The lean tuning is not entirely accurate. The stock LR ECU on these stays in closed loop any time the 02's are functioning, keeping the AFR right around 14.7 regardless of operating conditions once the engine is warm. That is slightly different than most other manufacturers because they typically have a performance enrichment mode where the ECU targets a 13.0 AFR once throttle position exceeds about 80% for more power. So technically it never runs lean, just leaner than most other manufacturers run their engines at WOT. I have tested this on several trucks, trailers load on uphill grades so I could keep my foot to the floor for several minutes - never stops cycling the 02s. You guys can easily check for yourself.

Given the above, it could be possible to tune by faking the ECU out with an Innovate Motorsports wideband and an adjustable vacuum pressure switch. The IM WB has mode to be used as a narrowband replacement, but with a programmable offset and switch activation. So you could program the offset to act like a NB at a manifold pressure of 85 kpa or above (basically WOT) delivering 13:1 afr.

The D2 engine almost never detonates even on low octane fuel. The combination of aluminum heads (almost no hot spots in the chambers) and an aggressive transmission program (assuring high rpm at high throttle openings) results in optimal conditions to prevent detonation.

I have two with over 220k on them. Best4x4 swears he has a high mileage one with OEM head gaskets that he has owned since new, I suspect he has taken very good care of it and it has never overheated. Easiest way to bulletproof is keep clean oil and coolant in it. Replace the entire cooling system. It has some peculiarities live everything else but once understood it is quite good. Not quite as good as an iron block SBC, but what is?

 

That doesn't explain the reputation for always eventually going to need a new engine eventually due to a crack in the cylinder and/or head-gasket. One reason to need to "keep coolant" in the car could be if it's boiling away or leaking away through a crack in the cylinder. I have an American V8 now and I never have to add coolant... never. I have to add oil all the time, since it leaks oil, however.

I'm still going with the incompatible antifreeze corroding and weakening the cylinder walls. Then it gets low on coolant since it's being leaked into the hot cylinder boiled away and then detonates due to the heat and the head gasket is part of this whole process of overheating. That explains the common failures, but I'm just guessing. Maybe some cars never used that particular anti-freeze?

 

Also, the AFR being the same doesn't guarantee there will not be detonation... my current V8 is pinging now on hot days only and only when going up an incline on the highway and only sometimes and now it has about 175,000 miles on it, the pinging is probably because it hasn't had new spark plugs and the air filter changed since at least 113,000 miles when I bought it... adding octane booster turns it into a zippy almost completely different engine (even with the old spark plugs, which I still haven't changed since I don't drive it much.) So a lot of different things can cause detonation despite the computer trying to keep a consistent AFR. Just thinking as I type.

 

I had a factory replacement 4.6 that NEVER had Dexcool in it ever and it developed a crack in the block behind cylinder 5. It also ran the 180 degree thermostat for over half of its life.

As for detonation, these have knock sensors that retard the timing upon any sign of detonation, As long as those are working, and you will know if they are not, you should be ok on that front.

My guess, and it is a guess, is that the combination of poor quality control at the casting stage and forcing the engine to run in the 220's led to most of the problems.

 

I think he would be lucky to get $10k assuming the mileage is above 100k. If I was shopping in the ~$20k market for a Discovery, I would be expecting something more like this: https://www.apvintagemotors.com/2004...-28677/6934178

I think that he is dreaming at $29k, but I think it would probably be worth about $20-25k given the low mileage and extras. Price will probably vary in different parts of the country too.

The margins would be better on the ACE LS swap if you could get a deal on nice used engine with service history. All of the custom parts on the Trailhead swap is what makes it expensive. If the market on Discos continues to increase then it might be more feasible in the future.

Which is why I think the LS / engine swap is the best way forward. It takes the issues with the Rover V8 out of the equation.

 

The margins would be better sure with the ACE kit but still slim. I think best bet is to wait for TD5s to be legal to import and it's a easy swap over and you'd gain real value in double to triple the efficiency (those of us at elevation would kill for the consistent performance over mountain passes). LS are awesome motors but they have issues of their own and still like to leak oil lol. From a monetary stand point and time stand point I can replace a rover v8 like 4 times before I come up on the price and time to do an LS swap. A 99 4.0 block with 4.6 crank/rods, 4.0 pistons, upgraded cam and lifters with fresh seals and hoses with the inline mod should be plenty reliable. The power from an LS would be sweet but other than that it doesn't offer enough upside to swap over to (for me at least). I'll get there in my rover v8, albeit just a little slower. Also, I'd ruin the rover driveline off-road very quickly with an LS, which would incur major costs to upgrade as well.

 

US Federal law requires that vehicles sold for general use, that means actual use as opposed to display, advertising or movie use, meet current US standards and crash test standards. No vehicle can be manufactured or imported for sale that does not meet current US vehicle standards.

Unless, the vehicle is over 25 years old. Then it can be imported. This is not specific to Discoveries or Land Covers but applies to all vehicles.

 

I guess you could live in an area with no emissions or inspections and have a farm and import a td5 as an agriculture motor and then do the swap lol but the number of folks in that situation are going to be slim who are disco fans.

 

From what I have heard, I think the TD5 swap may be at least as difficult or maybe exceed the difficulty of the LS swap. The with the TD5 you also need the ECU, electric throttle pedal, engine harness, and the TCU, bellhousing, and torque converter adapter plate (if automatic), and the R380 and accessories (if manual). I believe there are also some fairly sizable body harness modifications as well. Might even want to grab the body harness and BCU from the donor too. Really you would need an entire donor vehicle from the UK, or someone in the UK who knows all the necessary parts and have them strip them out of a donor and ship them. I think that would wind up being pretty expensive in the end, might even exceed the LS by the end of it.

The piece of mind from the LS is the biggest thing for me. I don't feel inclined to check the coolant tank every time before I drive it. And I haven't broken the driveline off-road. Should probably go knock on some wood now.

 

In my opinion, there is nothing inherently wrong with the LR engine.
What causes the perception is a combination of issues.
1. Emission controls led to the engine being run at many more degress toter than originally intended.
2. The factory temperature gauge is near useless. Seriously, if it shows any movement above normal you a minutes from a check engine light and ruined head gaskets.
3. Land Rover dealerships charged ridiculous prices for repairs. $1000 to change saprk plugs was normal.
4. The land rover warranty was near useless, even if you only did service at land rover dealerships.
5. They were expensive vehicles.

Mine in 2004 cost over $50,000 and the head gasket job cost $10,000 and the extra warranty paid nothing toward that. It was a rip off, but the dealerships had disassembled the engine and it was 8K to put it back together.

Expensive cars, running at the edge of their heat reliability, coupled with exorbitant repair costs lead to a bad reputation.

Now, it's easy to monitor your coolant temp, there is plenty of information on how to do repairs, and you can find usable new and used parts outside of dealer prices.

Do the inline mod, and have a method of checking coolant Temps and you have a reliable vehicle.