Hot Rods MODEL A SADDLE TANK PROBLEM....

Here's whats up...dual saddle tanks... the poly ones behind the side apron... gauge started
reading a little BEFORE empty , even when the tanks are full ,... there's a toggle switch, when you switch from side to side the gauge reads all the way empty in the center... then goes up a little to each side...gonna have to take half the car apart to get to the top of the tank..... but, here's the puzzle,.. I've had these before and hated them... and have never installed them in a car..I've had boats with side tanks and there's a valve that switches side to side... this one there is no valve.. the fuel line on each tank goes to a T right before the pump.


.is there a chance that there's a fuel shut off in each tank??? I put some lucas in the tanks and went and topped both tanks off..... on the way home one side started showing a quarter tank...


could it also be that they set it up to draw off each side together???

these tanks suck, they hold about 6 gals... and you are always putting fuel in one side or the other..

I ran it out of fuel yester day, right by a gas station, I put almost 7 gals in the passenger side, pretty much bone dry.. went from my house to the shop,.. but filled up the drivers side first... so I figured that the driver side was empty... because that's the side I ran on... after filling I had to use starting fluid to get it to prime...when I went to fill up, figured the dr. side was empty... it was still full??????

is it possible to just put a T and pull off both tanks at the same time, and could it be that all the switch does is switch the sending units, but does nothing else???

thanks for any and all replies

PUZZLED IN VEGAS................

 

ALSO, the fuel lines come out at the top of each tank..

 

the other thing they did was put a roll over ball check valve tying both vents together... no vented gas caps,... so wouldn't that stop the vents from working,... the roll over valve is up, so the ball is seated... so now if it did roll over all the gas would drain out....???? Right???

 

LTL were the first ones to build such tanks. Theirs came with a switching valve and individual vents. The caps were not vented.

Somebody else copied the concept after LTL, and maybe they didn’t include the good valves and vents. But I don’t know why you couldn’t add them to your set.

 

does each tank have a fuel shut off valve? the vent hoses come out of the top of the tank, and they tied them together with the roll over vent valve in the center... and with further investigation I see that where they went under the frame, there's places on the exhaust where fuel was leaking... probably when the tanks were full or on a hill, and to fix it they reversed the vent to upside down????? the lines droop lower than the top of the tank...

 

Go to a semi truck parts store . They can fix you up with the right parts . There’s a manifold that can draw from both tanks at the same time. As long as it is mounted close to center of your car . The top manifold draws from each fuel tank. The bottom one is fuel return. This is on my 66 KW . Hope this helps you.

 

The ones my friend had a while back had an electric crossover valve that was controlled by a toggle switch; switch in left position it drew from the left tank and connected the gauge to the left sending unit. Switch in right position did the opposite.

 

thanks, as I don't know how the system works, I don't know if there is a problem...car was built some where around 2000 or maybe a little later... could be that they only run one side??? but both lines hook to the T.... maybe the fuel on the one side is old???? doesn't smell bad... but... the way the t is to me,... if one side runs out it will just suck air,... unless the is a electric valve in each tank... it's all braded line an fitting or I could just put a shut off valve or clear filter to see if you switch to one side the fuel stops on the other????? still puzzled

 

Based on what he posted and this ad, they might be Tanks tanks.

 

Try to disconnect one tank to see what happens, then do the same with the opposit one.
But yes the vent bellow the tank sounds more like a drain than a vent.

 

thats the way it was told to me when I bought it,and what I've done was each time I drive it ,make sure to top off one side, then on the way home top off the other..but I think whats been happening is it really only pulls off the one side.. there is no valve.. both tanks go to a "T" , then to the pump... both tanks have canister filters at the tanks.. and I think what happens is with both tanks and filters full , it pulls fuel from the least resistance side.. then when that side runs out it pulls air ,... so even though the left side was full it runs out of gas and sucks air from the right...personally, I don't see a way that it will work proper the way it's plumbed...... the vent is not an issue because I can separate the two and run the vents on each side up the wheel wells..would just have to put a little filter to keep road dust from going in the tank..

 

looks close, but mine the fill tube comes out the back and goes to the wheel well, not out the side apron...

