Sorry if this point has been discussed a lot previously. I tried to find as many threads as I could but I´m still unclear. It seems obvious that there were timing chain adjuster problems and something about nicasil cylinder lining problems in the early model XJ8´s.
At what point did the factory address these issues and come out with a car with updated parts? In other words what are the best years to get an XJ8 without having a concern about the timing chains or motor going bad and what are the years to avoid if that´s my main concern?
I´ve seen many of these cars recently and they are beautiful. I saw a 2001 Vanden Plas at the dealer in San Diego yesterday and it was incredible. $15000. But that might be one of those bad engine years. They had a 2003 that was not a vanden plas for a thousand dollars less. Perhaps that´s a safer choice though.

 

Nikasil motors were installed in '98 and '99 models. Nikasil if not abused, (overheating, high sulfur fuels used) is actually superior with regards to wear characteristics than steel liners. Nikasil is an extremely hard and wear resistant coating if properly taken care of and I believe has a bad rep not mostly justified.

Early generation tensioners and chain guides were an issue. I am not sure exactly when they switched to the lastest versions from the factory and I believe upgraded parts were made available after the last X308's finished production.

It really boils down to how well maintained the car was. Tensioners wear out and even the latest version installed from the factory are probably good for about 120K miles.

The main concern is the transmission. It the same 5 speed ZF tranny used in Bimmers and MBZ also. The are also good for about 120K miles before they need a rebuild.

I know one customer with a '99 XJ8 with 245,000 miles. Nikasil motor, compression is still strong across all cylinders and no more than 4% blow-by in the weakest bore.

 

Thanks for the info Wazari. So is the engine in my 2002 S type the same as what they used in an XJ8 for that year? No problems at 90K. It runs like a dream with the 4.0 V8 in it.

 

I would get a 2002/2003-
No nikasal-mid 2000 and earlier had these
2nd generation tensioners-engine number higher than 981XXXXX-Search Jag-lovers for article
No throttle body stalls-'98/99 model years only

 

Yes same motor.

 

Thanks for the feedback guys. A couple more questions. I tried to find the engine number on my V8 S type to see if it falls within the range with the updated tensioners. The handbook says the engine number is on a raised pad near the thermostat housing.
I sold Honda parts for over 20 years, but I´m somewhat lost under the hood of this car. I can´t find the engine number, the raised pad, or the thermostat housing. Can you help me?
Also I searched jag lovers for the article with the info mentioned about the updated chain tensioners and the serial numbers, but can´t locate it. Any chance you can help guide me to it? I very much appreciate the help. I´m new to Jags. Just a little over a month and now I have three and I want to learn as much as I can. Thanks again.

 

PLEASE CAN ANY ONE ADVISE IF A 1997 XJ8 WITH AJ26 ENGINE HAVE NICASIL LINERS

 

Jagman:
The first US MY XJ8 was '98, and yes, I am pretty sure all had Nikasil until the 2001 change.

 

panza:
I believe they changed the number pad location in 2000. On the XJ8, I understand it is below the left manifold, visable htrough the wheel well, but I have yet to actually see mine.

 

Here is the article.


A Jaguar owners group reports engine failure due to timing chain tensioner failure:
"you are at risk of a failure of the camshaft secondary timing chain tensioner which, in the worst case, can lead to catastrophic engine failure and a replacement bill of $10,000... The January issue of Jaguar World Monthly magazine describes the failure "of those brittle timing chain tensioners" as common and proceeds to lead the reader through the relatively demanding repair. It appears the plastic housing of the tensioners become brittle with age so the failure is just starting to show up on the early V8's built. Accumulated mileages of 50,000 to 70,000 have been mentioned. It is not clear if or when Jaguar might have changed the plastic material whose aging is at the heart of the problem.

