Thread: Developing HD plastic sill tanks for Defender

Originally Posted by Xtreme

Here's a picture and dimensions which you may find useful, for a batch of steel tanks I had made for 110's quite a few years ago.

A few pointers to watch:
1. Not all Defenders enjoy the same dimensions. I had to reduce the width by 10mm after discovering that the initial batch wouldn't fit a friend's 110. Dimension shown on attached drawings is after correcting for width.
2. Pay special attention to the breather line/s to avoid slow filling &/or possibility of airlocks and not achieving full capacity. I'd fit front and rear breathers if I ever made these again.

These tanks don't wrap around chassis outriggers and have a capacity of 55 litres (drivers side) and 35 litres (passenger side). Also, tanks don't protrude below chassis rails.



HTH

Thanks Roger, that's exactly what I was thinking re defenders being all a bit different. I have made the wood mock up a nice fit but have decided to relax the fit some what to make sure it will fit hopefully all defenders. Being plastic and long and skinny I will mount the tank with straps to hold it in place, and foam rubber can make for a snug fit. Once I have the new wood mock up finished I will try get someone with a tdi, Td5 and puma defender to make sure it will fit, could be different brackets/fittings/wires etc in the way?

I'll be trying my best to have good breathers and filler so it will fill quickly with a hi flo pump even. Keep the tips coming, very helpful.

Cheers, Andrew.

Originally Posted by Shingleback

Thanks Roger, that's exactly what I was thinking re defenders being all a bit different. I have made the wood mock up a nice fit but have decided to relax the fit some what to make sure it will fit hopefully all defenders. Being plastic and long and skinny I will mount the tank with straps to hold it in place, and foam rubber can make for a snug fit. Once I have the new wood mock up finished I will try get someone with a tdi, Td5 and puma defender to make sure it will fit, could be different brackets/fittings/wires etc in the way?

I'll be trying my best to have good breathers and filler so it will fill quickly with a hi flo pump even. Keep the tips coming, very helpful.

Cheers, Andrew.

I'd be careful about using foam rubber - it will hold moisture/mud etc and although that won't affect your plastic tank, it has the potential to rust the chassis or whatever it would be wedged against. I'd much prefer to have a void that I could regularly clean out with a high pressure hose.

Maybe a few small spacer knobs moulded onto the tank at appropriate positions would achieve the "snug fit" without the possible rust potential. The length of the knobs could be ground/filed to accommodate variations in individual vehicle dimensions.

Originally Posted by Xtreme

I'd be careful about using foam rubber - it will hold moisture/mud etc and although that won't affect your plastic tank, it has the potential to rust the chassis or whatever it would be wedged against. I'd much prefer to have a void that I could regularly clean out with a high pressure hose.

Maybe a few small spacer knobs moulded onto the tank at appropriate positions would achieve the "snug fit" without the possible rust potential. The length of the knobs could be ground/filed to accommodate variations in individual vehicle dimensions.

Some good ideas thanks, I know what you mean about foam holding water, rubber would be ok though. Once I have the new wood mock up finished I'll play around with the fit. Have to be careful filing knobs off as you could create a thin weak spot, but another option is brass inserts with screw in adjustable legs with a rubber pad that you could simply adjust to fit, just like levelling your fridge. But I reckon the straps will hold it nice and snug, will have a play. Thanks again, Andrew.

Originally Posted by Shingleback

G'day all, I'm in the early stages of design and development of heavy duty rota moulded plastic sill tanks for Defenders.

I'm just after some feedback, input, ideas from those who can help with things like;
* shape/profile, who hits their sill tanks?
* who has a steel sill tank, how much clearance is around the tank?
* filler set up's, transfer pumps, gauges, switches etc

Tell me what you think!!

Cheers, Andrew.

Hi Andrew,

I've got a pair of Mulgo stainless steel sill tanks on my 130.

