FrontRunner 45 gal aux tank install w/ pics

[Blueegg]

It is nice to know you have 700, 800 or even 900+ miles of driving range, and to pass others waiting in line for fuel is really cool. My long ranger tank is a great mod. for me.
Speaking from experience as a trail/expedition guy and not a rockcrawler, a 34 gal is fairly tough. It makes alot of noise when it hits, and makes you think you've destroyed the thing but no leaks yet.
I've got some ideas on a simple yet strong bolt on skidplate and would love to see what others have done.

 

[mot]

Looks pretty slick!!

Great job!!

 

[MSGGrunt]

Would welding on an additional thickness of stainless steel on the bottom of the tank suffice? Still looking for advice on the fuel gauge and sending unit.

 

[AdventureBuddies]

How about a side profile pic, from about bumper height. It would give a good idea as to departure angle with the aux tank.

This should give you a good idea. The clearance from the ground to the bottom rear corner of the Kaymar is about 24". The clearance from the ground to the furthest back corner of the aux tank is 19".

Basically, coming off an even shelf rock, the tank won't hit and the weight will be carried by the Kaymar. This has happened to me lots of times and I don't think the big aux tank changes that. The risk of hitting the tank is when coming off a boulder that's narrow enought to "fit" up under the truck between the width of the bumper.

By the way, those mud flaps are trimmed so don't use them for perspective.

 

[AdventureBuddies]

Would welding on an additional thickness of stainless steel on the bottom of the tank suffice? Still looking for advice on the fuel gauge and sending unit.

That would help with a scraping incident, but won't change anything if the weight of the truck is partially on the tank. It would either tear open or the brackets would rips from the tank welds.

My plan is to fab bolt on protection that doesn't touch the tank and will be able to take a lot of weight.

 

[george_tlc]

Just an echo here of some of the concerns... YES you NEED a SKID PLATE ON THAT TANK.

It's not just coming off a shelf that is an issue with a low hanging tank. It IS the articulation ability of the 80. If you've never driven behind another 80 while driving a deeply rutted track with rocks (even river rocks etc) you have no idea just how much that rear axle will move & tuck and twist to keep the 80's bum level.

and

and

and those pics are with no load in the rear end and 863 oem coils. Put some 'expedition' weight back there and your overall level height will be less to start with and it will articulate all the way to the bump stops.

cheers,
george.

 

[80t0ylc]

This should give you a good idea. The clearance from the ground to the bottom rear corner of the Kaymar is about 24". The clearance from the ground to the furthest back corner of the aux tank is 19".....

As your truck sits, what is the distance to the ground from the lowest point of the aux tank? In post#3, in the bottom picture you can just see the bottom of the rear axle tubes. It may be the angle of the camera, but to me it looks like the lowest part of the tank is like 15" or 16" off the ground. IMHO you need to consider the entire bottom exposure with your plans for a skid plate.

 

[SOCALFJ]

I'd say there's just a little bit of difference between your tanks clearance and AventureBuddies 45 gallon tanks clearance, wouldn't you? It might be worth some protection, dontcha think?

Little bit? I'd say there's a huge difference... i can see my entire diff and trac bar. Looks 50% lower than mine... 24 vs. 45.... thats a slight difference in size. From the side view and the rear you don't even know i have an aux tank.

Years ago I had Arrow Tanks, then in Placentia, CA, build me a 50 gallon tank for my '79 Chev. Luv 4x4.

Good ol' Aero tanks... they're in Corona now right down the hill from my house and i will never give them my business. They're apparently too big to care about customers anymore.. but thats a whole other thread.

It's not just coming off a shelf that is an issue with a low hanging tank. It IS the articulation ability of the 80. If you've never driven behind another 80 while driving a deeply rutted track with rocks (even river rocks etc) you have no idea just how much that rear axle will move & tuck and twist to keep the 80's bum level.

Im confused as to what your saying? The aux tank is behind the axle... how does the axle articulation have anything to do with the tank? Are you saying it will hit the tank under full flex? Are you saying when you flex the tire will rub on the tank?.. thats impossible too, because the tank sits inside the frame rail not outboard.


