Fuel Line Bullet Dodge

[Paulporsche]

I've been using this braided fuel hose as the return line from the WUR to the FD for at least 10 years. It's a Wurth product, rated for something like 175 PSI, that I got from Stieg @ HP Cars (formerly Heimrath Porsche). He said they used it for fuel lines for all existing models.

Last Friday I went out to the garage to check tire pressures prior to a trip planned for Saturday. I started the engine, just to see if everything seemed OK. When I shut it down, I smelled gas. Opening up the lid I checked around the WUR and FD but found no wet areas, but the smell remained. When I checked around the back of the FD I found wetness and this break in the hose, right where it was clamped to the fitting.

I was able to cut the line, wrap some vinyl around the end to provide some stress relief, and reattach it. I've also altered the routing of it to try to further relieve the stress. I've run the engine since and everything seems fine.

Glad I found this in my garage rather than on the road!

BTW in the pic I'm expanding the hole somewhat to make it more visible, but it was definitely big enough to leak.

[dap930]

If there is ethanol in your fuels then this is going to happen as time goes on. I would replace the hose again. Currently no one makes ethanol compatible braided fuel hose. I have been researching manufactures with on luck.

[BoxsterGT]

I offer Braided SS Metric Hose that is E-85 rated........



Dennis- If you email me I will send you info on E-85 rated Braided SS Hose for your 930.

Paul- Can you tell us the model year of your SC and a bit more about the braided hose made by Bosch and purchased from the dealer? How is this hose retained on the original CIS fittings?

Polyamide tube is the factory material of choice for CIS. Polyamide tube is E-85 safe, and is the fuel system material most used world wide by Auto Mfgs today.

The fittings used with Polyamide tube are NOT the correct ones to use with Hose. The barbs for hose and tube are quite different.

Clearly, what you show is Hose. Only recently has Porsche started using E-85 rated Hose for their replacement fuel lines. It likely you have the old material and not E-85 rated.

Hope this helps.

Len

[3rd_gear_Ted]

35 to 40 year old fuel lines of whatever material is the weak link in the chain.
Blissful Porsche originality is potentially catastrophic.

If you adhere to RBM (reliability based maintenance) logic as Boeing and Airbus do, just by virtue of the age of the part versus the risk of failure, a replacement plan for said hoses is a prudent thing to do.

[Paulporsche]

Thanks guys. I'm almost certain the break was caused by stress, rather than ethanol, but I may replace the line, just to be safe.

Len,

I have the black plastic lines, rather than the metal SC ones. I'll email you.

[turbobrat930]

Originally Posted by dap930

If there is ethanol in your fuels then this is going to happen as time goes on. I would replace the hose again. Currently no one makes ethanol compatible braided fuel hose. I have been researching manufactures with on luck.

Here, I will help you on your research... HEHE... Any PTFE lined hose will be ethanol compliant...

https://www.summitracing.com/search/department/fittings-hoses/part-type/an-hose/ptfe-lined/yes?SortBy=Default&SortOrder=Ascending&N=4294951003%2B4294924175%2B4294924170%2B429492073 1%2B4294865045

[DanielDudley]

Originally Posted by Paulporsche

Thanks guys. I'm almost certain the break was caused by stress, rather than ethanol.

I think it is a bit of both from how it looks.

[Paulporsche]

Thanks turborat and Daniel. I'm looking into replacement.

[BoxsterGT]

The CIS system up until Model Year 1979 uses Polyamide Lines for most of its component fuel transfer.

This is a typical FD to WUR line............



and uses M10 and M12 Female tube fittings, NOT hose fittings.

The connection is a mechanical one with assembly tools required. Any hose clamp or strap clamp is not adequate for the high pressures of CIS.

