In tank fuel pump: How to

[TchncnDen]

Mods: I wasn't sure where to put this so feel free to move.

This is how I put an electric fuel pump in a blazer tank for use in my 71 pickup, but the method should work for just about anything with a gas tank.

For supplies you will need:
gas tank
fuel pump
4" vent cap from hardware store
3/8" threaded rod long enough to reach the bottom of tank plus a couple inches
5/16" and 3/8" steel fuel line
hose clamps
3/8" SUBMERSIBLE fuel line (regular fuel line will not work)
cork gasket material

The first thing I did was cut a hole big enough for my vent cap to fit through in the tank. I used a plasma cutter but I was working on a brand new tank. If you are using a tank that has ever had gas in it take the proper precautions before any cutting of any kind, blades make sparks too. I am not going to tell you how to prepare an old tank for cutting because I want no liability in this matter, look it up and be safe. I made my cut freehand so it looks kinda like I put a piece of cheese in the tank and had a rat gnaw the hole, if you have a big enough hole saw that would be better.

Next I used a piece of paper to trace the hole I just made and then drew a circle about 1" larger in diameter around that hole. Then I made marks for six holes big enough for #10 screws close to the inner circle. Put this template over the hole in the tank and use a center punch to mark the holes for the #10 screws and drill them out. The reason for putting them close to the edge is so you can tack them into place. My closeup pictures of this didn't turn out but you get the idea.

[TchncnDen]

Now take that same template and cut a piece of sheetmetal to the outer diameter and center punch the six #10 holes and drill them out big enough for the plate to easily fit over the mounting studs. You will also need a hole for the 3/8" threaded rod, the fuel line clamps, the pump wires and the two fuel lines. I elongated the fuel line holes so the lines could sit closer to the tanks while coming out at a 90. It will take a little trial and error on where to drill these holes, I have no dimensions and you may find a better way. I tried to make use of the factory reliefs in the tank to run the fuel line.

Cut a sheet of cork gasket material to fit between the mounting plate and tank.

[TchncnDen]

Now you need to weld a little mounting tab to your threaded rod, this is so you can attach the vent cap.

I took a wild guess and decided I wanted holes in the vent cap to allow a 30 second drain time. I ended up with one 1/4" hole and one 5/16" hole on opposite sides of the cap, as low as you can get them but not on the bottom. It was a good guess because I ran out of gas before I had my gauge hooked up and I used every last drop.

[TchncnDen]

Now it's time to bolt the top plate on and start figuring out the lines. I ended up with the top plate and vent cap not being concentric so that the sump would be on a flat part in the tank. Now is also the time to set the length of the threaded rod so the sump sits flat on the bottom of the tank. The tank will sag some when it is full but by the time you need the sump it is nearly empty so just make sure it sits flat while empty.

Once that is all set start bending your lines. You want the return line to drain into the cup so make it long enough but leave about 1/2" from the bottom so that it isn't restricted. You can't see it in the picture but I have a clamp holding it to the sump. Make your supply hose long enough to reach your pump while using the least amount of very expensive submersible hose. I think it would be best to braze your lines to the top plate. My brazing experience is only slightly greater than zero, so I quickly burned a hole in the fuel line while doing so. I bent a new line and decided to just tack them into place with the mig, then I used gas tank epoxy to fill the voids.

[TchncnDen]

Now you just install the pump, put the whole assembly in the tank, install the tank, run your wires and fuel line and call it a day. Once everything is figured out trim the threaded rod flush. I ended up shimming the pump side of the tank down about 1/2" and also routed about 1/4" out of the bedwood directly over the lines so the lines and bed wouldn't hit. I probably didn't have to route the wood, but I decided it was worth the extra insurance.

I bought a new tank, 25' coils of fuel line and a walbro 255lph fuel pump off craigslist from a guy making more horsepower than the pump could deliver. Add in the submersible hose, wiring, filler hose, junkyard fuel door and filler and I have less than $400 in my complete fuel system. I tested it the hard way and it uses every last drop of gas, I don't have to worry about starvation or air lock and it is way quieter than an external pump. I hope this helps someone out.

[Jdubs71]

I like the idea of using the rear marker as the fuel door. Any issues with the nozzle not fitting. PS nice write up by the way.
Justin
Posted via Mobile Device

[TchncnDen]

It's a little tight getting the cap on and off but the nozzle fits fine. It actually fills faster than my 98 dakota.

[1970 C10 MJW]

subd

[TypeSL2]

That is a pretty cool setup man. Thanks for sharing that. That is definitely something I am going to look into. Great write-up.

James

[Low Elco]

Nice writeup! This may come in handy!

[elf w/capital T]

Awesome, i am debating on the tanks inc pa4 pump but this looks like fun and do able, now just gotta free up my tank before i cut! Thanks for the write up!

By chance does any one know the depth of the tank? Im at work