944 Fuel lines and safety help

[GTR34]

Hello guys,

It came to my attention today to go out and inspect my engine bay fuel lines after a terrible dream that my 944 had a catastrophic engine bay fire. Here are some photos - the lines look okay to me, nothing wet at the ends. I am aware of the jumper line recall and I am beginning to consider the replacement of the engine bay fuel lines for something more reliable. There's just one thing that is worrying me, though - the condition of the steel lines coming from the hole in the fender well. Are these still alright? They look pretty corroded or something of the sort. Any recommendations as to what I should do?

[GTR34]

Come to think of it, weren't the original lines suppose to have a globe seal type connector at the end of the steel lines that had to be cut off? Have my fuel lines been replaced at some point?

[djnolan]

Those hard lines look suspicious and you need to clean them off and see if they are corroding. And some of the clamps are not proper fuel line clamps. The clamp in the 1st picture is ok but the 3rd picture does not show a proper fuel line clamp.

A lot of the older cars had what is known as a single barb fuel line system with aluminum crimp collars. This is the most basic type of system there is.

Later cars had a combination of triple barb and threaded couplers and these have a higher performance/pressure rating and higher safety margin.

A couple of weeks ago there was a good flame-fest going on on pelican about how to deal with single barb systems. If you replace those lines with the latest fuel line hoses and can use crimp collars to seal them you are doing well.

However if you don't have access to a crimp tool and collars (and who even knows what one looks like?) you could use either single or double fuel line clamps (new) like you have. Use two clamps behind the barb in case one clamp breaks. Accordingly there is a Porsche TSB that states it is ok to use fuel line clamps to replace the crimp collars. (haven't seen it posted) Accordingly clamps are good up to 50psi, in other words non-racing applications. (someone please verify this)

Whatever you do check it often and make sure the clamps stay tight.

For the short fuel line jumper you can buy a replacement with crimp collars rather than trying to bend the hose and use clamps.

[GTR34]

Interesting, would you recommend cutting the fuel lines shorter and using braided lines and threaded connectors like many do? I hear there's a lot of controversy over them but several guys use them in their race cars and have no problems. Those hard lines are just bugging me. To put it this way, am I safe to drive it to and from school? I just picked up a fire extinguisher today and it's now behind my passenger side seat if anything happens. For now would it be wise to use a proper fuel line clamp or just go with something higher pressure, modifying the system? I am a bit fearful of using hose clamps again. I really don't want a car-b-q.

[GTR34]

Here's my situation. This is a safety thing so I don't want to skimp on cash and roast my car. What is the absolute best method besides trying to find crimps and a tool to crimp the connectors? Or is that the best way by far? This is a tutorial that I've found:

http://www.944online.com/pdf/SSfuellineinstall.pdf

[Techno Duck]

I am not crazy about those hose clamps on the high pressure line.

I recommend replacing those lines completely. Lindsey Racing makes a nice kit that uses a proper compression fitting to eliminate any clamps on the high pressure line. The return line still uses a clamp on the regulator which is fine.

FUEL LINES 944T / 944 at LINDSEY RACING - Your Porsche Performance Parts Center

You use a small tubing cutter and cut the hard lines inside the wheel well, then put the compression fitting / ferrules on so your connection point is inside the wheel well and away from the exhaust. This can all be done with basic hand tools. The other nice thing about this is you will remove that section of hardline that looks fairly beat up.

Remove the passenger side fender liner and trace back the hard line back along the frame rail to see how it looks.

I would replace the jumper line between the rail and damper aswell if you are unsure of the history of it.

[Rasta Monsta]

FWIW, Rennbay also has a nice kit that covers this repair.

[CHICKS]

Products

It's a nice kit, a lot of us have it.

[Bukowski]

What about the rest of the fuel lines - e.g. along the car underside, leading to the tank, etc.

[djnolan]

Originally Posted by CHICKS

Products

It's a nice kit, a lot of us have it.

For any number of reasons I would not try this repair at home if you don't have the proper experience. What does a Porsche shop charge for this conversion/installation?

To me it seems kind of radical to cut the hardlines and install compression couplings.
I once had some trouble with compression couplings on a water line so I wasn't about to try them on a fuel system. Needless to say I didn't want to see my house, car or neighborhood go up in flames.

