Has anybody put their subtank on the roof? (1 Viewer)

[Dave 2000]

I carry 2 x 20 litres cans on the roof, it is diesel so comparatively safer. If it was not such a bureaucratic nightmare I would go for the sub tank above the spare, so jerries on the roof it is, if there was room I would have them inside, but diesel is smelly (forever) if split inside. I reckon I would have more regular need for extra fuel than a rear winch, have you considered to learn how to use snatch blocks and winch yourself backwards, if you know the technique it can be useful?

Then go for the underslung sub tank, or sell the boat tank and get the above mentioned long range tank.

Regards

Dave

 

[artech]

What I wonder is, where are you going that you need the additional fuel? Or is it more a convenience thing that you just want to fill up once a month or something? Is this something that will be up there all of the time but only filled when you are going somewhere where you may need the additional range?

Good question! My main aim in having a sub tank is sustainability. I'm in public safety, which means the worse things get the harder we work. Up heah in Maine we get blasted with winter storms fairly frequently and back in 98 we had a real whopper and some areas went 3 weeks without power. No power means no gas pumps, and this became a fairly significant operational issue in some areas.

I'm not expecting to have to drive my rig for three weeks with no gas stations, but at least I could get more range to get to one that was open. Or, I might have to leave my truck running for several days at a time to provide heat or electricity(from either the battery or inverter) to keep radios going or whatever. Or use it to provide transport at those times when nothing else can get through(and that's why we drive 'em!). So I envision pretty infrequent use for the subtank, say maybe once or twice a year, and the rest of the time empty but ready for a big fuel up in case we get a blizzard or hurricane coming.

Some day I'd like to do Moab and could see needing it then, but in reality it probably will hardly ever get used. That's why I thought the gravity feed would be better than a fuel pump, because if I ever did need the fuel I'd REALLY need it and not just for myself. There are folks counting on us to be able to do our job regardless of anything else that might be happening. Flood, fire, earthquake, pandemic, zombie apocalypse, whatever. You call 911 and we're coming.

Extra gas would be damn handy in a crappy crunch type situation like that.

And I wish to hell I had known about the long range tanks the winter before last when I had to buy a brand new factory tank to replace my rusted out one. That was a lot of money right there.

 

[LS1FJ40]

Based on what you are saying, I get where you are coming from. I would think jerry cans would just be a simpler solution but I kind of dig where you are going with this.

Carrying fuel outside (rear or top) increases risk. It is debatable which is a greater risk.

One thing I would think about is UV resistance of whatever you are putting up there. It is going to bake in the sun. Unless you are thinking that this will sit in the garage and get thrown up there come winter time or in case of an emergency. Which then, according to Murphy's law, will happen when it is sitting at home in the garage...

 

[retrofive]

To frank, based on what your intended reason for this is, I'd say barking up the wrong truck for the job.

 

[Dave 2000]

A 'wanker moment' was when on the roof filling the two jerry cans, something distracted me and I did not close the lid on one. A few yards down the road and I see the splashes on the screen, fortunately I saw it and pulled off the road quickly.

After looking for someone to kick my arse and closing the can, I returned to the garage and washed the roof with the hot power washer. No road contamination and once a solvent was used to nake sure the wipers were clean I carried on.

If......and I mean if, what might have happened if it had been petrol, and was ignited as it run under the hood? Given there would undoubtedly be fuel also in the front vent as well this could have been a fatal event.

If I had a petrol motor then there would not be petrol on the roof, I see the OP's situation (and applaud his emergency work), but think I would be looking for an alternative solution.

Regards

Dave

 

[inkpot]

You need to buy property outside of city limits so you can have above ground fuel tanks. Farm Service and others routinely fill up 500 gallon gravity feed tanks on ranches and farms. It is also cheaper.

 

[MoJ]

Locating fuel outside of the frame is dangerous. It doesn't matter if it's jerry cans or otherwise. Putting cans on the bumper or roof increases the odds that one will die in a blaze of glory. Do it right and put the reserve tank where it's meant to go.

 

[dirtyboots]

There be sounds of slosh
The air has vapors of stink
Ain't no partying

A haiku about mounting a large gas tank on the roof.

Also how would you connect the tank? If exterior you risk being disconnected when driving through Amish country or other parts of the world where scythes can be encountered. If inside you can't throw around your Oddjob hat.

