Building 10 Disco 2 vehicles for an expedition company..

[lwg]

I’m 6’5” and love the headroom of my D2. The real issue is the legroom. If you don’t need the rear seats it’s super easy to mod the D2 seat to add tons of legroom.

Also, honesty I’d take a D2 over Defender any day. Defenders are terribly uncomfortable, ride rough and straight up scary offroad in the D90 form due to short wheelbase. I really think they are really only popular due to their looks and uniqueness. Not saying their simplicity isn’t a factor outside the US, but within the US parts availability is much greater for a V8 D2.


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[The Rover Shop]

Yes, I was planning on making one or two of the fleet with an extra couple of inches of legroom for taller clients..

 

[The Rover Shop]

So, for those who want to know this useless bit of info...this is why the 4.6 blocks fail and have overheating issues.. now this is a gems block and less prone to the slipping liner and overheating problems..rumor has it that when they went to the 4.6 block for the disco2 (03 & 04) they scrimped a little on the amount of aluminum they used in the block to save a bit of money.. so over the years the of many many heat cycles the different expansion rates of the steel liner to the aluminium block allowed the liner to get a little loose in the aluminum block, causing the liner to be a little loose and moving up and down causing that noise that is often mistaken for the lifter noise... so along comes the T-Top liner..this liner cures the problem by allowing the head gasket to firmly seal the liner into the block and thus eliminating the problem, the other common problem with these blocks can be coolant weeping around the liner to block and causing misfires etc and also allowing combustion gases to enter the cooling system causing an overheating of the coolant..the t-top liner also cures that... if you see the pic of the top of the block you can faintly make out the line where the liner meets the block, unfortunately the gasket mainly seals on the block and not the liner, allowing the only sealing surface of the combustion gases to be done through the “interference fit” of the liner pressed into the block.. see above mentioned problem..the 4.0 and the 4.6 are identical block as all the did to increase to 4.6 was stroke the motor by using a different crank, but then they used a lower dish piston to keep the pressures down..4.0 is 9.35:1 and 4.6 is 9.37:1.. they did the increase in the displacement not for more horesepower but more torque... from memory the 4.0 was 190 hp and 220 ftlbs of torque and the 4.6 was 217hp but 300 ftlbs of torque..
So there you have it, your useless bit of info for the day.

 

[Victory_Overland]

So there you have it, your useless bit of info for the day.

That's some good info right there! So in your expert opinion, does the Darton Sleeve solve pretty much all of the problems with reliability on the 4.6? In your post, are you sleeving all of the motors you have coming in for the expo vehicles and if so, what are you other changes you plan to make on the block rebuild outside of the normal 4.6 install?

Interesting read!

 

[dwh]

Knowing nothing about these engines and going only by what was posted...

So one can (and probably should) do the t-top liners to the 4.6 block.

But since the 4.0 block is identical, but with more aluminum beef, one could also just use a 4.0 block with 4.6 internals?

Or the ultimate, a 4.0 block with 4.6 internals *and* t-top liners?

 

[The Rover Shop]

I used to just take all the 4.6 internals and put them into 4.0 blocks and it works perfect..the earlier blocks, either the 4.0 or the 4.6 gems were almost never heard of having the problems.. and yes, just for sheer reliability and problem solving I will be redoing the blocks even if I am using the 4.0 blocks, some of the trucks may be the earlier disco2 4.0 versions (99-02)... I will also be cleaning up the cylinder head ports to improve air flow and removing and resealing the oil gallery plugs at the rear of the block as they are often overlooked and have been know to leak oil. I will be going with the performance Kent cam from turner also as this is reportedly compatible with the obd2 perameters but can give an extra bit of torque. I will be also cleaning up some of the rough I tenal casting where the oil flows back down just to allow better oil return to the sump. I am also having the rods shot peened and reconditioned. But the t-top liners are supposedly the rectification for coolant leaks into the sump, coolant leaks into combustion chamber, compression getting into cooling system and causing overheating and excessive pressure in the cooling system.. I will try and add pics and explanations as this build progresses..

