fuel lines in tunnel

[ado]

I am replacing my old fuel lines with copper tubing in the tunnel and i was wondering if there would be a problem with both lines being the same larger diameter. I'm not sure if the smaller line is to reduce pressure in the system.

Thank You............

[TheCabinetmaker]

be careful with copper in the tunnel, if not secured vibration may wear a hole in it, copper is more susceptible to this than the stock plastic tubing. You can buy Nylon fuel rated tube of the same diameters from industrial supply places like Graingers for very little cost. the nylon tube has lasted over forty years in all my 914's except where damaged by battery acid. The new plastic tube should do likewise. a much better choice over copper I think for this one reason.

you may want to keep the tubes stock sized, as that allows a more direct replacement of the rubber hose bits that terminate on the plastic tube. you still have to contend with the two different sized fuel tank fittings.

I used the Grainger plastic tubing to replace acid damaged short pieces in the engine bay, the tube in my tunnels are still original from near as I can tell.

[ado]

the copper lines are covered with a heavy plastic coating used in oil furnace application. The connection to the tank is with a marine fuel line which i can fit over either tube. So i guess the size of the return line does not matter..
Thanks for the quick responce..............

[Tobra]

I would be concerned also about work hardening with copper lines. The little bit of movement you will get could cause the copper lines to get brittle and crack.

[Dave at Pelican Parts]

Stainless lines are a known solution. You can use truck brake lines of the appropriate sizes, and bend them up yourself, or buy pre-bent ones from places like Tangerine Racing. I would recommend those over the stock plastic lines, which I would in turn recommend over any copper lines.

Once the tubes are in the center tunnel, they are not exactly going to be easy to inspect for problems.

--DD

[The cap'n]

Copper? NEVER, no matter what variety of copper. Same size? Probably not unless you use the larger diameter for both.

The Cap'n

[bowlsby]

copper and pressureized fuel do not mix =

[Peter Zimmermann]

I did my tunnel lines a few years ago, and used stainless lines from Tangerine Racing - beautiful product.

[Rotary'14]

Our kind forum sponsor also sell SS fuel lines for our 914s if you need another option
Porsche 914, 914-6 (1970-1976) - Fuel System - Page 1

plus you'd be supporting our sponsor

-Robert

[porschetub]

Originally Posted by bowlsby

copper and pressureized fuel do not mix =

Very true ,as mentioned it needs to be fully supported ,everywhere, it is prone to cracking more than most think,best used for plumbing IMO.
I have a roll of 1/4inch plated steel line that I used in my speedster rep chassis,I plug welded extra support bars in the tunnel to support it just incase ,to me the best affordable solution.
The op could use quality plastic line but again it needs to be supported to stop "fretting"over time,this line is very durable but needs the inner support ferulles to prevent collapse when clamps are used on to rubber hp and return lines hoses.

[ado]

Thanks for all the great input on this.
I'll consider the options.......