How interchangeable are the AJ16 and AJ6 engines? The reason I ask is I believe the engine in my 96 XJR is done for. The compression is horribly low and when I did a leak down test I had air gushing out the pcv. I can only get it to start by putting some oil down the cylinders. Than it cuts off as soon as I give it gas.

I can get a AJ6 from a junkyard not too far away for pretty cheap. What is usable between the two engines? Are the engine blocks the same?

 

Well, I don't have the answer, but there are a few threads here if I recall on going the other way... swapping in an S/C engine.

I don't think it is trivial, but more knowledgable minds are sure to chime in.

But it's not impossible as I've seen a few XJRs online for sale that now have N/A engines installed.


Curious, what happened to yours that caused such a total failure? These engines are pretty bullet proof from what I understand, although just like anything they aren't indestructible of course.



BTW, I am in Sanford if you ever want to meet up at some point


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The previous owner blew the motor. I think it was from poor maintenance. The car had the spark plugs for the non-supercharged engine in the car when I got it.

 

It would be possible to mechanically replace an AJ16 engine with an AJ6 engine. However, the cam cover of the AJ6 engine does not have the screw holes to retain the on-plug coils. They would end up just sat on the top of the spark plugs which could cause problems with robustness of HT connection. Alternatively you could tap some holes through the cam cover and try to use thread sealer to stop oil leaking up the threads from the com cover. Either solution may work, but is not ideal. You would also then need to source an ECU, air meter and injectors from a naturally aspirated X300. Given the amount of work involved in changing the engine, wouldn't it be worth paying a bit more money and buying an engine from a scrap XJR6, rather than turning an XJR6 into an naturally aspirated X300 with an AJ6 engine. I would have thought that the difference in value between the two resulting cars would be similar to the difference in the price between the two different replacement engines. I would recommend spending a bit more to make the car worth a bit more.

 

Thanks for the info. I will probably just end up parting the car out.

 

If you do, please let me know if you do part it out so I can come by and check out the car and see what parts I could possibly use since I am just 45 minutes up the road.

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How much do you want for the complete XJR?

 

I've managed to secure another engine. So hopefully with a lot of elbow grease I will have the car back on the road.