 

[The Rover Shop]

If you really want you can use the 4.6 internals with the 4.0 pistons, this then gives you a considerably higher compression ratio as the 4.6 pistons have a deeper dish to reduce the compression....I once built an engine low that and it absolutely was a screamer...I will post up pics soon of the difference in the piston tops..

 

[Kgh]

About 90% of UK forum discussing liners and gas/water leak by are also mentioning stock LR fuel mapping and temp as one of the root causes for slipped liners. Are you going to do any ECU remaps?

Also note that the UK fellows are seeing this on any block except the 3.5. 3.9/4.0/4.6. Later years worse as emissions mapping ran them hot.

 

[EricTyrrell]

As a former user of ARP head studs, I'd forget them in this application. Even if you're willing to re-torque them (remove valve covers on a dozen D2s... good luck) as specified and required by ARP, it's a waste of time and money. They don't do anything for this old engine that quality torque to yield stretch bolts don't.

To take it a step further, I'd just buy a dozen rebuilt engines from a quality rebuilder who addresses their weaknesses, at a quantity discount, and with warranties. I'd use the massive savings in time to concentrate on other areas of the trucks, and improving the experience of your expeditionaries.

 

[EricTyrrell]

I'd also forget about heavy, approach angle reducing, crush can laden, damage amplifying ARB bumpers.. but hey they're cool looking! D2 ARBs have one practical use, hitting cows. There are several better bumper options, including the stock one with a winch or hitch receiver mount.

I know steel wheels can be (hopefully) hammered back into shape in case of slight deformation, but Rover alloys hold a bead better than the steel wheels.

Make sure the heavy, COG raising, MPG reducing (reducing already terrible fuel range), noisy, and expensive roof racks are really needed. That additional cargo space better be absolutely critical to endure all the negatives. Shoot for overland practical, not overland shic.

 

[The Rover Shop]

Many good pointers there.. reason for the arp head studs is mainly due to the fact that I have numerous times gone to do the final 90degrees torque down and the threads have pulled. Causing me to have to pull the whole lot off again and redo it all with timeserts, hoping that by eliminating the movement of the bolts while torqueing will alleviate this potential.. re having another outfit do the engines, my old Shop is on successive engine install number two for problems with engines from a larger supplier of them... there are many other things I like to do to the engines such as flushing blocks, installing block heaters, smoothing rough castings, installing custom cams etc etc... plus I like to have done it myself so in the event of a problem I’m completely familiar with them... these trucks will be also driven by clients and customers so the added protection of the ARB bumpers is paramount, plus the addition of bushcables and driving lights and additional led turn signal marker lights are nice...it’s hard to beat the ARB bumper for strength and fit, I would probably say they are the most sold bumper in the world... and im. It desire how you can genuinely say the stock front bumper is a good bumper, you only have to look at it hard enough and they break...and the factory brush guard and winch mount bumper is no much better... there is a reason even Land Rover selected the arb fromt bumper for their longitude expedition vehicles...they knew their stock ones are shite...As far as the racks are concerned I am having a friend of mine who owns one of the larger rack building companies make some minor tweaks to their low profile Safari rack specially for us, since we will be using a roof top tent the rack is pretty much mandatory, and will be used for solar panels, traction mats and lightweight storage as well as additional lighting and awning support, but yes, will be wanting to keep CoG as low as possible. I prefer the steel modular wheels also for ease of hi-lift jack adapter use, it’s much easier to lift the wheel up without having to lift your suspension all the way before the wheels start to lift.. never built overland shic... google...worlds most well built defender...

 

[Nonimouse]

Some interesting stuff there

I rate a D2 highly for it's comfort and ability. Obvisously over here the V8 option is the more reliable 4.0 but it's rare and only in the top spec. So the nightmare of the sunroofs is ever present
That extra load space works well for me - although with a bit of minimalisation and very small trailer, the D1 works
The TD5 is a nice engine but unreliable and a total PITA to render operational. It's a fitters engine, not a mechanics engine. One or two have been converted to 300tdi/R380, which seems a sensible way to go; and my intended route in the near future
If they are to be used RoW, then I'd suggest moving away form Warn to a more reliable manufacturer.
Also if they are to used in Europe, move away from heavy roof loads - the legal max is just 65kgs
Obviously ACE is excellent but it would be worth maching the ali block the pipes go into so it's threaded, then move away form the crappy LR pipes...

