Installing custom fuel lines

[rossman]

I'm preparing to install custom fuel lines in my 240z. I plan to run the feed and return up in the top passenger side of the tunnel similar to this. The tubing is 316L 5/8" (feed) and 1/2" (return) .035 wall. I borrowed a set of manual pipe benders and 37 degree flaring tools from a guy at work. I'm looking for advice, tips, tricks, etc. on how to best attack this project.

 

I believe the trickiest part of my install is going to be tucking the pipe far enough in the tunnel to clear the z32 gearbox and shifter mount. Here is a picture of the situation. It's hard to tell but the 5/8" pipe I'm holding clears the shifter mount by about .25". That is with it on top of the old pipe. I have removed all of those lines except the brake line. The new runs will of course be up against the tunnel offset by the thickness of an Adel clamp. I'll probably trim a little off the shifter mount for good measure.

 

 

[z2go]

This is what I did with mine, running a 3/8" feed line and 5/16" return. I also routed new 3/16" brake line, and I did not run a vapor recovery line. I ran the 3/8" line on the other side of the tunnel, and it gave me a lot of room to work with. It cleared everything just fine. It looks like I have a lot more room to play with around the transmission (Camaro T5) but in looking at your pictures, I think it could work too. I found that the biggest thing is getting everything out of your way when running the new lines. The less crap to hang up on, the better. I don't know what kind of lines you are using, but I was using Copper/nickel alloy lines, which can be bent by hand without kinking. That made it really easy to get them to fit where they needed to... I would secure one end of the line where it needed to be, and then bent around to the next point, mounted it, and so on. Regardless, best advice I could give is to drop the tail of the transmission to give yourself a lot of room to work.

[rossman]

This is what I did with mine, running a 3/8" feed line and 5/16" return. I also routed new 3/16" brake line, and I did not run a vapor recovery line. I ran the 3/8" line on the other side of the tunnel, and it gave me a lot of room to work with. It cleared everything just fine. It looks like I have a lot more room to play with around the transmission (Camaro T5) but in looking at your pictures, I think it could work too. I found that the biggest thing is getting everything out of your way when running the new lines. The less crap to hang up on, the better. I don't know what kind of lines you are using, but I was using Copper/nickel alloy lines, which can be bent by hand without kinking. That made it really easy to get them to fit where they needed to... I would secure one end of the line where it needed to be, and then bent around to the next point, mounted it, and so on. Regardless, best advice I could give is to drop the tail of the transmission to give yourself a lot of room to work.

 

Cool, thanks for the reply. I hadn't even considered routing on the drivers side. I'll have to look at that.

 

I'm using 316L stainless. It's impossible to bend by hand...at least for me.... I do have some really nice benders though.

 

I forgot to mention a couple of things:

 

1) The engine and differential are out of the car now so I pretty much have unobstructed access to the entire tunnel.

2) I have never used tube benders.

[junglist]

Where are you getting your adel clamps? Something special or just what you can pick up at Home Depot/Lowes? Are you going to just use self-tapping screws?

[z2go]

Glad to help.

 

I would agree that the stainless is impossible to bend by hand. Do you have any extra tube to practice on? I would do some practice bends, see how far you can get away with bending the stuff before it kinks, and how gradual you need to make the turns. There's really not a lot of bends you need to make through that tunnel. However, I see a lot of time spent on your back with tube benders underneath the car in your future

 

Seriously though, I would practice with the stuff as much as possible, make some funky shapes, see if you can make sharp bends all with one swoop, or if you have to make small incremental bends until you get the desired shape. Like most things, the tools will probably make the difference in the ease of this project.

 

The adel clamp solution works really well too, I was very pleased how well they secured the lines, and exactly where I wanted them, too.

 

Be sure to update, I'd like to see your final solution.

[z2go]

Where are you getting your adel clamps? Something special or just what you can pick up at Home Depot/Lowes? Are you going to just use self-tapping screws?

 

One option is though J&P Cycles, I ordered stainless steel ones in a 10pk for a little less than $1 a piece. The ones at Lowes are not necessarily stainless (at least they weren't here), and were a little more pricey. I used 1/4" zinc pan head machine screws with matching nuts (bought a 50 pack at Lowes) with a washer on the inside, and some blue loctite. So far so good. Just need a helper to hold the screwdriver on the inside while you tighten the nut on the outside.

[rossman]

Where are you getting your adel clamps? Something special or just what you can pick up at Home Depot/Lowes? Are you going to just use self-tapping screws?

 

McMaster-Carr. Nothing too special, stainless/EPDM. I'm going to use sheet metal screws for the initial install. Once I'm happy I'll drill out the holes and install small machine screws with locking nuts.

[rossman]

Do you have any extra tube to practice on?

I have two 10' sticks of each size. One stick to screw up and one for the final install.

 

I see a lot of time spent on your back with tube benders underneath the car in your future

No doubt.

 

Be sure to update, I'd like to see your final solution.

Will do.

[rossman]

Here is what the transmission tunnel looks like now. I'd say I have pretty good access Old hardened bags of concrete work well for stand-offs to hold the suspension.

