Can I replace my AJ27S motor with a AJ26S motor without having any problems and is it compatible. I would be taking a 98 or 99 and putting it in a 01

 

I'm not sure what a S motor is, but if you have a supercharged engine you basically can not use a normally aspirated engine. The transmission, ECM, TCM, wiring harness and several other minor details are different.

 

How much of the engine do you want to swap ? I believe ( but could be wrong ) that the coils are different, with different connectors, so they and the wiring would have to be swapped over, at the very least. The other sensors may have to be swapped as well.






I also believe that the throttle body is different, so it may be better to swap the whole induction system from the old engine to the replacement engine. But there are much more informed people on this forum than me that could point you in the correct direction.

 

I think it's been done, as mentioned the electronics need to be catered for along with the following...
Crank sensor ring gear needs the 27 version fitting to the back of the crank so the ECU gets the correct signal
Throttle body.
There are 2 cam position sensors of the 27, you'll need to add the extra one which means removing the reluctor from the 27 and fitting/setting it in position as per the AJV8 course manual that can be downloaded on this board. I'm not sure if it's a head swap, as the extra cam sensor fits in the backside of the head and I'm not sure if there's provision for it on the 26....

If going for an early one I'd have to see a set of decent compressions before parting with money.

 

Okay I got that. What about buying a 4.2 supercharged from a xkr would it bolt up to the transmission and any mods needed. I need to find a replacement engine for my xjr trying to find the best and not to expensive way. What way would you go? I'm looking to just drop it in and bolt to tranny.

 

Unless your are doing all the work yourself and a lot of it for an out-of-direct swap area the best solution is to find a direct swap AJ26 to AJ26, AJ27 to Aj27. Otherwise you will spend a lot of labor resolving the mechanical/ electrical issues.

Anything can be done, it is just a matter of money.

 

What's the difference between the AJ26S and AJ27S? I know the AJ26 was used until about 2000, but what is the actual difference?

 

The differences are what Sean B pointed out earlier in the post, cam sensors, throttle body, crank sensor ring gear, and ECU.

 

Oops, missed that one.