I was thinking about buying a 2000 XJR original owner all service records the car has just had 7k in repairs it has 115k on it but the timing chain has not been replaced no noises runs smooth should I replace it from a reliability stand point ? what is the cost on the average with parts and labor the car has always been adult driven your feedback would be appreciated thanks

 

Timing chain failure without associated secondary failure appears to be very rare.

 

Could you explain what you mean by your term secondary failure ?

 

The cam chains have a primary chain from the crank to the intake cam sprocket and then a secondary chain from the intake cam to the exhaust cam. It is thought that because of heat at the heads that the OEM plastic chain tensioners on the upper or secondary chains are very prone to failure with a high percentage taking out the engine.

Much lower failure rate on the lower/primary tensioners.

It is an absolute must that you verify that you have the later metal tensioners on the secondary chains. It is the tensioners that fail, not the chains. While a broken chain can occur due to tensioner failure it is usually the chains that jump a tooth or two on the sprockets and bend a valve or two.

DIY replacement of the secondary tensioners is less than $140, less than $200 if you choose to replace the valve cover gaskets. Easy job. $800 at a indy shop, $1200 at a dealer.

 

Is there a " mileage " recommendation on replacement of the guides/tensioners.

 

Not really. Some have failed at 50K mi or less, some still functioning at 100K. It's more an age/temp. situation.

 

Does the 2003 to 2009 cars have metal tensioners ? what about the XJR cars ?

 

All of the AJ26/27 engines from '96 to August '01 had plastic tensioners both XK8's and XKR's. Everything past August 13, 2001 had metal tensioners. Those dates are engine build dates.

Note that my '02 XK8, built in June '01, had plastic tensioners.

A previous '00 XK8 had the original plastic tensioners replaced under factory warranty at 40k miles.

 

Some late 4.0 and all 4.2 have metal, same for XJR. Plastic was used until after engine number 010813xxxx, but the exact changeover is a little cloudy.

I see test point beat me again.

 

+1 if it has non-metal-bodied tensioners you're on borrowed time. Replace & the guides. Same engine as 4.0 S-Types, same fix!

 

+2 on doing the tensioners. False economy to put it off, since the downstream problem of having to repair a head, or worse, swap in an engine (which will probably have to have the job done anyway unless it's a later mill) when (not if) they fail. It's a matter of material science: plastic in a hot section of the engine coated with petroleum and byproducts of combustion will weaken a lot sooner than cast aluminum.

And, in the interests of giving into the shipwright's disease (see below, from many sources: JagForum, Lotuseuropa mailing list, etc), might make sense, while you're there, and it hasn't been done, to do the crank seal, water pump, thermostat, and replace the thermo housing if it's plastic at the same time. Why chance cratering a beautiful ride for lack of taking care of relatively inexpensive components while you have to take them apart anyway?

Just my $.02, for what it's worth.

--

Shipwright's disease goes something like this: Gearhead owns a classic British car. Car has burned out interior light. Gearhead decides to change bulb. Gearhead notices Lucas socket is corroded, decides to change socket. Gearhead notices wiring frayed while trying to change socket. Gearhead decides to change wiring. Gearhead notices headliner foam is rotted while changing the wire. Gearhead decides decides to change the headliner. ...and goes on and on and on and on and pretty soon, Gearhead is undertaking a frame-off restoration of his ride because of a burned out lightbulb.

 

no matter check them out. mine went on my 2002