 

[mudgudgeon]

Based on your description of intended use, I think having a cache of jerrys at home would be a better option.
Or have the tank stored at home empty, mount it on the roof and fill if you think it's going to be needed, use a jiggle syphon to to of your main tank if needed. No permanent connection, no 20 gallons of vapor the roof when it's not in use. Obviously, this reduces your level of preparedness, but increases the safety.

Or, get a smaller winch, or hitch mounted winch, and have a custom made subtank for under the rear floor.
I used a $10 2nd hand 90litre Prado tank to increase my sub tank capacity (45l standard), but lots of guys in Australia have long range tanks in the rear with capacity up to 150, or 180 litres, plus 90l in the standard belly tank.
Personally, I think 180l in the rear has more disadvantages, than advantages, but it gives you an idea of the potential capacity under there.
Plenty of room for a custom sub tank, plus winch if you're clever about it. But $$$

 

[Mandrake]

You work in public safety? Kind of an odd occupation for someone who constantly disregards the advice of those on here when the questionable safety of your decisions is brought to light. I assume you'll be booger welding the tank like you did your front suspension? Keep fighting the fight, kid; you've got all the answers, so no need for our input.

 

[Hornd]

Try it on a Jeep 1st!

 

[bwakeling]

I have been looking at building a swing out to carry some gas around in when on the trail. Need it most often when winter wheeling and burning tons of fuel breaking trail. Have had a few times out on the wild when I almost ran out of gas. Wouldnt carry gas anytime other than heading to the trail.

Most carriers look as though the gas would be up above any impact unless you get rear ended by a semi. Especially if you are lifted and on 35/37's.

 

[malteserunner]

Expanding on one of @mudgudgeon 's suggestions.

Get a receiver mount for the winch. Add a front receiver, since your ARB does not provide a winch mount, and you'll have front/rear winch capabilities. Then mount a tank underneath.

 

[artech]

You work in public safety? Kind of an odd occupation for someone who constantly disregards the advice of those on here when the questionable safety of your decisions is brought to light. I assume you'll be booger welding the tank like you did your front suspension? Keep fighting the fight, kid; you've got all the answers, so no need for our input.

No need for input like this, that's for damn sure.

Mebbe you ought to actually read the whole post before writing stuff like this.

 

[lugueto]

If you're only going to use the tank eventually, why not use fuel cans? Why would you do such an invasive modification when a simple solution is available?

I agree with most everybody else: its a bad idea. The roof is just not a good place for fuel. Even though the risk of roll over is there, think about less extreme cases, like running into a parking ceiling or a big tree branch. While fuel cans will most likely just fall off and survive, the fuel tank will be more solidly attached. You will rip the roof rack off, probably rupture the tank and leave an open fuel line leaking..

How will you attach the tank to the rack? How do you plan to plumb a fuel line from the roof to the fuel tank?

I do understand the need for extended range, especially given that you will need that for your duty. I have my vehicles with sub tanks, but they're safely under the vehicle. I would only consider an under-vehicle tank for auxiliary purposes.

That said, a rear winch is very rarely used. A few friends installed them after seeing a couple of competition vehicles use them, but they never actually used them themselves. It is added weight that rarely helps. Get yourself a good winching kit with extensions and a couple snatch blocks. If you need to go backwards, use recovery ramps.

Don't see negative criticism as annoying, try to read between the lines. Judge by the general concensus, not by a single opinion. Weigh your priorities, I hope you reconsider your rear winch option.

 

[artech]

Well, with a few exceptions I think we're having a pretty decent discussion here about the merits and drawbacks of a roof mounted system vs. other options. Points and counter-points are being raised, questions are being asked, information is being provided, ideas are being exchanged; these are all good things.

I'm definitely leaning away from trying this on my own build, not from any of the emotional outbursts in the thread but from some of the valid points being brought up by the knowledgeable folks here. I liked the built in tank that veggie80 did with his truck(which is simply awesome, by the way!) and bought a similar tank with the idea to pretty much duplicate that build. It looked like a very good option.

Then I had the idea of maybe trying something different. So I posted up asking if anyone had already done it, and so far as I can see the answer is no, for many reasons (a few of which I don't believe to be valid, but I'm not attacking anyone because of their own individual hang-ups either.) There are some good solid reasons not to put this particular tank on my particular roof rack, but I still don't see why it couldn't be done with the proper kind of anchors, fuel cell, and a mix of aviation and maritime fuel valves and connectors.