The tensioner pushes on the bicycle-type chain between intake and exhaust camshaft sprockets to keep the slack side of the chain from whipping. With the wear and stretching of higher mileage there is more slack. When the tensioner fails the chain slack may allow the chain to jump one tooth on a sprocket and then the exhaust valves open and close later than normal. Performance will suffer. But if the chain jumps two teeth or more the rising piston at the end of the exhaust stroke hits the exhaust valve which is still open, and that instantly is the end of your engine. Tooth jumping happens especially as the engine kicks into life when you start it. Jaguar has redesigned the secondary tensioner 3 times since V8 introduction. Technical Bulletin 303-30 dated 12-98 recognizes a rattling noise caused by tensioners at cold start and notes a revised design with noise dampener clip added. This change commenced with engine No. 98102106XX and will be installed on earlier engines under warranty. If your engine qualifies - and you do have that noise, right? - you might try the warranty road." http://www.jcna.com/library/tech/tech0028.html

 

Couple significant dates:

Conversion to steel cylinder liners from Nikasil - August 18, 2000 with engine serial number 0008181043. That date was at the engine plant. Cars assembled after that may have had Nikasil until the supply line units were exhausted.

Conversion to metal chain tensioners - August 13, 2001. Most, but not all of the '02 MY had the updated tensioners. Same note above applies.

Your dealer can supply the engine serial number via the VIN. Ask nicely.

 

The TSB issued by Jaguar says that the problem afflicts cars with VIN numbers between 812256-F41862. My 2002 XJR was built on July 1, 2001, but the VIN is round a thousand higher (F42xxx) than the range given in the TSB. I therefore figured I was fine, but then I read in the above post that the changeover happened in August of 2001. I'm wondering if I should check my tensioners or not. Thanks in advance for any help.

 

The above dates of engine assembly have been quoted by just about all forums for several years. My '02 XK8, built in June '01 based on the driver door column label had the plastic tensioners with cracks at 40k miles when I changed them.

I would ask a dealer to look up the engine serial number. My bet is that you have plastic tensioners.

 

Hmmm...I'm sorry to hear that. I had assumed when I bought a 2002 that it wouldn't have that problem, but I didn't even think to look at the actual date of manufacture until later. It does say 7/1/01 on the door jam. Did you have the primary tensioners changed also? What's the engine serial number or range that would indicate that there was/wasn't a problem? Lastly, does your VIN fall within the range quoted in the Jaguar TSB for XK's? (001001-A24195) Again, thanks for your help.

 

Any chance the following info I found elsewhere is correct? If so, it seems likely I would have 2nd gen plastic tensioners. Seems to be some question as to whether these are really any better than the 1st gen of plastic tensioners. My car only has 39,000 miles so hopefully I could drive it a little more before I get a chance to change them.

"1st gen tensioners introduced with the new V8.
2nd gen tensioners introduced around the time when the V8 was revised from Nicasil to steel bores.
3rd gen introduced when the 4.2 was launched in 2003 and later (around 2005) made available with shorter bolts as a retro fit to the 4.0 and 3.2."

 

Check the engine number - it is the only true way to tell, using the changeover number described by Testpoint:

"... the transition date was August 13, 2001 at the engine plant. The engine assembly date is the only way, short of pulling a valve cover to verify the status. Plastic or metal has no direct link to the VIN number. The engine serial number has the date encoded in it. The above date would produce a serial number of 010813xxxx. Your engine serial number can be obtained from a dealer using the VIN."

 

Thanks. I guess I'll have to reconcile myself to likely changing them eventually, since if this info is correct my car, built July 1, would have had an engine built prior to the August changeover date. I'll check with the dealer though on the serial number. I have read that XJR's seem to have less trouble with the secondary chain tensioners, but better safe than sorry.

 

Don't worry, be happy!

The plastic tensioners may or may not fail tomorrow or the next day. A new engine is only about $13k.

 

Since my engine only has 39,000 miles, I don't think I want to spring for a new one yet. I think I can manage the repair myself with a little more research. (I'm liking the "no special tools needed" approach--lifting the cam a little, but there seems to be some debate about that also). Nearest Jaguar service is 100 miles away.

 

i have a 99 xj8 runs like new everyday with 142000 miles.. so good i spent money on a custom exhaust that wakes it up even more.. very smooth plenty of power handles awesome