Len

[Paulporsche]

I found an old thread of mine on this forum from 2004, which is when I replaced that line. It is Wurth 895.132, 3.2mm ID, 7 mm OD. It is DIN 73379-8. It is rated at 175 lb. I have seen on the web that it is suitable for use with E85 fuel, which is far beyond the 10 or 15% we use. I am contacting Wurth to see if they can verify this.

Regarding the connectors, isn't this particular return line under significantly lower pressure than the 5 bar of our system? The people at Heimrath told me at the time that I didn't even need a clamp in that application (!). I used them for my own peace of mind. I've had this setup for 13 years, which is something over 40,000 miles.

BTW I am in contact with Len about this, and I may just go for one of his lines, again, just to be sure.

[BoxsterGT]

This is not the return line, unless we are speaking of different lines. This line sees the fuel pressures that control the mixture.

It is where the Fuel Pressure tester is hooked up, so the entire pressure range shows here.

The actual return line is low pressure and does not need crimps but the factory still does use clamps. I don't think they ever used "none".

Len

[Paulporsche]

I have heard back from Wurth and they don't recommend this for fuel lines. Funny, this contradicts what the dealer and Wurth told me back in '04, and I've been using it so long!

Anyway, I'm in touch with Len. I just have to see if he has the appropriate fittings for my setup, which currently appears to be using banjo fittings for this line at both the WUR and the FD.

[BoxsterGT]

There are lots of combinations possible, and a 1980 SC had steel fuel lines originally, so you or someone has changed it along the way.

Show me what is needed and I will make it......




Len

[david.avrahami@]

I serviced my car 20 years ago with Heimrath on lawrence avenue. when he sold his business and retired, He warned me that the new owners "do not know what they are doing".
Since then I only used Mike Gohn, Heimrath mechanic who is probably the best Porsche air cooled mechanic in the GTA...905-392.7244

[Paulporsche]

Thanks David. Yes, there was a lot of bad blood between the old and new owners. I bought the line in 2004. Not sure if it was Heimrath of HP at that point. I'll look into Mike.

Len, the line looks like this illustration. See yellow line, ignore red dot. Porsche AG calls it PN 93011051300. I would need the line, the banjo fittings at each of the 2 ends and the 4 washers. I have the hollow bolts. I think the banjos on the 2 ends are the same size, since the washers are all numbered 73, and the bolts, 72.

BTW is this in fact a return line? Does anyone know what fuel pressure runs through it?

[BoxsterGT]

Most WURs have a 10mm thread and the FDs have a 12mm thread. I have the correct Banjos and bolts and copper crush rings for both.
Now all I need is the tube length you want?
And, yes your bro can come over to pick it up. It will be done tonight pending length info.
It is $45 as discussed earlier.
Len
PS - This should connect at the top of the FD at adapter #71, not the side.

[Paulporsche]

I really appreciate all the help, Len. I have put a socket over the heads of the 2 banjo bolts. The same 12mm socket fits snugly on both the HEADS of the bolts. I don't know what size that makes them, but 12mm fits both the heads. Perhaps you could verify this size by comparing to your bolts?

Also, I don't have a top rear port on my FD. The back side of that top port on mine is completely solid. It has no ports. As with my WUR the system must have been cobbled together when the mods were done. The only area able to accept the far end of this line is at the back. I think it is the second port from the right as seen from above.

A 52" line, plus ends should be sufficient. And you might as well supply the bolts too. Let me know how much more these will be.

I have a call in to my brother. If you email me your phone number, he will call you to arrange when he can come by.

Thanks again.

['76 911S 3.0]

Barricade® Fuel Injection Hose (MPI) | Gates Corporation

[Paulporsche]

Seem like a viable alternative for lines, Jason. Any recommendation for clamps/connectors? Was there a spec for sizes?

[Paulporsche]

Success! I received Len's line yesterday afternoon and installed it this morning. It fit fine and appears to be leak free. Ol' Yeller rides again!

Thanks to Len for putting up with my unusual requirements regarding fittings and sizing, and for his quick service.