I recently purchased a 2008 Jaguar XKR. Does anyone know if the internals on the 4.2 engine were upgraded on the XKR or did they just slap a supercharger on the same engine that is in the XK?

 

There were many changes between the two engines. They did not just slap a S/C on top and call it good. I know the compression ratio was reduced to accommodate the S/C. I believe the rods and pistons were also changed. Search the forum, there are many threads describing the changes you asked about.

 

Same con rods, steel crank, camshafts , heads however you guys get the forged pistons and the lower comp

 

what @ the oil squiters under pistons?

 

errr, read the ‘Curriculum Training - Technical Introduction’ publication??

07NP-XKR en 10/2006 PRINTED IN USA

 

Thank you. I had it out on the 1.5 mile Charlett Motor speed way for a track day. Was a little concered and didn't want to push it to hard since I wasn't sure about the internals.

 

I appreciate the info. Had it on the Charlotte Motor Speedway for a track night . Wasn't sure how hard I could push it. Good to know its been beefed up.

 

Nice! Thought our cars had cast cranks. Good to know! Kind of surprising the cams are the same though...seems the S/C variants would do better with different cams. Orrr maybe this is made redundant by the VVT?

Either way, good info!

 

all have a cast iron crank, bedplate accounts for that. weakest point for sure is the powder forged rods

VVT version has NA cams before they had their own profile

 

Powder rods and pistons are able to handle higher horsepower than traditional forged parts and are considered nearly unbreakable.

 

Hey, and my son is in negotiations with a dealer to buy a 2007 XKR right near me, with my assistance. I may eventually need to pay attention to all these 4.2 threads.

 

Basically, the cliffs is that the SC is much easier to change the SC oil on (the screw is up front), and the water pump is fine, and the timing bits are fine, and theres no direct injection and its fine. For the most part, the issues he'll have are X150 platform issues, not 4.2L related ones. So like the duck bill and the shrinky dash.

I do recommend he gets the audio aux kit:

https://rimmerbros.com/Item--i-C2P16491

and the Bovee 1000 30 pin device so he can bluetooth music over:

https://www.ecstuning.com/b-tune2air...r/wma1000~t2a/

and a Mongoose/Mangoose Cable so he can use SDD to turn on the Aux port that the physical kit gets him. I will say the Bovee is great in that I don't do anything, I synced it and it just works. I've had more fiddlyness with OEM built in bluetooth in some cars, and have tried like the TuneFly in my Maserati and gave up and ended up getting a Bovee for that and its great there too.

 

I totally forgot about that stupid duckbill thing. I live in a desert so I didn't care even if I had a 4.2, but he lives in Washington so a crap-ton of humidity.
I have the SDD that he'd use since he's an apartment dweller and his mom attempted to raise him after he was kidnapped to a different state than me, so I didn't get a lot of grow-up time with him so he's kind of behind on a lot of 'man' things.
I've also already suggested the BOVEE to him.

 

I've got the following specs for AJ33&aj34 both being a 4.2 although the AJ33 not running vvt on the S/C to me it looks like whether non vvt or vvt the S/C has run the same camshaft specs
. Going off the sheets it appears the S/C and N/A have always shared the inlet camshaft and only run different exhaust cams.
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S/C 240° 9mm lift inlet / 220° 8.1mm lift exh (AJ33/34)

N/A 240° 9mm lift inlet / 230° 8.5mm lift exh (AJ33/34)

 

Please do your research before u call yourself buying a fast car.With that said,you pretty much just answered your own question.