I have been using my 2001 XJR as my daily driver for the last several years, and it has been great. At this point though the miles are adding up and the engine is starting to get tired with increased oil consumption, some smoke on initial startup, etc. Since I purchased the car used, I don't really know how well the engine was cared for in its early years. It is a Nikasil engine.

I am looking toward engine replacement options:
1. a low mileage engine out of a 2002-3 XJR/XKR
2. a rebuilt engine from one of the various re-manufacturing companies
3. ?

I don't have an unlimited budget, but am committed to keeping the car because the rest of it is in great shape, and besides, I love it.

So I am looking to the membership for opinions on what to do. If anyone has experience, negative or positive they would like to share, I would appreciate it. Or if anyone has the engine I am looking for, please let me know.

Thanks in advance.

 

I think you are too pessimistic about your Nikasil engine. I would sure change the valve seals before I gave up on it for a little startup smoke. You did not say how many miles were on it, but my expereince on several Jags is that the rest of the car is worn out before the engine.

Any MY AJ27 SC engine should drop in fine.

 

How much oil is it using? (It may well be OK.)

 

Yes, how many miles?

And how can it be a Nikasil engine? Thought those
ended before the 2001 model year.

Maybe your rings/valve guides/valves are gummed up.

You could try Restore which is a engine treatment
often recommended by Brutal.

Or, something like Rislone to free up the rings.

Or, a short course of "TC-W3". Search the forum or internet
for references to that phrase for info and techniques. The
reasoning behind its use is well founded in my opinion.

No doubt some stalker will be along in a few minutes to
"debunk" that last suggestion, or all of the above.

Your engine, your choice.

 

I have a 98' XJR that I bought from the previous owner with 234K miles on it about a year ago. Oddly enough, I worked on it the previous 2 years. The owner wanted it as reliable as possible. Much like your car, the engine was getting tired. Mine also has the original nikasil engine in it. It absolutely refused to build boost despite it was running ok. I didn't hook a vacuum gauge to it when I acquired it, but I'm sure it was reading low. Anyways, fast forwarding thru some other technical long winded conversation, I had it towed to the house and pulled the heads off of it. The exhaust valves were severly pitted. I didn't want to waste my time by doing a liquid leak down test on the heads, but if I had I'm sure they would've looked like a waterfall coming out if the ports! The valve seals were absolutely toast as well which is why it burned oil frequently. He never overheated the engine and always had the oil topped up. Even though the rings probably have wear on it, the cylinder walls look really good! I have one head back on and I'm in the process of doing the valve adjustment on the other one on the table. I'm sure once it's back together it'll run well with the thinner 4.2 MLS head gaskets and rebuilt supercharger. : )

 

Thank you all for the reply's. Mine is an early 2001 and I have verified it is/was Nikasil. The engine has never been overheated; at least since I have owned it. Current mileage is 146K.

I will give Restore a shot to see if I can prolong things, but I am sure an engine is in my future. If I had the shop/garage space, and time, I would remove the heads and have a look, but I don't have either and to have an indy do that here would be an expensive proposition if I wind up having to do a transplant anyway. It seems to be a common opinion of members here that a transplant is less expensive than a rebuild.

The last couple of days, the idle has been rough, not missing, just rough, and only at idle. No codes or CEL. Already replaced the fuel filter and run some injector cleaner - no difference. Plugs were replaced at 100K. Other ideas?

 

Oh and I cleaned the TB (not very dirty), just replaced the MAF, and didn't find any vacuum leaks (at least not yet)!

 

Try cleaning the full and part load breather pipes, and the drill (3/32 I think) down the part load hole to un clog it.


There is a thread about it on here somewhere.

 

Check the long term and short term fuel trims. At idle, then under load.

 

Guess I'm in the same boat then with regard to Nikasil. How do you
confirm that?

Try the TC-W3 routine.

Best result I've heard of is that one person who was pleased with TC-W3
usage poured some in the gas tank of a buddy with a badly smoking Ford
Ranger ... without telling him. Next week, buddy is very pleased and asked
what he had done. Anecdotal yes, but in line with similar accounts.

BTW, with a Nikasil block, with the exception of gummed up rings, it is
more likely top end. The story behind Nikasil is that if it survived beyond
the high sulphur gas years, the cylinder walls are going to be in good
condition.