Ok, I have a 2003 se7 and the engine recently blew. Now, my question is this. The shop I took it to said the ONLY engine I could use to replace it is another 2003 4.6L. Is this true? If so, this really limits my options and makes the repair bill a lot more expensive than I originally thought. I appreciate any responses on this matter, you all are the best when it comes to LR knowledge.... Shane

 

No, not really. If you want to stick with the 4.6 and keep it simple you can use one from an 03-04 DII or late 99-02 P38 Range. The important thing is to make sure the replacement engine has the same emissions as your old one (W/ or WO SAI) as the evap systems, ECM, Chassis harness and fuel pump are different.

If you wanted to switch to the 4.0, to do it right, you'd need to swap a lot more stuff, ECM, Cruise ECU although the cruise ECU can be reprogrammed to 4.0 tune etc. Fundamentally the only difference between the 4.0 and 4.6 is the crank and rods.

 

what blew on your engine? the lower end? you can run a 4.0 ,4.2 or 4.6 lower end with your heads all the same block just a different stroke "i believe". that way at most the engine cpu may have to be remapped and that that is a debate that goes back and forth all the time. Because once it is open loop it should be making adjustments in real time using the engine sensors not the mapped program.

 

Exactly right on the stroke, you can even go to 4.8 with no issues or 5.0 with a little grinding of the block and oil pan and, of course, a Motronic tune.

When switching from one stock configuration to another it really doesn't make sense not to change the ECM. The open loop maps aren't just used at startup. The ECM is constantly switching between the set open loop maps and adaptive closed loop maps throughout the drive cycle. Anything other than idle, cruise or very light acceleration you're running on the stored open loop maps. There's always the difference between will it work and the right way to do things but as cheaply as used ECMs can be had there's really no reason not to swap it. As for a re-flash, Land Rovers Pro-Flash will only update like tune to like tune and the only aftermarket diagnostic system I know of with re-flash capability for the Motronic is Autologic and I can't say if it will allow re-flashing of a different tune either.

 

Get a used 4.0 with SAI (all '04's had it [secondary air injection]), get a used 4.0 ECU and you are good to bolt it right up.

 

He has an '03 but either way all did not have SAI.

 

A 4.0 will lower the horse power quite a bit as well as the valve/resale.
If a 4.0 is installed, you do npt have to change the ECU, only reprogram it from a 4.6 to a 4.0.

 

He will loose about 15horse power but save about $3,000 in the cost of the engine plus avoid all of the problems the 4.6 has.
It is easier to just swap the ECU than to have it reprogrammed and cheaper.
Used 4.0 ecu's are under $100 on e-bay, the stealer is going to charge no less than $120 to reprogram his.

 

You guys are amazing, so I'm in the san antonio area, any suggestions on where to get an engine from and does it have to have the SAI? thanks

 

That depends, does your truck have SAI now?
Landrover Discovery - Product Instructions for Landrover Parts
If so you must buy another SAI engine, if you dont you will not pass emissions testing if you have them where you live.

As far as where to get a engine from, e-bay, local dismantlers.
Car-Part.com--Used Auto Parts Market also check Craig's List.
If you do a search on the forum there was a guy who bought a whole new engine from England, shipped to his shop for under $5000.
I do not remember the name of the place he got it from.