Fuel Lines question

[its55]

All, I'm in the process of replacing my fuel lines in the engine compartment.  My question is, what is the proper fuel line / tubing to connect to the fuel line stub out at the fire wall?  Anything special?  I did manage to shove a 1/4" line onto it and hose-clamp it, but am wonder if that's the best / correct way as of course I want it to be completely secure.  Any pics you might post would be helpful as well.  Thanks!

[AceAndrew]

5/16 - 8mm hose preferred .  1/4 is likely to be pretty anemic.  Use hose rated for fuel injection systems for a little extra insurance.

 

hope that helps!

[AustrianVespaGuy]

13 minutes ago, AceAndrew said:

Use hose rated for fuel injection systems

This in 5/16", readily available, cut to a length make things tidy, and call it a day!

[NYNick]

I was at a Tech Tactics presentation about classic car restoration at the Porsche Parade once. The presenter was a nationally recognized Porsche restoration specialist who focused on 356's. 

 

He told us that the only part he deviated from OEM were the rubber fuel lines. He made it VERY clear to use high quality fuel injection lines like Andrew suggested. I think they were Goodyear, IIRC. I bought an entire roll to do my 2002. Not cheap but high quality.

 

This is one area you can't afford to cheap out on.

[TobyB]

So one of the STUPIDEST parts of the 2002

(and there are a few)

is that connection from the plastic

line to a rubber line.  It's awful.  The plastic line's

not rated for compression, it's not 'ribbed for your safety'

and it's also not all that great with a big heavy rubber hose 

vibrating on it all day long.

Yes, it's lasted a long time- but as everything ages, it gets

even more tenuous.  The plastic, in particular, gets less plastic

and more brittle.

 

My solution is to replace the whole line with metal an-6 (5/16)

and run it under the car.  Which has its own shortcomings.  And is a LOT of work.

 

Hey, that was just a rant.  

 

t

 

[2002iii]

On 74+ 2002's I prefer to use the metal return line as the fuel feed and cap off or remove the silly plastic line.

 

On older models you can run your own metal line under the car.

[its55]

Are y’all saying that the fuel line from tank to firewall is originally (and therefore mine) plastic?  If that’s correct, that it has lasted 50 years is pretty darn impressive. 

[John_in_VA]

31 minutes ago, its55 said:

Are y’all saying that the fuel line from tank to firewall is originally (and therefore mine) plastic?   

 

Yes - a special plastic that runs inside the car along the passenger's side.

[stephers]

I save old antennas and cut small pieces off that fit tight up inside the plastic line for about 20mm , that way the clamp has something to tighten on       Most antennas are stainless steel and thin walled so they make perfect donors for stuff like this

 

Thanks, Rick

[BarrettN]

The "Barricade" line of Gates hose is a good choice for this, as a bonus it's not hard to find. If you live where there's an O'Reillys auto parts, they stock it. 

 

[its55]

The reason I started this topic was that after filling my tank for the first time this week, I had a fuel leak which was obviously coming from under the hood somewhere.  So, I replaced the fuel lines from the firewall plastic line to the carb (a Weber).  I think now I have learned (from the great discussions in this forum) that this is not the issue but rather the return line is unused and uncapped somewhere down under the hood!  So, I will be investigating this today!?

 

Question - why a return line on a carbureted car with a mechanical fuel pump?  Did the original Solex need it?

 

 

[TobyB]

There was a bypass valve that reduced fuel pressure at high manifold

vacuum, letting fuel recirculate to the tank.  This took pressure and

potential wear off the float valve, and also significantly reduced the frequency

of vapor lock.  By the 70's, the vapor pressure of fuel was on the way down.

 

Unfortunately, the valve was a 'lifetime' item, the 2002 was supposed to last 5-8

years, and so most of the valves failed and were simply removed.

 

t

 

[its55]

19 minutes ago, TobyB said:

There was a bypass valve that reduced fuel pressure at high manifold

vacuum, letting fuel recirculate to the tank.  This took pressure and

potential wear off the float valve, and also significantly reduced the frequency

of vapor lock.  By the 70's, the vapor pressure of fuel was on the way down.

 

Unfortunately, the valve was a 'lifetime' item, the 2002 was supposed to last 5-8

years, and so most of the valves failed and were simply removed.

 

t

 

Very interesting, thanks!

 

[John76]

Here's a sketch of the fuel system.

Your leak is most likely from the uncapped metal return line under the left side of the car. This is used as the supply line from the electric fuel pump near the tank on Tii's.  A rubber hose is connected to the metal line underneath the battery tray and has a 1-way valve (flows towards the tank) before connecting to the fuel return valve. As Toby points out, the valve allows a greater amount of fuel to flow back to the tank when manifold pressure is high, and less under higher engine loads (low vac.). The return valve does not close completely. It always recirculates some fuel back to the tank to keep it cool, which helps with the vapor lock issues experienced with "open" carb equipped cars.

Modern cars have completely sealed fuel injection systems, and even the fuel tanks are sealed, so the "new" gas is not an issue.

Tip: Be sure your fuel tank is vented though the plastic line from the rubber filler neck. This goes to the vapor tank and charcoal canister.

Happy Motoring,

John

 

 

[its55]

13 minutes ago, John76 said:

Here's a sketch of the fuel system.

Your leak is most likely from the uncapped metal return line under the left side of the car. This is used as the supply line from the electric fuel pump near the tank on Tii's.  A rubber hose is connected to the metal line underneath the battery tray and has a 1-way valve (flows towards the tank) before connecting to the fuel return valve. As Toby points out, the valve allows a greater amount of fuel to flow back to the tank when manifold pressure is high, and less under higher engine loads (low vac.). The return valve does not close completely. It always recirculates some fuel back to the tank to keep it cool, which helps with the vapor lock issues experienced with "open" carb equipped cars.

Modern cars have completely sealed fuel injection systems, and even the fuel tanks are sealed, so the "new" gas is not an issue.

Tip: Be sure your fuel tank is vented though the plastic line from the rubber filler neck. This goes to the vapor tank and charcoal canister.

Happy Motoring,

John

 

 

Thanks John.  I'm 99.9% sure this is the issue.  A previous owner added a weber carb to my 2002, which does not require a fuel return.  Apparently he (or his poor mechanic) left the steel return line un-capped in the engine bay.   This makes sense because after I filled the tank, I drove home and stopped on a downhill slope (front facing downhill).  At that point fuel began to spill.  Glad I don't smoke!!

 

Great drawing by the way!!!

 

I'll get under there this afternoon and verify and cap off and/or let ya'll know what I find.

 

13 minutes ago, John76 said:

 

 

Edited February 8, 2022 by its55