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Hard fuel line replacement

Posted: Fri Dec 27, 2019 7:18 pm
by DustyDave
I am looking to replace the 4 hard steel fuel lines on my '78 Fiat Spider (Carbureted) as two of them have rust damage beyond repair. I have not found that any of the usual suppliers carry fuel lines on their web site. Does anyone know of a supplier of fully formed hard fuel lines for the spider?
If not, has anyone fabricated the fuel lines? A few challenges I see...
1) not sure how to put a bead on each end to hold the hose with a hose clamp. I checked with 3 local industrial hose companies and all say they can't do it. It seems maybe putting a bubble flair on each end may work? or maybe don't crimp the bubble flair fully to give just a mild bead? Thoughts?
2) I would like to make it in stainless steel to prevent corrosion and rusting, especially given it is under the car? I believe it will be difficult to bend, but I like the corrosion protection. Thoughts or experience on using stainless steel?
3) One local supplier suggested using Bundy tube as it is more flexible. He said it would be fine for fuel, but I am not so sure... anyone have experience with using Bundy tube for fuel lines?
4) Also, the tubes are 6mm (return) and 8mm (supply) OD. It appears that it is much easier to get 1/4" and 5/16" line which are close. It seems that since I will be connecting both ends of tuning to a rubber hose with fuel hose clamps would be fine using tubes with the English dimensions?

If anyone has thoughts or experience with any of these questions, responses would be greatly appreciated.
Thanks,
David

Re: Hard fuel line replacement

Posted: Tue Jan 07, 2020 11:27 am
by basso
Hi David,
i have renewed all the fuellines - it is a lot of work :)

I used Kunifer* to form the fuel lines ( *do not know how it is called in english ) it is a rust free line usually used to replace brake lines. My Spider is an 2000 i.e. and needed a special flöare ( double Flare ) to fit into the Fuel hose adapter. I used 8mm Lines all the way. I described my replacement in my restauration thread ( https://www.124fiatspider.de/forum/tech ... ion/page16 - it is in german but i think it is understandable with google translator ;)

p.s. I printed fuel line holders on my 3D printer ( i dont like the original metal clamp holder ). That was neccesary because Kunifer Lines needed to be fixed every 30 cm..

Stainless steel is not allowed in germany because it cant be bend without having little craks in it ( wich will lead to fuel loss in future due the cars vibration ).

bundy ( never heared bevore ) is the same as normal steel or?

Cunifer is the best material for the job - it is easier to bend ( with your hands ) in an small radius.

Sorry i cant find a translation for cunifer... but here is an Ebay autcion... https://www.ebay.de/i/233450625821?chn= ... gKQZPD_BwE

Hope i was helpful :)

Re: Hard fuel line replacement

Posted: Tue Jan 07, 2020 2:56 pm
by 18Fiatsandcounting
For what it's worth, Cunifer is an alloy of copper (element symbol Cu), nickel (symbol Ni) and iron (symbol Fe). I guess an "r" was added at the end of the word to make it sound better. The alloy has very good corrosion resistance properties, especially to seawater (salt water).

I guess the chemist in me is showing! :D

-Bryan

Re: Hard fuel line replacement

Posted: Tue Jan 07, 2020 3:29 pm
by RRoller123
"fer" ferrous? or maybe ferric?

Re: Hard fuel line replacement

Posted: Fri Feb 28, 2020 8:37 am
by Frankd1
i believe the Cunifer lines here are commonly referred to as NiCopp, Nickel/Copper etc if you were to buy them at the auto store or online. Very easy to work with and good corrosion resistance.
I am looking at these for my 78 Spider. Mine is going on a rotisserie so that should help ease the installation.

Re: Hard fuel line replacement

Posted: Fri Feb 28, 2020 10:09 am
by SteinOnkel
I used aluminum tubing on my efi conversion in my other car. Works killer.

Easy to work with, cheap and abundantly available at the hardware store. Also, it's safe. I wouldn't order jack online, any home depot has what you need and then some.

An alternative would be copper tubing used for refrigeration. I used that in the Fiat. Suuuuper easy to bend. Fun fact, the US Coast Guard requires copper for gasoline engines, see here:

https://www.uscgboating.org/assets/1/As ... 002.01.pdf

Page 59.

Cheers
Steiny

Re: Hard fuel line replacement

Posted: Wed Mar 11, 2020 10:26 pm
by baltobernie
+1 on the Cunifer. Soft enough to work without tools, but stiff enough to resist deformation. Replaced my hard fuel and brake lines with this product from Federal Hill Trading Co. 5/16" supply and vent, 1/4" return. About 13 feet each required on my 1973. Can't remember if your 1978 has interior or exterior routing, but I would have routed mine outside if the factory didn't build 'em that way.

You won't need any nipple on the hard line transitions to soft lines; carbureted engines operate with 2-3 PSI. You'll also want to make sure your new soft lines are rated to at least SAE J30R6 if you use gasoline containing any ethanol. Don't forget the big fuel filler hose, which always contains a couple of inches of gas inside. Some cut corners here and use a section of radiator hose (at 1/4 the price). Look for the proper SAE markings on this hose before installing, which is a difficult-enough job without having to do it twice.

Image

Re: Hard fuel line replacement

Posted: Thu Mar 12, 2020 5:03 pm
by SteinOnkel
1978 has them running inside.

I would use Gates for fuel line and nothing else.

Cheers
Steiny