For what it's worth.. im not fighting anyone on the skid plate deal.. i think if we had a 45 gallon tank we'd have one for sure... im just saying for what we do with our 24... there's no need for us.

 

[george_tlc]

Im confused as to what your saying? The aux tank is behind the axle... how does the axle articulation have anything to do with the tank? Are you saying it will hit the tank under full flex? Are you saying when you flex the tire will rub on the tank?.. thats impossible too, because the tank sits inside the frame rail not outboard.


For what it's worth.. im not fighting anyone on the skid plate deal.. i think if we had a 45 gallon tank we'd have one for sure... im just saying for what we do with our 24... there's no need for us.

Nothing confusing - the pictures should explain the 'issue'. When the axles articulate the arse end (well, some of the bottom/chassis/tanks etc) will be a LOT closer to the ground. The pictures show pretty clearly I thought that bits of the vehicle get a hell of a lot closer to the ground. Consider 'stuff' in the middle of the track, very common when you have ruts dug into the wheel track. You then come to a deep rut on one side and say a 'bump' on the other side. The axles will articulate and the bum/tank/etc will go smash onto the 'stuff' in the middle of the track.

i.e. I'm saying that the static height of the tank above the ground has very little to do with how safe you think the tank is from hitting something. Tuck those wheels into the arches and then consider what clearance the tank has over the ground. Then figure some wheel ruts and 'stuff' in the middle of the track...

Most of those huge oz tanks are for driving distance on sandy tracks, dirt roads etc etc. I've got a pretty good idea of the typical oz terrain they are used in.

I understand that the tyres etc won't contact the tank... I do have a subtank on my 80 - I think I'm one of the early 80 guys that installed one in my US spec 80.

cheers,
george.

 

[Atoyot1031]

IIRC, the Long Ranger is about half the capacity of the Frontrunner. All you have to do is hit the right rock or obstacle with momentum and your going to be slicing sheet metal. Going forward there's prolly slim to no chance 'cause you'd hang up before it reached your tank. But if you back into or onto this obstacle (don't forget your vision is quite handicapped in reverse) it's gonna get you.

FYI, according the Long Ranger site the capacity is 166l (43.8 gallons), which puts my capacity approaching 70 gallons (x 12MPG ~ >800miles).

I've never heard of anyone here puncturing an aux. tank. IIRC, Beno beat the piss out of his OEM tank. Not saying it can't happen, just saying where my truck has been it hasn't come close to happening yet, and 5" of lift and 37s helps as well. It does look like that other tank sits lower.

 

[SOCALFJ]

Nothing confusing - the pictures should explain the 'issue'. When the axles articulate the arse end (well, some of the bottom/chassis/tanks etc) will be a LOT closer to the ground. The pictures show pretty clearly I thought that bits of the vehicle get a hell of a lot closer to the ground. Consider 'stuff' in the middle of the track, very common when you have ruts dug into the wheel track. You then come to a deep rut on one side and say a 'bump' on the other side. The axles will articulate and the bum/tank/etc will go smash onto the 'stuff' in the middle of the track.

Gotcha now. Of course anything is possible... and i'd like to think if i came to a track that deep i'd have a spotter first if need be.. because im not just worried about the aux tank at that point , but the t-case, stock tank and the muffler being ripped off. Not to mention if the track is that deep, and im articulating through it i'll be paying attention to my diffs as well.

Usually thats why i straddle situations like that.. if_i_can.

 

[AdventureBuddies]

Interesting direction this thread has taken. It seems there's an arguement over whether or not a tank that hangs as low as mine does needs a skidplate aks yet everyone agrees it needs a skidplate.

So let's move this in a productive direction. I could use some ideas on the design of the skidplate. It needs to be light but super strong. I'm not doing any welding on the tank itself or on the chassis. I'm thinking of some vertical 2" steel that bolts to the inside of the chassis and welded to some 2" angle stock which spans the width of the back of the tank and protects the trailing edge. The steel plate would be attached to that angle steel. Haven't worked out how the front of the skid plate would anchor. Not sure if that makes sense. I'll get a drawing up for some input.