They are well made, sit flush with the chassis and are tapered up at the sides. They have survived numerous offroad trips, including the OTL up and back with no issues. I haven't ever hit them but have bellied the 130 on the crest of one dune, and slid over a number of others, with no ill effects. I definitely do drive a little more carefully at times with a grands worth of tank under each side. They weigh about 19kg per side. They have held up well, and I am happy with them. Sill tanks are the way to go.

I have 83 useable litres in my right hand diesel tank. I dont have a 2nd fuel gauge, but work it out by pumping approx half (40ltr) into the main tank twice using the main gauge. The outlet is at the back of the tanks, so I pump the last of the fuel out when going up hills.

I had a Y filler made up, and can fill the sill tank up with full flow from the servo. It is important that the breathers rise all the way from the tank to the filler, so the fuel can't pool. You will need 3 breathers, one for each of your tank sections, with one at the front of your first section.

Some photos and more details are in my build thread post #167, and I think there are some more of the water tank earlier on - http://www.aulro.com/afvb/projects-t...ml#post2485144

The left one is used for water and holds 65litres. It could certainly hug the battery box better for a little more volume. Maybe there are differences in battery box shape over the years ? I have a 300tdi. Re fitting - they are very tight between the chassis rails and the channel on the outside edge under the doors. With only 5-10mm between the heads of the gearbox cross member bolts. There is also not much clearance with each of the outriggers. Land Rover is sure to have variances here too. Make sure there is enough room for rock sliders, side steps etc to bolt on.

All the best with your project.
Alan

I have had a steel sill water tank on my County since I got it in 1993, and I am pretty certain it was fitted from new. It extends about an inch below the chassis rail, and the bottom was not strong enough to use as a skid - I have replated it twice! The front is also very susceptible to stone damage, and although the steel stands up to it, the paint does not, and I suggest the front of a plastic tank would need protection, perhaps a replaceable moulded extra layer.

My extra fuel tank is between the LH chassis rail and the prop shaft, in the position occupied by the exhaust system except on Isuzu engined Landrovers. It has a substantial skid plate on it and has given no trouble. The filler on it is to a 'Y' on the standard filler.

John

Originally Posted by danialan

Hi Andrew,

I've got a pair of Mulgo stainless steel sill tanks on my 130.

They are well made, sit flush with the chassis and are tapered up at the sides. They have survived numerous offroad trips, including the OTL up and back with no issues. I haven't ever hit them but have bellied the 130 on the crest of one dune, and slid over a number of others, with no ill effects. I definitely do drive a little more carefully at times with a grands worth of tank under each side. They weigh about 19kg per side. They have held up well, and I am happy with them. Sill tanks are the way to go.

I have 83 useable litres in my right hand diesel tank. I dont have a 2nd fuel gauge, but work it out by pumping approx half (40ltr) into the main tank twice using the main gauge. The outlet is at the back of the tanks, so I pump the last of the fuel out when going up hills.

I had a Y filler made up, and can fill the sill tank up with full flow from the servo. It is important that the breathers rise all the way from the tank to the filler, so the fuel can't pool. You will need 3 breathers, one for each of your tank sections, with one at the front of your first section.

Some photos and more details are in my build thread post #167, and I think there are some more of the water tank earlier on - http://www.aulro.com/afvb/projects-t...ml#post2485144

The left one is used for water and holds 65litres. It could certainly hug the battery box better for a little more volume. Maybe there are differences in battery box shape over the years ? I have a 300tdi. Re fitting - they are very tight between the chassis rails and the channel on the outside edge under the doors. With only 5-10mm between the heads of the gearbox cross member bolts. There is also not much clearance with each of the outriggers. Land Rover is sure to have variances here too. Make sure there is enough room for rock sliders, side steps etc to bolt on.

All the best with your project.
Alan

Thanks Alan, very helpful info, and love your Landy by the way! I've made some rock sliders which will fit no problem with the sill tanks. Was thinking of attaching a bash plate to the rock slider from the chassis and make it so it will hinge down for easy cleaning if needed. Good to hear you can fill no worries, I'll definately be fitting plenty of breathers. So how much clearance is between the top of the tank and the floor? Need space to run the breather lines.