 

 

 

 

Here are the tools I borrowed for the project. 5/8", 1/2", and 3/16" benders, flaring tool, reamers and tube cutters. He also gave me a few basic instructions like, do a couple of trial bends first, work left to right, bend a little and test fit, repeat, etc.

 

 

 

A friend of mine suggested making a template out of something soft first than using that as a guide for the real deal. Any ideas what I can use? Looking for something that doesn't cost $100 a stick...

Edited April 18, 2011 by rossman

[z2go]

A friend of mine suggested making a template out of something soft first than using that as a guide for the real deal. Any ideas what I can use? Looking for something that doesn't cost $100 a stick...

 

Get a roll of solder, the thicker the better. It will bend exactly how you want it to, and won't cost much, and will hold its shape pretty well (at least in small sections).

[zgeezer]

I used 3/8 inch CuNiFer copper alloy tubing for both pressure and return. Took about 5 hours, including beer and bs time to run both sets and terminate with AN-6 hose barb fitting.

 

I was working on a shell wi/o engine, trans, or rear suspension. I kept the gas tank as a guide for where to terminate the ends. I removed my smog line, pressure, and return line from the tunnel, threw away the hard rubber spacers and the routed the CuNiFer line from the back to the front inside the orginal clamps. For the most part this was quite simple, but around the emergency brake there was a small clearance problem. I bought three feet of hose rated for pressure and gasoline. I cut about 10 three inch segments and then split them lengthwise.

 

I slipped one segment over each line where it was run through the original metal clamp. In effect, the slip hose insulated the CuNiFer line from rubbing and allowed for a tight hold by the original clamps.

 

In the very back I used the Adel type clamps from Home Depot and mounted them with self tapping screws. I left only two of these in place.

 

Up front, I moved the line over to the driver"s side by mounting the line directly to the pan with self tappers. Once I had the line adjusted in place, I went back and removed the self tappers, drilled out the hole a bit and mounted a stainless steel big headed machine screw in place with washers, loc tite, and self locking nuts. Again all out of Home Depot.

 

I now have two lines without break mounted in the same space that contained the original lines. I used the split hose to prevent abrasion or contact with any metal parts.

 

CuNiFer is a Copper, Nickel, Iron alloy used as brake line in Volvos and Mercedes, among others. It comes in rolls and I found it to be just a bid more resistant to bending than 3/8 soft aluminum, but far, far, far more resistant to kinking.

 

I have photos, but I've not been able to post photos to my album for more than a year, after the last major change in application.

 

G

[rossman]

Zgeezer - thanks for the input. I'm really looking for advice on installing large hard stainless tube. I realize it's going to be more difficult but I'd like to give it a shot since I already have all the tube and tools.

[z2go]

If you get frustrated and fed up with the stainless tube, I second the comments made by zgeezer. The Cunifer tubing is amazing, I used it for everything.

[RTz]

The tubing is 316L 5/8" (feed) and 1/2" (return) .035 wall.

 

Rule of thumb is to size the supply line to the fueling requirements of the engine, and size the return to the flow capacity of the pump. Said another way... the return would always be at least the size of the supply, and often larger.

[rossman]

Rule of thumb is to size the supply line to the fueling requirements of the engine, and size the return to the flow capacity of the pump. Said another way... the return would always be at least the size of the supply, and often larger.

 

 

Maybe but A1000 fuel regulator has a -6 return port. Seems kinda silly to put a 5/8" or larger return line on a -6 port.

 

 

[RTz]

I understand. But I would ask, why the need for a 5/8" supply?

[rossman]

I understand. But I would ask, why the need for a 5/8" supply?

 

 

Only because the pump (A1000) requires a 1/2" minimum ID. 5/8" is the closest standard size tube that meets this requirement.

 

 

[rossman]

I bent most of the 5/8" feed line; tucking it up in the tunnel as tight as I could get it. Took me close to 3 hours to do this one line. Most of that time was spent measuring and visualizing. I may spend a little more time getting the engine end a little tighter against the fire wall. The pump and engine ends are long so they can be trimmed to fit once the mating components are installed.

 

 

 

 

 

 

 

 

 

I also spent a great deal of time deciding where to locate the pump. It's so darn big there aren't many choices. I finally decided to locate it just in front of the tank in the space where the factory electric pump mounted...except much lower so that it is just even with the bottom of the tank.

[Tony D]

Well, I see it's too late for my warning of "Don't forget to slip the section of Sch 80 Pipe over the lines to keep them intact should the clutch come apart..."

 

 

Make yourself a 1/4" thick plate, and bolt it to the chassis to cover your lines in the vicinity of the plane of rotation...

[rossman]

Well, I see it's too late for my warning of "Don't forget to slip the section of Sch 80 Pipe over the lines to keep them intact should the clutch come apart..."

 

 

Make yourself a 1/4" thick plate, and bolt it to the chassis to cover your lines in the vicinity of the plane of rotation...

 

Yeah, it might be a little hard to bend sch 80 pipe around those bends . 1/4" plate seems simple enough...if it will fit. Thanks for the tip Tony!

Edited May 10, 2011 by rossman