Fuel line replacement lessons learned., Replacing Fuel Lines in 914 Options

[jperret]

Fuel line replacement lessons learned.

My son and I replace the fuel lines in our 73 2.0. We used 3/8 inch thin-walled aluminum. We tied a cord to the old lines when we pulled them out and use the cord to steer the new lines into place. We pushed the new lines in from the rear of the car. Using the string and guiding things by hand using the access ports in the center tunnel were all that was needed. The diagram I found on the site of the tunnel cut open was really helpful. Finished with a few restarts in about ½ hours.

Lesson learned: Don’t try to attach a wire (we wanted to run a +12 battery line up front for a future headlight upgrade) to one of the lines as you pull it through. The wire get chapped. We just used another string and pulled another one through its own access holes.

Bending the lines at the rear of the car was a bit tricky. This is the end with the most bends and the most pipe in the way. As the lines exit the rear passenger compartment they must make a right angle bend. There is not enough room to do this correctly.

Lesson learned: Use a fitting here. 90 degree bends in this tight space with a lot of tubing in the way (to minimize the number of joints) is not easy. I crimped the tubing, so I had to put in the elbows. I did not have room to flare the ends so I used a 3/8 inch ferrule bead elbow.

The rest of the bends went well; we were able to make a neat installation with minimum number of connections.

Now comes the fun! We installed a fuel pressure gauge.

This diagram was also very helpful.



Lesson learned: The fuel pressure guage and this diagram are invaluable for trouble shooting tools and worth the money. I plan to just install it permanently.

The pressure was too high. We bypassed the fuel pressure regulator and the pressure was still too high. So it had to be a blockage in the return line. Before this along the way we tried switching the lines out of the gas tank (dumb move).

Lesson learned: On the ‘73 the line that comes out of the bottom of the tank, closest to the front of the car is the RETURN. This has a tube that goes into the bottom of the tank, and it’s outlet is very close to the bottom. The SUPPLY line is the one towards the rear of the car and it goes further into the tank so it does not suck gunk from the bottom.

Well you guessed it! When we switched the lines as part of “try anything” phase of our trouble shooting we sucked gunk in to the nozzle of the gas tank pick up. We tried to blow it out with no luck, so we had to take it apart at the gas tank.We cleaned it out and it all worked great!

Now that we have done one, I could do it again in less than 1/2 day.

[914helo]

Thanks for the lessons learned. (IMG:style_emoticons/default/smile.gif) There's always someone who is going to undertake this soon (like me).

[PinetreePorsche]

Guys, a Q: I've got dual Webers, so run at much lower fuel pressure. I don't know if a po ever re-did the fuel line, but am I not much less at risk of fire with the low-pressure system? -Chris

[So.Cal.914]

If you have no leaks now... Yes.

[Cap'n Krusty]

Not to rain on your parade, but thin wall aluminum tubing is just about the last thing I'd use for fuel line in an automotive, boat, or aircraft application. The Cap'n

[firstknight13]

(IMG:style_emoticons/default/agree.gif) (IMG:style_emoticons/default/biggrin.gif) chris foley has stainless steel lines available for sale in the club........ i am not afilliated with him but he is the " MAN" (IMG:style_emoticons/default/biggrin.gif)

[ChicagoChris]

Got to go with the captain on this one. (IMG:style_emoticons/default/agree.gif)

You are going to have some measure of galvanic corrosion. That is dissimilar metals tend to corrode each other. Lots of things effect the rate it corrodes mostly moisture and salt content. (even if you never drive in the rain the moisture in the air is enough)

You should, if you havent already, isolate the tubing from the steel and you will be ok. (IMG:style_emoticons/default/piratenanner.gif)

party on.

[tracks914]

There is a reason the automotive industry won't use aluminum for this type of application.

[highways]

(IMG:style_emoticons/default/popcorn[1].gif)

[morph]

why is aluminum not a good idea?
i have some i got from a buddie that he uses it on his dragster.
james

i just re read i guess it helps to read the all the posts.

[DerekKim]

Roughly how much of the high pressure fuel line, the lighter red was needed?

[JeffBowlsby]

Race cars use aluminum tubing fuel lines sucessfully, but I guess they are carefully monitored. I have seen thickwall aluminum tubing used on a street 914 for about 8 years with no issues whatsoever.

[jperret]

Roughly how much of the high pressure fuel line, the lighter red was needed?

About 3 feet. I left the fuel pump in the rear near the engine so the "high pressure "(35 lbs or so) runs are short.

[bd1308]

so whats the material of choice?

Ive heard of copper being used, but I was leary of that material flexing, as I learned in my materials class for ME that copper work hardens and is soon prone to stress cracks after that.

SS seems to be popular but i'd make sure it was mounted securely to the firewall and the bulkhead up front if i installed it.

SS the way to go?

[JeffBowlsby]

Actually I think the OEM Nylon is 'the bestest'. It is durable, capable of very high pressure, easily shapeable with heat and has low friction losses with fluids. Its only weakness are that it hardens with age and with exposure to moisture, and it does not do well in a fire...

[bd1308]

Yeah but where does one get the plastic stuff?

I'd change it if it were easy to do so...

[Hammy]

Yeah but where does one get the plastic stuff?

I'd change it if it were easy to do so...

Britt,
I put in SS lines (from Chris) by myself and it was fairly easy. Most likely gotta take tank out. RR wheel removed. Hardest part for me was attaching fuel hose from SS lines to bottom of tank, all done from underneath the car.

[ChrisFoley]

...
Hardest part for me was attaching fuel hose from SS lines to bottom of tank, all done from underneath the car.

It is common to use long enough hoses under the tank to lift the tank out, then disconnect the hoses. This way you don't have to drain the tank 100%.