I have a 1998 jaguar XJR that I’m working on It currently has low compression on cylinder 4.
I think it has the nikasil engine. I am planning on rebuilding the engine, new piston, rings, new head gasket and new timing components. I will most luckily pull the motor to make it easier. I’m not sure whether to go with a new engine block or how would I go back to the regular steel liners that was introduced in 2002 how would I do that. Another question are there any companies that sell forged pistons for this type of engine or anything interchangeable that will fit.

 

Hi,
as you state that your car is a 1998, you are probably in the wrong forum to get proper help.
This is the forum for the X350, built from 2003 onwards.
Best regards,
Thomas

 

I've moved your question from X350 to X308 forum. Members here with the same model will be able to help.

Graham

 

You may want to borescope that cylinder first. Do you know if the engine overheated, ingested something or what happened that it was running good then it wasn’t?

 

It's more likely a dropped valve seat or bent valve.

 

When I did my compression test, I added a little bit of oil into the cylinder, and the compression was raised back up to spec. So I’m leaning towards possibly piston rings

 

I have a few old NIKASIL engines from when I worked at the dealer. Insurance companies would send a used engine for replacement and not want the core back.

I did take one worn engine from the late 1990s over to a machine shop to get new liners installed.
New liners matched to the pistons with new rings from a cast iron liner engine. (NIKASIL RINGS are different)

I still have the engine but never installed it in a car.

It can be done if the Nickel Silicon liner is destroyed.