my version of the tank vent mod

[redneckaggie]

well gentleman I am in the process of doing many things to the truck and first on the list was the fuel selector valves, tank vent, and showerheads. I pulled the sending units and tested them with an ohm meter and they seemed fine, spliced fuel hose onto the pickup with a beak cut into the bottom of them. My idea of the tank vent mod was a little different approach and I must say I like the way the rear tank turned out.

I pulled the roll over valve out of the front tank and threaded a 3/4 npt x 3/4 hose plastic fitting and ran 3/4 hose up past the frame rail. there I teed in the roll over valve and past that I connected to a fitting ran into the filler neck. this was kind of a pita.

On the rear tank I decided to go a different route and drilled a new hole and jb welded a hose into the hole that the 3/4 npt x 3/4 barb would thread tightly into. then it was just a matter of connecting hose from that fitting to the top of the neck.

I tested them and they seem to work equally well


Next on the list is to refinish the seat and do the system. I just bought a fosgate p3 shallow mount and have had a fosgate 500 watt amp sitting around for a while. Thinking a custom ported box around 1.5 cu ft+port. while all of that is out of the truck I will fat mat the cab and do the body lift and then comes the turbo. hopefully I can get it done within the month, I have way to many projects going on.

 

[jaluhn83]

I'd be warry using plastic hose. Use fuel hose. You can get it in 1/2", not sure about 3/4" but you shouldn't need that big of a hose for a vent line, 1/2" is fine. The fuel will probably rot the plastic.

Sounds very similar to what I did on my rig. Mine works well it's just sensitive to where you put the nozzle in - not sure why but putting it all the way in makes it trip all the time. Might need a baffle or something? I just leave it partially in and it's fine.

 

[subway]

just trying to get this without pics , you put a larger vent from the tank to the filler neck so that it can breath easily during filling. you then T'ed of that and placed the stock rollover valve higher up in the system so it could still vent and be legal? that actually sounds like a better plan!

 

[redneckaggie]

I should have taken pics but I always get busy and forget. But yes that is essentially what I did on the front tank. On the rear tank I drilled a new hole in the tank to mount the fitting to run the vent hose. This is what I should have done on the front because trying to T in the roll over valve while still keeping it vertical and keeping the vent line running downhill was kind of a pain.

Forgot to mention I gutted the filler necks at the same time.

The plastic fittings I used are for spray rigs so they are chemical resistant. The hose is not plastic it is a reinforced type hose that we use for oils at work.

I also got the interior gutted yesterday for installation of the fat mat and painting the trim. The bench seat is at the upholstery shop getting restuffed and recovered with two tone blue and silver vinyl

 

[PackRat239]

The rollover valve has nothing to do with venting the tank on fill up, its only job is to let air INTO the tank when fuel is being pulled out of it, to keep from developing a vacuum in the tank, and starving the engine of fuel. It also keeps fuel in the tank in the event of an accident. By removing the valve, (which I see no problem with) you are creating a secondary vent system for the tank. Actually a much better system than the factory, who is constrained by the epa emissions regulations.

 

[chris142]

International Harvester used Plastic Diesel truck air line for fuel line in the 70's. My 73,1210 had it from the factory. If it's ok to use with gas I assume Diesel is ok?

 

[jaluhn83]

Some is, but some isn't. Many different types of plastic and it's not always easy to tell them apart. Just have to be careful.

 

[redneckaggie]

The rollover valve has nothing to do with venting the tank on fill up, its only job is to let air INTO the tank when fuel is being pulled out of it, to keep from developing a vacuum in the tank, and starving the engine of fuel. It also keeps fuel in the tank in the event of an accident. By removing the valve, (which I see no problem with) you are creating a secondary vent system for the tank. Actually a much better system than the factory, who is constrained by the epa emissions regulations.

I understand this, this is why I kept it in place since I was essentially making a closed loop system with the cap on and vented system with the cap off. I dont really see a problem with removing the valve but I didnt like the idea of having an open hose leading into my fuel tanks hanging out under the truck. hence venting into the filler neck above the end of where the pump nozzle would be while filling. Now I have a vented tank that I can fill as fast as I want and dont have to worry about diesel getting everywhere when I fill up.

 

[GRU]

This sounds just like how i did mine. Worked great on the dually. Did the same thing in Blue and didnt make any improvement!! Very frustrating...

 

[redneckaggie]

are you sure that the vent lines are not getting clogged with fuel due to a valley in the hose?

 

[6.9poweredscout]

International Harvester used Plastic Diesel truck air line for fuel line in the 70's. My 73,1210 had it from the factory. If it's ok to use with gas I assume Diesel is ok?

They did it on the gasoline and diesel scouts! My terra was the nylon hose. Whenever I replace the lines I just go to fleetpride and get air brake hose....alot cheaper than rubber hose too!

 

[6.9poweredscout]

anyone have any pictures of the fast fill mods? can't I just put a fitting in the top where the rollover valve goes with like a 5/8 hose, then weld a 5/8 pipe on the top of the filler neck so the air escapes. or am I missing something here? getting sick of not being able to fill my front tank, they must have removed the vent hose when they installed the transfertank as it takes 15 minutes to fill, you can barley pull the handle t fill it or else it pops off of pukes out fuel everywhere!

 

[trackspeeder]

anyone have any pictures of the fast fill mods? can't I just put a fitting in the top where the rollover valve goes with like a 5/8 hose, then weld a 5/8 pipe on the top of the filler neck so the air escapes. or am I missing something here? getting sick of not being able to fill my front tank, they must have removed the vent hose when they installed the transfertank as it takes 15 minutes to fill, you can barley pull the handle t fill it or else it pops off of pukes out fuel everywhere!

That will work. I tossed the rollover valve and replaced it with a threaded plastic fitting. Ii don't remember the size I used. But it screwed into the grommet.

 

[6.9poweredscout]

Perfect!

 

[subway]

You still need some sort of venting to allow air in to replace the fuel you used.