In my 1999 jaguar xjr I've decided that buying a new engine used is going to be the easiest and most time and cost efficient way. Found a 2nd hand aj26s engine block from a car on 120k which had very good service history and had the block replaced in 2013 and upgraded to the steel liners along with timing chain and tensioners. While I have the new(used) block out what components should I be looking to replace? I don't want to go to deep and get heads resurfaced and change bearings. But what should I atleast change bear minimum?

 

How many kilometers are on your car?

 

car itself just ticked over to 60000 miles (96560km). New engine is from a car on 120000m(193121km) unknown milage block was replaced at.

 

That's pretty low mileage for that engine to need replacement. Even if
you replace it...I would rebuild it for a spare.

 

I believe it failed due to the niksail lining being scored, couldn't imagine the price of reboring and relined. Not a bad idea to attempt to rebuild it.

 

Oh, now that makes sense. I was thinking along the lines of Randy about low miles. To the best of my understanding, Nikasil cant be bored over. I’ve heard of a light honing but, that’s about it. The Nikasil coating is applied to the aluminum cylinder walls. I’m sure the walls could be recoated but, that’s some serious $£€.
Get the 4.2L MLS head gaskets and all new head bolts. Get a new rear main oil seal and cap seal just above it too.

 

Thank you for all the great suggestions, did a medium price up on parts like timing chains, seal kits, water pumps etc... just tipped over the £1000 mark. Still need to buy the bloody timing tools. God cars are an expensive hobby... all about those smiles per gallon 🫠

 

Have you boroscoped the cylinders to look for any scoring? I am suspicious that you may just have sticky rings from sitting. There various recipes out there you can use to soak the rings, diesel, auto trans fluid, acetone etc. I would give this a try before embarking on an engine swop. Put some decent miles on it with the Italian tune up after you let them soak

 

put a camrea down the bores and saw signs of scoring, along with every seal on the block leaking. £600 for a block with heads and covers which has steel bores + shipping. This will be a nice summer project