Fast Fill Mod - Roll Over Valve
 

I'm about to put a 38 gallon rear tank in my 96 and am going to do the fast fill mod to it at the same time. I'm currently trying to decide what to do about the roll over valve/tank vent issue. I haven't been able to find any F Super Duty's in the local yards to source the big 2-port roll over valves, but don't want to cause any vacuum issues by eliminating the roll over valve. I have seen the folks that have tee'd the factory valve into their vent hose, but it seems like there's got to be a way to do a cleaner install. I haven't seen any threads of people doing it this way, but why not drill a new hole in the top of the tank and either mount an aftermarket roll over valve in it, or mount an elbow to hook the filler vent line to?

Or have a missed some newer thread that someone has discovered a better way to do it?

How bout a fitting like this one?



Leave the factory roll over valve as is, mount this fitting on the tank and run hose to the filler neck fitting. Could even mount it closer to the fill hole on the tank, which would require less hose and make it easier to keep slack spots out of the vent line.

Seems to me if you did that it would defeat the function of the roll over valve?

In the case of an actual roll over, any fuel going through the vent hose should just go to the filler neck, where the tank is sealed by the filler cap.

Do our trucks have an actual roll-over valve? I thought it was just a vent, located where the roll-over valve is typically located on a gasser. :confused:

Yes. Check this write-up and look about halfway down for a picture of a gutted rollover valve...

1994-1997 Power Stroke FAQ - Fuel Tank Vent Mod

This is an older version of Jim's write-up. I believe he changed it on the write-up on his site because of the issues he had with vacuum in the tank. On his site he mentions using the alternate roll over valve, which is no longer available.

Glacier Diesel Power p/n 0307-TVK
 

I am wanting to do the tank vent mod. and I found a tank vent kit from Glacier Diesel Power for the '03 to '12 Dodge trucks. You drill a hole in the fuel tank and install their bulkhead fitting and hose. Then you have to do the fuel filler neck mod. and connect their 3/4" hose to your modified fuel filler neck. Now you can keep the factory fuel tank vent.

Since that last post, I came up with another solution... Instead of tying the vent into the rollover valve, I drilled a hole in the tank next to the fill hole, put in a barb and sealed it up with JB weld. Gutted the fill neck and put a barb on the side of it, then routed the hose between the two. That way I can leave the stock rollover valve in there. So far, I've been extremely happy with it. I have not tried a "big rig" nozzle, but the regular nozzle on full flow works great all the way up to about a half gallon from full. I will also add that I have to pull the nozzle back an inch or so. If I shove it all the way in, it won't work. Before the mod, I couldn't even run the pump on half flow without it clicking off.

Here are a couple of pictures.

First, the barb I added to the tank:

https://cimg2.ibsrv.net/gimg/www.for...ad475ab9e7.jpg



Next, a picture in the truck. Notice that I am a dumbazz and didn't think the whole project through, so I ended up with the barb on the wrong side of the filler neck. I looped the hose around and it works great, but would have been better on the other side.

https://cimg9.ibsrv.net/gimg/www.for...6205db523a.jpg

I am guessing the placement of your hose barb on the tank is preventing you from getting that last half gallon before the pump shuts off. Pump will only fill to the level of your vent. Good solution though for the ones who want to keep the rollover valve.

What rollover valve?

How is the JB weld holding up? I like this Idea more than the mod to the tank breather.

No issues so far. Like pwjackson said, placing the barb a little higher than I did should help to get more fuel in before the pump shuts off. If you're replacing the tank, test fit it in the old tank to make sure you get it right. And drill the smallest hole possible so the barb threads in nice and tight. I think I used a step bit to drill mine. Be sure to prep the surface good and put the JB on there thick. I let mine cure for a couple days.

Where did you connect the other side of the hose? to the fill tube? it looks like its just hung there. did you weld in a bung or a tube ? I don't think a brass fitting would work well as it would get into the way of the nozzle right?