Quick fill fuel necks

I am making a quick fill fuel filler neck and I'm wondering, is the roll over valve really necessary? Im having trouble incorporating the valve into the vent hose assembly. Might by-pass it for now and come back to it later but I gotta get the rear tank in and working. What do you think?

John

John, I've read that others have drilled out the roll over valve and used it as a vent. I know Matthias and I did this on the Night Moose in order to make the fuel tank transfer setup idea work. I suppose as long as you don't roll over, there would be no consequence to doing this.

as long as he doesnt roll over. nobody expects to roll over... well not many of us... i know one of these days alice......

My thinking was that the rollover valve also served as a vent and only closes when you roll over. If I install a hose on it that goes up to the filler neck, making the rear tank a sealed unit, in theory the fuel tank will be placed into a vacuum state as the fuel is used out of the tank. Has anyone had any trouble with this. I know, Im probablly thinking too much, haha

And if it's a sealed fuel system for the rear tank, nothing would leak out if I roll over anyway, right?

I can't speak for all years, but the presence of and design of the roll-over valves in the main vent-hoses drastically limit the venting of the tanks and are the real cause of the notorious slow-filling and puking of fuel into your boots.

I completely removed and discarded them from my tanks many many years ago and can use the rapid-delivery pumps that the big boys use.


My truck weighs 10,000-plus as it sits and is often hooked to huge cattle-trailers; if I ever were to roll-over, a few gallons of fuel pouring out are gonna be the least of my worries.

160k87F250 said:

My thinking was that the rollover valve also served as a vent and only closes when you roll over. If I install a hose on it that goes up to the filler neck, making the rear tank a sealed unit, in theory the fuel tank will be placed into a vacuum state as the fuel is used out of the tank. Has anyone had any trouble with this. I know, Im probablly thinking too much, haha

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160k87F250 said:

And if it's a sealed fuel system for the rear tank, nothing would leak out if I roll over anyway, right?

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If the tank cannot vent to the atmosphere, then it will pull a vacuum and run the engine out of fuel.


These are diesel engines that draw about twenty times the amount of fuel that actually gets used, cycling the rest through the return-line system; if it cannot replace the drawn fuel with outside air, it will not run.

Where are the roll over valves?

gatorman21218 said:

Where are the roll over valves?

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Its a little plastic thing on top of the fuel tank.

gatorman21218 said:

Where are the roll over valves?

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On my 1985, they were at the ends of the 7/16-ID vent-hoses that poke through rubber grommets on top of the tanks.

hmm ive been meaning to do this for a while now. First things first gotta fix the brake system

MIDNIGHT RIDER said:

I completely removed and discarded them from my tanks many many years ago and can use the rapid-delivery pumps that the big boys use.

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So what did you do about the hole on the fuel tank where the rollover valve was?

160k87F250 said:

So what did you do about the hole on the fuel tank where the rollover valve was?

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A copper elbow fitting(1/2 or 3/4 I forgot which) fits right in the grommet where the rollover valve was. I soldered a piece of pipe to the elbow and brought it out to the outside of the frame, Then slipped a hose over it and looped it up in the body cavity, and then wire tied a piece of screen over it. It works beautifully as a vent for higher speed filling. If I let the filling station nozzle automatically shut off, I get a little puke of foam out of the vent pipe, but that's it.

160k87F250 said:

So what did you do about the hole on the fuel tank where the rollover valve was?

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The actual roll-over valve was not itself directly plugged into the tank; like I already stated above, the valves were attached to the ends of the vent hoses.

Other year-models may actually have the valves plugged straight into the tanks; if so, just remove the valve and replace it by feeding a length of 1/2" hose through the LUBRICATED grommet, letting at least six inches protude into the tank; the remaining length is routed somewhere where water cannot enter.

I just removed the valves and screened the open hose ends.


Several years later, I removed the 7/16 vent hoses and replaced them with 1/2" hoses.

The 1/2" hose slid right into the lubricated grommets where the old 7/16 hose had been.

I TEEed these new 1/2" vent hoses together, and then TEEed that into the vent hose from the THIRD tank, then routed that single main vent to a point up high and dry just underneath the top framework of the head-rack, between the sleeper and head-rack.


With all tank vents TEEed into one main vent hose, should any of the three tanks become over-full, the excess will find it's way into whichever tank that has room for it.

So the weather warmed up today and I got bored enough to do my fuel tank swap and fix that pesky vent valve that was causing me to get pissed at the pump.

I bought new tanks from autopartsdeal.com and new straps as well. Went to the local ford dealer and bought new grommets for the roll over valves to. and over to murdocks for fuel transfer hose, screen, and a copper 90 degree bend, some other small stuff as well. So here are the pictures of what I did

1 - 26512 Hose from Carquest. ($30)
2 - 3/4" 90 degree copper elbows ($3)
1 - 14' section of fuel transfer hose with static wire ($24)
1 - tube of permatex ($5)
1 - 19gal side tank and straps st05 ($100)
1 - F6TZ9B076AA grommet ($7)
1 - Roll of aluminum bug screen ($8)

Once back in the truck I ran the vent hose up along side the fill neck hose and routed it thru the holes where my old 7 blade connector was mounted on the bed and turned it down on the inside of my bed liner.