Fuel Tanks And Lines

All the years of technology have had no effect on gravity.

There is no top draw. There's a port near the top, but it still draws from the bottom.

Whether the line is outside the tank from the bottom, or inside the tank, at the bottom.

Gravity is doing the same thing to each one.

 

Don't the lines frrom splitter to the tanks have to be identical in length as well?

 

No, fuel in the lines past the splitter is already headed towards the tank. Equal size is important, but as long there's no odd angles or drops/lifts, different lengths are ok.

 

On top draw fuel will return to tank when engine is shut down that is why you have to have a check valve in the splitter to hold prime. That can also drain back filters on older set ups. With mechancals that don’t have an extra pick up pump that means the injection pump is sucking air till it gets fuel. With bottom draw the fuel is already held in the line all the way to the filter by the weight of the fuel above it.

 

The reason I ask is that our 378 used to have a splitter for both draw and return, all built into one fitting. The return lines had one that was wound up much longer than it needed to be, and the same lenght as the other. Maybe just ease of manufacturing? My assumption was that they needed have the same friction loss in each.

We have since changed that to bottom draw for other reasons, but every once in a while, despite trying to keep both vents clean, it would drain one tank and fill the other.

 

What year is it? I don't guess I've seen a valve like that

 

89. Our 89 379 had bottom draw and crossover.

We did away with it, but I might have it laying around somewhere.

 

Should work, but I'm curious why you wouldn't just use your normal pickup in the top of the tank?

It may not be a concern for your application, but hit a gator just right and you'll break that fitting. With your pickup tube inside, you eliminate any possibilty there.