 

[roverpat]

Are you going to be running the Gulf market grey thermostat that opens at 180? Also there is a coil pack relocation kit that would allow easier access if you needed to get to them while in the field. If you were to relocate the coils you could then open up the rear coolant passages to allow better coolant flow to the back of the heads. It is well known that the back cylinders run hotter due to the coolant not being able to flow out and back to the front. You could do a crossover coolant tube arrangement that would have coolant flow out the back of the right head and the other end would go into the front left of the intake manifold coolant passage and vice versa for the left head. Might also help with keeping temps down. We all know that engine does not like heat. Are you going to be putting in engine oil coolers from 4.0 disco 2 engines?

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[The Rover Shop]

Some interesting stuff there

I rate a D2 highly for it's comfort and ability. Obvisously over here the V8 option is the more reliable 4.0 but it's rare and only in the top spec. So the nightmare of the sunroofs is ever present
That extra load space works well for me - although with a bit of minimalisation and very small trailer, the D1 works
The TD5 is a nice engine but unreliable and a total PITA to render operational. It's a fitters engine, not a mechanics engine. One or two have been converted to 300tdi/R380, which seems a sensible way to go; and my intended route in the near future
If they are to be used RoW, then I'd suggest moving away form Warn to a more reliable manufacturer.
Also if they are to used in Europe, move away from heavy roof loads - the legal max is just 65kgs
Obviously ACE is excellent but it would be worth maching the ali block the pipes go into so it's threaded, then move away form the crappy LR pipes...

G’day mate...I know your knowledge on winches is right up there, you were my go to guy when restoring the winches on my camel trophy trucks and actually sourced me a camel trophy husky superwinch strengthening bracket... was really using the warn winches just for ease of parts and purchase availability... the main reason for not going with the diesels is the cost factor of sourcing and installing all of the necessary components to make the gas engined Disco into diesel ones, and then the added PITA of ordering parts...here I can go to just about any junk yard and find the parts I need for the gas engines....these vehicles will be predominantly used trips throughout the Americas..

 

[The Rover Shop]

Are you going to be running the Gulf market grey thermostat that opens at 180? Also there is a coil pack relocation kit that would allow easier access if you needed to get to them while in the field. If you were to relocate the coils you could then open up the rear coolant passages to allow better coolant flow to the back of the heads. It is well known that the back cylinders run hotter due to the coolant not being able to flow out and back to the front. You could do a crossover coolant tube arrangement that would have coolant flow out the back of the right head and the other end would go into the front left of the intake manifold coolant passage and vice versa for the left head. Might also help with keeping temps down. We all know that engine does not like heat. Are you going to be putting in engine oil coolers from 4.0 disco 2 engines?

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Some of our trips we have planned go up into some of the colder climates so the reduction in engine temps with a lower temp thermostat may affect cabin heating a bit, boy would I love to be able to source an older style thermostat setup for these trucks... I’ve been playing with the coolant flow properties on the blocks, heads and Intake manifolds and I was looking into using an in-line electric coolant flow pump like the ones used on the mercedes Benz vehicles for additional flow, just allow it to suck more coolant flow through and aid the water pump pushing coolant through..and agreed, any piston failures I have seen in these engines have always been overheated in the rearmost cylinder (usually number 8) due to it being the last one to receive coolant flowing over it, i was also looking at possibly installing one of those high cfm bilge compartment air blower pumps in the engine bay on an ambient temp sensor that switches it on automatically (and may put manual override switch inside) and blows engine compartment air out and over the back of the engine area, reducing engine compartment heat buildup and cooling the backs of the engine and coil pack areas..was thinking of going to a different coolant than the dexcool and possibly using one of the water wetter additives that aid in more efficient heat transfer, will also be installing the madman engine monitoring system with overheating alarm and has the ability to switch a fan relay on, which I will wire into the a/c cooling fan circuit as an overheating backup measure.. thanks for the input...all very good points...