I’m building a fuel tank for one of my car projects, a Lamborghini Miura. I’m a first time fuel tank builder and am hoping someone can help provide some information.
The tank is made of .063 aluminum (5052 grade I think), is cut and bent but not yet welded together. I’m not concerned with the welding as I can do that. Here’s a picture of the tank. The odd shape is because the Miura is a transverse mid-engine and this fuel tank is located under the dash and down the chassis middle between the seats.
I’d like to use an in-tank fuel pump if feasible. My most basic question is how best to get the power wires through the tank in a leak free way?
Expanding on that, I’m guess some sort of access hatch is needed in order to service the fuel pump and pickup if/when required. Is there an aftermarket fuel tank hatch like this available? Something with the power wires, fuel lines (outgoing and return) are plumbed, fasteners and gasket engineered to stay leak free. If so, where do I find such a thing?
Also, where should I locate the hatch? My gut is to locate on top of the tall portion of the tank to minimize the gravity related fuel pressure against it. The downside of this is it complicates locating the fuel pickup in the middle of the tank (to minimize low fuel starvation under acceleration/braking) and will result in longer fuel lines than otherwise.
A simpler location is on the lower portion of the tank in the middle. This would simplify fuel pickup location and internal plumbing as that’s between the internal tank baffles. The downside is there would be gravity related fuel pressure on the sealing surface until the top 1/3 or so of the tank is emptied.
The car will be powered by a Coyote V8 with an 8 stack Weber style EFI. I think this means a return fuel line will be required but I’m not certain on that point.
Or should I just keep is simple as possible and use an external fuel pump? The back of the tank is only about 1 foot from the engine. Part of the desire for in-tank pump is to keep it clear of heat, etc. and because the engine compartment will be very tight. If external pump, then my only concerns would be related to the fuel level sending unit.
I guess what I’m really asking here is if an access hatch and bunch of through tank fittings can be effectively sealed against gravity fuel pressure. The tank will be removable from bottom of the car but I don’t want to be doing that as the engine coolant, heater, and A/C lines run under it. So a major hassle if there’s a leak down the road.
I know this is a non-Cobra application but I know from being a Cobra guy myself, you guys have a broad set of automotive experience.