CIS Fuel Line Alternative

[Paulporsche]

While fooling around trying to fit connectors into my broken black nylon line (MCMaster Carr style) I came across another option.

Wurth makes a flexible synthetic rubber fuel hose w/ a woven sleeve. It is 3.2mm ID and 7.0mm OD. Its DIN no is 73379-8. The nylon is 73378. It is rated @ 175PSI, although it is tested @ 360 and has a bursting pressure of 720.

The product number is 895.132.

It may not be quite as sanitary looking as the slim black nylon since it requires hose clamps, but it is considerably easier to work with. Unlike the steel or nylon, it is extremely flexible, similar to the braided covered vacuum lines. The stock connectors work with it. I am currently using it as the control pressure line from the WUR back to the fuel dist.

In Canada it sells for $109 for 10m, or about US$2.40/ft.

FYI/FWIW

[smestas]

Paul,

Where do you order it from?

[Paulporsche]

Smestas,

I can get it here in the Toronto area from their rep or warehouse which is only about 25 mi from me.

In the USA, they have a website

www.wurthusainc.com

I had trouble getting it to work. Thanks to RickM I have a NJ office contact

(201) 825-2710

They may be able to direct you to a left coast office.

[azasadny]

Paul,

Thanks for the info. Here's the link...

http://www.wurthusa.com/en/service/home.php

[HarryD]

Paul,

I applaud your diligence to find an alternative but I have to ask.

When I was trying to repair my leaking nylon line, I considered the same approach using SAE Fuel injection rated hose.

But I got to thinking, the Porsche engineers are not dummies and usually (not always) have a reason for their "weird" selections.

I looked at where they used Nylon vs rubber hose in the CIS and noticed that all non-metal tubing on the high pressure side of the fuel system and downstream of the filter, was nylon tubing. Once the fuel went through a regulator (WUR etc), it became a braided hose or metal line again. Before the filter, it is a braided hose or metal lines as well. Possibly, they were concerned with how rubber hose degrades and did not want rubber particles getting into the fuel distributor or individual injectors. For this reason, I decided to stick with their original design.

Anyway, my $0.02.

[youngkang]

.01 at best.

[Porsche_monkey]

My solution: Steel line outside the car.

[Paulporsche]

Harry,

I think your point is valid. I was concerned about the same thing so when I talked w/ the Wurth rep he told me the hose is actually plastic, not rubber. They refer to it as a synthetic rubber.

On the DIN website they refer to it as fuel hose.

I have noticed that the DIN number is one higher than the nylon line number, which seems encouraging, but I admit I don't know exactly how the specs compare.

IF ANYONE OUT THERE HAS A DIN SPEC SOURCE I WOULD CERTAINLY LIKE TO SEE IF WE CAN DO A COMPARISON OF THE TWO.

I also talked to the folks @ Heimrath Porche who originally sold me some. Thay have been using it on Porsches, and they have worked on thousands of these cars over the years.

As an industrial designer, I am guessing thet the nylon line is used because it has a more sanitary appearance, without the need for hose clamps. Those heat shrunk like fittings sure look cool, and the thin lines rout fairly easily behind the airbox cover.

PBH,

This weekend I had a chance to see another poster's car (thanks, Randy) w/ steel lines. They seem fine, but he did say that they occasionally do get in the way of other tasks in the engine compartment.
I also was looking for something I could use to quickly make a repair and get me going again.

So for now I am using nylon on all lines except the flexible on the control pressure return line. I will try to find out more info and post it when I get some.

Thanks to all who responded.

[Porsche_monkey]

I have a short piece of fuel line with JIC adapters from tubing at the tank end. The other end of the tube ends at the end of the floor pan, goes JIC from the tube to the fuel pump and it's stock from there to the engine.

There is no interference in the engine bay. No chance of a fuel smell in the car. The only downside is you could crush/break it if you bottomed out the floor pan.

PS Paul where did you buy your engine?

[Paulporsche]

PBH,

Thanks for the info. The particular lines I am referring to are in the engine compartment. They are the fuel lines from the fuel distributor to the injectors, and WUR and back.

About 12 yr or so ago, my 77 engine started smoking badly. I heard of a 3 that had been rebuilt and enlarged to 3.2 by Rudy Bartling for a track car for a fellow PCA/UCR member. The engine was put into a 914/6 which was promptly trashed in Corner 2 @ Mosport (big surprise). Herman Lausberg @ Avlanche Motors got the engine from the owner and installed it for me. It has had approx 65000 miles trouble free miles on it. (knock knock). The ignition is via an S distributor and has no emission control system.

[Porsche_monkey]

Jealous. Very jealous.

[oneblueyedog]

I remember seeing white nylon injector lines in a photo on a Porsche racer (917?).

I had a kinked and abraded WUR to Fuel Distributor line. It was a Sunday. I wanted to try and fix it. I went to HDepot and got some Nylon tubing nearly the same size.

I boiled the ends and notched a pair of common pliers. I heated the fittings with a heat gun and then quickly grabbed the hot boiled end if the Nylon tube with the pliers. I then pressed the nylon tube on the fitting end. I had the fitting in a soft jawed vice.

You have only a few seconds to press it on, but it worked and has been leak free for 6 years. It looks very 917 too.

[Paulporsche]

Oneblueyedog,

I now have some of the black nylon from McMaster. I was discouraged by either JW or Wayne (can't remember which) and HarryD who said that the hot water technique was still very difficult to get right. My friendly mechanic tried w/ a heat gun w/ poor results. So far my flexible textile braided fuel hose is fine, but I'm going to try my hand @ the heat shrink method. I'm glad to hear your HD hose did the trick.

PBH,

To quote the King, "Thank you...thank you very much." The engine is extremely tractable and uncammy. Works well in town @ low speed and on the highway. Pickup @ highway speeds in 5th is VERY good. A friend and I went to Mosport last month for the ALMS races. He couldn't believe how smooth the thing was, especially for a 28 yo car.

Where are you located? Are you in PCA?

[HarryD]

Originally posted by oneblueyedog
I remember seeing white nylon injector lines in a photo on a Porsche racer (917?).

I had a kinked and abraded WUR to Fuel Distributor line. It was a Sunday. I wanted to try and fix it. I went to HDepot and got some Nylon tubing nearly the same size.

I boiled the ends and notched a pair of common pliers. I heated the fittings with a heat gun and then quickly grabbed the hot boiled end if the Nylon tube with the pliers. I then pressed the nylon tube on the fitting end. I had the fitting in a soft jawed vice.

You have only a few seconds to press it on, but it worked and has been leak free for 6 years. It looks very 917 too.

White ones are also available from McMaster.

[Porsche_monkey]

I'm very close to the airport. Yes I am in the PCA.

[Paulporsche]

PBH,

You have a PM