Hey all,


I'm back working on my Jag projects. Anyway here is the deal... I am doing a 4.2 swap. The engine was out of a 4.2 xkr so I have the Appropriate heat exchangers and all...


I have already swapped the front cover and balancer valve covers and from my 4.0 engine. Ill be using all of my 4.o accessories and had already converted to the late model supercharger so that and the proper heat exchangers should be a no brainer.


It doesn't appear anything else engine wise needs to be changed. Am I missing anything>? Ive read the swap articles but they almost always are using non xkr specific engines.


If I missed anything Id love to know


Many Thanks


Damon

 

The S-Type R (X202) and XJR (X350) have COMPLETELY different intake/exhaust/sump from the XKR (2003-2006).
The AJ34 should be mostly compatible with the AJ27 block/heads.

The main things to worry about should be the Induction manifold adapter and Exhaust manifolds. I don't know if the torque converter drive plates are the same for AJ27 and AJ34 so you need to look at that.

The basic block/heads looks like it will bolt right in.

bob

 

That's why I have a 4.2 from an xkr to begin with. Not from an s type or xjr. I have a 4.2 xjr also so i'm pretty familiar with the differences.


I didn't look into the flexplate yet. I have both. Haven't really looked to see if they were different. I believe the exhaust bolt pattern is the same its the intake that is different thus the XKR intercoolers/manifolds.


I just like to have everything set before I begin. Many thanks

 

Flexplate is the same and the exhaust bolt pattern is also the same. I have done several conversions and for others to know, you can easily swap the lower bedplate from a STR/RR engine to the original 4.0 one. You can check the main swap thread in the engine section for more info.

Next is prepare how you want to do the fuel rail setup, so feed and return line which you need to add, and the fpr (and what pressure you want to run). The 4.2 injectors flow a bit more, so your fuel trims will be a little off, but it will work.

 

Thanks Avos..I'm actually finally getting around to installing the twin screw on my XJR as well:L)


I was thinking of just using the 4.0 injectors to not mess with anything. Do they not fit? I hadn't really even compared them. I'm only doing the swap because I developed a rod knock and figured.....May as well upgrade! has anyone developed a tune for use with the newer injectors? Id definitely go that route

 

I got triggered when you said : "The engine was out of a 4.2 xkr so I have the Appropriate heat exchangers and all..."

You either have to modify the 4.0 intake manifolds so it fits the 4.2 heads (so you retain the original injectors and heat exchangers), or you fit the 4.2 manifolds/injectors/heat exchangers.

When you modify the 4.0 intake manifold they will get a new position about 5 or 7 mm iirc backwards, so you also need to fix the connection between the supercharger outlet and the heat exchangers. This is easy if you have a twin-screw kit as its only a different outlet plate, so I had no issues here when I did my swap originally with the stock 4.0 parts.

Good thing with the 4.2 parts you have now, you don't have to reposition some parts on the fuel rail as you would have to do from a str/xjr 4.2 engine rail (although easy for a good welder).
- You need to get the 4.2 fuel line that sits between the fuel rail and pipe on the frame (is a direct fit).
- Remove the fuel temp sensor front he 4.2 fuel rail, and drill a hole there and then connect there the return line, you can use a connector with the same thread as is already there for the fuel temp sensor.
- Install a FPR on the return line, I have used Tomei L with succes, and best one with high flow which I use now is the Kinsler 140.
- No tune needed for it, but if you want you could go for the Pro-M MAF and have it programmed for a but more fuel flow.

Hope that helps.

 

Seem I still have to do some mods but not that much. Ill update when I get the new long block In and start putting things together