Fuel system

Began the week with the idea that I’d finish the fuel system and mock up the cooling lines. Maybe get the radiator and fan mounts squared away too. This was not to be. But I did figure out the fuel system.

The Suby engine, being fuel injected, has a complicated fuel system with no fewer than three steel fuel lines going back to the tank. It also has two fuel pumps in the tank–one to send gas from one side to the other, over the drive shaft hump, and the other to send fuel at 35-40 psi to the fuel rails on the engine.

There is also a pressure regulator on the engine, a fuel filter, a charcoal canister, a rollover valve, and any number of wires and relays–which I’m not even worrying about for now.

First thing was to salvage the Subaru’s fuel lines, which disappeared through the firewall next to the master cylinder and could not be seen anywhere after that. The manual told me they were under the car, so I got down and checked with my fingers, then with my eyeballs. Found a bulge under the rocker on the driver’s side & thought maybe they were buried in undercoating. A minute with the scraper (and a quarter pound of undercoating and crud in my hair) convinced me they weren’t there.

I took a break and, when my wife wasn’t home, tested my thermostat. It started opening about 170 degrees F, which is just about right.IMG_4169IMG_4168

So that one’s good to go back in.

Went back out after the fuel lines. I found them on top of the rocker panel, under the sill and under a piece of white plastic, nicely ensconced in custom separators.


An hour or three of pulling plastic parts out, prying, cutting (with a sheet metal scissor), more prying and finessing got me the whole kit. Saved the grommet too.


These are beautiful. The long straight part is just about right for getting them close to the tank.

But where to run them?

I had thought I’d go outboard, in the channel under the pan. That would let me screw clips to the ends of the bolts that hold the body on the pan.

But the more I looked at that solution, the more I wondered: what happens under the tank itself? I have to bring the fuel lines out, under the car, then up through a hole in the floor…

I decided finally to run them next to the tunnel, inside, on the passenger side of the car. There is actually a slot in the front “firewall” that would allow two (or three) lines to pass through. The positive battery cable comes through there and runs on the floor, tight against the tunnel, to a grommet behind the passenger seat and then out and over the torsion tube.


The fuel lines could do the same.

Then what?

Samba people have advised running an external fuel pump from a Ford F-150 truck. Some Speedster builders say use one from CB Performance, run a return line back to the top of the tank, and drive on. But that pump alone is over $200.

And I want to run a “swirl tank” because I autocross now and again–and because it just makes sense in case one is running low on fuel. (A “swirl tank” is usually a baffled-off area inside your fuel tank that keeps fuel from sloshing about under hard cornering. Modern high-pressure fuel pumps use gas as a lubricant and when they suck dry they sometimes die. And the engine usually does, at least temporarily).

This guy got lucky in a junk yard: a late 1980s VW Fox has an external fuel swirl tank, made of plastic, that fits the bill perfectly. And here it is. $15–whoopee! Oh. Out of stock.

I emailed and called the company. Left messages. We’ll see.

After a few hours of research, my finger hovered over the “buy now” button at Summit Racing. This in-tank solution from Aeromotive just looks too good. Everything all set in one bolt-in solution. But at $440, I hesitated.

Eventually I decided that the Bosch fuel pump for the Ford (Part Number 69100). Found it online for $105. I went down to Advance Auto to buy a tube cutter, flare kit, tube bender, various fuel fittings and that pump. They said it was out of stock forever, so I bought the Airtex variant at $86.

Next idea: if not in the tank, where to put all this junk? I want to put the Suby’s fuel filter up front as well (since every pound I can remove from the rear wheels is a very good pound). The answer was easy. Under the fuel tank, ahead of the passenger compartment, there is a huge “dead space” boxed by fiberglass. Years ago I made a port into this space on the driver’s side, in an effort to get my brake rod adjusted right and find access to the master cylinder.

As I also plan to run my coolant lines through this space, it was time to open up the passenger side.

IMG_4186 IMG_4187 IMG_4188 IMG_4189 IMG_4190IMG_4191
You could hide a good sized dog in there. The trick now is working in it. There’s not a lot of room for hands and arms once you’re scrunched into the wheel well.


Here’s the key: see the light? That’s in the box, shining past the tunnel into the passenger compartment. That’s where the fuel lines will go. Under the rug, you’ll never know. I’ll run my oil pressure gauge line there too. And my heater hoses and the temp sender for the temperature gauge–all up where the passenger would put her feet. I got this planned out.

More cutting:



I’ve always thought Bridget would make an excellent coke mule. The tunnel. These spaces. It’s almost like she was made for that sort of thing. Except: no access panels until now.

I was thinking to mount the machinery on the front panel to make it easier to hook up the wires and hoses. So I made the replacement out of some diamond plate that came with the house.

IMG_4202IMG_4204Then I decided to get to work on my swirl tank. The inspiration came from one of the many stainless water bottles my wife and I have around the house. People keep giving us these things–they’re quite the marketing gimmick–but we’ve never used any of them because, well, they aren’t thermoses.

IMG_4206What they are is air-tight. Since the swirl tank is a low-pressure item, I wondered if I could get my fittings in them gas-tight.

I hacksawed off the handle of the shortest bottle–a souvenir from Namaste Solar of Boulder, CO, which a buddy of mine co-founded a few years back. I drilled a hole in it and screwed my 90-degree fitting in it. It cut threads! Nice.

Then to the top (the bottom). Up here we need a fitting for the fuel inlet from the tank–necessarily a gravity feed in this application. Next we need a fitting for the return from the injection rail. Finally, a third fitting for overflow, which will pipe to the top of the fuel tank. That’s a lot of fittings in a 2.5-inch circle.

Also, the metal is pretty thin. This isn’t a nitrous oxide tank or even a fire extinguisher. But it is better than a beercan. I ground the paint off the surfaces, drilled the holes, sunk my fittings and then mixed up the epoxy.

IMG_4205The idea was to bury all the fittings in goop. It should also grab the threads and leach just a little into the can. If I was really thinking I would have drilled a half dozen little holes in the can as well so the epoxy could leach through those and form a bubble on the other side. But I was not thinking, so this will have to do. (Or not. I just figured I’d try it).

IMG_4208(the threaded fitting was for another 90-degree fitting…before I realized that the straight fittings next door mean I can’t turn an L fitting into that port). Duh! IMG_4207

The tank, meanwhile, needed the other L-fitting so the overflow line will stay under the hood. As it’s plain steel, I soldered that one.

IMG_4216 IMG_4211 IMG_4212 IMG_4213 IMG_4217The final fitting, at the bottom of the swirl tank, got some epoxy reinforcement. I realize that this epoxy will not stick to this kind of plastic. But I think it will act like a washer/nut on the inside of the lid, and that may be enough.


If not, I will get another lid, center the hole and put a washer and a nut on it.

Next, we plug the lines, fill the bottle and turn it every which way but loose for two weeks to see if it leaks.


Meantime I now have to set about fitting all this stuff in that box. Right now I’m thinking: cup holders.


About stuntmidget

I'm a poor mechanic and general wisenheimer. I love old cars and the stories behind them, true or not.
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