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Stop fuel spills- filler neck modification

Mach1 Driver

Well-Known Member
This is a relatively easy way to stop spills when fueling. It can be done with hand tools and no welding is required. I added a PDF version.
 

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  • mustang filler neck7.pdf
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interesting. I've made a similar and much less complicated mod that works quite well. It looks like his is also going to work well but a bit overkill and a lot of work. I have made a few variations for Stangfixers so I will let them speak for them selves but I have driven my car in 18 states and filled it at a lot of different stations. I can fill at full blast and the auto shut-off works. No splash back either. I welded mine and used engine paint. I've had no rust and no issue of sparking.
filler up.jpg
gas tank 3.JPG
gas tank 1.JPG
 
interesting. I've made a similar and much less complicated mod that works quite well. It looks like his is also going to work well but a bit overkill and a lot of work. I have made a few variations for Stangfixers so I will let them speak for them selves but I have driven my car in 18 states and filled it at a lot of different stations. I can fill at full blast and the auto shut-off works. No splash back either. I welded mine and used engine paint. I've had no rust and no issue of sparking.
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Good post tarafied1. I have no quarrel with your approach, I've seen it before and it works if you can weld and have the equipment. I used simple tools with my method. Either way I think they are both good modifications that solve the problem and I don't advocate one over the other; it is simply a matter of the tools available and the skills.

As far as paint goes, OK you haven't had any problems but the manufacturers use conductive hoses and filler necks to lessen the possibility of a static discharge. The car industry has to deal with hundreds of millions of instances where static discharge could be a problem. Its the prudent thing to do in my opinion and engineers like me tend to be conservative. By the way, the CJ Pony fuel filler neck I used was originally painted with conductive paint- I tested it with an ohmmeter. I couldn't find a fuel resistant conductive paint so decided to use zinc plating because it is conductive and more durable than the paint that CJ used.

I would guess that being able to fill on high may be dependent upon the pump more than either your modification or mine. The nozzle extends through the hole and they should be in similar positions in either case and the flapper should be completely pushed out of the way and not an issue. But perhaps you are correct and there is some turbulence issue due to the construction in my modification. I don't really know and it only irritates me slightly IF it must be set to medium ;)

One advantage is the flapper that helps prevent a surge of fuel out the rear from aggressive acceleration, and I would guess that 100% of this group is guilty of that. If you would like to see that happen, and your cable provider (I have Comcast) allows you to call up previous episodes of Bitchin Rides, go look at S1 Ep14 at around 28 minutes. The owner picks up his 69 Stang from Kindigit and there's a shot from the back as he pulls away under heavy acceleration...and gas comes out from around the cap.
 
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I'm not bashing yours at all or promoting the one I made. In fact I didn't realize it was your idea. I was thinking you found it on the interweb and was asking for opinions. I reread my post it it kinda sounds like I was putting it down, didn't mean to come across that way. I was just sharing my opinion since you said comments were welcome. It's definitely something done by an engineer! The drawings are nice, too! Looks like the ones you would see on a patent. So I am sorry if I came across as a loud mouth jerk!
I know the design you have is much more "professional" and safer but I am a bit of a hillbilly. I originally only intended to do my car because of the issues you mentioned. The main reason was the problem I had of only filling at medium and even that could be messy. My biggest concern was the nozzle would never auto shut-off so I had to guess when it was close and slow down and listen or it would overfill. It was a PITA! Less of an issue to me but also a problem, the pop-open caps are bad for spilling out as you accelerate like you said. When I shared the idea here, many here were interested so I made a few and tweaked it based on the feedback from them. That was largely due to the very fact that pumps in different states have fume catchers and other features that might effect the idea I had. It was mentioned in my thread and I thought about the flapper but never really followed through with it. Well actually I did make one but it didn't work well (I still have too). I also originally used the sealer stuff for gas tanks to paint some of the fillers I made but all the while I was using my 1st prototype on my car and no rust or problems so I just stuck with engine paint for rust protection. I honestly never worried at all about sparks or static.
Just like you also mentioned, every gas pump is a bit different. That also was why I made some for the guys here. It gave me feedback on how they worked. As I mentioned too, I have driven my car in 18 different states now on HRPT and have encountered a lot of pumps. I can still fill at full blast. I think most of the guys that use the ones I made can as well. I did make sure the hole was a tight fit around the filler nozzle and that the vent hole on the filler nozzle would be inside the plate. Your design looks like it should work at full too. Not sure why you might have some splash?
Yours is probably a commercial product, you could sell as a kit or to the Mustang supply houses. Especially since you don't need a welder! Mine is redneck, but it works for me.
 
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One advantage is the flapper that helps prevent a surge of fuel out the rear from aggressive acceleration, and I would guess that 100% of this group is guilty of that. If you would like to see that happen, and your cable provider (I have Comcast) allows you to call up previous episodes of Bitchin Rides, go look at S1 Ep14 at around 28 minutes. The owner picks up his 69 Stang from Kindigit and there's a shot from the back as he pulls away under heavy acceleration...and gas comes out from around the cap.
Somebody is watching their TV very intently! lol

I suppose given your frustrations with fuel spillage you were specifically looking for it but still quite funny that anyone would catch it.
 
I need to do something for mine now that I think to be within weeks of firing it up. I had this on my list to go after later but given the potential damage I probably should just do it now and be done. Hate adding to the punch list though.

Yeah, I said weeks {.}.
 
tarified1 wrote: I honestly never worried at all about sparks or static.

No I didn't take your post as criticism, but thanks for your reply. Honestly I would feel much better about your design if you had it zinc plated, otherwise they are very similar.
 
