Has anyone relocated a gas filler on a chev w/duel tanks

[77crewcab]

I am in the process of doing this for my Crewcab. The burb I got the tank from was one I couldn't cut on but I found an older truck at the same yard that I could cut on. What I did was cut out about a 6x6 square around the gas cap opening (Note: I got this to match what is on my truck it is the gas cap only style with no door) I also cut out the little hump over the filler neck inside the bed. I think the older suburbans had this setup as well with the hump over the filler neck. From what I can see, once the tank is installed and the new gas cap opening and hump patched into the bed it should work as designed on the subs. That is the plan anyway as currently I don't have everything together to make sure. As for the switching isue I plan to run and extra switch solenoid ahead of the stock one. I wil have two tank switches on the dash one to switch the saddle tanks and the second to switch from saddle to burb tanks. But for the extra long haul I am also considering adding a 90gal transfer tank in the bed. 170 gallons should make for one long roadtrip.

 

[dremu]

Any ideas of what to do if I put a burb tank in the back of my crew cab and left the two saddles in there. As far as switching fuel tanks? I could run a crossover to one of the saddles and the back but I dont like the idea of the gas being able to move freely between the tanks. Many time when I go riding I park the back end of my truck in little natural valleys so its easier to run my bike up and down the truck. I could see the fuel moving to the rear tank and spilling out the filler neck. Does anyone know of a selector that allows me to chose between 3 tanks? I would just use a regular 3 position switch in the cab but dont know what to do about the tank selector.

Tank selectors aren't cheap, and I've only seen DUAL-tank switchers, so two of them is $pendier than I wanted to throw at it.

You'd have to do some kinda kludge for left-saddle-to-right-saddle, and another for saddle-tanks-to-rear-tank.

Could do a crossover for the saddle tanks and then use a switcher for front-to-rear?

-- A

 

[73k5blazer]

I made my own custom crossover pipe to fill from one side. It's an '86 C10. Got the idea from another C10 I seen at the pump one day. Wheel well filler. Might have to stuff it a little more for a 4x though. I fabbed up my own bracket to hold it, and used a piece of pipe secured to the bed (not the frame). Most expensicve part of the whole setup was the large diameter filler rubber and the 5/8" vent rubber. The valve I bought is a Borg Warner FSV2A (6 port all electric, steer clear of the generic 3 port valves, they suck)
I added the second tank, it wasn't OEM.
There's probably some saftey issues involved. I know the OEM's do alot of testing around how the filler necks leak or don't leak in various crashes and such, and I'm sure my setup doesn't mean OEM standards. I made the hard pipe as short as possible (only the width of about the inside of the wheel wells) and used the rubber filler to connect it, that way I have a little crush zone from the side.

 

[dremu]

I made my own custom crossover pipe to fill from one side. It's an '86 C10. Got the idea from another C10 I seen at the pump one day. Wheel well filler. Might have to stuff it a little more for a 4x though. I fabbed up my own bracket to hold it, and used a piece of pipe secured to the bed (not the frame). Most expensicve part of the whole setup was the large diameter filler rubber and the 5/8" vent rubber. The valve I bought is a Borg Warner FSV2A (6 port all electric, steer clear of the generic 3 port valves, they suck)
I added the second tank, it wasn't OEM.
There's probably some saftey issues involved. I know the OEM's do alot of testing around how the filler necks leak or don't leak in various crashes and such, and I'm sure my setup doesn't mean OEM standards. I made the hard pipe as short as possible (only the width of about the inside of the wheel wells) and used the rubber filler to connect it, that way I have a little crush zone from the side.

Where'd you sneak the crossover pipe -- did you fit it between the frame and the bed, or does it go under the frame? Got pix?

-- A

 

[mudhound72]

For mine 3 tank setup I was planing on haveing a 2nd set up like 77Crewcab was talking about, I am lucky to have everthing allready from a different truck that I parted out

 

[73k5blazer]

Where'd you sneak the crossover pipe -- did you fit it between the frame and the bed, or does it go under the frame? Got pix?

-- A

Between the frame on the bed. There's room.

The right zip tie there was just to apply downward pressure while I installed a little retainer to the back face of the bed rib which is holding the back of the stainless steel clamps there. (I wish they'd have used a stainless ring screw with that stainless band!) I put a small piece of 1/4" rubber on the top of the frame rail just in case the pipe dips down.

The only other problem with the setup is you need to watch when your filling, since there's so much extra pipe and vent, the gas filler shutoffs don't work so well and by the time it shuts off automatically, there will be gas on your feet, especially if the pavment slopes even slightly toward the pump. My passengers get a puzzled look on their face when I say I don't like a pump because of the way the pavment is around it.
You need to be careful how far under your mount the filler neck as well, I had to make a second bracket, my first one wouldn't allow the pump filler to get in there.
Oh yeah, I had to notch a bit of the wheel well metal out, the bottom inner front corner, it has a lip that sticks down from the bottom of the bed, need to shave it off to clear the rubber as it passed thru to the crossover pipe. YOu can kind of see it in the middle picture, it's in the shadows there above the vent rubber.

 

[ntsqd]

LOL!

