46' Constellation Fuel Line Schematic

[lplikas]

Need information on fuel line and valve lineup for a 46 Constellation. Schematics could help. Any information would be appreciated.
Thanks.

[campjer]

Are you looking to replace the entire fuel line system with new? What size are your engines? Is 46 the year or length? Fuel systems are actually quite simple in their operation (not much different than plumbing for water). Provide a bit more information and I can put together an illustration as a guide.

[jahearne]

I have some questions about replacing fuel lines. Obviously, marine requirements are different than cars where my experience comes from.

Now there's rubber fuel hose that is USCG approved, so that's fine from tank to water seperator to engine, so we no longer have to run grounded hard lines. Do fuel lines on the engine block from carb to fuel pump have to hard lines?

We still have to ground the fuel tank and filler, right?

I'm running Edelbrock carbs on 327F. On cars, I've used simple compression fittings and steel hard lines the same used for brake lines only larger 5/16" & 3/8" with 45 degree flare. On boats I'm considering AN fittings 37 degree flare, but have no "racing" experience using them.

[evansjw44]

Rubber fuel line do not satisfy the requirement for tank grounding. The Coast Guard approval does not address this issue, only that the rubber tubbing meets thier standards for tubing. You need to run ground wires for each tank and the fill pipes. Compression fittings are not permitted. Fuel fittings on hard lines are flared with copper tubing. Some allowance has been made for specialty fitting found in the air craft industry.

[jahearne]

Got it! I must ground the tank and filler. Can I use aluminum fuel line or does it have to be copper?

Thanks Jim!

[evansjw44]

Aluminum fuel line would be not be adviseable. Aluminum "cold flows" which makes them subject to leaking. Use soft drawn copper.

[jahearne]

Thanks for the advice. Do you have a source for copper line?

[evansjw44]

I buy mine at a local hardware store. Its used for water and gas piping. Many auto parts stores carry it too.

[campjer]

Brings to light a question that arose a couple weeks ago when I was shopping for copper line. Is there any difference between copper fuel line (that you would buy at an automotive store) and copper tubing of the same diameter that you would buy at a home supply store?

[jahearne]

The auto parts stores around here don't carry copper that I've seen, but i see copper lines for running water to your refrigerator and stuff at hardware stores. Can it take the punishment in a marine environment?

The reason I asked for a source, is that in my search for fuel line nothing copper comes up; it's all rubber USCG approved or AN aluminum hard line or stainless hose for auto racing. I'd also like to learn more about "cold flows".

I'll double check a few autoparts stores for copper. So far I've learned a lot. Thanks,

[jahearne]

Surely there may be a difference, but i've found two reliable sources. Aircraft seamless copper tubing and Cunifer, copper alloy used in British sport cars. The Aircraft tubing is much cheaper, 10' min. order.

http://aircraftspruce.com/catalog/mepages/coptubing.php

http://store.fedhillusa.com/

[jahearne]

Sorry lplikas we never answered your question, but if you could provide some additional details.

I can across these articles:
http://newboatbuilders.com/pages/fuel.html
http://newboatbuilders.com/pages/safety_fuel.html

"Metallic fuel Lines: If you use metallic fuel lines, the ones that run from the fuel tank to the fuel inlet on the engine must be one of the following; seamless annealed copper, nickel-copper, or copper-nickel. From the fuel pump to the carburetor they can be any metal you want to use. Beware. You could set up a galvanic couple and the tube will be eaten away like powder. Choose carefully if you use metal fuel line from the pump to the carburetor. Do not use Copper tubing. "

According to that statement, no copper seamless in the pressurized line from pump to carb. Based on the next quote, we're not to use copper at all; only copper-nickel like that british Cunifer.

"Metal fuel lines also have problems. Copper in a marine environment deteriorates rather rapidly. Plus that it is subject to galvanic corrosion. So metal fuel lines have to be certain materials such as copper-nickel or nickel copper. Steel lines are also allowed. A big problem with metal fuel lines is vibration. Vibration loosens fittings, and fatigues the metal, resulting in cracks, usually at the fittings. So metal fuel lines are usually kept short, and there are short flexible lines between the metal fuel line and the engine inlet"

Using two dissimilar metals is like a battery. But there has to be an electorlyte such as salt water. Can gasoline be an electorlyte?

If I use aluminum fittings with copper lines, aluminum is less noble and the fittings would corrode first providing there's an electorlyte.

Or we can just use A1 rubber hose throughout with double clamps, stainless steel clamps 1/2" wide if I'm reading those articles right.