To show a braided line in a fuel system we ran the following photo of a fuel tank in a ’32
In the January Shop Manual column we replied to a question from Charlie Jensen who was having a problem with braided fuel lines deteriorating as a result of using gasoline blended with ethanol.
While small-diameter flexible fuel line compatible with ethanol is readily available in parts houses, its wise to specify the type of fuel used when using braided line for AN systems. The reason is braided line is used for all sorts of applicationsoil, air, water, and of course all types of fuelbut the type of hose used inside the braid differs. As Brett Clow from Aeromotive explained in our response, only braided line made with PTFE hose should be used with ethanol.
A number of readers responded to that column explaining how they too had had a host of problems with ethanol thinned fueleverything from split fuel lines to plugged filters and carburetors full of chunks of rotted rubber hose. In one case a short section of the wrong rubber hose between an inline fuel filter and the carburetor was enough to cause a problem.
While fuel lines were the subject of our response, we did receive a few comments on the fuel tank we used as an example:
I have been banging on old cars since 1957 but check your ink religiously. You can never learn all about hot rods. You do a great job of helping all of us with grease in the blood.
On page 134, Pain in the Gas, that pic looks like a well-engineered high-tech 32here comes the but: is that a bottom-fed tank?
Ya gotta drive em,
Via the Internet
In a subsequent email, part of which appears here, Jim added the following:
Henrys tank had a 5/16-inch NPT drain plug and the pick-up tube is from top down to bottom. Your pic looks like a 1/2-inch NPT bung. Bottom-fed tanks were outlawed by DOT in 1962. Get in a crash or if a line breaks it will feed a fire. JM
More Gas Pains
Q. Your column in the January issue of SR got me thinking. The fuel system in my 50 Ford has been giving me fits. Ive had leaks, chunks of rubber-looking stuff in the filters and in the carburetors. Im going to install all new hoses that will stand up to E-10, but Im wondering if I should change the gas tank while Im at it.
I originally built the car in Pro Street style with a plastic fuel tank in the trunk. The tank has a sump with dual outlets pointed to the rear. The filler cap is a large twist type, and it does have a flapper in it to act like a rollover valve and there is a regular rollover valve on the vent.
With the problem Im having with leaking lines, my question is, should I change the tank for one that wont drain completely if a hose fails?
A. Jim and Bob brought up an important issue, bottom feed fuel tanks should not be used on street carsas they both noted a broken line or fitting will drain the tank, which could lead to a catastrophe. Tanks like the one in Bobs car are often used in drag racing and have the outlets positioned at the bottom so that under hard acceleration there is no possibility that the pickup will be starved for fuel.
Over the years many parts have found their way from the dragstrip to the street. And while some are more appropriate than others, bottom-fed fuel tanks are not a good choice for street cars. So, to answer Jims question, yes thats a bottom feed, and we should not have used it as an example. As for Bob, yes wed recommend you change that tank for a top-feed version.