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914World.com _ 914World Garage _ Plastic vs SS Fuel lines

Posted by: billd Aug 11 2005, 12:15 PM

I'm starting my conversion back to EFI and noticed that the plastic fuel lines running through the tunnel are not in bad shape. I'm tempted to use them as is. Anyone on the board have experience with the longevity of these plastic lines? If they are an accident waiting to happen, I'll replace them with SS.

Posted by: jet1 Aug 11 2005, 12:22 PM

Mine don't look to be in bad shape, but I plan on replacing them just to be safe. All the 914 I have had in the past have had problems with the fuel lines.

Posted by: Travis Neff Aug 11 2005, 12:22 PM

I would say where those old lines are most fragile is where they exit the cabin and turn into the engine bay. I had another car which had a facet fuel pump hooked directly into the plastic lines and when I removed the pump the plastic shattered - that was a fun experience with a full tank of gas.

I just replaced mine as I moved my fuel pump up front and it seemed like a good time to do so. I used 5/16 brake line in 60" lengths. The hardest part was making the lines inside the engine compartment lots of bends - so I got some extra tube for mock up first.

Posted by: tat2dphreak Aug 11 2005, 12:25 PM

I replaced mine while the engine was out, just for peace of mind... I went with aluminum lines... very easy.

Posted by: URY914 Aug 11 2005, 12:30 PM

I replaced mine with aluminum lines.

I also took the plastic lines and tried to get them to crack. Bent them, squeezed them in a vice and twisted them with pliers. No cracks.

I'm thinking I should have let the plastic ones in.

P

Posted by: scott thacher Aug 11 2005, 12:37 PM

but paul the AL are lighter

Posted by: tat2dphreak Aug 11 2005, 12:37 PM

QUOTE (URY914 @ Aug 11 2005, 01:30 PM)
I replaced mine with aluminum lines.

I also took the plastic lines and tried to get them to crack. Bent them, squeezed them in a vice and twisted them with pliers. No cracks.

I'm thinking I should have let the plastic ones in.

P

mine were the same way URY.... the bastards looked new! just dirty on the engine end... oh well... better to know now though...

any issue with aluminum lines cracking?!

Posted by: Travis Neff Aug 11 2005, 12:48 PM

The ones I just replaced were in great shape and I could have left them be. On my other car, the tunnel portion of the lines were great, but once it entered the engine bay they were fragile and did shatter.

Posted by: Lou W Aug 11 2005, 01:11 PM

Fine through the tunnel, then practically fell apart in the engine compartment. Im replacing mine, cheap insurance.

Posted by: tat2dphreak Aug 11 2005, 01:14 PM

QUOTE (Lou W @ Aug 11 2005, 02:11 PM)

Fine through the tunnel, then practically fell apart in the engine compartment. Im replacing mine, cheap insurance.

very cheap... I bout 25 feet of aluminum 3/8" line for $19 and 10 nice padded clamps for $7 or something... damn good deal!

Posted by: bondo Aug 11 2005, 01:18 PM

QUOTE (tat2dphreak @ Aug 11 2005, 11:37 AM)

any issue with aluminum lines cracking?!

I used an aluminum return line when I put FI in my Mustang. No cracks, but there was a spot where it could rub on a parking brake cable, and it was starting to wear a groove in it. The aluminum is really soft, and I suspect that wear is the biggest danger.

Posted by: zymurgist Aug 11 2005, 01:50 PM

I'm getting ready to put 3/8" steel brake lines in Babydoll for both lines, with brass flare elbows where the lines enter the engine compartment. Seemed like the most hassle-free installation that I could think of.

Posted by: tat2dphreak Aug 11 2005, 01:59 PM

QUOTE (bondo @ Aug 11 2005, 02:18 PM)

QUOTE (tat2dphreak @ Aug 11 2005, 11:37 AM)

any issue with aluminum lines cracking?!

I used an aluminum return line when I put FI in my Mustang. No cracks, but there was a spot where it could rub on a parking brake cable, and it was starting to wear a groove in it. The aluminum is really soft, and I suspect that wear is the biggest danger.

I thought the same thing, so I put homemade grommets whereever it would rub...

Posted by: billd Aug 11 2005, 02:15 PM

Sounds like its good insurance to go ahead and replace the lines. How hard is this to do with the engine in place? I imagine that makes bending the line along the firewall and up through the tin even harder.

Also, do folks recommend using a single piece or using two pieces with an AN elbow fitting at the firewall. A single piece is less likely to leak, but harder to bend into shape.

Posted by: Travis Neff Aug 11 2005, 02:20 PM

I was able to use a 60" length through the tunnel and make a 2" and a 3" bend into the engine compartment two short hi-pressure hose connections into the compartment lines - so I didn't need to do elbows and such, less likely to leak from what I understand.

Posted by: tat2dphreak Aug 11 2005, 02:23 PM

QUOTE (billd @ Aug 11 2005, 03:15 PM)
Sounds like its good insurance to go ahead and replace the lines. How hard is this to do with the engine in place? I imagine that makes bending the line along the firewall and up through the tin even harder.

Also, do folks recommend using a single piece or using two pieces with an AN elbow fitting at the firewall. A single piece is less likely to leak, but harder to bend into shape.

I did a single piece... not that bad, but no engine in the way... it would be hard, but possible with the engine in place... just have it jacked up enough and it can be done, just not going to be fun.

Posted by: Travis Neff Aug 11 2005, 02:41 PM

You can do it with the engine in the car, a little more of a pain to do, but putting the line through the tunnel is not much of a problem.

Posted by: lapuwali Aug 11 2005, 03:15 PM

You guys really need to click that 914 Info button at the top sometime. There's a tech article on this very subject, complete with lots of pictures.

My two cents on replacement, if you're planning on doing an EFI retrofit, absolutely replace them if you're going to be putting the high-pressure pump up front. Nothing like old plastic and high fuel pressure to start a nice fire.