Hey,

Would anyone happen to know if I would be able to take a xj8 engine like the short block, and replace it with my XJR short block?

thank you so much in advance.

 

I'll take a shot at this, but your question is very vague and I'm not entirely clear on the specifics of what you are trying to do....so, the answer to the question you've posted is both yes and no and first question back to you is what MYs are we discussing?

If you're trying to replace an 8 engine short block with an R, physically everything major should bolt up, but you'll never get it to run.

Again, it is not entirely clear what you want the outcome to be - Are you going from a SC to an NA using an SC shortblock? If so, the compression ratio of the SC is much less than an NA. That will be your first major problem. If you're going the other direction, using an NA block with the SC accessories, then same first big problem in reverse, way too much compression for the SC equipment.

Now, for the REALLY big show stopper - the electronics - None of the engine management system in either scenario (NA to SC, or SC to NA) is going to work to let that hybrid motor run.

This is the short answer, but let's see what you come back with and go from there.

 

sorry for the lack of info. It's a 2004 XJR I have. My bearing broke, and I have the option of picking up an XJ8 engine for a cheap amount. I was hoping everything was plug'n'play with it, but apparently there is more to it than that. Thanks for the info steve

 

No problem. Now that I understand more what you're doing, definitely no. You're headed down a very deadend path

Here is one very small but show stopping example, and there are many: The NA engine setup uses VVT units, the R setup does not. In this example alone, all of the electronic signals to/from the ECM used to manage VVT would not exist in an R management system, or vice versa, the NA wired car is looking for those signals and they wouldn't be coming. If you used the heads from the NA in an NA car, along with the R short block, then you'll have a very underpowered engine at 9:1 compression instead of 11:1...on and on.

Sorry there is no optimism here, but it is just a downward spiral.