6x6 Defender

[munro]

I'm just fishing for thoughts, ideas & opinions at this stage. As soon as finances permit I have this desire to build what could be termed the ultimate tourer, at least in my eyes.

My vision is to start with a Defender 130 dual cab 300tdi. Have the engine replaced with a new balanced & blueprinted (if possible) 4BD1T Isuzu and mated to an Automatic transmission which has a modified valve body to handle towing down hill engine braking. ( I hope that makes sense). Then when that is done to have a 6x6 conversion with an 8 foot tray.

The idea is to be able to either tow an off-road camper-van similar to a Quantam or Conqueror or carry a slide-on camper.

I know where I can get the 6x6 conversion done and the cost but getting information on the engine/transmission has led me to ask here.

So is my ideas a good or bad one?
Are there any advantages in a 6x6?
Is it possible to get a new Isuzu 4BD1T?
Are their any advantages in getting a new or overhauled engine balanced & blueprinted?
Where would I get such a conversion with transmission done and approx cost? I would prefer someone who actually knows & understands Land Rovers.

I am not a mechanic nor a rock hopper, just a budding grey nomad with a head full of ideas at the moment.

Thanks in advance, all ideas, opinions & suggestions welcome.

[Lotz-A-Landies]

There are many and varied 6X6 options out there, some good, some not-so-good and some very poor.


(In the image above it is possible to be driving on only the front axle assembly, the 2nd & 3rd being crossed up without traction and in fact with the weight to the rear no traction on the front axle.)

The issues are that if the 2nd and 3rd axles are spread apart they will scrub the tyres and also if their centres are greater than ?1000mm they need (by law) to be load sharing. Independent coil springs can not load share.

Chassis: The problem with a lot of 6X6 systems is that articulation is limited so in acute ramp over situations the 3rd axle is suspended off the ground, cantilevering the load to the rear of the 2nd axle and the weight of the 3rd axle on the spring mount of the second axle. (Image below)



The best load carrying arrangements are off-set load sharing leaf springs.

Drive: Most 6X6 conversions give you constant 6X4 (drive 1st and 2nd axle, lazy 3rd) with 6X6 only engaged on low ratio or on CDL lock dependant upon system. Very few have a 4th power dividing diff between the 2nd and 3rd axles. Some like the Perentie 6X6 have a separate drive from the transfer box to the 3rd axle. Some of these systems have no high-range capability.



Other 6X6 have a double pinion diff on the 2nd axle (Image above - very troublesome),



while others have a variety of drives involving a drop box on the prop shaft from the transfer box to 2nd axle (image above) or from the pinion of the 2nd axle. (Image below) These later systems have both high and low ratios.



There is a recent thread on 6X6 in the REMLR section and another 6x6 drive and suspension.

[akelly]

If you need the 3rd axle for load carrying capacity you may want to consider a lazy axle - much simpler than a driven one.

My father has a 6 wheel land cruiser, dual cab tray back. He and Mum are grey nomads (dont tell them that!) and have a slide on camper for big trips. They have been everywhere in the damn thing - a really good tourer. A bastard to drive around town, mainly beacuse the suspension is set up to carry the camper.

Down side is the expense of tyres - the rears scrub out very fast.

YMMV.

Adam

[munro]

Lotz-A-Landies thanks for that. Had a look at the links and seems to be more trouble than it's worth.

akelly, not really interested in a lazy axle setup.

Anyone with info or ideas on the engine/trans swap I am proposing?

[isuzurover]

Why not just buy a perentie 6x6 then do an auto conversion???

I am unsure why you would need a 6x6 AND a camper trailer???

[Lotz-A-Landies]

I like the idea of an Isuzu 4BD1-T in a 130 (it is what I plan to use in my 150) but would be wary about an auto. You may want to investigate automatics that are fitted to Isuzu NPR of other models that used the 4BD1-T and mate that to the LT230 transfer like some members are doing with Isuzu gearboxes.

[munro]

Why not just buy a perentie 6x6 then do an auto conversion???

I am unsure why you would need a 6x6 AND a camper trailer???

The camper trailer is for the wifes comfort. We plan on at least one big lap of the island so the comfort of the van will be appreciated. However, there are other trips that I wish to do and the wife doesn't so me and a mate or two with tent & swags. No trailer on these ones. It's a pain sometimes but happy wife, happy life.

Can you buy perenties? I thought they were military only. Excuse my ignorance. The main reason I was looking at a 6x6 was to get the tray length. I am still debating with the Mrs. about the camper trailer, as the alternative that she would consider is a Northstar slide-on. She insists on internal shower & toilet and no or not much canvas. Of course the 6x6 is not important if we go the camper route and not the slide on. I am just trying to cover all bases of information at this stage.

However, I figure that by buying a vehicle that is around 15 or so years old there is a good chance the motor will need a reco job. So in my mind I figure why not go for something that may be better. The choice if the Isuzu 4BD1T seems to get favourable comments. The Mrs can't drive a manual so auto it must be. Thanks again for all input.

[Nero]

The Army are going to start flogging off their Mogs and Macks soon might be easier and simpler than sinking a heap of money into stretching a 130 to do the job. The 4BD1's have a reputation of extremely long service life and they removable liner motor so are relatively cheap and easy to rebuilt. Other than the motor may run a little smoother I don't think their would be much advantage in a blue print and balance unless you start going for some really big boost numbers.

[isuzurover]

The camper trailer is for the wifes comfort. We plan on at least one big lap of the island so the comfort of the van will be appreciated. However, there are other trips that I wish to do and the wife doesn't so me and a mate or two with tent & swags. No trailer on these ones. It's a pain sometimes but happy wife, happy life.

Can you buy perenties? I thought they were military only. Excuse my ignorance. The main reason I was looking at a 6x6 was to get the tray length. I am still debating with the Mrs. about the camper trailer, as the alternative that she would consider is a Northstar slide-on. She insists on internal shower & toilet and no or not much canvas. Of course the 6x6 is not important if we go the camper route and not the slide on. I am just trying to cover all bases of information at this stage.

However, I figure that by buying a vehicle that is around 15 or so years old there is a good chance the motor will need a reco job. So in my mind I figure why not go for something that may be better. The choice if the Isuzu 4BD1T seems to get favourable comments. The Mrs can't drive a manual so auto it must be. Thanks again for all input.

The 4x4 and 6x6 landies, along with the unimogs, will be sold off by the army starting mid year.

The perentie 6x6 has about a 2.5 tone payload capacity... A unimog has more.

Both could take the world's largest trayon and still have payload to spare...

[PAT303]

IMHO the 6x6's will go for big dollars,same with the mogs so a civvy 4tonner cab over would be a better choice. Pat