Technical Fuel block on firewall; hard lines to carbs question

Like the title says - I'm getting ready to plumb up my fuel system. I want to run a hard line up my firewall to a fuel block, feeding two carbs. Hard lines look better that rubber, but I'm a little concerned about the integrity of copper lines. Would steel lines, with a loop, have enough flexibility to not break? Or should I just run rubber from the firewall to the carbs?

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You need something flexible. Hard lines will crack.

 

Your engine “ wiggles “ in the engine compartment. Your body also flexes, a hard line would not last long. If you are determined to do it, be sure you put several coils in the line, so that the flex is spread out!






Bones

 

Yeah, this is what I was expecting. I saw a car using copper lines with loops... sometimes I think the rubber looks a little less "finished", but I do like the look of the fuel block on the firewall...

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You could attach the fuel block solidly to the firewall and run hard lines to the carbs, but with short segments of rubber hose (either at the fuel block or at the carbs) to absorb the vibrations. This would also require bracing the hard lines with some sort of bracket(s) to keep them from flopping around.

Notice the short hoses between the carbs and hard lines on this roadster?

 

And do not use copper for fuel lines.......vibrations will make it work harden and crack. For a "second" on that statement..........your car will not pass NSRA inspection if it has copper fuel lines.
Possibly what you saw was NiCopp lines that, although can be polished to look like stainless, will turn a coppery color after a few years. NiCopp would be the way to go unless your building a jewel showcar, like the roadster pic.

 

I like those short rubber hoses on that roadster. That looks very clean!

 

Pretty simple really...

When you step on the throttle, the engine moves toward the right.
When you back off the throttle, the engine moves back to the left.
When you hit the throttle, the engine moves toward the rear.
When you hit the brakes, the engine moves forward.

Design for those movements.

Mike

 

The only time you want to run fuel line like the roadster has, is with solid motor mounts. Thats a fire waiting to happen when they break, and that short section of hose is not going to help.

There is a reason the factory mounted the fuel pumps low down on the later engines, its closer to the crankshaft where the rotation ( movement ) in the frame less. Less movement is easier on fuel lines. 4"" to 6" minimum engine to frame.

 

Another point is the difference between a show car and a driver. There are things that work and look cool on a show car but wouldn't live very long on the street and I'd say hard gas lines are one of those items.

Can't imagine running down the road at 55 having a gas line break spraying gas on the windshield just in time for some spray to hit those hot headers, bam!! In an heart beat it's a scene from Christine !!

 

I've used braided stainless, hydraulic type hose with fittings on some O/T cars....... but that might not be a look you want on an old rod. But how about mostly hard lines with about a one-foot section of hose parallel to the valve cover, then fabricate a shiny, chrome cover to float over the hose portion and hide it?

 

Or, mount the regulator / fuel block on the engine, run the hard lines, but run rubber up to the block out of site. You have the same look without the fire hazard.

 

Fuel pressure regulator mounted to the firewall running down to the aluminum fuel log.

 

Whatever you decide, you gotta have rubber somewhere to isolate the vibration differences between the engine and body/chassis.

 

Agree.....

 

Another reason Ford moved the fuel pump forward , to the side and low, was to eliminate “ vapor lock” common on the Flatheads, with the fuel pump high, in the middle and toward the back. Ford did this in 1954, Chevy followed in 1955.





Bones

 

when did chevy EVER have it high and in the rear?

 

Chevy never did as far as I know. They came out with the 265 in 1955 and had the fuel pump in a similar place as the Ford Y block. The car manufacturers were aware of what the others were doing . Ford learned that they had the fuel pump in the wrong place on the Flathead and corrected it on the Y block. Chevy was aware of the Flathead problem and did the same thing as Ford.... only on the other side.

 

Here's what I did on my '31. Works fine, not too obnoxious, but still looking for something different.

 

I went ahead and used rubber lines..

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I know it's been a couple of months, but what regulator and gauge are that? Any special fittings going from the outlet to the gauge?

 

As has been said never use copper lines for fuel. They work harden and become very brittle. No one needs to take a chance for an engine fire on their rod.

 

I did this one with long tube nuts for a look, couldn’t find the right fuel Block so I made my own. The choke and PCV were re done too with or inside nicop but I couldn’t find that pic.

 

I know you plan on time at the track racing your buddy that called you out, If the track tech in gives you a hard time about too much hose (more than 12") run hard line up to about 4" from the fuel block.
I always slightly bell the end of the hard line enough on the hose end so the hose clamp would have a really hard time to slide off.

 

It’s no secret that the less rubber and less worm drive clamps the better it be and better it will look.

What goes with that is it won’t be so easy, it won’t be so quick, and not as cheap.

 

I would be surprised if tech at a track would pass fuel lines above the bell housing ?

 

No, firewall mounted fuel blocks with hoses running to the carbs will not pass tech.

 

This is how i have mine. Don't think it looks too unfinished. use some Wittek vintage clamps like i did and she'll look perfect. The fuel line under the car is fuel rated braided stainless line. Always been a believer of braided stainless under car for durability. I would be worried about flex in any hard line. Does look great but do not want to burn my car down.

 

I've been studying the copper debate...... Everything mentioned as far as I've read here is in the name of safety, and very well regarded. Would I,should I, etc........ If you have short runs, and they are FIXED, without ANY movement between corresponding parts,I don't see an issue........ There is also a cosmetic factor to this equation.......
I'm going to venture into the copper world for lines.....Burst pressures of lines exceed my flow numbers immensely. I'll have ZERO vibrating parts/connections, as they will be fixed tight,and absolutely no wiggle room.
I'm glad peep's here are looking out for those who might not be all understanding of certain things.......