twin fuel tanks

[wally1]

ive just got my hands on another fire extingisher, looked through some of the old threads but could not see how to plumb them together. Looking at some pics of marys back where its being stripped down and it looks like they just used a t piece, would be gratful for any help cheers wal

 

[Steves2580]

Hi Wal,

You're right, Mary just had a T in the fuel line, only problem with that was I had to remove both filler caps while refuelling.
Just because I'd fill one tank, put the cap back on then realise half the fuel had gone from one tank to the other.
It did take a while to fill, as the fuel was only passing through a 6mm pipe!

Worked well though

Steve ;D

 

[Phaeton]

That's not how she was originally built, she used to have 2 fuel cut off solenoids, 1 on each tank, there were 2 switches in the centre console & a couple of LED's to tell you what was open. They were powered by the ignition but you could switch them both off, so the only fuel she had was what was in the carb. You could run on one tank until it went dry then flick the switch to bring the other tank in, you then had option to run for 5 minutes, then shut one of the valves again so you could run again until dry this meant you had just over 5 litres across both tanks left so go looking for a petrol station. Also meant when you were filling the tanks the valves were shut so no fuel was equalising. But I suspect the Birmingham butcher removed them.

Alan...

 

[Steves2580]

Birmingham Butcher!! Ha Ha

Mary was a mess, poor little thing!!
There weren't any solenoids, the LEDs were disconected and only one tank was being used!!

Steve.

 

[wally1]

thanks for the replies steve and alan. in my case i have an indicator that tells me i have a couple of liters left if they are joined with the t piece would that mean i have the same amount left in the tank with no indicator at that given time or does one run out before the other or does the fuel pump take from the nearest tank first or do you just play it by ear. im a bit confused !!! :-\

 

[Steves2580]

Hi Wal,
If you just use a T then the tanks will empy equally, unless one tank is lower than the other!
If your tanks are at equal heights then the fuel will be equally used, so as you say the tanks indicator will register what's in each tank.

Steve.

 

[Phaeton]

Here's a picture of both tanks along with both solenoid's

Small orange things on back of subframe

But as Steve says not really needed, although a single tap on one of them would make them easier to fill, just so you could shut one off in the petrol station, but both tanks will empty fairly levelly.

Alan...

 

[wally1]

Thanks again it now makes sense as I was going to put the one I've just got slightly higher so that it always emptied first that way when the indicator came on I would definatly know I needed to fill up cheers again. Wal

 

[wally1]

Tap idea also makes a lot of sense cheers Alan

 

[esdebe]

Note that the equalising effect will only be the case if you have the take off on the bottom of the tank if you are syphoning the fuel out of the top you will need to make sure both tanks are a the same level otherwise when the higher tank empties it will start to suck air (unless you can turn of that tank) My dual tank system used to be top fed and I used a lot of complicated electronics and two solenoid vales to automatic switch between tanks. I changed all that for a bottom feed system with a simple T and 6mm fuel lines, less complicated and works with no issues. Even when filling up it doesn't transfer from one tank to the other that quickly with a 6mm line (maybe a drop of 1 or 2 cm), and it means that you can brim the tanks as by the time you have done the second tank the level has dropped enough to allow for any expansion that may occur on a hot day.

 

[wally1]

ta very much for the replies pretty much going with bottom feed and level tanks just one more thing on this subject ive taken off oridginal tank to getan idea brkts etc and all thats on the bottom is a blob of somthing with a copper pipe coming out im not sure if this is maybe [cant spell] araldite,might even be solder idont want to knock about or clean to much in case i start a leak how have most others done this wal

 

[Phaeton]

I've used both steel pipe & welded it through the bottom & I've used copper pipe & the 2 part Epoxy Weld stuff. When you put the pipe into the bottom of the tank make sure it's up 5mm or so to stop it picking the shit up.

Alan...

 

[wally1]

thanks again Alan -wal

 

[esdebe]

I used one of these in each tank http://www.ebay.co.uk/itm/Kart-Fuel-Tan ... 519d176c39

I trimmed it back to inside the tank the tail was about 5mm, this also meant that I could put a socket over it and a long extension bar through the filler hole to hold it while I tightened it up. I then used something like Permatex® Hylomar® Universal Blue Racing Formula Gasket, and a fibre washer to prevent leaks....

 

[wally1]

thanks sounds easier than welding wal