gas tankS need a solution to 3 tanks and switching.

[original balzer]

For some reason or another my 77 K20 only came with 1 gas tank on the pass side.

I thought someone might have removed the other one but the bed doesnt have a filler hole I even looked inside to make sure someone didnt patch it. So I looked at the frame and it does not appear the driver side saddle tank was ever installed.

I have a few tanks so putting one in wont be too big a deal.

Thinking about it my 1972 K5 had 3 tanks. the main rear tank and 2 home made side tanks.

I have a K5 tank as well......

So I want to install it too.

My 72 ran on eaiter the main tank OR BOTH aux tanks at the same time.
Is there a way to single out 3 tanks? Im guessing all 3 tanks would need vent and return lines. would the return lines need to be switched as well?

Also was wondering if anyone has ever run 1 filler neck for more than 1 tank? I would think that if a T was used down low and the vent tubes all ran to the 1 filler neck it sould work ok. This way the first tank would fill up then spill over through the T to fill the other tanks. The vent tubes would have to be higher than the T Im sure. It would be crazy to fill up all 3 tanks at once.

Please give your thoughts and sugestions.

OH FWIW I would like to graph a fuel door into the bedside, being a 77, it has the gas cap without a door and its actually a pain to fill due to the angle.

 

[cabledawg]

MY highschool buddy had a 72 Ford with three tanks. The stocker behind the seat and two saddles. He had a manual valve for the fuel lines and a dash switch for the fuel gauge. I dont know if this would work for a Chevy product as well, but he could hold 70 gallons between the three tanks. I'm trying to find a way to do this on a Burb, but I dont have as much room under the body as a pickup does under the bed.

 

[apache]

Plumbing aside Borg Warner makes a 12v generic tank switching valve for fairly cheap,worked great on my 74 K10. Just need a toggle and some wire.

 

[dieselponyexpress]

When i installed a pass side tank on my CUCV K30 i put on a pollak 6 port valve. It switches fuel and return lines and has electric connectors for gauge and aux fuel pump. Works like a charm since 3 years now. Iirc this is like the factory dual tank setup is made. Working with 3 tanks you would need 2 of the valves.

Pollak.
Look at the pdf link on that site too. There's a schematic of a 3 tank connection.

Walter

 

[original balzer]

When i installed a pass side tank on my CUCV K30 i put on a pollak 6 port valve. It switches fuel and return lines and has electric connectors for gauge and aux fuel pump. Works like a charm since 3 years now. Iirc this is like the factory dual tank setup is made. Working with 3 tanks you would need 2 of the valves.

Pollak.
Look at the pdf link on that site too. There's a schematic of a 3 tank connection.

Walter

Perfect thanks Walter.

 

[original balzer]

Im thinking when I do this,I will make the K5 tank the main and the saddle tanks aux.

I cant even remember what size the tanks are. IIRC the tanks on the 83 diesel are 18 gal I think the tank in the 77 is only 15 gal. The blazer tank is 30ish+/-.

Somewhere around 60 gal......yea that should be enough.

 

[kevin400ex]

When i installed a pass side tank on my CUCV K30 i put on a pollak 6 port valve. It switches fuel and return lines and has electric connectors for gauge and aux fuel pump. Works like a charm since 3 years now. Iirc this is like the factory dual tank setup is made. Working with 3 tanks you would need 2 of the valves.

Pollak.
Look at the pdf link on that site too. There's a schematic of a 3 tank connection.

Walter

thanks fo the link. this is how im doing my crewcab as well. i am putting in a 40 gallon suburban tank in the rear and am going to use 2 valves total, one to switch between the rear tank and the saddle tanks, then another to switch between right and left.

 

[original balzer]

thanks fo the link. this is how im doing my crewcab as well. i am putting in a 40 gallon suburban tank in the rear and am going to use 2 valves total, one to switch between the rear tank and the saddle tanks, then another to switch between right and left.

WOW hope ya dont ever have to fill that with race gas.

I will do it the same main tank will be the rear K5 tank then aux 1 and 2 for the saddle tanks.

I wonder is steel exhaust tubing tould be suitable for the filler plumbing?
I would still like to have 1 filler for all 3 tanks. That might take some doing but its what I want

 

[cabledawg]

I think its a good idea, but I dont think you have enough room between the body and frame to squeeze the fill tube between them. Even if you could, it could be high enough to cause back pressure that would make most auto shutoff pumps to trip. You'd have to have such a slow fill rate, that you'd be better off just moving the pump to each tank.

Have you looked into using a transfer pump between the tanks? Have it running while your filling up to get the aux tanks. They usually have a high volume rate, but I dont know if you can use it while filling up.

Edit: What did you use for the aux tanks on the K5? Since I'm having a hard time finding a tank to fit under the Burb without exposing it below the frame, a custom tank might do the trick. I was just looking at 5-10 gallons on each side, or at least 10 if I go with just one. Either way the tank has to be really flat, long and skinny. I've got a 30 gal that will be replaced with a 40 gal shortly, but I wanted an aux tank just in case.

 

[original balzer]

Dang! nothing ever goes my way LOL.

I just went and looked, and heres the problems for the K5 tank.

1 theres crossmembers in the way

2 my bumper is in the way, well the supports to the recever hitch.

3 the exhaust is in the way.

first 2 are not that big of a deal but the exhaust sounds AWESOME the way it is. Im not sure I want to change it in any way.

Also looking at it I dont think there is a way to do 1 filler cleanly. Ill have to do some measuring.

I would like the single filler behind the driver side rear tire,centered between the wheel well and tail light. I can figure it out im sure.

 

[dieselponyexpress]

Perfect thanks Walter.

Glad I could help - just a small benefit regarding the info I got from this forum so far.

Let us know how you solved your 3 tank issues.

Walter

 

[original balzer]

Edit: What did you use for the aux tanks on the K5? Since I'm having a hard time finding a tank to fit under the Burb without exposing it below the frame, a custom tank might do the trick. I was just looking at 5-10 gallons on each side, or at least 10 if I go with just one. Either way the tank has to be really flat, long and skinny. I've got a 30 gal that will be replaced with a 40 gal shortly, but I wanted an aux tank just in case.

Sorry I missed this. My 72 K5 had home made tanks behind the rockers and up between the bed side and inner bed. I cant remember for sure but I think they was 14 gallon each. On it there was a brass valve just inside the drivers door on the floor, with 2 settings main tank and both aux tanks at the same time. I could fill the driver side but the pass side leaked after 10 gallons. The main tank always ran crappy too. I think it was full of rust or something. The truck had 5 filters on it as well, 2 on the main tank 1 on each aux tank and 1 near the carb. I replaced a lot of filters HAHA.