Exhaust tube to make fuel filler tube???

[scherp69]

As some of you have seen, I decided to put a Camaro filler neck onto my Acadian (Nova) but now I have to figure out how to connect the filler tube to the gas tank. I was thinking about getting some standard exhaust tubing and running it through the floor (welded of course) and running it to meet with the tank filler tube. Is there any issue using exhaust tubing to do this? The outside will be painted and matched to the underside and trunk, but want to make sure won't be an issue running fuel through it. Thanks in advance guys.

[CamaroAJ]

i would use stainless if it were me. nothing worse than a tank full of rust.

[Musclerodz]

no issues, it is galvanized so you should not have rust issues. Try to find seemless tubing if you can

[scherp69]

Thanks Mike that's what I was hoping to hear. I don't have an adapter to weld stainless so it's much easier just using standard tubing.

[SLO_Z28]

Theres no rust issues, the 69 Ford truck I built has a old piece of exhaust pipe scrap as a filler neck for the second tank. Been working fine for 10 years now.

[Musclerodz]

Originally Posted by scherp69

Thanks Mike that's what I was hoping to hear. I don't have an adapter to weld stainless so it's much easier just using standard tubing.

Be very careful welding the pipe if it is galvanized. The gas that comes off it is poisonous.

[scherp69]

Originally Posted by Musclerodz

Be very careful welding the pipe if it is galvanized. The gas that comes off it is poisonous.

Thanks Mike. I'll keep that in mind. Never knew that.

[speedshftr]

Be very careful welding the pipe if it is galvanized. The gas that comes off it is poisonous.



wow i never knew that.ill have to tell the guys at work.thanks

[JRouche]

Haha, seems the gas is harmful

Now, for the tube. Im not sure but you will get some rusting. Not from the clean pipe. But every joint will have raw steel filler and degraded burnt zinc. The pipe thats not been welded on will be fine. But every joint will be a hot bed for rust. And if you use the recommended welding practice for joints you will make a gap the size of your filler wire. And you will get some strands of filler that poke through to add to the available rusting issue. And eventually those strands can break off and end up in the tank, sit on the bottom and start a lil rust factory. After they have already started the rust factory on the tube joint.

Now, because you dont have the welder to do stainless thats out. So you work with what you have. Some steps you might be able to take. For the joints. I would do a solid butt joint with NO gap. Bevel the ends nice and clean so the point of the bevels rest tightly against each other. If you clean ALL the metal of its zinc coating, and use a nice slow hot bead to not just lay the bead onto the joint but to really melt the parent metal you should be fine for strength. It will be strong and you wont get any stray wires inside of the tube.

Then comes the question of all the raw metal inside the tube, and the flakes and dust of the burnt zinc. My experience with gasoline soaked raw metal is that it wants to rust now. The gas dries it out severely and it will attract moisture like a dry sponge in the desert. And the moisure from the tank will rise and settle on the cool tubes. Those joints will rust quicker than just about any other piece on the car. Not that the joint will break in your life time. But it will wash rust into the tank and for me, it would be always on my mind. I would alway remember every time I went to fill up. I have this rusting seam in there and it would just eat at me.

So any amount of protection will help. But it has to be fuel proof. Gas is a great solvent. Most coatings will soften up and be removed to just end up in the tank, possibly the filter.

So if you want to protect the welded seam look for a purpose designed coating for fuel tanks.

Then comes the issue of how to get it into the inner seams of the pipe. Ideally the pipe would be removable, then you could coat it and install it. But it doesnt sound like thats gonna be the case. Im not sure. Are you gonna build the pipe in place and weld it while in the car?

I would drop the entire tank and filler tube. Map it out in the car so you know it will fit. Mark it up to final shape. Then remove the entire assembly and make the joint from the tank removable. Use a silicon joint. And the same thing for the filler neck. Make a silicon joint for the neck.

By using silicon joints you get some extra bennies. First, you didnt talk about when you have to weld on the tube on the tank. Is there already a rubber hose joint there? You cant weld on the filler tube with it attached to the tank. Unless you have done some fuel tank welding before its a sure way to burn the place down. You have to completely void the tank and my fav is to fill the tank completely with water (after all the fuel has been drained and washed out). With the tank full of water it wont have any more fumes, just water. Its a pain in the butt. But thats where rubber ( I like silicon) sleeves come into place. You dont have to weld on the tank tube and it gives a means for removing and installing the gas tank. And for some cars that have a floating body, like on rubber body bushings it gives the flex between the floating body of the fuel filler area and the rigid frame mounted tank.

So, if you can make it so the tube is removable then its a matter of coating the inside of the tube after you have done all the welding. And that would be up to the various manufactures of gas tank coatings. How long does it take for the coating to adhere. Cause you will have to place the coating in the tube and rotate it till it has cured some. I wonder if some of the coatings supplied for exhaust systems would be fuel compatible? They have some wands that extend into the tube to coat the inside. I dont know.

Again, I wish some of you guys were closer. Id love to cut some stainless tube up and TIG weld it up tight for you. No issues with rust then. Damm I hate living in the boondocks sometimes. LOL

So.... Back to reality. You will weld it up. Umm, yeah, the zinc does give off some fumes. All metal does, hell stainless steel is one of the worst. Always keep yer head out of the fumes, no matter what you are welding. But Im sure you already knew that. I sure hope you arent welding the filler in place, the tube to the tank. The fumes from the gas tank trump any fumes from any welding. Big time explosion. The heck with some lung and blood poisoning. The skin grafting from a major burn is killer. And its not so much the grafting that hurts, with all the peeling of the good skin to make new skin. Its the washing. Yup, the endless deburring of the toasted, rotting dead skin. Thats the bitch of it all. Dont weld on the tank in place. JR

[scherp69]

Thanks JR. I'm not sure if I've painted a clear picture though of what my plans are. None of the exhaust tube that I plan on welding will actually be welded directly to the tank itself. Here's what my plans are:
- I've welded in a filler panel from a camaro between the tails lights, so now it's like the camaro set up.
- I'm using the Ridetech filler cap and filler neck.
- On the inside of the trunk, I want to weld in a piece of exhaust tubing that will go from the inside of the trunk to under the car
- The ridetech filler neck will connect to exhaust tube with rubber hose
- The filler neck that is connected to the gas tank will connect to the exhaust tube under the car with rubber hose
- So basically I'm just using the exhaust tube in the middle to connect to the filler cap tube and the gas tank filler tube
- I only plan on welding the outside around the exhaust tube where it goes through the trunk floor and out the bottom of the car

Hope this paints a better picture of what I'm doing. I only plan on using maybe 12 to 18" of exhaust tube. As for any gas fumes.....I don't even have the tank yet to consider putting fuel in it.