[Bigmant773]

I’m going to leave this here since there is NO info on it online.

For removing the ECM (or ECU, same thing but manual lists it as ECM), here are the steps.

For the purposes of showing you all where it is, it is on the passenger side, behind the glove box. The manual says to lower the glove box as you see above. But this isn’t necessary. It’s much easier to get to below the glove box by removing the bottom trim panel, and then the right hand side panel. But again, this will help show you where it is.

Looking through the glove box, you’ll see a silver box mounted on the right hand side firewall. That’s your ECM. The second picture above is the ECM from below with the bottom trim removed, but the side trim still in place. The side trim covers the connectors and therefore needs to be removed.

And there she is. Now remove the four connectors on the rear. The leftmost and right most connectors are push button. The middle three you unclip as follows:

First push this button to release the lever

Lower the lever

Lower lever all the way and the connector pops right out.

And here are all the connectors in order of how they came out. They only go in one spot, so it’s dummy proof, but just in case anyone needs the info.

And there it is out. Now it’s off to Tornado in the UK for a reflash! Hopefully this helps someone, somewhere, someday!

 

[Bigmant773]

Exhaust came out today, it’s not a terrible job, but exhaust work is always messy, gross, and it sucks being on your back under the Disco.

Found this on the passenger side catalytic converter, a hairline crack running up the weld seam. Good news is the local junk yard will give me $100-200 bucks for them, which pays for about half of a new set. I’m sure someone here will say weld it back up, but given that the truck is 20 years old and these are already looking gross, it’s time for some new ones.

Also fun fact, the Magnaflow exhaust has two tips, one that looks stock, and a dual tip that honestly looks amazing. Both are chrome, so provide a nice updated look over the stock exhaust. There is also no silencer on the Magnaflow which is mounted after the muffler on the stock exhaust, so I’m hoping that shaves off 20-30lbs. Anything helps on these old motors!

New exhaust isn’t on yet because I cut a rubber mount to get the old exhaust off. They were pretty decrepit looking anyhow, so probably for the best to use new.

 

[Bigmant773]

Ok bad news first. Machine shop called today and said the crankshaft was not repairable to within spec. So the crankshaft is unfortunately done.

The good news! What better time for a 4.0L to 4.6L upgrade. 4.6L crankshaft, rods and pistons is all it should take, and since the ECU is out for remapping, that should take care of the electronic side.

According to Tornado, there are some gains to be had by swapping to a 4.6L MAF sensor and box lid, because the stock 4.0L version of both are smaller and therefore slightly restrictive. Opening up the passageway in combination with a tune for the increased air apparently helps. For $100 or so bucks, I figure it might be worth it.

Regardless of air however, in 2002 the hp rating for the 4.0L was an abysmal 188hp. In 2003 and the 4.6L it went up to 217hp. So all the other mods aside, this alone should be a good increase, and hopefully by the time we are all said and done we are in the range of 250-300hp. Fingers crossed for 300 haha.

So more research on that needed, but looks like more upgrades are on the horizon!

 

[V50_M66]

Ok bad news first. Machine shop called today and said the crankshaft was not repairable to within spec. So the crankshaft is unfortunately done.

The good news! What better time for a 4.0L to 4.6L upgrade. 4.6L crankshaft, rods and pistons is all it should take, and since the ECU is out for remapping, that should take care of the electronic side.

According to Tornado, there are some gains to be had by swapping to a 4.6L MAF sensor and box lid, because the stock 4.0L version of both are smaller and therefore slightly restrictive. Opening up the passageway in combination with a tune for the increased air apparently helps. For $100 or so bucks, I figure it might be worth it.

Regardless of air however, in 2002 the hp rating for the 4.0L was an abysmal 188hp. In 2003 and the 4.6L it went up to 217hp. So all the other mods aside, this alone should be a good increase, and hopefully by the time we are all said and done we are in the range of 250-300hp. Fingers crossed for 300 haha.

So more research on that needed, but looks like more upgrades are on the horizon!

Kind of what I figured on the crankshaft. Interesting about the 4.6 parts, but I believe one of the reasons the 4.6 makes more power (and cracks blocks more often) is because it’s also bored out. I don’t really see how you’re gonna hit 300 hp on on a modified 4.0, but if you can, it would make it far more driveable. Looking forward to see what you do

 

[Bigmant773]

Kind of what I figured on the crankshaft. Interesting about the 4.6 parts, but I believe one of the reasons the 4.6 makes more power (and cracks blocks more often) is because it’s also bored out. I don’t really see how you’re gonna hit 300 hp on on a modified 4.0, but if you can, it would make it far more driveable. Looking forward to see what you do

From what I read, there isn’t a boring difference between the two, it’s just a stroked engine.The bore remained the same size as the previous 4.0 at 94 mm, but the engine was stroked by 10.9 mm giving 82 mm in total.

