Just today bought a 1999 XK8 coupe. Original owner, 110000km, all service records. Happy camper. Has the 4.0 Nikasil engine but runs perfectly. Timing chain tensioners not done. Do I need to do them immediately?

 

Yes. You currently own a grenade with the pin pulled.

 

Welcome to the forum. You’ll find a group of enthusiasts who are generous with their knowledge and experience .

While the cam chain tensioners are being dealt with go ahead and replace the water pump and upgrade to the aluminum thermostat housing.

Also, the XK-8’s have a transmission that has a record of A drum failures. Although I don’t know what other steps can be made to mitigate a failure likelihood, at the least, a transmission fluid R&R should be considered if you don’t know when it was done last.


Z

 

Don't worry about the liners, they won't be a problem at this point because fuel quality is much better now. The chain tensioners will need looking at though. You must get the upper and lower tensioners done, often times people just get the upper ones changed and don't bother with the lwoer ones only for them to fail. Better to do it sooner then later, you wouldn't want a wrecked engine.

 

the lowers never fail only people with income to dispose change them. there’s people with literally 400k miles on the original guides, there’s even people who made it past 200k on the original secondaries lol

their car will lose the transmission long before the guides break guaranteed

 

and odds are before that happens someone will first crash into you while they are texting and driving .

but just in case you beat those odds, fix the known issues. Just google “known issues with Jaguar XK-8” and you’ll know what to address.

https://www.google.com/search?q=known+issues+with+Jaguar+XK-8&rlz=1CDGOYI_enUS904US904&oq=known+issues+with+Ja guar+XK-8&aqs=chrome..69i57.24046j0j7&hl=en-US&sourceid=chrome-mobile&ie=UTF-8


Z

 

The consensus is that its actually caused by a hydraulic overpressurization of the clutch pack. Some owners who'd paid attention noticed some shifting anomalies just prior to the bang and come to find out that the bore of the main pressure regulating valve in the valve body was worn and the piston would get momentarily stuck. There's a Transgo kit that replaces that original piston with a new piston of a different length so that it rides on an un-worn section of the bore or a Sonnax kit that involves reaming out the bore so that its smooth again and a new piston of a larger diameter. The Sonnax kit would seem to be the better, longer lasting solution, but its much more expensive and not a DIY job - you have to send your valve body in to a specialist who has the jigs and tools to ream it out. A lot of owners with mileage 75K+ go ahead and do one or the other as a preventative measure. Its really not difficult at all to R&R the valve body and it needs a fluid change anyway.

 

Terrible advice

 

Yes, and do them ALL, ALL the guides and ALL the tensioners and ALL the chains, they can come in kit form. Being that the biggest PITA of the whole job is getting the crank nut off (which is not hard, just requires a scary amount of force) do it properly the first time, which means ALL.

.......................and l am a cheap as you will ever meet, even to the point on occasion when its come to cost me more in the long run.

 

The primary tensioners aren't subject to catastrophic failures since they're not subject to the lateral forces that the secondaries are. However, the plastic on the chain guides disintegrates over time and the pieces end up in the sump, where they can get sucked into the oil pickup. See this post from Terry Young:

https://www.jaguarforums.com/forum/x...1/#post2112274

I know it's a much bigger job, but I'd do them all. My

 

why even go through the effort of fitting an aliexpress chain like most people do here. the original iwis chains are extremely high quality and have zero wear when they come out.

the guides eventually break at the bolt, get pushed aside and make a rattle just like the 2 valve ford modular. nobody else is as neurotic and paranoid about chain guides as jaguar guys, and then they mickey mouse the job with the wrong parts anyway 😂

 

Your assumptions are about as accurate as your advices, not very.

 

When you have the tensioners done you'll love the car. I made a trip this summer from Calgary to Prince George via Banff, the Columbia Icefields and Jasper and the car was a joy to drive, 2600km round trip and the car performed flawlessly. People generally come to the forum because they have a problem with the car that they need help solving. If you only read these posts you would think that the car is a problem waiting to happen. Regular driving and maintenance and the odd Italian tune up seems to really help the car. A few people like Zray, EnjoyEverySandwich and myself have posted about the great trips they have made with the car. Look these up to get a feel of how great the car really is.

 

This is just not true.... It's not.

The lowers (tensioners) in a car that had 36k (put this engine in my 215K car) were split around the piston/cylinder on one of the 2 orange plastic originals. They do fail. In my car, in the original engine both lower tensioners were cracked/split, and in the 36k swap engine, guides were cracked and pieces were found in the sump on both... I changed upper, lowers and guides in both.

I swapped an engine into a 2000 s-type last spring... All uppers, lowers and guides were toast... I was swapping the engine because the uppers failed (car came to a friend from auction that way), it jumped teeth and the LH head was ravaged as a result...
They do fail. Ppl should be careful saying that it's a myth...

For the OP... I'm not saying all them things above to freak you out BUT am responding to the idea that they don't fail...

Take you time,,, but change them quick. It's not that bad a job at all.

 

it’s not a myth it’s just easy to milk them for a very long time. lower tensioner failure is pretty rare. i can show you an perfectly good set of lowers and guides from a car with 130k, i had another with 170 that was perfectly serviceable too.

cracked guides are not an issue until they are completely broken and being pushed aside or clog the oil pickup. cracked tensioners aren’t either unless they simply will not extend with oil pressure, you get an obvious noise…. the secondaries are a must change because when the pad falls off it jams the chain, destroys the head and it’s game over.

i’ve done this job almost a dozen times already it’s a walk in the park. if they can’t do it themselves it’s not worth getting shafted 2k over. i didn’t even waste 3 hours of my life doing it on my own car, predictably the POS composite head gasket gave up long before the guides did.

 

^^^^^** this .

when I had settled on looking for an early XKR for my daily driver, the very first thing I did was google “known issues for the 4.0 XKR”. That led me to the forum and the impressive knowledge base within.

Armed with this information I narrowed my search to include only those cars that had already had the tensioners replaced.

Unfortunately for my cars previous owner, they waited too long change the tensioners and disaster / failure struck at the 115,000 mile mark.

After having the car repaired, at no small expense, it was put up for sale which is where I came into the picture. Some 3.5 years and 54,000 miles later I have been enjoying a very reliable car and had
the pleasure of numerous cross country and trouble free trips .


The point is, if the repair and maintenance history is unknown or murky, just get the job done before history repeats itself and you have to pick up the tab.

Z

 

Welcome