Saddle Tanks, Dual Fill.

[Low83]

Have the saddle tanks on my Silverado and remember a few moons ago Traders Trucks used to carry a kit that allowed you to fill both tanks at once, it was a cross over pipe that connected both filler necks, Traders doesn't sell it anymore so does anybody remember seeing a kit like this anywhere???

[PHOENIX]

That sounds like a great kit. Be sure to post here if you find it.

[79BIG10]

I've never heard of that but I bet it would be a big seller.

[Prerunner1982]

ive thought about this before but with where the tanks are mounted and where the necks go, i believe it would either have to go down under the frame then back up on the other side. being routed around the driveshaft, or go through a large hole cut through the frame..i have yet to figure out way this would work, well of course a bodylift was put on and the bed was raised away from the frame..but i am against that...

jon

[79Silv4x4]

I remember seeing the kit and thought about getting one--it was back around 1994 or so and, if I recall correctly, the kit was somewhat pricey (like $300 or so), so I never ordered one. Haven't seen one advertised since.

[gchemist]

Wonder why people look at us funny when we pull up with the passenger side tank?

[79BIG10]

I know people hate it when I take up the whole row between two gas pumps and fill up both at the same time. Man it's $$$ but no stopping for a long time on a trip

[Malo83]

Old thread, still looking for the KIT

[kstephens1223]

it is an old thread, but that would be nice to have, im plannin on making my own bed cover out of diamondplate, and i figure i can make a small partition at the front of the bed, bring both filler necks up through the bed floor, then run the passenger side filler across inside the partition and have both necks side by side at the front of the bed on the drivers side.

[78 Big10 454]

My cousin bought that kit for his 77 SWB. It didn't work for diddly, reasons I can't remember. He pulled it after a few months, IIRC. I used him as the guinea pig, to see if it was worth getting for my truck. I went with a 26.5 gallon Transfer-Flow tank, instead.

[ARAMP1]

I always wanted to do something like this. I've heard of guys running a hose from the bottom of one tank to the bottom of the other and there were complaints when you parked on uneven ground and it took forever to fill up because it would cross over to the other tank. Seems like a 2" pipe from filler neck to filler neck might just do it. And I had to do a 3" body lift to fit the transmission. Hmmmmmm.

[tucsonjwt]

Just convert your box to a dump bed. Lift the bed, pass the gas pump hose across the frame, fill up the other side - as long as the gas pump hose is long enough.

[ARAMP1]

Originally Posted by tucsonjwt

Just convert your box to a dump bed. Lift the bed, pass the gas pump hose across the frame, fill up the other side - as long as the gas pump hose is long enough.

Don't know if you're joking or not, butthats actually pretty sweet.
Posted via Mobile Device

[406 Q-ship]

I did a dual filler on my 74 SWB. It started life as a right side tank truck. I got a second tank (actually I got 2 tanks to not down the truck), cleaned them of all fuel and welded in a 3/4 NPT bung in the bottom front edge of both tanks. Do not put the bung in the bottom of the tank or something could break off the fitting (that would be really bad). I drilled a hole in the frame at the approximatly the transmisson crossmember, then ran a steel braided -8 hose under the truck clamped to the trans crossmember. You have to interconnect the vent hoses for both tanks so they can vent out of whichever side you are filling, if you don't do this step you could end up taking a bath in fuel when the other sides tank burbs the air through the crossover hose (I learned this when filling aircraft tip tanks). No need to buy a kit it is a pretty simple modification, once you get pass the pucker factor welding on used fuel tanks.

I did this modification for two reasons. One I am too lazy to fill the second tank. Two I am too cheap to buy a crossover valve. Actually I thought of doing a EFI on this truck at one time but using the crossover and two EFI fuel pumps was too expensive the hoses are nutz on an TBI dual tank truck. Biggest down side to this, you have put at least 10 gallons in the truck when gassing up, if the truck gets tilted to the left the fuel will run away from the pickup in the right tank when fuel is low. I do not recommend this mod on a lifted or 4x4 truck that get rockcrawled.

[kstephens1223]

Originally Posted by 406 Q-ship

I did a dual filler on my 74 SWB. It started life as a right side tank truck. I got a second tank (actually I got 2 tanks to not down the truck), cleaned them of all fuel and welded in a 3/4 NPT bung in the bottom front edge of both tanks. Do not put the bung in the bottom of the tank or something could break off the fitting (that would be really bad). I drilled a hole in the frame at the approximatly the transmisson crossmember, then ran a steel braided -8 hose under the truck clamped to the trans crossmember. You have to interconnect the vent hoses for both tanks so they can vent out of whichever side you are filling, if you don't do this step you could end up taking a bath in fuel when the other sides tank burbs the air through the crossover hose (I learned this when filling aircraft tip tanks). No need to buy a kit it is a pretty simple modification, once you get pass the pucker factor welding on used fuel tanks.