 

Those are just the earlier version. I’m not sure anyone carries them anymore. It was made to run tubes all the way to the back bumper to fill the tanks. I’ve got a set mocked up on my project- not plumbed so I’m no help with your questions

 

You are correct.

 

OK< still might be able help. did you get the kit to install, and are there switch over valves in the tanks???

 

first pic is vent line going under the frame

#2 roll over vent upside down

#3 filler neck, yes it looks like rv sewer pipe/sink drain pipe, but it is welded metal


#4 canister filter.. one on each tank...

#5 "T" connection at pump

 

Not LTL. Probably from Tanks.

 

for me, the last pic is where "I" think it's wrong..... I think there needs to be a switch over valve right there.... and don't see how that could ever work... seem like the pump will take the least resistance, and pump that side dry...

 

the vent line is easy, I'm just gonna unhook the "T" and run the vents up high in the wheel wells with a filter

 

Go back to having gas in your lap. Actually safer than saddle tanks.

Honestly I doubt it will ever work right, You can get a tank switch and valve from a 80s chevy truck and isolate where you are pulling from.

 

No there’s nothing in the tank just fittings. I think they tried to feed off two tanks on your set up and with out a very large added cross over tube just doesn’t work well.

tanks makes a switch over valve that also lets you use one gas gauge for both tanks. With to tank 2 and the gauge shows the second tanks level. I will use one to manually switch tanks as most people have poor luck trying to feed off two at the same time.

I would say with the shared vacuum/ breather and the shared fuel at the T and no cross over it’s just a badly set up fuel system.

I think your toggle is just switching gas level sensors for the gauge and that’s it.

there is a spot in each tank for a roll over valve to be installed.

out of curiosity can I see where the fuel caps landed?

 

they're in the wheel well right infront of the tire, wifes gone so have to wait for a piv... pretty easy to get to and better than the holes in the apron IMO...

 

Filling sounds messy on a wet weather day, but fuel feedback at the filler goes on the ground, not on the apron.

 

last model A I had it would spit on the aprons and running boards

 

Not sure how this would work BUT if it were mine, I'd start over..

1- I'd get rid of everything first just leaving the tanks...

2- I'd run a line (3/8) from each tank to a "T" leaving them short as possible AND back by the tanks. No filters, nothing in the hoses just hoses and the T.

3- then I'd run a #8 braided hose from the T forward to a gas filter right before the fuel pump, then from filter to fuel pump..

4- I'd put separate small oem style roll over valves on each tank, making the hoses as short as possible.

5- I'd also try and replace the gas caps with vented caps...

This does a couple things, any resistance from a filter will affect both tanks equally at the same time. It also shortens the distance between both tanks drastically, and should allow flowing fuel from the T to help draw from the other side at the same time.

That's what I'd do.....


...

 

QUOTE="lostone, post: 15318565, member: 232653"]Not sure how this would work BUT if it were mine, I'd start over..

1- I'd get rid of everything first just leaving the tanks...

2- I'd run a line (3/8) from each tank to a "T" leaving them short as possible AND back by the tanks. No filters, nothing in the hoses just hoses and the T.*********the cross over would be under the oil pan*********

3- then I'd run a #8 braided hose from the T forward to a gas filter right before the fuel pump, then from filter to fuel pump..*******al that would have to be in front of the engine*****

4- I'd put separate small oem style roll over valves on each tank, making the hoses as short as possible.******what is this????********

5- I'd also try and replace the gas caps with vented caps...******vented won't work because the fill tube is level with top of the tank******

This does a couple things, any resistance from a filter will affect both tanks equally at the same time. It also shortens the distance between both tanks drastically, and should allow flowing fuel from the T to help draw from the other side at the same time.

That's what I'd do.....


..QUOTE
answered each question...thanks a million for the ideas...

 

pretty sure this is the switch i have

 

so all I need to do is add this valve where the two fuel lines come to the t, correct,... that and add a wire to the switch????

 

The Jag XJ6s have a changeover valve that switches tanks. The senders switch over when you switch tanks.
We once tried using just a T on twin tanks and the fuel feed worked ok, but if one tank ran dry the pump would just suck air from the empty tank even if there was some fuel in the other. Then, overnight, the fuel would flow from the full tank to the empty one. The gauges were pretty much useless in my one-empty-tank scenario.
Adding the valve and switching the gauge over at the same time fixed my problem.