Engineering A Simple And Aesthetic...
Engineering A Simple And Aesthetic Fuel System On Roy Brizio's '55 Chevy.
Planning a fuel system may not be one of the most exciting aspects of building a car, but it's a system that you want to be efficient and bulletproof. It is, of course, of utmost importance to ensure your engine's performance, and carries the most volatile substance in your car. It's not something with which you want to take shortcuts, or worry about while you're driving.
There are a few basic elements to consider in any fuel system regardless of what type of induction you're running: fuel line, pump, and filter. Depending on your intake system, you might also want to consider a fuel pressure regulator and/or a pressure gauge, and if you are using a fuel injection system, you will need to install a return line from the engine to the fuel tank in addition to the main line.
The first thing we did was...
The first thing we did was move the fuel filler access to inside the trunk. We started with a Rock Valley stainless steel fuel tank, which was made for a stock '55 Chevy fuel filler.
Your main line can either be hard steel or rubber hose. I recommend steel tubing because it will last longer and withstand damage, while rubber lines will eventually fatigue and crack. Of course, you will have to use a small portion of rubber line between the frame and the engine to compensate for engine vibration, but it is much easier to replace this small section than the entire line.
There are also two types of fuel pumps and schools of thought: mechanical and electric. On one hand, mechanical pumps seem to be more reliable overall, they are quiet, and they produce an adequate amount of pressure for most carburetor systems. Mechanical pumps take horsepower to run, however, and engine rpm will vary pressure. In certain cases-for instance if you have a Flathead with multiple carburetors-the stock mechanical pump might not be strong enough to pull enough fuel for efficient operation, in which case an electric pump is an easy solution.
We cut off the original hose...
We cut off the original hose flange and made a filler piece out of stainless sheetmetal. These tanks are made out of stout 14-gauge stainless.
Electric pumps, though less reliable, are sometimes easier to change if they do fail, and they produce steady pressure at any engine speed. They can be loud, and they also use electric energy, which can be equated to horsepower robbed at the alternator if you want to get technical. We used an electric pump here, though a mechanical pump would have been just as effective for this setup. If you're using an electronic fuel injection system, then you will need to use an electric pump specifically for that system, many of which mount inside the fuel tank. If you're using mechanical fuel injection, well then God help you.
A fuel pressure regulator will limit any inconsistencies in any carbureted system. If you're concerned that an electric pump might exceed the pressure rating of your carburetor(s), a regulator takes any guesswork out of the equation. If you're running Strombergs, for instance, and more fuel seems to be coming out of the float bowl gasket than into the combustion chamber, a regulator will (theoretically) help.
The shape was slightly over...
The shape was slightly over half round, so we made sure to achieve a precise fit. We bent a 90-degree angle in the filler piece on a brake. After double-checking the fit, we welded in the filler piece.
A fuel filter is imperative to the operation of your induction system and the life of your engine. There are plenty of sizes and styles of filter from which to choose, ranging from small inline filters to large removable canisters. Some people go as far as to use a large filter just out of the fuel tank, as well as a small inline filter up near the carburetor. I suppose you can't have too many filters as long as they flow well. We used one "race" rated canister filter between the tank and the fuel pump.
In addition to taking care of the necessities of your fuel system, you can also make it look good. There are hundreds of little tricks and flourishes you can use if you care. In this article, we'll show you a few aesthetic changes we made to the system on Roy Brizio's '55 Chevy, but each application will be different and present its own options. The fuel system isn't the coolest part of your car, but have some fun with it while making it safe and reliable.
If your tank isn't already...
If your tank isn't already equipped for a breather, you will need to install one. When working with any type of 90-degree fitting, always make sure there is enough clearance for it to thread in before drilling the hole. We then drilled the tank and welded in a threaded bung. Once you're done welding a steel or stainless steel tank, be sure to do a pressure test (or at least a leak check with water) to ensure there are no gaps or pinholes in your tank before filling it with fuel.
We installed the breather...
We installed the breather tube (which will accept a ball-check breather fitting) close to the sending unit so we would only have to cut one small access hole in the trunk floor.
With the original filler neck...
With the original filler neck filled, we began planning where to place the new filler neck. Those black lines indicate the left and rear edges of the tank under the floor. By using the fuel tank mounting strap bolts (arrows) as a guide, we determined the exact center of the fuel tank below. Roy decided to mount the fuel filler in the center of the floor. If you're going to store luggage in your trunk, this might not be the best place for it, but Roy generally drives a roadster so he packs light. We placed the filler as far back (closer to rear bumper) on the tank as possible to make it easier to access.
