Thread: 3 fuel tanks, one fill up point?

Originally Posted by steveG

They are called a "Pollak" valve. Pretty sure you need to use 2 of them to cover 3 tanks.

Steve

thanks for the right term

Fuel Selector Valves on Pollak

Originally Posted by Jitterbug

I still have the switch on the dash, when i got the car both factory tanks were just loose inside the truck and one of the filler points on the side was blanked off. I will see if the switch is attached to anything...

the pollak valves worked well in the 6x6's that i drove

Originally Posted by Blknight.aus

one filler point that goes into a 4 port manifold.

one for the filler one for each tank. Because youre working with diesel, you can weld one up out of standard steel then coat it with silver solder over the welds to ensure its fluid tight.

Im looking at making mine from a some box steel and some pipe stock

Dave, what are you using for filler hose? Just had a quick google and it is $100+ for 900mm, going to get expensive quickly when joining 3 tanks spread around the truck...
Fuel Filler Hose - Hose Online | PVC | Rubber | Australia

I was going to use the OEM filler hose for in and out to the main tank then use some 2 inch diameter stuff to get down to another pipe manifold down to the individual tanks.

Originally Posted by Jitterbug

Dave, what are you using for filler hose? Just had a quick google and it is $100+ for 900mm, going to get expensive quickly when joining 3 tanks spread around the truck...
Fuel Filler Hose - Hose Online | PVC | Rubber | Australia

what size hose are you looking for?

a quick call to a supplier i can get the following

3in $40.32/m
2in $27.70/m
this has the wire reinforcement so that the hose hoses it shape.....its actually suction hose

i couldn't recall what size the inlet is on a defender

I've seen filler necks modified with an additional pipe for a sill tank a little bigger than the tip of the bowser nozzle, you fill the main tank by placing the nozzle past the side of the pipe and fill the sill tank by inserting the nozzle into the pipe.

You need sufficient height and large breather tube size for gravity to do its work filling the secondary tank. However you can expand the size of the connecting pipe after it leaves the confines of the filler neck to reduce the resistance to flow and increase the speed of fill.

The issue will be whether you can get one to drain quickly enough for Hi-Flow bowsers or even if you can get three pipes of sufficient size into the one location inside the filler neck.

Connecting all tanks together for supply has advantages in a diesel where you don't want to run out of fuel before changing tanks. There are however down sides where you also run the risk of leaking all of your fuel if you hole one tank and you lose the ability to balance your fuel load by using particular tanks first.

i'm with lotza....i'm not sure that you will be able to have the one fill point......

to connect the two sill tanks so that you can fill from the one side would mean the connecting pipe would nearly have to run under the chassis rails leaving it rather exposed

where possible using truck stops means you will have a pump either side of your car so there will be no need to move it..........not sure how often you will come across this

for all your highway use i would just use the one tank and fill as required. buggered if i like driving more than a couple of hours withut a break

the nly time you should have the need to fill all three tanks at once would be an extended off road adventure, i imaginee you will have a range >1000km, in australia it would come across fuel in most place......i know you are planning overseas travel which i cannot comment on

I will see how much space i have for large enough dia pipe, even getting common fill point for the front two tanks would help and mean that i could fill all 3 without having to move the car.
By 'connecting all the tanks together' what do you mean? Do you mean just connecting them with hose to, in effect, make one large tank? if so wouldnt you see all the fuel rushing to whichever was the lowest if you are on a hill? I guess check valves only allowing flow to the tank with the fuel pump would solve this to some extent.