Whats the best engine to use in a tri axle?

marjon said:

Gearbox?

J

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defender box. R380

Thor 1950 said:

defender box.

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Oh ok as simple as that

A stock R380 would be torn apart with high HP mainly Torque

I'd go for TD5 with a few mods and a remap.

TDV6 snaps cranks.

You won't find a finer engine than a 200Tdi two and a half litres of pure godliness with a rip snorting 113bhp and more talk than donkey out of Shrek.

Or...............

For something so cumbersome you could go for a BMW 3ltr M57 engine as fitted to the Range Rover L322, get a running 330d and fit the engine and trans in one lump with a remote transfer case, which for you might be better to get the positioning right for the third axle drive?

Harnesses and such available from Rally Raid and ECU mapping and deleting is easily found online, post it with specifications and they send it back to plug and play.

6x6 or 4x4?
If the former how are you going to power the second 'drive' ? Also a lot of frictional power losses so you'll need something meaty up front

Henry_b said:

Can't get much simpler than a Carb'd RV8

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'Real Steel' used to do a kit to stroke a 3.5 RV8 to 4.3, grunt without the liner risks associated with a 94mm bore unit.

norseman said:

6x6 or 4x4?
If the former how are you going to power the second 'drive' ? Also a lot of frictional power losses so you'll need something meaty up front


'Real Steel' used to do a kit to stroke a 3.5 RV8 to 4.3, grunt without the liner risks associated with 94mm bore unit.

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Aye don't know if they still exist.

The liner issue is thanks to the Water jackets being off centre between the cylinders the thinner side obvs cracks when cooked the liner shrinks away from the block.
Coscast blocks were better cast and I believe they solved the issue.

I once drove a 130 camper we were working on- with all the kit and auxilliary tanks it probably weighed closed to 4500kg. It had a standard 2.2 Puma engine with a modest tune on it. It went as fast as you would sensibly want to go in such a truck! TD5 should be fine as well with a similar tune (remap, larger intercooler) and possibly a lower-geared transfer case if 5th gear isn't getting much use.

Little point going full 6x6 unless you're doing some serious off-roading. Stick with 6x4 for simplicity. Although Kahn (for all the bolt-on crap) actually had a neat setup on their 6x6s where drive to the third axle was engaged when the transfer box was in diff lock. Just a electromagnetic clutch from the second axle.

FlyingPete said:

Although Kahn (for all the bolt-on crap) actually had a neat setup on their 6x6s where drive to the third axle was engaged when the transfer box was in diff lock. Just a electromagnetic clutch from the second axle.

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Not a drive-through from the leading rear diff then ?

norseman said:

Not a drive-through from the leading rear diff then ?

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Basically a 'drive-over' from the middle diff. There's presumably a gear or chain drive up so the shaft can reach over the top of the diff. A clutch inside the take-off disconnects the drive to the third axle when diff lock is disengaged. So on the road you have 6x4 so all six wheel can turn at different speeds, and you avoid having another lever or button to press when you want 6x6. Not sure who makes the modified axle but would be good to find out where they come from.

FlyingPete said:

Not sure who makes the modified axle but would be good to find out where they come from.

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Yes it would. Some of the TACR1 & TACR2/2A's had 6x6 but most were the simpler 6x4 configuration.
The US military is good on this subject, drive-through diffs that also have driven flanges (if that's the term) on the back of the rear drive as well. You don't have to tow similarly equipped trucks, you just connect a shaft & drive the disabled unit.
nb: Some of us are old enough to remember the days when a 6x2 could be retrofitted with a roller each side of the chassis that was forced down (by air/hydraulics?) between the tyres to create drive to the drag axle

Only trouble with a drive-through is that the rearmost prop usually turns the opposite way. Unless the diff on the third axle can be rotated 180 degrees, you'd need to mount the axle upside down. With the Kahn drive-over setup, the gears in the take-off drive mean the 3rd axle is a standard rear axle and only the added middle axle is a custom build.

FlyingPete said:

Only trouble with a drive-through is that the rearmost prop usually turns the opposite way. Unless the diff on the third axle can be rotated 180 degrees, you'd need to mount the axle upside down. With the Kahn drive-over setup, the gears in the take-off drive mean the 3rd axle is a standard rear axle and only the added middle axle is a custom build.

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WW2 GMC's had a drive- over set up, but with no intermediate diff the resulting axle tramp meant some owners removed the short shaft & carried it in the truck, just in case of off-road traction problems.

@FlyingPete
Foley use these up and over boxes on their conversions.



Look to be cable operated but could easily be electric solenoid?