We marked the center of our...
We marked the center of our filler neck location and drilled a small hole through the floor right down through the top of the tank, which was pressed up against the trunk floor. This way, the filler neck will be perfectly centered in our trunk floor hole.
The tank was removed from...
The tank was removed from the car and then, using our small hole as a pilot, we drilled a hole the same diameter as the outer diameter of our new filler neck.
The rough edges were cleaned...
The rough edges were cleaned up using a burr bit to ensure a perfect fit for the new filler neck.
A hole was drilled in the...
A hole was drilled in the trunk floor using the pilot hole we drilled earlier, and the edges were filed smooth. The diameter of this hole was determined by the diameter of the drip tray shown in step 6.
While we were busy cutting...
While we were busy cutting up the trunk floor, we measured for a fuel sender access hole. We took measurements to the front and rear edges of the fuel sender in the tank based on the location of the filler neck.
We measured the width of the...
We measured the width of the sender opening, and double-checked the depth of the opening to create the dimensions of the access hole.
The measurements were transferred...
The measurements were transferred to the trunk floor, and we cut out a square opening with a cut-off wheel after marking the outline of the fuel sender access hole. Here's where all of our diligent measuring paid off. The filler hole is centered over the tank, and the fuel sender access hole matches the indentation on the fuel tank for the sender and the breather fitting.
We used this preformed drip-catch...
We used this preformed drip-catch for our trunk floor to protect the carpet from drips once the car is upholstered. We checked the fit of the fuel neck with the drip-catch in place just to be sure everything lined up before welding anything in place. We also determined how tall the filler neck should be.
The filler neck was tacked...
The filler neck was tacked in place at the appropriate depth and the tank was then removed to finish-weld the neck in place. The finished neck puts the top of the cap flush with the top of the drip-catch bezel, and there is plenty of room for insulation and carpet between the trunk floor and the top of the bezel. We will also add a drain hole to the drip-catcher before final installation.
With the tank completed, we...
With the tank completed, we turned our attention to mounting the filter and the pump. We used an Edelbrock electric fuel pump and a Fram canister filter. We fabricated some simple brackets to mount each unit to the frame, and we added some rubber cushions to the fuel pump mount to dampen the sound.
The fuel filter should be...
The fuel filter should be mounted closest to the tank. Although it came with a bracket that could be mounted directly to the frame, we raised it up so it didn't hang beneath the framerail, which required us to make a simple mounting plate.
We simply transferred the...
We simply transferred the holes from the supplied mounting bracket to a piece of 1-inch strap with a center punch and copied the width of the supplied bracket. We then cut the ends and punched 3/8-inch holes according to our center-punch marks. The bracket was then tack-welded to the top of the 'rail until the final position was determined.
The fuel pump bracket was...
The fuel pump bracket was slightly more complicated since it required two mounting screws for the filter, and three separate mounts for the rubber standoffs. We sprayed a piece of 1/8-inch plate with Dykem and transferred the mounting holes for the pump. We then punched three holes for the standoffs in an equilateral triangle around the mounting holes for the pump. We cut the plate in roughly the shape the holes made and then rounded the corners.
We welded two studs into the...
We welded two studs into the plate to make it easier to remove the pump once it's attached to the frame, and bolted in the rubber mounts to make sure everything fit properly. The pump will be mounted next to the filter, making sure there's enough room between them to install and service the fuel line.
After marking the frame for...
After marking the frame for the fuel pump-mounting holes, we drilled and tapped the frame to thread the rubber mounts directly into the framerail and then mounted the filter and pump. We installed fittings and hose ends to get an idea of how we were going to route the fuel line, and we marked the fuel tank (note the "X" on the right corner of the tank) for a new pickup location.
In order to install a new...
In order to install a new pickup, we removed the tank and drilled a hole for the new pickup tube. We used a stainless pickup tube supplied by Tanks. Since it is mounted in the side of the tank, we needed to bend it at an angle to reach the bottom. We marked a line on the tank as a rough template.
The pickup tube was bent with...
The pickup tube was bent with a tube bender until it matched our mark on the tank. Once the tube was formed, we welded it in place before reinstalling the tank in the car. Next month we'll cover the installation of the Russell braided fuel line and fittings.