I'm building a 50 gallon diesel tank to go in the back of my truck, and have a couple of questions for those that have transfer tanks now. I'm planning to have a pulse pump to transfer the fuel. I could do it by gravity, but it might be kind of slow. With a 45 GPM pulse pump, it will fill the tank (29 gal) in under an hour, and if it runs dry, it won't hurt the pump.

1. Do I need to run a vent line from the main fuel tank to the transfer tank? If the main tank is sealed then I presume I'll need to do something like this so I don't pressurize the main tank when transferring.

2. I was planning to vent my tank while filling just like the main tank is with a vent line near the top of the tank running up to a point on the fill tube where it is above the end of the nozzle when filling. I'm planning on using a vented cap. Will this work? Does the main tank run the vent to a carbon canister like gas cars do, and if so, would I be well advised to do the same?

Thanks for any help.

 

I may be misreading e-mail but I am assuming you want a standard transfer tank? It almost sounds like you will hook into existing fuel system to fill up stock tank(s)? You don't need anything more than a normal vent for your DIY tank. Weld a bung or an entire L shaped fuel line connector, pointing it 180 away from cab. Doesn't have to be 180 but that way rain won't get it when driving. I'll try to make direct answers below.

1. No. Pressurizing the main tank doesn't apply unless unless this is not a transfer tank.
2. Put a normal vent in it, see above. Vented cap is OK. I wouldn't run a vent line.

I don't know a pulse pump is, but 45GPM is really pumping fast at max. Your 29gal tank will be overflowing in 65 seconds. I think I am misreading your e-mail about what you want?

 

Sorry, 45 GPH. It's an aftermarket pulsating solid state pump like those used on carbureted cars.


Maybe I don't understand what a transfer tank is. I thought it was a tank that you fill and then when needed you transfer the fuel from that tank to your main tank. Am I wrong? I'm planning to pump the fuel into my main tank rather than hooking into the main fuel system. Will I be pressurizing the main tank when I do that?

 

Why not use a gas station type nozzle and 12 volt pump? Northern hydraulics or similar mail order can set you up and then you can fill machinery in the field as well as your own tanks. More easier to remove if you need, too.

 

I've been looking at doing this myself. One thing you might consider is installing a fuel gauge sending unit in the tank and gauge in the cab.
How are you or what are you making the tank from??? Just curious I need to get started on building one for my truck. Also I will check the number but NAPA has a little pump perfect for this.

 

mtncrawler,

I don't have any fields or farm equipment, but I do have a ski boat, some motorcycles, and four wheelers. One of the reasons I'm doing this is so that when I take my boat or bikes out for several days, I can fill the 50 gallon tank with gasoline and transfer it to my toys. I think I'll just use a 100' garden hose for the transfer to the boat though. The tank will always be above the toys, and siphon should work fine. Otherwise, it'll take an hour to fill the tank. I'll just put the hose down through the fill neck. For gassing up my motorcycles and four-wheelers I'll use the pump and a short piece of 3/8" hose.

I don't particularly care if I can see how much fuel there is from the cab. I may put a sight glass or something on the outside of the tank, or maybe a temperature strip. I'm considering putting in a heater core inside too in case I ever want to run biodiesel. Problem with that is if it ever leaks I'm in trouble and would have to cut a hole to fix it so I don't know -- maybe not.

I'm building it out of 14 gauge steel (kind of heavy but easy to weld). It will be 54" long, 12" high (to fit under my tool box), and 20" wide. I'll drill and tap a steel block with pipe threads and weld it near the top of the tank for the fuel line, and run a tube inside (maybe brake line or something) to the bottom corner of the tank. To empty, just drive on a curb and turn on the pump. I'll coat the inside with epoxy paint to keep it from rusting (might get it galvanized, not sure). It'll also have a baffle in the middle. I'll weld it with my mig and rely on the epoxy paint to fill pinholes (or silver solder or braze if necessary).

Thought about putting an in-tank pump etc. but I don't have enough room between my tank and tool box.

Any one have an answer on the pressurization of the fuel tank?

 

Here where I work we use several transfer tanks in pickups to fill heavy equiptment on jobsites. Even had a loader with a fuel tank too small to run a long shift so we mounted another tank on the hood above the engine that would gravity feed into the loader fuel tank. Since your'e talking about pressurization I'm guessing thats kinda what you want to do. It will be necessary to have a shut off valve in the feed line to close off transfer until your truck tank has room for more fuel. You can't have constant direct feed from a higher mounted tank or you'll have fuel going everywhere including vents and filler caps on the truck. Somethings to consider when building your tank - leave the pickup tube an inch or so high from the bottom so water and contamination doesn't get picked up. And instead of using an epoxy paint for the inside get the sloshing material specific made for this purpose. I have had radiator shops hot tank old fuel tanks and coat them with this stuff with very good results. And if I were going to warm a fuel tank I sure wouldn't use an in tank mounted engine coolant heat exchanger. That just seems like a good way to make a big sloppy mess. Hope this helps.

 

Thanks.

I am using a pump to fill the main tank. So, it'll only fill when I flip a switch in the cab. I 'll have to either put in a valve, or some other way to make sure that when I turn off the pump it doesn't keep siphoning. Shouldn't be too hard to figure out.

I guess I'll just have to give it a try to find out if the main tank is sealed or not. If it is, I'll have to add a vent for when I want to fill it.

Maybe I should put in two pickup tubes (or a pickup tube and a drain plug) -- one an inch or so up and the other right near the bottom. That way, I can drain the tank more effectively when needed.

I know about the gas tank sealer, and have used it quite effectively. However, there is an epoxy tank sealer that my brother used to use to seal tanks on house boats that I want to look into. I am more concerned about preventing rust than I am about sealing the tank.