 

[george_tlc]

I doubt that a light but super tough design exists, that would support the weight of the rear end pushing down hard on rocks etc. I think all you can do is fabricate something that would bend/deform and prevent the tank from being pierced. The metal of most after market tanks is pretty thick so not too likely it would be cut into, but having a 2nd skin to absorb the cutting action wouldn't be a bad idea, especially given how much the 80's rear end can move closer to the hard ground versus a leaf sprung vehicle. Based on that thought I'd say a metal 'cup' that fits the contours of the bottom of the tank and then mounted/strapped etc to the tank would mostly do the job. Sometimes something with a bit of give is better than a rigid system that will potentially crack/break with sharp bits...

The after market 160l tank on my swb nissan in oz has a few scrapes that have just lightly dented the metal without any real damage. I did have a crack develop on a gusset that was allowing diesel to slowly seep through the crack. It was re-welded with some new plate and an extra gusset. This was after years of corrugated roads. 160l of fuel is heavy and any weak spots in the tank supports or brackets will eventually make themselves known...

cheers,
george.

 

[SOCALFJ]

I would go 3/16" steel and hug the tank as close as you can for clearance reasons. Make sure you drill drain holes in it so water doesn't get trapped between the tank and the skid. I had a after market gas tank skid on my XJ and i actually landed on it quite a few times with my tires in the air.. if you build it right you won't have to worry at all. I would tie it into the frame and the hitch points.

 

[MSGGrunt]

The FrontRunner tank from CampingLabs is stainless steel. Shouldn't any Plating that is welded onto the bottom of the tank for added thickness/protection be stainless as well? Would this plating need spacers or welded flush with the tank?

 

[AdventureBuddies]

Still looking for advice on the fuel gauge and sending unit.

If you use that shorter sending unit, the gauge will read empty when you still have 5 gal or so of gas left. You'll never know how much is left which sort of defeats the purpose of having the sub tank fuel gauge. You might be able to extend it though to make it more accurate.

 

[MSGGrunt]

I've found a sending unit that is 12 1/4 long/deep. The section of the tank where it will be installed is 12 1/2 deep. Made by VDO with an adjustable VDO gauge. Thoughts?

12 1/4 deep fuel sender. Part Number: 224-063
Fuel Senders: VDO Tube Type Sender (90-0 Ohms) for Adjustable Gauges - egauges.com

Adjustable Fuel gauge. Part Number: 301-106
VDO: Vision Black Series Gauges: Fuel Level Gauges - eGauges.com

Bolt-on Fuel Sender Mounting Kit. Part Number: 226-451
226-451: Fuel Senders: Classic Instruments Lever Arm Sender (0-90 Ohms, Late GM) - egauges.com

 

[MSGGrunt]

I'm thinking 1/4 difference won't be that big of a deal. I normally don't like to even let my main tank get that low. I could go without an gauge, but it would be good to have some idea how much fuel is in the tank.

I'm leaning towards plating the bottom of the tank with a thicker piece of stainless steel for added piece of mind. For my needs I do not need a skid plate that bolts to the frame separate from the tank, but more thickness on the bottom will be a good compromise.

 

[80t0ylc]

It would be well for those considering beefing up the bottom of the aux tanks, to realize that the pounding the bottom is exposed to is only part of the trauma. When you come down on it (with the weight of vehicle) the tank mounts are being stressed also. And ruptures can happen near the mounts, as well as the bottom being torn open. This is from experience. AdventureBuddies' plan to have a skid plate that keeps the weight and stress during contact on the skid plate and off the tank and mounts, although more difficult to achieve, would be the best protection. That said, I think that for expedition use, with proper caution, the stock fuel tank type of protection would work well.

 

[MSGGrunt]

Besides the protection issues, got it and will be addressing these, I have several questions about the actual install.

1. I too am installing a fuel sendor. Will JB Weld hold up over the long haul or should the washer be welded to the tank before any fuel is added to the tank?

2. If I go the welded on route it will be stainless to match the material of the tank. Or at least that will be my initial plan.

3. When cutting the hole in the tank for the sending unit I assume it would be a good idea to keep as many filings out of the tank as possible. My plan is to hook my shop vac exhaust up to the large filler inlet to preasurize the tank and block off all other inlet/outlets.