust any of that offshore crap in my experience whatever is printed on it doesn't have anything to do with the product. I don't know how they get away with it I guess lax enforcement

[RWebb]

teflon liner or viton??

[wdfifteen]

Originally Posted by RWebb

It also says WP 6.9 bar (not sure what WP means, but I assume it is rated to 6.9 bar, which just happens to be approximately
5,175 torr {or a tad over 100 psi fer y'all Anglais system folks}).

Now, people have posted on der Samba Vanagon forum about the Et-OH compatible hose having an internal liner (which used to be blue then changed to a black color). I cut this hose open and it does NOT have a liner, even a black one.

So, I thought I would post this to see what people here thought. Maybe someone on here is an expert in fuel hoses...

WP = Working Pressure
Our tech editor did a piece on fuel hoses and it is on my desk now. He discusses working pressure, maximum pressure, permeability, and chemical resistance of the various fuel lines available. I'll post the info when I get to the office tomorrow.

[porsche4life]

We use goodyear hose on all of our stuff. Seems to hold up the best. Always a pain in the ass to get. Dad just keeps a 25ft roll of the common sizes in the shop. Order online when its empty...

And yes, we do have that many motorized things...

[wdfifteen]

Originally Posted by RWebb

Patrick - any info yet?

Crap. Sorry. I forgot. Tomorrow. I promise.

[VINMAN]

All the fuel lines on my Polaris PWC were ruined. The pickup lines in the tank literally disintegrated. ( stranding me out on the water....) the rubber diaphragms in the carbs fell apart later on. All the replacement hoses and rubber parts I put in are some type of silicone derivative that is supposed to be ethanol resistant.

[BoxsterGT]

I can offer any diameter & length you may need of the latest Multi-fuel hose from Cohline in Germany.

I make up custom fuel & oil hoses & lines for the early Porsche models and keep just about every fitting that may be used on a Porsche in stock.

Also keep in stock Metric braided SS for those who desire bling...........





Len at Autosportengineering dot com


PS- Note for RWebb - perhaps you might also like to know............, I make a permanent Fuel Tank Vent Fix kit for those of us who own Vanagons and are paranoid about fuel tank grommet leaks.

[URY914]

I get my low pressure hose from a marine supply house. They are made to withstand UV and other bad stuff.

[Porsche-O-Phile]

I'm 99.9% that ethanol crap (and what it does/did to rubber lines) is directly responsible for my 951 going up in a blaze of glory a few years ago. And I actually checked/inspected the fuel lines fairly regularly (no external splitting, dry rot, visible damage, etc. God knows what the insides looked like but I have my suspicions...

[porsche4life]

Jeff, your car is why I replaced my lines, and avoid etoh like the plague.

[widebody911]

I just replaced the fuel pump on my '77 911, which caused the fuel line to crack. ^$!&%!&%^&)!^(!

The fuel line I've been getting for my ACVW's only seems to last a couple of years before disintegrating.

[wdfifteen]

Our tech writer did a piece on this. I finally remembered to dig it up. Here are his pertinent comments:

"Gates Corp. warns that all rubber products have a limited life on a given application. Service life can be adversely affected by:
* External abuse, such as kinking, crushing, abrasion, or high-end pull
* High pressure or high-surge pressure
* Exposure to higher-than-rated temperatures
Fuel hose has three standards: SAE 30R7 for low pressure, SAE 30R9 for high fuel-injection pressure, and SAE 30R10, for fuel line that is submerged inside a tank.
According to Gates Corp., at times, more aggressive fuels can extract the oils that give SAE 30R7 hose its flexibility. The result is a brittle, stiff tube that will greatly reduce the performance and service life of the hose.
Fuel-injection hose is designed for low-permeation contact with a wide variety of alcohols, alcohol fuel blends, and diesel fuel. Gates SAE 30R9 hose uses a laminated tube of fluoroelastomer as a thin-wall inner layer backed by traditional compounds. This first layer protects the rest of the hose from attack, swelling, or permeation from aromatics, oxidized gasoline (as can occur in fuel-injection systems), ethanol, oxygenate additives, and a wide range of petroleum-based products.
The laminated tube will resist cracking caused by “sour gas,” which forms when unused gas is returned to the fuel tank. As an added benefit, this hose construction reduces emissions because fuel can’t evaporate through the hose walls.
Therefore, Gates engineers assert that the best choice for automotive fuel line hose applications today is fuel-injection SAE 30R9 hose. For installers, it is the best choice for reduced comebacks and for high-performance, assured trouble-free service in a changing fuel environment.
Points to Consider
Gates Corp. says in systems with a return line to the tank, fuel can go sour quickly from exposure to engine heat. Even if we don’t have a fuel return line, we shut down a truck engine and then leave it for a week or month. The engine heat starts gumming, or souring, or oxidizing—whatever you want to call it—and it has a lot of time to deteriorate because the vehicle is not a daily driver. Maybe the next time that we start the vehicle, we’re feeding the worst gas in the system into the carburetor. Using STA-BIL year round may help in this scenario.
The other standard, SAE 30R10, is for fuel line that is submerged inside a tank. It has barrier material on both the outside and inside and is made for high fuel-injection pressure..
I checked three lengths of fuel hose in my shop. All were 30R7—the cheap stuff. When it’s time to reorder, I’ll look into 30R9.

[RWebb]

Thanks, Patrick!

Jeff - it is critical to inspect the interior of the hoses where the clamps ... ah... clamp. Every hose I pulled on the VW (about 12 or so ends) had cracking right there (and nowhere else). I'll try to take and post some pics when I get a chance.

[RWebb]

This shows how every hose looked after I removed them from my Vanagon, about 20 hose ends. Note that the end of the hose (where the clamp compresses the rubber) is chock full of splits. There is no discernible damage in the middle of the hose, despite being run on a 10% Et-OH mix for many years (in Oregon).




Like every other rubber component on the car, fuel hoses need to be replaced periodically.

[RWebb]

Here is the latest controversy on [Vanagon] rubber fuel hoses:

The only rubber hose anyone can find that is Et-OH rated (J30R9, or even the R7) is sized at 5/16" I.D.

That means that it is almost 1 mm larger ID than the OEM hose, which was 7 mm.

So, there is discussion re what to do -- i.e. is a larger ID hose that is Ethanol rated better than older material hose that matches the OEM I.D.??

Certainly, rubber is flexible -- I wonder if the additional crush from clamps will accelerate cracking and hence fuel leakage at the ends of the 5/16" hose ??

I thought I'd post it here because of the high engineer density on the Pelican Porsche forms. As lendaddy noted on another thread The Samba is pretty scattered.

[BoxsterGT]

I can get 7.0mm x 12.0mm fuel hose from Germany, as well as the usual 7.5 x 12.5 that I have in stock. I will ask in the am for a product sheet on this to see what it will handle for the latest mix of fuels and post what I learn.

Len