If I had to guess, I would honestly contribute cracked blocks or issues with 03-04 engines to a less reliable oil pump and the tooling at the factory for creating the blocks being nearly 50 years old. When Land Rover stopped making the engine in 04 they apparently had a tough time selling the tooling because it was so old.

 

[Bigmant773]

Another update on the journey! So doing some reading, there are apparently some performance gains to be had by using a 4.6L crank, 4.6L rods and 4.0L pistons. This increases compression (apparently) somewhere in the range of 10:1 or almost 11:1. According to Rave, stock its 9.35:1.

Now my question for this would be, according to Rave, the compression for BOTH the 4.0 and 4.6L engines was 9.35:1, which makes me curious as to how compression was the same. Looking at some images of the two, it looks as though the 4.6L piston has a deeper dish to keep compression the same between 4.0 and 4.6L engines. At the very least this will save me $600 in new 4.6L pistons when I can just reuse the 4.0L ones.

Anyone think any different, or see something I’m missing?

 

[V50_M66]

View attachment 95222
View attachment 95221

Another update on the journey! So doing some reading, there are apparently some performance gains to be had by using a 4.6L crank, 4.6L rods and 4.0L pistons. This increases compression (apparently) somewhere in the range of 10:1 or almost 11:1. According to Rave, stock its 9.35:1.

Now my question for this would be, according to Rave, the compression for BOTH the 4.0 and 4.6L engines was 9.35:1, which makes me curious as to how compression was the same. Looking at some images of the two, it looks as though the 4.6L piston has a deeper dish to keep compression the same between 4.0 and 4.6L engines. At the very least this will save me $600 in new 4.6L pistons when I can just reuse the 4.0L ones.

Anyone think any different, or see something I’m missing?

I’ll have to check but still I think the bore is different. Longer stroke + same size bore = higher compression. Could also be a different piston design. I’ll have to dig deeper on that. Keep in mind with higher compression you’ll likely have to run premium all the time to avoid knock, which is gonna hurt at the kind of mileage these get and current gas prices

 

[Bigmant773]

I’ll have to check but still I think the bore is different. Longer stroke + same size bore = higher compression. Could also be a different piston design. I’ll have to dig deeper on that. Keep in mind with higher compression you’ll likely have to run premium all the time to avoid knock, which is gonna hurt at the kind of mileage these get and current gas prices

We are already running premium 100% of the time anyway, so I don’t think that will make much of a difference for us. Unless the mileage plummets? Then I might care with the trips we take!

 

[V50_M66]

We are already running premium 100% of the time anyway, so I don’t think that will make much of a difference for us. Unless the mileage plummets? Then I might care with the trips we take!

Depending on what compression ratio you end up with, what you end up doing with it, and how it’s tuned, that’s a possibility. Talk to Tornado about it - they’ll know better than anyone when it comes to these things.
You also don’t need to run premium on a stock engine with stock tune, so you could be saving quite a bit of money there if you wanted. But if you run premium anyway, might as well get some benefit out of it.

 

[YETIX]

Increasing compression in an already problem-prone engine seems dicey to me. But I struggle to tie my shoes some mornings so what do I know?

 

[Bigmant773]

Increasing compression in an already problem-prone engine seems dicey to me. But I struggle to tie my shoes some mornings so what do I know?

No arguments there, but just for sake of a good discussion, theoretically I am thinking I should be good. I feel like most of the head gasket issues these trucks have stemmed from issues from the factory, that being the poor manufacturing process due to old tooling, sub standard head gasket material, and factory coolant that eats away at everything.

Fixing those issues with machine shop work, quality head gaskets, and modern ARP head studs to clamp it all together should HOPEFULLY eliminate the reliability issues and make extra compression not an issue.

Like I said, just for discussion and thinking out loud. I’m also trying to convince myself that this will be the case hahaha

 

[V50_M66]

No arguments there, but just for sake of a good discussion, theoretically I am thinking I should be good. I feel like most of the head gasket issues these trucks have stemmed from issues from the factory, that being the poor manufacturing process due to old tooling, sub standard head gasket material, and factory coolant that eats away at everything.

Fixing those issues with machine shop work, quality head gaskets, and modern ARP head studs to clamp it all together should HOPEFULLY eliminate the reliability issues and make extra compression not an issue.

Like I said, just for discussion and thinking out loud. I’m also trying to convince myself that this will be the case hahaha

I agree that it’s probably not a great idea, but then again I wouldn’t know since I haven’t tried to upgrade anything on this engine. Would love to see it work just as much as you

 

[YETIX]

No arguments there, but just for sake of a good discussion, theoretically I am thinking I should be good. I feel like most of the head gasket issues these trucks have stemmed from issues from the factory, that being the poor manufacturing process due to old tooling, sub standard head gasket material, and factory coolant that eats away at everything.

