[interjen]

Hello all, at the risk of starting a civil war between RR owners, Which would you buy?
I currently own a 4.0 P38, i need to replace the engine. I have a 4.6 engine but, Do i replace it with the same 4.0 or the 4.6? All the for's and against's please...
Thank you.

 

[q-rover]

Although it may be tempting to fit the 4.6 consider your gearbox.
The torque converter in the 2.5 diseasel and 4.0 are the same, the 4.6
has a larger as standard.
So at a minimum replace the TC as well, if you do go for the 4.6.

 

[interjen]

Thanks for the reply, i have the complete car so can fit everything to transfer it to a 4.6. Would like to know all the for's and against's though.
Regards

 

[kmagnuss]

4.6

 

[Chris X]

Well, if you already have a 4.6 and all the parts, and would have to go find another 4.0 and pay for it, sounds like the 4.6 may as well be the choice. I know nothing of the issues you would encounter but seems like the position you are in makes the choice pretty straightforward, unless I misunderstand the question and you have to go purchase one or the other. I'd be tempted to go for the 4.6 myself.

 

[viperover]

Dont forget to have the engine ECU rest for 4.6

 

[rhino_ed]

4.6 ... oh wait, already crossed that bridge.

 

[Scotty]

4.6

 

[Ferdinand]

4.6 without doubt - once tried a 4.0 - almost fell asleep.....

 

[interjen]

Thanks for all your replies, i was all set to change to the 4.6 but thought i would see what your thoughts were before i did it in case for some reason it was a bad move. I will start removing the 4.0 today, does anyone know of any things i need to look out for when removing/fitting the complete units? will i need to swap BECM aswell? does anything else need swapping other than engine and box? is all the running gear the same?
Thanks again

 

[SERSAN]

Hi,

You will need to change Becm, Engine ECU and Keys... If you don´t want to pay extra.

The engine and gearbox its straithforward.

Regards,

 

[Jos Geuze]

Hi

The engine ECU can be set for 4.0 or 4.6 with the help of a diagnostic computer. This same diagnostic computer can reset the synchronisation fault if you decide to fit the other engines ECU. The shifting behavior of the auto box is programmed differently for each engine type. look if the autobox ecu´s of your car and the donor car have different part numbers as I am not sure whether it is programmed in the engine ecu or the gearbox ecu as the engine ecu has selection possibilities for 4.0 or 4.6 and Manual or Auto box. I would rather pay for the reset and reprogramming of the ecu´s then to replace the whole BECM as vin number etc will not be correct anymore and you will also have to change the locks from the donor car onto your car and use the donors cars keys.

Regards

Jos

 

[big-t]

There is NO replacement for displacement. `)