Replacing 4.6 in a 2003 Disco II

[weaksauce123]

I have a 2003 Disco II that has a dropped liner in it.

I have noticed the 03 and 04 4.6 motors are expensive and hard to find. What is the difference in that and the 99 - 02 Range Rover 4.6?

Is there a way to use on of those motors instead? I think I found confirmation the blocks are the same. What would I need to swap from my 03 motor to make it work?

Thanks for any help!

Jeff

 

[99Discovery]

I'm hoping I never have to go through this *knock on wood*, but if I do, I already have a plan:

I think you should decide at this point how much you want to keep the Disco. If you have a lot invested and plan on journeying for many more years: Bite the bullet and get a properly build long or short block with top-hat liners already installed. This is going to cost you more than the vehicle is worth, but it is the only real surefire way to mitigate this thing form happening again.

Honestly though, as much as I love my Disco, the moment the liner goes, I'll be in the market for an LR3/4 or L322. It would just be time to move on. (Unless I could find a running D2 for $<2500, then I'd consider transferring all my off-road goodies, serviceable drive shaft, etc. to the other D2 and go for as long as that one takes me...

 

[weaksauce123]

my issue is the 03 I have is MINT with just this issue. If I can get a motor for $1k I will stick with it, otherwise I'm parting it out.

 

[jymmiejamz]

If your liner 'dropped' then just drive it as there is no issue this will cause other than noise. Do you have a cracked block confused with a 'dropped liner'?

 

[jymmiejamz]

You can use any Bosch 4.0/4.6 block without any modification. You can use a GEMs 4.0/4.6 block if you swap the crank sensor bracket.

 

[mpinco]

From what I understand you can swap over 4.6 crank/rods/pistons into a 4.0 block. The earlier the block the more reliable it is. As the 4.0/4.6 neared the end of its life quality dropped and tooling wore out. In addition rising emissions standards force Land Rover to run higher temps, adding stress. Most block related issues I read were P38's / DII's.

So, would the ideal config be a 1995/6/7 vintage GEMS 4.0 block with 4.6 internals?

 

[The Rover Shop]

If you actually compare the 4.6 vs 4.0 blocks side by side you will notice a variety of differences, the castings were very different around the cam journals and on the back of the motor the 4.6 has a cross hatching casting, Rumour has it that they reduced the amount of aluminum in the later blocks hence the problems. The 4.6 is a stroked 4.0, crankshaft, connecting rods and pistons are different, however, you can use the 4.0 Pistons with the 4.6 crank and connecting rods and this will give you a higher compression 4.6, but you may run into overheating problems as the compression is prone to finding its way past the upper liner sealing surface causing overheating...(ask me how I know....).. The 4.0 Pistons have less of a dish shape to them than the 4.6 Pistons thus lowering the compression on a 4.6.

 

[weaksauce123]

awesome! so looks like I am going to grab a bosch 4.6, drop it in the 03 and then take the rods, pistons and crank from the old 4.6 and dump them in my 97 XD 4.0

is there a noticeable difference in acceleration and towing power with the 4.6 over the 4.0? My 97 XD is such a slug, it wont get out of its own way.

 

[jymmiejamz]

is there a noticeable difference in acceleration and towing power with the 4.6 over the 4.0? My 97 XD is such a slug, it wont get out of its own way.

Yes.

 

[The Rover Shop]

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