Some gas tank questions

[olddog]

I have had gas fumes in my trunk and have had a small leak drip under the car if you fill the tank, since I bought the car. I finally got around to pulling the tank. I filled it with water to find the leak. Then removed fuel pump (EFI) and fuel gauge sending unit (two separate holes). Tank is made of a heavy gauge sheet metal ~1/16" thick and bare metal on the inside.

Two leaks: 1) fuel gauge sending unit was poorly installed. 2) the vent tube on the fuel pump is poorly designed.


Questions:
I see what looks like light surface rust inside tank. Perhaps my putting water in it caused it, but it was only in it a few minutes. Normal? Should I consider an epoxy coating for fuel tanks?

Fuel sending unit had sheet metal screws into tank. Fuel pump has a decent design where there is a thick ring inside the tank that bolts thread into. I would like to make something similar for the sending unit. Is the sheet metal screws plenty good enough or should I make a ring to bolt to?

Fuel pump has a vent on it and the fuel tank has a vent near the fill neck (opposite sides of tank). I don't see a need for two vents. I would like to plug the vent on the fuel pump. Any reason not to? BTW the EFI uses a return line.

I may have some more questions later.

[WardL]

I expect the rust came from the ethanol in the gasoline and not your recent fill with water. If you do epoxy coat the tank, be sure it will handle ethanol. Many older boats have epoxy lined tanks not compatable with ethanol. I would choose something that will handle up to 85% ethanol. I'm not saying you should use a new coating of some kind, but it seems like you want to do something to stop the rusting.

[Dwight]

Olddog
I have a local union mechanical shop that has build several gas tanks for us out of aluminum and stainless.
I draw them up and the sheetmetal guys cut, bend and weld them perfectly.
They install baffles, bung, ports, what ever we want. Price has alway be very fair.

They are hot rod guys and understand our needs. Great bunch.

If you want to see what it would cost to have one build just drop me an email and I'll put you in contact with Vic.

Dwight algunruner@aol.com

[olddog]

Thanks Dwight. I plan to re-use this tank. It is very light surface rust. I let it sit empty over the winter, planning to do this work. A local Rod Builder told me that was a no no. I'll clean it up and use it. He also said he would leave it bare and not put Epoxy coatings in it.

I have found a mounting kit for the fuel level sending unit. If there is enough meat, I may go with blind nut certs.

This tank had cork gaskets. I'm thinking of rubber gaskets rated for gasoline and E85.

[Trueoo7]

Originally Posted by Dwight

Olddog
I have a local union mechanical shop that has build several gas tanks for us out of aluminum and stainless.
I draw them up and the sheetmetal guys cut, bend and weld them perfectly.
They install baffles, bung, ports, what ever we want. Price has alway be very fair.

They are hot rod guys and understand our needs. Great bunch.

If you want to see what it would cost to have one build just drop me an email and I'll put you in contact with Vic.

Dwight algunruner@aol.com

What he said...I can attest to the craftmanship of these guys. They built one for me from a sketch. Fit was perfect, no leaks, with all the fittings in the right place, as I had asked for. They sent me pictures of the finished product. Going on 2-3 years now and not one problem with it. Highly recommend them.

When I told some race car friends I was having it made out of aluminum and the price, they said there's no way as the metal alone will cost that much. Let's just say they are still in shock!!

[Ron61]

Can you get the light surface rust out of it? If so I think I would do that as it is only going to get worse and then you may have a problem with it plugging fuel filters and such. But with this lousy gas we get any more, I am not sure that even if you got it completely cleaned and treated it would stop the same thing from happening again.

Ron

[olddog]

The rust is very light. It's not solid, just specs spotted here and there. I'm going to try a vinegar lemon mixture I was told about, this week end. I can almost rub it off with a penetrating oil and a rag, so I think it will clean up. I'll report back.

[chomama1]

One thing about the leaking gas tank, when I bought my FFR and drove it home with my friend following me, he reported that I was spilling gasoline every time I accelerated. I took it in to the shop and they found a rubber gasket around the fill tube was torn. They replaced it and all is dry now.

[olddog]

The Vinegar and Lemon extract did a real good job of cleaning up the tank. Mostly shiny metal, but there are a few spots left.