For the 03/04 Disco's, is this just a plug and play or is there some major retrofit work involved?
Replace 4.6 with 4.0
- Thread starter expectthebest
- Start date
People have just plugged them in, and they work.... but I do know that 99-02 and 03-04 do have some things different like MAF. But it probably works anyway. (not speaking from personal experience here.)
Also, most if not all NAS 03 and 04 have SAI..... so you'd want to find a 4.0 with SAI if you don't want to swap the heads from the old 4.6L
Also, most if not all NAS 03 and 04 have SAI..... so you'd want to find a 4.0 with SAI if you don't want to swap the heads from the old 4.6L
I've got 4.6 internals in a 4.0,( both bosh) sitting on a engine stand. If you're mechanical enough just swap all the 4.6 parts into the 4.0. Then you'll still have the power and s.a.i
Coldwater said:
because the 4.6's are ticking time bombs due to oiling issues caused by poorly machined 4.6 blocks.
ptschram
Well-known member
Some Dude said:
The last $500 4.0 I bought needed a crankshaft.
I'm putting a 4.0 into a 2003 DII due to supply and demand. I can get a 4.0 a lot cheaper than a 4.6.
We've done it more times than I can count, just about everything is identical.
I have the internals for a 4.0 that I'd be happy to swap for your 4.6 parts. I'm having problems finding decent blocks so I have two sets of the 4.0 parts. The heads are the non SAI but I wouldn't think you'd want them. PM me if you're interested.
You are going to seriously devalue your vehicle (not that LRs maintain their values all that well) by installing a lesser displacement engine. When you try to sell it, the buyer will not be convinced that the 4.0 is better than the 4.6. If the 4.0 block is really that superior, the follow the advice mentioned previously and convert a 4.0 to a 4.6.
Personally, I'd stick another 4.6 in it. Yes, 4.6s seem to suffer failures, but there are a whole lot of 4.6s with high mileage on them that arent failing. In fact the number that dont fail significantly outweigh the number that do.
Paul you know enough about failure rates to know that there are many more 4.6s that are doing fine vs the ones that fail. For all the reasons that Rover V8s fail, does the oil pumps significantly amount to more than any other cause? I'd like to see some data. My impression is that the conventional wisdom on 4.6 oil pump failure rates has much to do with the volume of discussion about the issue. Just my opinion.
Personally, I'd stick another 4.6 in it. Yes, 4.6s seem to suffer failures, but there are a whole lot of 4.6s with high mileage on them that arent failing. In fact the number that dont fail significantly outweigh the number that do.
Paul you know enough about failure rates to know that there are many more 4.6s that are doing fine vs the ones that fail. For all the reasons that Rover V8s fail, does the oil pumps significantly amount to more than any other cause? I'd like to see some data. My impression is that the conventional wisdom on 4.6 oil pump failure rates has much to do with the volume of discussion about the issue. Just my opinion.
Last edited:
I think this is an excellent point. What % actually fail? If a replacement is necessary, what is the difference in cost between the two? This is great info that will help me to decide on the used disco I end up buying.NVRover said: