Hello
There is Jag Xk8 -01 for sale and seller says there is 1st cylinder valve is stucked. I'm afraid that is nikasil problem.
There is also one S-Type -00 with 4.0 v8 for sale which is badly crashed but has good engine.

So I think what differences there is between Xk8 Aj27 and S-type Aj28?

 

A stuck valve is not an indication of a nikasil problem, but might be a failed chain tensioner causing a bent valve, or overheating causing a dropped valve seat. It might be repairable.

I'm not certain about the S type engine so I'll not comment.

 

ALL 4.0 Jaguar blocks will fit any AJ26, AJ27 or AJ28 application. The oil sump and heads are different as well as the front timing covers. The sensors, brackets, accessories etc. are all different but the mount holes are all there.

Any 4.0 can be made to work if you have BOTH the original and the replacement side-by-side and create the one you need.

bob

 

But i think seller may try to cheat.
But it is great if block is same

I will call and go see that xk8

Thank you for help!

 

Car is running but with 7 cylinder. I dont know how seller knows it is valve problem but if he tested 1st cyl pressure and there wasnt or it is low it can also be nikasil, right?

 

Could be many things, but nikasil is the least likely as it's only one piston. Nikasil was damaged by high-sulfur fuel that hasn't be around for years and years.
It could be anything from a head gasket leak to a hole in a piston. Unless you have a very good reason to buy this one, I'd steer clear.