Good luck on your travels, looks great.

Cheers, Andrew.

I haven't managed to dint mine, but did wedge the mud flap against the tank driving over a rock like a proud upright beer box in the middle of the track. For a tourer I don't think you would dint them. We have done done gnarly things, but not extreme in our 130. You polish them fair bit over dunes, but they slide well and don't get hung up at all. Kind of figured with other steel fuel tanks I have had in the past take a good dinting, so these will be no different.
Stones with plastic may be an enemy, even with LR big mud flaps on, a good out back road peppers every thing with stones. My tanks were well and truly stone chipped and the shocks were stripped bare. I guessI have some good stone dints in the OE tank and it's still going.

Drain plugs, fit them.

Yours look longer than Mulgo's. I wondered with mine how they would hold up for several hours of huge corrugations at 100 only fastened at the extreme ends. If you have driven the Fink to Alice road after the race you will know what I'm talking about. But they did without issue as well as several other corrugated roads in their time.

The tanks sit 30 to 50mm under the floor from memory, enough to shove a hose in there anyway.
My rock sliders (more so running boards) fit with the tanks. The bolt along the outrigger in two places. I live in fear with hindsight that if I hit something big and bend things a bit, it may be a real job to undo things. The tanks fit snug around the outriggers, maybe 10 to 15mm gap either side. A tad more would not hurt. My brush bars run into sliders which are made form 50mm seamless roll gage tube, so hopefully it does't bend to much in the first place. But we have pivoted the car using them on tree and nothing moved, much to my relief.

Originally Posted by newhue

I haven't managed to dint mine, but did wedge the mud flap against the tank driving over a rock like a proud upright beer box in the middle of the track. For a tourer I don't think you would dint them. We have done done gnarly things, but not extreme in our 130. You polish them fair bit over dunes, but they slide well and don't get hung up at all. Kind of figured with other steel fuel tanks I have had in the past take a good dinting, so these will be no different.
Stones with plastic may be an enemy, even with LR big mud flaps on, a good out back road peppers every thing with stones. My tanks were well and truly stone chipped and the shocks were stripped bare. I guessI have some good stone dints in the OE tank and it's still going.

Drain plugs, fit them.

Yours look longer than Mulgo's. I wondered with mine how they would hold up for several hours of huge corrugations at 100 only fastened at the extreme ends. If you have driven the Fink to Alice road after the race you will know what I'm talking about. But they did without issue as well as several other corrugated roads in their time.

The tanks sit 30 to 50mm under the floor from memory, enough to shove a hose in there anyway.
My rock sliders (more so running boards) fit with the tanks. The bolt along the outrigger in two places. I live in fear with hindsight that if I hit something big and bend things a bit, it may be a real job to undo things. The tanks fit snug around the outriggers, maybe 10 to 15mm gap either side. A tad more would not hurt. My brush bars run into sliders which are made form 50mm seamless roll gage tube, so hopefully it does't bend to much in the first place. But we have pivoted the car using them on tree and nothing moved, much to my relief.

Thanks for the info and ideas, very helpful. Drain plugs, I will fit them! I know what you mean about outback stones peppering everything underneath, I'm pretty sure the plastic will be resistant to the abuse but the full length bash plate/stone guard will do the trick.

Yes mine is another section longer than Mulgo's, which is why i'm estimating around 90-100 Liters capacity considering Mulgo's are about 80L. Being able to wrap around things forming fancy shapes to utilize available space is just another advantage of the plastic over steel. And yes I've made clearance to access the big nut on both the radius arm and the trailing arm without having to remove the tank.

30-50mm clearance under the floor is a fair bit, but I can see why having good clearance all around is a good idea which is why I'm about to re-make the wood mock up to hopefully fit all 130's.

The tank will be held in position with 3 or 4 straps which I'm going to make up before I make the next wood tank. They will basically be mounted off a bit of flat bolted along the outside of the chassis rail and to a length of 40X40 SHS bolted inside the sill channel. The tank will have a small recess for the straps to fit into.

Cheers,

Andrew.