But how do you get three tanks into a bobtail? What, are they like five gallon tanks?

-- A

They sometimes come with a second tank under the driver's side. Depending on the year it's either a 10 or 11 gallon tank. That guy just added a 3rd tank under the passenger side.

How about posting up some pic of that, I did have the crazy idea of running both the factory tanks and also installing a 40 gal Berb tank that I have and I think that would be kind of a trick think to do.

I also like the idea of a cross over pipe. It gives me something to think of

"On my old, dead HD...."

..... 170 gallons should make for one long roadtrip.

BTW, that would be about 1,140 lbs of fuel.

 

[77crewcab]

BTW, that would be about 1,140 lbs of fuel.

And at today's price of gas it would cost about $500 to fill up. It would hurt my pocket but not the crewcab.

 

[K5er4Life]

Ok so I have been doing a little brain storming when I realized that our diesel trucks at work that have two tanks draw from both sides equally.

What if I was to reroute the selector switch to a tank in the rear (40 gal burb tank, which my bro has already in a burb hes parting out ) then for the saddles tanks splice in a "t" that will allow gas to be drawn from both tanks. I will still have the issue of one tank having to be filled on the oppossite side of the truck but thats no big deal. Then I could route all the emission related vents, etc. to the rear tank and leave emission related stuff on one saddle tank. All I would need is one line going to the opposite saddle tank and I could cap the rest of the ports, or vent one if need be.

The only thing that makes me wonder if that would work is hoping that the gas will be drawn out at equal rates, and drain completely until I switch to the burb tank in the rear. Its carbeurated so pressumbly the gas would draw from whtever tank would be more full until the gas levels out in both tanks.

Did that make sense at all? Maybe I can explain it a little differently or better. Or maybe Im talking out my ass, which this wouldnt be the first time that has happened.

 

[mudhound72]

Ok so I have been doing a little brain storming when I realized that our diesel trucks at work that have two tanks draw from both sides equally.

What if I was to reroute the selector switch to a tank in the rear (40 gal burb tank, which my bro has already in a burb hes parting out ) then for the saddles tanks splice in a "t" that will allow gas to be drawn from both tanks. I will still have the issue of one tank having to be filled on the oppossite side of the truck but thats no big deal. Then I could route all the emission related vents, etc. to the rear tank and leave emission related stuff on one saddle tank. All I would need is one line going to the opposite saddle tank and I could cap the rest of the ports, or vent one if need be.

The only thing that makes me wonder if that would work is hoping that the gas will be drawn out at equal rates, and drain completely until I switch to the burb tank in the rear. Its carbeurated so pressumbly the gas would draw from whtever tank would be more full until the gas levels out in both tanks.

Did that make sense at all? Maybe I can explain it a little differently or better. Or maybe Im talking out my ass, which this wouldnt be the first time that has happened.

That is a very good thought but I dont think it would draw the same, and then when eather tank went dry it would no longer draw from the other tank cause it would follow the path of least resistance witch would be sucking air

 

[K5er4Life]

Thats what I was thinking but when I look at the tanks on the trucks at work, one tank just has one feed line going into it and no selector switch for either tank. I just drove the truck from Seattle to here in Los Angeles and when I would only fill up one tank it would draw from that one until the gas was level. The second tank doesnt have a fuel gauge sender in there, and if I would fill up the tank with the sender I would show a full tank, then gas would drain quickly (thats what the gauge would show) until it got to the same level as the other tank then the gauge would drop alot less quickly. Of course this was my little experiment with that truck over the course of the 1100 mile trip. I asked our mechanic at work but hes no do english too good. I could easily understand if the gas ran out in one tank than the other would be useless because I would be drawing nothing but air.

Would it make sense that if one tank had more fuel that there would be a slight bit of more pressure on the fuel draw in that tank then the other. And as a result it would be easier for the fuel pump to draw from that tank and as a result it would draw from that tank until they became level? I think I can setup a little model to test this theory. If I take two 5 gallon buckets, have one a 1/4 full and the other completely full, take a fuel hose, splice in a "t" going to each bucket, then use my vaccum pump to pump out the water. then in theory the bucket that is more full will draw the water until it equals out. Because the water will take the path of lesser resistance. Damn, anyone a hydrodynamic engineer here?

 

[mudhound72]

Sounds like a good expairment

 

[K5er4Life]

Ill let you know how it turns out and what Im going to end up doing, just in case anyone wants to do the same.

 

[JUNIOR-K5]

I have a 40gal burb tank tbi with sending unit and good pump I have no use for if anybody intrested make me an offer.

 

[K5er4Life]

so I was talking to my dad about his old flatbottom boat with dual 12 gallon tanks on it, and he said that if you have a fitting that is like this -< and not an actual perpendicular l- then the fuel will draw pretty equally. On his boat one side would need slightly more gas than the other but I figure that was because that little boat was always bouncing all over the place. I do think this would work fine.