First, build a solid mounting system and install a crash rated fuel cell. Run the fuel line out the bottom of the tank and through the roof with a bulkhead fuel fitting and run wire reinforced USCG or aviation rated fuel hose down the C-pillar next to the sunroof drain hose and T into the factory fuel fill line inside the quarter panel, putting an accessible aviation fuel shutoff valve somewhere in the line. Run the vent hose the same way or just direct vent the tank on top. Maybe with the right vented fuel cap you wouldn't even need a vent line and could just remove both gas caps when transferring fuel to give the air someplace to go. The fuel fill would have to be on top, and either aircraft or maritime fittings should work there. No pump needed, just simple infallible gravity feed. Add a gauge and sender or just a mechanical gauge on top, and bob's yer uncle, there you are. Just like in a light aircraft.

My particular tank would have to be substantially reworked to change all the hose attachments over, and that would be costly and the tank would then be untested in a different configuration. Not too excited about that, actually. Plus, the welds would have to be pretty much x-ray quality to match the factory ones, and that's just not the kind of welding you get done at the local garage. I'm sure somebody would have pointed that out early on if I had posted up some pictures of the tank as it sits, but not being the sharpest spoon in the drawer it took me a bit of pondering to realize it.

And really, the only thing I didn't like about the above mentioned build(thread here: Aluminum Subtank Under $300) was that his tank sat a bit low in the back, but my tank is almost three inches less in height than his and should be a better fit. Mocking it up puts the bottom about an inch below the frame rails, just about perfect. The install should be straightforward and the plumbing less complicated, although I will need to have some kind of fuel transfer pump to run it that way.

Now I just have to figure out something different for my winch. (Anybody wanna buy a really big winch?) Anybody ever tried mounting a winch inside the truck to the 4 third row floor attachment points? Doesn't seem like those 8 bolts (working in a shear plane)would be strong enough for a big winch though. Or the body mounts might fail under the torque. And the tailgate would abrade the line, and on and on. Well, there's gotta be some way of mounting this winch. Anybody seen that mid-mount that that brit did on a rover that could pull either front or back? That was some inspired stuff right there! Gotta chew on that idea some more and see where it goes...

So I think this has been a pretty fruitful discussion by and large, despite all the butthurt it caused. There seems to be some good info here for anyone who want to try this setup going forward, and hopefully someday someone will do a nice job on one and post it up.

And don't be hating on somebody talking about trying something new! Common wisdom once held that the world was flat, that space travel was impossible, and that lidocaine was the best arrhythmic for all cardiac arrests. But we learned...

 

[surfpig]

 

[1973Guppie]

Bad idea. I don't think you can really compare jerry cans to a full time tank on the roof. You are not comparing apples to apples. You are comparing apples to oranges. A full time tank will need lines and be used at all times. That means it always having fuel and an exit line full of gas. Most people like myself whom have jerry cans on the rear don't use them on a daily driving basis. Mine are used only for long distance off road trips and are filled near the trailhead. Again, 2 totally different scenarios. I would bet that 90% plus of the jerry cans you see out there on the road are in fact at that time empty.

 

[artech]

You know, I had completely forgotten about using those back in the day, I wonder if they are still dumping them off as military surplus? Probably be a diesel setup these days, but that could be changed easy enough ...as could the trailer hitch...hmmmmm...

 

[ZackR]

Here's what I would do:

1. Sounds like you need to have extra fuel around for emergencies and or when the power is out. The perfect chore for a gasoline storage tank with a manual or 12v pump.

2. To transport the fuel around (for yourself or others) I'd go with jerry cans (good ones). Leave them at home until they are needed. Store them safely during transport.

3. If you need to have extra fuel on board at all times (increased range) then I'd look into a sub tank mounted underneath or replace the OEM tank with a larger one (does Man A Fre still make the 38 gallon tank?).

4. If you are hauling a ton a stuff and also need extra fuel on board (to dispense to others) a pickup truck might be a better tool for the job.

5. Another idea is to make a "rescue trailer" of some kind that has all of your gear, including extra fuel and supplies that you can hitch up and go when needed. Then you wont be dragging it around when not needed.