Fixing those issues with machine shop work, quality head gaskets, and modern ARP head studs to clamp it all together should HOPEFULLY eliminate the reliability issues and make extra compression not an issue.

Like I said, just for discussion and thinking out loud. I’m also trying to convince myself that this will be the case hahaha

And heat. Heat kills these things. I assume you're going to upgrade the cooling too.

 

[Bigmant773]

And heat. Heat kills these things. I assume you're going to upgrade the cooling too.

That’s actually a great point, and something I might look into now that everything is apart. Off the top of my head, there’s not a whole lot that you can do except change the thermostat to a lower temperature model.

In my performance diesel experience, there was stuff we could do like open a freeze plug at the back of the block and route in coolant to keep the block a more even temperature, but I’ve never heard of anyone doing that on these engines.

 

[YETIX]

That’s actually a great point, and something I might look into now that everything is apart. Off the top of my head, there’s not a whole lot that you can do except change the thermostat to a lower temperature model.

In my performance diesel experience, there was stuff we could do like open a freeze plug at the back of the block and route in coolant to keep the block a more even temperature, but I’ve never heard of anyone doing that on these engines.

From what I understand, you can swap for a better radiator, fan, and fan clutch, and (I believe) there is a better water pump you can use. That plus the lower temp thermostat should help a lot.

 

[Bigmant773]

Coolant In-line Thermostat Mod

Ok I think I have upgraded the coolant system sufficiently! Found the above guy who sells a good looking inline thermostat mod which allows coolant to flow more freely, reduces temperatures slightly, and allows you to use normal thermostats that you can get at a local store.

I went with the 170 thermostat after reading posts that it will throw a code on 2002 and earlier discoveries with anything less. Anything less than 180 on 03+ models will throw a code as well. While I know that won’t reduce the temperatures to 170 per se, it should create a much more consistent temperature and lower temperatures slightly.

From the research I did, bigger radiators, custom water pumps etc etc will cost hundreds if not a thousand or so. At $95 I think this mod fits the bill of improving the truck, and not breaking the bank.

 

[V50_M66]

Coolant In-line Thermostat Mod

Ok I think I have upgraded the coolant system sufficiently! Found the above guy who sells a good looking inline thermostat mod which allows coolant to flow more freely, reduces temperatures slightly, and allows you to use normal thermostats that you can get at a local store.

I went with the 170 thermostat after reading posts that it will throw a code on 2002 and earlier discoveries with anything less. Anything less than 180 on 03+ models will throw a code as well. While I know that won’t reduce the temperatures to 170 per se, it should create a much more consistent temperature and lower temperatures slightly.

From the research I did, bigger radiators, custom water pumps etc etc will cost hundreds if not a thousand or so. At $95 I think this mod fits the bill of improving the truck, and not breaking the bank.

That should help, yes. But even with the inline mod, the truck is really only capable of cooling to 100 over ambient (i.e. 190 at 90F ambient when moving with AC off - that will spike with AC usage or stop-and-go traffic). The radiator just isn't big enough, and the water pump doesn't flow enough coolant to keep it down.
I'd run a separate relay to the electric fan so you can turn it on whenever you want, which helps on my truck significantly at lower speeds, and at least consider a larger radiator.

 

[Bigmant773]

That should help, yes. But even with the inline mod, the truck is really only capable of cooling to 100 over ambient (i.e. 190 at 90F ambient when moving with AC off - that will spike with AC usage or stop-and-go traffic). The radiator just isn't big enough, and the water pump doesn't flow enough coolant to keep it down.
I'd run a separate relay to the electric fan so you can turn it on whenever you want, which helps on my truck significantly at lower speeds, and at least consider a larger radiator.

To be honest, I’m not even sure my electric fan works. I’ve been meaning to check for awhile and never got around to it. It should come on with AC, or when the truck is above…210 degrees if I’m not mistaken?

 

[V50_M66]

To be honest, I’m not even sure my electric fan works. I’ve been meaning to check for awhile and never got around to it. It should come on with AC, or when the truck is above…210 degrees if I’m not mistaken?

With AC when ambient is over 80F, then turn off over 60 MPH. And then when coolant temp is over 212, or when engine bay temps hit like 150F after 15 seconds from shutdown or something like that. 212 is wayyyy too hot IMO so I have mine wired into a relay with a switch inside. Much better control of the temps.

 

[Bigmant773]

Some non engine related updates while I wait for the machine shop! Decided to replace the steering arms with terra firma heavy duty versions as well as replace the front and rear sway bar links. All of them were pretty shot, and having the exhaust out made the rear links much easier to remove.

Don’t get me wrong, it was a dirty, grimey, gross job, but not hard by any means. While I was under there, I noticed the boots on the ball joints are all shot, but there is no play in any of them. I was going to change them out, but after some research it seems most people say if there is no play then don’t mess with them.

So that will be a job for another day! Or someone else 😂. I can’t wait to get the ol girl running again to see how much better the steering is now.