 

[ntsqd]

I think you've stated that you plan to, but just to reinforce it, if you pair the draw of two tanks together also pair the vents of both tanks. You want to make sure each tank has identical venting. Probably would have to be pretty significant difference, but not make things as equal as possible. I doubt whether it's a 'T' or a 'Y' fitting makes much difference. What is more important is that both tanks have the same resistance to flow. If one has more restriction than the other, the tank with less vent or flow restriction will drain first.

Also, the info I have on pairing fuel tanks is that it is legal to do so with diesel tanks, but thanks to a bunch of fires caused by hairbrained schemes during the 70's fuel crunch it is not legal to pair gasoline fuel tanks. Nor is it legal to set one to fill another, via pump or gravity, w/o some sort of over-fill protection safety device. If that bothers you, might want to check into it; my info could be out of date.

 

[K5er4Life]

I think you've stated that you plan to, but just to reinforce it, if you pair the draw of two tanks together also pair the vents of both tanks. You want to make sure each tank has identical venting. Probably would have to be pretty significant difference, but not make things as equal as possible. I doubt whether it's a 'T' or a 'Y' fitting makes much difference. What is more important is that both tanks have the same resistance to flow. If one has more restriction than the other, the tank with less vent or flow restriction will drain first.

Also, the info I have on pairing fuel tanks is that it is legal to do so with diesel tanks, but thanks to a bunch of fires caused by hairbrained schemes during the 70's fuel crunch it is not legal to pair gasoline fuel tanks. Nor is it legal to set one to fill another, via pump or gravity, w/o some sort of over-fill protection safety device. If that bothers you, might want to check into it; my info could be out of date.

ahh sounds like some cali-bastard crap.

Luckily I have a decent smog guy who I dont think would bust my balls if he noticed something like that. I guess if I was that worried about gas not draining equally while I was out on the road I could splice in a ball valves into the feed lines right under the truck where its easily accessed in between the frame rails. But I dont like the idea of having another hose connection where there might be a potantial leak. I have this weird thing about simplifying everything and having less connections for gas lines. Because last week I had a gas leak at my carb on my '86 crew cab, a little backfire later and she was up in flames. My poor 80K original mile beauty caught fire. Luckily the damage is fairly minimal compared to what could have happened.

 

[4xcrazy]

Thats what I was thinking but when I look at the tanks on the trucks at work, one tank just has one feed line going into it and no selector switch for either tank. I just drove the truck from Seattle to here in Los Angeles and when I would only fill up one tank it would draw from that one until the gas was level. The second tank doesnt have a fuel gauge sender in there, and if I would fill up the tank with the sender I would show a full tank, then gas would drain quickly (thats what the gauge would show) until it got to the same level as the other tank then the gauge would drop alot less quickly. Of course this was my little experiment with that truck over the course of the 1100 mile trip. I asked our mechanic at work but hes no do english too good. I could easily understand if the gas ran out in one tank than the other would be useless because I would be drawing nothing but air.

Would it make sense that if one tank had more fuel that there would be a slight bit of more pressure on the fuel draw in that tank then the other. And as a result it would be easier for the fuel pump to draw from that tank and as a result it would draw from that tank until they became level? I think I can setup a little model to test this theory. If I take two 5 gallon buckets, have one a 1/4 full and the other completely full, take a fuel hose, splice in a "t" going to each bucket, then use my vaccum pump to pump out the water. then in theory the bucket that is more full will draw the water until it equals out. Because the water will take the path of lesser resistance. Damn, anyone a hydrodynamic engineer here?

The big truck tanks also have a crossover tube, so even if you fill one tank up, it still allows for the fuel to crossover to the other tank,,(equiflow) try it sometime, fill one tank, let it sit for awhile, come back to it, and the gauge will read lower.
The feed line may only draw from one tank, but both tanks are feeeding it via the crossover tube.

I actually ran a truck "out of fuel" once because if this setup, pulled off at a rest area to make something to eat, parked on a slight hill leaning to the passenger side, i was runnin alittle low on fuel, but wasn't to far from the fuel stop, anyhoo, parked for about 45 minutes or so, went to leave, and essentially ran out of fuel because the drivers side tank had drained into the passenger side tank. The fuel levels were "level" according to gravity, but there was less in the driver tank because of the hill and the angle my truck was at. I was able to get it rolling enough to level it out some to get more fuel back in to the feed tank, but it was a real P.I.T.A.

 

[mudhound72]

If anyone is intersted I have another duel tank setup, worked when the truck was parked. Comes with the switch some of the wiring and the selector

 

[ntsqd]

ahh sounds like some cali-bastard crap.

Luckily I have a decent smog guy who I dont think would bust my balls if he noticed something like that. I guess if I was that worried about gas not draining equally while I was out on the road I could splice in a ball valves into the feed lines right under the truck where its easily accessed in between the frame rails. But I dont like the idea of having another hose connection where there might be a potantial leak. I have this weird thing about simplifying everything and having less connections for gas lines. Because last week I had a gas leak at my carb on my '86 crew cab, a little backfire later and she was up in flames. My poor 80K original mile beauty caught fire. Luckily the damage is fairly minimal compared to what could have happened.

Actually, I think it's DOT i.e. nation wide. But I've been wrong b4 & likely will be again.

I think I'd just bite the bullet and go with a selector btwn the saddle tanks.