filler neck mod question

[redneckaggie]

I have read about the filler neck mod and everyone keeps linking the same article from diesel stop where the guy plainly says that the mod caused vacum in the tanks. I kind of have the idea of doing something similar.

Here is the idea.

I will install a fitting in the grommet for the roll over valve and the filler neck(which will be gutted). I will run a hose between the two fittings but somewhere in between I will install a t and mout the roll over valve verticall above this line. wouldnt this give you the best of both worlds. Or are the caps supposed to vent on these trucks to prevent vacum?

 

[Fordsandguns]

All I did on mine was remove the rollover and put a 1" pvc elbow in its place with a 1" hose up between the cab and bed with a co8uple elbows on it to keep water out. Works good.
I'm not sure about whether the caps breath or not on these.

 

[riotwarrior]

I have read about the filler neck mod and everyone keeps linking the same article from diesel stop where the guy plainly says that the mod caused vacum in the tanks. I kind of have the idea of doing something similar.

Here is the idea.

I will install a fitting in the grommet for the roll over valve and the filler neck(which will be gutted). I will run a hose between the two fittings but somewhere in between I will install a t and mout the roll over valve verticall above this line. wouldnt this give you the best of both worlds. Or are the caps supposed to vent on these trucks to prevent vacum?

Sounds like a duplicate of what I am going to be working on ...

I have a bulkhead fitting for the Vent hole

then some 3/4 " ID tubing to a T that allows me to mount it vertically and install the ROLL OVER valve, then 3/4" tube up to filler neck...

I'll take pics of what I got thus far if you like. I'm like in for 20 bucks but I have the tubing to pick up along with the fittings I plan on using in my filler neck...that's it!

Good idea ya got goin on there...two great minds thinking alike gotta be onto something no????

Al

 

[lotzagoodstuff]

Interesting, never heard about the vacuum issue. Just wondering: have you done the "30 second open up the vent on the filler neck mod"? I won't say that it's the solutions to all the world's problems, but I will say it made putting fuel in my tanks a lot easier.

Can you post the link about the vacuum issues.

Thanks

 

[redneckaggie]

I already have the tanks pulled to replace the pickup tubes so why not go all out while its easy.

 

[MedicMoe]

I am curious to this mod. Anyone have any pics?

 

[Dave Barbieri]

I like the idea of being able to vent the tank as originally designed. So I used a knock out tool

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to cut another hole in the highest point of the tank top.

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I put the grommet and the 90 degree fitting there and kept the vent, which I now rerouted up to the fill receptacle. It's the black fuel line you see running on the other side of the filler neck. I drilled a hole in the plastic receptacle, pushed the fuel line through and reinstalled the vent cap that was on it originally.

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I have the original venting, so no new issues there, and I can now fill my tank much faster. No need to pack a lunch every time I need to fuel up.

 

[Mulochico]

I had a problem with vacuum buildup after the mod. It was because I used locking caps for the gas trucks. I was told I couldn't get the ones I needed (vented) as all were now "smog legal" (showed the same cap for the gas and diesel trucks). So I put the original caps on and have had no further problems.

 

[franklin2]

I thought the whole idea behind this was to get more airflow out of the tank when putting fuel in. I would think the roll-over valve would be a restriction to this airflow, just because of it's size.

I did this mod and I would say it should be mandatory to do for anyone who has one of these trucks. Fiddling around at the pump trying to get diesel into the stock system is a joke. I took the roll-over valves out, stuck a 90 in the grommet, and ran separate 1/2 lines for each tank out, looped them way up in the cavity behind the bedside, and then put a screen over the ends to keep varmits out. Works very good.

 

[junk]

I never had any issues with this mod. I used the factory diesel fuel caps which I believe are vented.

 

[bagpiperjosh]

I cant just make the existing vent hole bigger and use some jb weld to seal it?

 

[franklin2]

I cant just make the existing vent hole bigger and use some jb weld to seal it?

The existing vent is just a little slot above where the fuel nozzle goes in. Someone posted on here they took a screw driver and opened this slot up, and claimed good results, but I see it hasn't caught on very much, so it must not work as good as reported.

The vent system with the roll-over valve that we are modifying is not really intended to be a fill vent. It's just a vent to let air in as the engine takes the fuel out. But it sure works good when you enlarge it for a fill vent system.

I forgot to say I also took the small pipe in the filler neck out of my filler necks. That was reported to help with the filling problem also, and while it was a slight improvement, it wasn't enough to be able to fill the truck properly at the fill station without the fuel foaming out and cutting the pump off.

 

[redneckaggie]

the idea behind this is to vent the air upwards before the end of where the nozzle would be but still retain the factory vent that allows air to come into the tank as you are driving. As mulochico mentioned all gas caps are sealed now so without some air flowing into the tank it will become negatively pressurized and not allow fuel to escape. the idea of removing the roll over valve completely and running a hose with a filter on it will work fine but if your truck somehow rolls all of the diesel inside will be poured onto the ground(reason for the rollover valve being in the system). I am going to gut the filler neck anyway so that i can fit big rig nozzles so why not add a fitting to it and modify the system still leaving factory safety measures in place. If I were not going to gut the neck I too would probably just run a larger hose from a fitting installed in the old roll over valve grommet

 

[franklin2]

I am saying just look at the roll-over valve assembly. If the opening is let's say 1/4", then there is really no use running a 1/2" ID hose when the roll-over valve has a opening of 1/4".

As far as the safety reasons for the valves, that's a well known fact but unless you can come up with a larger valve that does the same thing, you will get a slap on the back for being safe while you are still standing at the fill station for 30 minutes trying to fill your tanks.

 

[fordf350man]

just a question does the powerstroke trucks have this same issue? if not can we just get a powerstroke filler neck or tank?