I did this modification for two reasons. One I am too lazy to fill the second tank. Two I am too cheap to buy a crossover valve. Actually I thought of doing a EFI on this truck at one time but using the crossover and two EFI fuel pumps was too expensive the hoses are nutz on an TBI dual tank truck. Biggest down side to this, you have put at least 10 gallons in the truck when gassing up, if the truck gets tilted to the left the fuel will run away from the pickup in the right tank when fuel is low. I do not recommend this mod on a lifted or 4x4 truck that get rockcrawled.

thats a cool idea, but wouldnt it take a long time to fill from one tank to the other through a 3/4" line??

[406 Q-ship]

Originally Posted by kstephens1223

thats a cool idea, but wouldnt it take a long time to fill from one tank to the other through a 3/4" line??

Nope, think about this the fuel nozzle is only about 3/4" in diameter. It takes time to fill becasue it now takes 32 gallons.....expensive too.

[jitteryguy]

the RG's that the military use's have two tanks and one filler , it's a 1" cross over on the lower side's of the tank's, been think'n bout try'n it on mine.
on the RG however it does take for ever to fill both tank's.

[68 TT]

Our square body shop truck in the air force 25 years ago was a single filler neck dual tank setup. It sucked. We had blocks of wood to drive the driver side wheels up onto so it would fill the passenger side tank completely. It probably only put 12-14 gallons in the passenger side 20 gallon tank if you didn't tip the truck a little.

I just passed the hose over the bed of the truck on my 78 K20 to fill the other tank without moving the truck. The hoses are plenty long enough to do it if you park close to the pump island.

[Tucson38]

Mr. Newbie here. Hello to everyone.
'85 GMC 4 WD HD 3/4 - 252,000 miles. Original owner.

I'd sure like to bypass the switching device GM uses. Seems way more problematic than necessary. I'd opt for using one filler neck for both tanks.

[Pyrotechnic]

DirtyLarry came up with an idea I really liked. He was having trouble using the solenoid switching valve with a high pressure fuel injection pump, so he ditched the valve all together. Instead, one tank is the primary with the fuel pump send and return plumbed to it. The other tank has an electric transfer pump that will fill the primary tank.

This is the route I plan to go on my truck. If you have a nice transfer pump, I bet you could fill your secondary, transfer that fuel to the other side, then refill the secondary all without moving the truck. Might take a few extra minutes, but you'd be really surprised how fast a good electric pump can move a gallon of gas at free flow.

[68 TT]

Originally Posted by Pyrotechnic

DirtyLarry came up with an idea I really liked. He was having trouble using the solenoid switching valve with a high pressure fuel injection pump, so he ditched the valve all together. Instead, one tank is the primary with the fuel pump send and return plumbed to it. The other tank has an electric transfer pump that will fill the primary tank.

This is the route I plan to go on my truck. If you have a nice transfer pump, I bet you could fill your secondary, transfer that fuel to the other side, then refill the secondary all without moving the truck. Might take a few extra minutes, but you'd be really surprised how fast a good electric pump can move a gallon of gas at free flow.

A high flow 255 LPH EFI pump would take almost 18 minutes to drain a 20 gallon tank. Even my 110 GPH Holley race pump would take almost 11 minutes to transfer 20 gallons. It would be fine for a transfer pump while driving but wouldn't save you any time filling tanks.

It needs to have some type of sensor to shut it off when the tank is dry so you don't burn it out. Just a toggle switch could work but you would have to keep a close eye on it and listen for the pump to start cavitation then shut it off. It wouldn't take long to kill the pump running it dry.

[hatzie]

Just get a diesel and fill at the truck pumps.

[Desert1957]

The problem with any Dual tank crossover system is it needs to be the lowest thing. Which means having a crossover hanging under both tanks. it will not equalize any other way.

Big rigs use it but have twice the ground clearance we do. if you do not want the crossover tube or hose hanging under your drive line and frame , the only other option is to mount the Suburban 40 gallon tank in the rear where your spare tire would mount. then fill it from the bed.

Desert

[Desert1957]

The problem with any Dual tank crossover system is it needs to be the lowest thing. Which means having a crossover hanging under both tanks. it will not equalize any other way.

Big rigs use it but have twice the ground clearance we do. if you do not want the crossover tube or hose hanging under your drive line and frame , the only other option is to mount the Suburban 40 gallon tank in the rear where your spare tire would mount. then fill it from the bed.

Desert

PS: my tank changeover valve just went up last month, original part on an 83 no what I can a problematic part.

[68 TT]

Originally Posted by Desert1957

The problem with any Dual tank crossover system is it needs to be the lowest thing. Which means having a crossover hanging under both tanks. it will not equalize any other way.

Big rigs use it but have twice the ground clearance we do. if you do not want the crossover tube or hose hanging under your drive line and frame , the only other option is to mount the Suburban 40 gallon tank in the rear where your spare tire would mount. then fill it from the bed.

Or you could put in a Blazer / Suburban fuel filler door assembly behind the passenger side wheel so it could be filled when the bed is loaded.