[GTR34]

Well Bukowski, I think the most imminent threat here is the questionable lines that pass right over top of 400+ degree F cast iron But of course, those should be inspected as well. Djnolan, I do see your point. However, hose clamps have their downside. I am slightly swayed because the braided lines can withstand higher pressure and of course look quite good, but... concerning safety, your opinion is highly valued as well. I never thought there would be so much controversy! Any other inputs, guys?

[djnolan]

You sound like a smart young man. The optimum repair for someone with access to a shop and mechanical expertise may not be the best repair for a DIY'er.

I am dismayed there is not a kit sold that uses high quality lines and clamps but does not require cutting the hard lines.

http://forums.pelicanparts.com/8245848-post49.html

[GTR34]

That's actually quite interesting. I'll have to wire brush my fuel lines tomorrow to see if they are alright or not. In the case of hose clamps, I suppose using two as a safety measure would work fine as well. Is there a standard hose that I could purchase and cut to length?

[Rasta Monsta]

Originally Posted by djnolan

For any number of reasons I would not try this repair at home if you don't have the proper experience. What does a Porsche shop charge for this conversion/installation?

To me it seems kind of radical to cut the hardlines and install compression couplings.

Radical? Not in the least. My race car has had this setup for many years, no sign of leakage.

Porsche shop? They'd charge the value of the car to replace the whole assemblies all the way back.

[Rasta Monsta]

Originally Posted by GTR34

I'l have to wire brush my fuel lines tomorrow to see if they are alright or not

Please don't. If you grind off the green coating, the lines will rust and fail.

[Techno Duck]

There is no reason to fear cutting the hard line. A compression fitting is exponentially better than a hose slipped over a barb with a clamp. This is even more true because the Porsche hardlines are metric sized, not SAE so unless you find a metric fuel hose its not a proper fit. Try squeezing SAE sized Aeroquip hose over barb... its really tough and ends up bulging the hose. The very early version of the Rennbay fuel hoses that came out years ago were setup like this and its not really a great fix.

The other major advantage of this is you move your potential leak source into the fender well rather than right over the exhaust manifold. But like i said, a compression fitting wont leak if done correctly (Which is easy to do).

Compression fittings are ferrules are used all the time for hydraulic tubing which sees far higher pressure than our fuel systems ever will. And take it from me, i work with this stuff every day.

[djnolan]

Edit: TechnoDuck, I didn't read your post before posting where it says cutting the hardline is not needed. Please elaborate on what kit to buy, etc....

The kits on Renbay, etc look like they were designed by a professional. However they may not be appropriate for the average weekender to install. I can only speculate on what might go wrong, especially with 30 year old hardlines.

I can also say I delayed for a year on replacing my fuel lines while deliberating on cutting the hardlines or not, and finding an alternative answer.

Just as the young gent who started this thread is probably going to do.

If there had been a kit available that used clamps I would have replaced them right away as he probably would have done.

[Techno Duck]

The hardline is required to be cut on all of these kits that use compression fittings; both the one from LR and Rennbay.

Hose clamps on the high pressure fuel line is not the way to go; especially with hose that is not the correct ID for the hard lines... regardless if it seems easier for the at home weekend mechanic to do with hose clamps. Like i said, the compression fittings only need a small tubing cutter and wrenches to do the install. If you dont feel comfortable doing this, bring it to a shop and have them install it.

[GTR34]

Good stuff, guys. I haven't wire brushed them yet so thanks for the heads up, I should have known they are coated. I'm considering pulling the inner fender liner to inspect the fuel lines and see if they're corroded or not. I'm swayed towards the compression fitting, however I will not install them if I don't know exactly what to look for. Anything you can tell me about this compression fitting method will be of use and I'll decide which I would like to do. I'm a bit partial to the 944online kit because it comes with both hoses and a jumper. In this case, I'd plan to use a heat insulation material around the lines and bag them with an aluminum head reflector covering like the one in this arrnworx tutorial

944 Fuel Lines : ArnnWorx Specialty Tools

Maybe a bit overkill but you can never be too safe. I think I'll inspect the hard lines this weekend (week is busy as heck)

[Rasta Monsta]

Originally Posted by GTR34

I will not install them if I don't know exactly what to look for.

You're looking for cracked, stiff or brittle rubber sections between the body and the fuel rail, and seeping crimps where rubber meets metal hardline.

It ain't rocket science. If your hoses are factory, it is good maintenance practice to renew them with one of the kits we have been discussing, regardless of what you might think after visual inspection. Also check the short "jumper" line at the front of the rail. . .subject to recall on some cars.