Somebody is watching their TV very intently! lol

I suppose given your frustrations with fuel spillage you were specifically looking for it but still quite funny that anyone would catch it.

I suppose so, but the guy launched like a rocket and got quite a bit of fuel out the back. Yessss I was standing in front of the big screen with the remote in hand and did replay it many times. Since it still has the original paint, the back of my car has quite a bit of discoloration around the cap.
 
tarified1 wrote: I honestly never worried at all about sparks or static.

No I didn't take your post as criticism, but thanks for your reply. Honestly I would feel much better about your design if you had it zinc plated, otherwise they are very similar.
Since you quoted Craig about sparks and static in particular and then again referenced having the part zinc plated I have to ask. Is the zinc plating for more than just corrosion resistance? I can't see how the plating would have an affect on electrical phenomenon. Maybe I am missing something?
 
Since you quoted Craig about sparks and static in particular and then again referenced having the part zinc plated I have to ask. Is the zinc plating for more than just corrosion resistance? I can't see how the plating would have an affect on electrical phenomenon. Maybe I am missing something?

Besides the corrosion resistance Zinc is a very good conductor. Many electrical parts are zinc plated. Fuel moving through the filler neck can build-up a static charge on anything it touches if the conditions are right. Since the fuel neck is grounded to the chassis it is dissipated.

People carry an electrical charge. Yours clothes move and rub, or you may shuffle your feet. Do that on carpet and you know the result when you touch a door knob, especially if the humidity is low. A very common cause of electronic failure is from people touching something they shouldn't. At the transistor level inside a chip it is the equivalent of a lightning strike. Under an electron microscope it looks like it got bombed. If you have ever been in a facility that makes electronics you will see conductive floor and table mats that are grounded, and the operators will wear wrist straps that plug into a grounding system to remove the charge from their body. They even have heel straps that go up above the shoe and around the leg, then walking on the conductive mat removes the charge. I would walk the assembly line with an electrostatic gun that would look much like a timing light and would register electrostatic charges, looking for hot spots. Pulling masking tape off the roll would develop a huge charge. Styrofoam coffee cups weren't allowed because they would carry a big charge. Yes I have a healthy respect for static electricity and what it can do- especially in a fuel tank.
 
I'm curious as to why the neck needs to conduct. The neck is insulated from the car via the hose and gasket short of the mounting screws. In most older cars I would guess the conductivity is not there.
 
I'm curious as to why the neck needs to conduct. The neck is insulated from the car via the hose and gasket short of the mounting screws. In most older cars I would guess the conductivity is not there.

In my design the upper neck has 4 sheet metal screws attaching it to the chassis and it is probably the first thing the nozzle touches and there may be a difference in potential between the car and pump, then as the fuel goes into the tank it flows down the lower filler neck, potentially creating a static charge there but it has the dedicated ground wire. The upper neck has 16.5 ohms between it and the chassis, which is higher than I expected but good. The wrist straps I mentioned in the previous post have 1 megohm resistors in them to prevent the person wearing them from getting electrocuted if they touch a live wire, and even with that much resistance the charge is dissipated to ground.
 
do late model cars not create any static because the filler necks are plastic? gas tanks are plastic too on some
 
do late model cars not create any static because the filler necks are plastic? gas tanks are plastic too on some

I can only ass-u-me that they impregnate the plastic with carbon/graphite to make it conductive- that is what is done with hose.
 
Just out of curiosity, why all of the hoopla over the fill tube being grounded to the chassis, static charge dispersal, etc ?!? There is no magic bullet in the OEM plastic fuel tanks or fillers. They are standard poly derivative plastics. Every metal filler neck that is bolted or screwed to the body is electrically "bonded" to it via the physical contact and generation of a static electrical charge within the fuel system is virtually unheard of. While the filler neck modification information (for either method), is pretty good stuff, why muddle the pertinent mod info with a bunch of info and debate on stuff that has no bearing on it? Not trying to stir the pot, just trying to steer things back on topic....i.e. a modified filler neck to prevent splash.
 
Craig I remember when you first started doing your modified filler. A quick question for you regarding your experiments. Did you ever try to remove the baffle/flapper from a newer tube and install it in a vintage tube? I have the filler from the '92 donor car and I have the original '66 filler. The tube diameters appear to be the same and I have toyed with the idea of removing the baffle/flapper from the '92 and then welding it into the '66. No sense in reinventing the wheel if you've already traveled this road!
 
Craig I remember when you first started doing your modified filler. A quick question for you regarding your experiments. Did you ever try to remove the baffle/flapper from a newer tube and install it in a vintage tube? I have the filler from the '92 donor car and I have the original '66 filler. The tube diameters appear to be the same and I have toyed with the idea of removing the baffle/flapper from the '92 and then welding it into the '66. No sense in reinventing the wheel if you've already traveled this road!
no I haven't. I did get asked to build one with a "check=valve" and I did. The guy who asked me to do it supplied the parts. It was a device marketed to the tri-five Chevy guys. I attached a few pics. He didn't like it so I made him one like the rest and he was happy. He gave me the one with the check valve for my trouble. I still have it.
Personally, the plate I installed in mine solved the problems. I think the flapper was to prevent filling with the wrong fuel. Leaded fuel nozzles are/were bigger and won't fit thru the small hole. If you try to fill it the flapper will cause the auto-shut-off feature to kick in. That's what I think anyway.
As far as fuel sloshing back out when full, I don't have that issue. My dad reports the same with his 66 that I did for him. Other results may vary...IMG_0232.jpg IMG_0305.jpg IMG_0306.jpg IMG_0308.jpg
 
Guess I need to send you a filler neck then Craig...

I do appreciate all the thought you've put into your mod mach1.
 
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