Stock Gas Tank to Water Tank?

[ntsqd]

One thing's for sure, you don't want to use the stock filler neck if you do put a water tank in the OE fuel tank location. Using the stock filler location might be OK if you can make it obvious that it is not for fuel.

Even in LDPE I wouldn't want to convert an existing fuel tank. Might use a new one, but if buying a new fuel tank why not just buy a tank mfg'd with drinking water in mind?

The venerable Holley "Blue" pump is 110 GPH and $130USD at Summit.
http://www.summitracing.com/parts/HLY-12-802-1/

The Carter rotary vane pump is 100 GPH and is $103 USD at Summit.
http://www.summitracing.com/parts/CRT-P4601HP/

Both of these are sub 20 psi pumps.

 

[REasley]

Poly fuel tanks are made from cross linked polyethylene and are incompatible with potable water.

 

[fyrfytr1717]

Is the fuel pump being discussed for a carburettor, or fuel injection? You can get some very high flow fuel pumps for fuel injection if needed and you don't mind spending a little money.

Maybe that explains the difference in pump speeds? It's very possible that my friend's fuel pump was for a carbureted engine. I believe the Comanche went to fuel injection in 1987, so my '88 should be fuel injected as well. Hard to tell for sure since the front half of the vehicle was cut off prior to my purchasing it.

Maybe a dumb question, and I really ought to double-check my 1988 XJ out back to be sure, but isn't the fuel tank in a Cherokee of this period made from fluorinated low density polyethylene, not steel?

The fuel tank in the XJ was steel up until 1997. I'm not as familiar with the MJ's, but I'm guessing that they were steel throughout their production years. Mine has a thin plastic "skid pad" strapped onto the bottom of it, but it is a steel tank.

The venerable Holley "Blue" pump is 110 GPH and $130USD at Summit.
http://www.summitracing.com/parts/HLY-12-802-1/

The Carter rotary vane pump is 100 GPH and is $103 USD at Summit.
http://www.summitracing.com/parts/CRT-P4601HP/

Both of these are sub 20 psi pumps.

Thanks for the links! I think I'll try hooking my stock fuel pump up to 12V and see what happens first. If I decide it is too slow, I'll probably try out that Carter pump. At 100GPH, it should transfer an entire tank in 12-15 minutes. That's more than fast enough for me and it's about the same price as a replacement OEM fuel pump anyways.

I just finished building my trail trailer out of a 86 2Door XJ. That said I kept the fuel tank in the rear as a fuel tank. the fuel pump puts out enough volume to transfer the fuel in about 20+Minutes. Not bad as a normal BS stop is about that long and lunch is usually longer for me. If you run the fuel tank back there you need to put some more weight up front to counter the fuel in the rear.

Just as a FYI to anyone reading through this. There have been a few assumptions made regarding the similarities between the stock XJ and MJ fuel tanks. While their construction was probably similar throughout the production run of the MJ, the tanks are shaped differently and mount up differently. The MJ carries it's spare tire where the XJ tank would be mounted. The MJ's tank is under the front, driver's side corner of the bed. Filling it will actually increase tongue weight as opposed to lessen it as suggested above.

Thanks again for everybody's input!

 

[fyrfytr1717]

Poly fuel tanks are made from cross linked polyethylene and are incompatible with potable water.

If this is true, I guess that pretty much rules out using a fuel tank as a potable water tank, regardless of whether it is steel or plastic!

 

[Mc Taco]

I know it has been covered and I am probably beating a dead horse, but why take ANY chances when it comes to your drinking water supply in the field and your gastro-intestinal health away from proper facilities.

 

[fyrfytr1717]

I know it has been covered and I am probably beating a dead horse, but why take ANY chances when it comes to your drinking water supply in the field and your gastro-intestinal health away from proper facilities.

I was just asking if it was possible. If I didn't care about my health, I wouldn't have asked and would have just gone ahead and used the tank for water... I dropped the idea at the first suggestion of trouble in this thread. No need (or desire) for water related gastro-intestinal issues here. Been there, done that! :sombrero: :costumed-smiley-007 :sombrero: (<---while hanging out with these guys)

 

[highlandercj-7]

my .02 worth

either keep the fuel as fuel or ditch it and install a proper water tank.

X2 If you need it for H2O, your better off with a new poly or SS tank or atleast one that was used for H2O before.

 

[robert]

As has been said, no way! It only takes a few parts per million for you to be able to taste petroleum in water. Some of the solvents used in fuel are more dangerous than the fuel itself. Potable water tanks aren't that expensive neither are dedicated fuel tanks.

Fuel injection fuel pumps are higher pressure because the system is pressurized (it has no reserve supply of fuel so to speak). Carb systems have a lower pressure so that the float bowel doesn't flood. If you are going to transfer fuel, use a proper fuel transfer pump; they aren't that expensive for the safety and piece of mind. Make sure it's rated for whatever fuel you are going to transfer too- there are diesel and gasoline pumps.

Air pumps are usually used for oil and grease transfer. Incidentally, everyone knows they should never, ever use oxygen for transferring petroleum products or around oily greasy rags right?