Hi everyone,

my 1999 XJR is currently in shop for various repairs, one of which is cam cover gasket change. In the process they checked the chain tensioners (they have been replaced) but there's probably too much slack going on on the secondary chain and the tensioner itself is wobbly.
Here's the video to see. Does the tensioner need to be replaced or the chain as well?

Also, what shop would you recommend to buy everything (primary and secondary tensioners, guides and chains set) if needed?
I prefer EU shops because of customs but wouldn't be a problem to order from UK.
Thanks

 

I hope this helps - I swapped all tensioners and guides on my 1998 X308 3.2L (no VVT) - VVT is a bit more work:

https://www.jaguarforums.com/forum/x...e-swap-266724/

I think I ordered the parts back then from the USA (many years ago) - on ebay (I am in Australia), after I found out that the parts are the same for 4.0L and 3.2L

 

What is the socket size for the crankshaft pulley bolt ?

 

The crank damper retaining bolt head size is 24mm.

 

You need to look closer at the tensioners!
When the engine starts oil pressure expands the tensioner to keep the chain at the correct tension in operation but the tensioner itself has an internal spring that keeps the chain tight until the oil pressure builds up.
If the tensioner is working freely when you lift the chain the tensioner should expand so from the video it does not look like the piston is working freely. (in fact you should not be able to lift the chain if the tensioner is working, it will be expanded.
I assume that the retaining pins have been removed when they were installed? In any case you should remove the tensioner(s) and make sure that pistons move freely.
regards daveR

 

Thanks.

 

That looks normal. At points in the engines rotation the valve springs are pushing the exhaust cam forwards so the top of the secondary chains goes slack. Turn the engine over a bit & it'll go tight again. It's this very pulsing of the chain & loads on the tensioners that make the secondary tensioners fail on the early designs.

 

You are right, the biggest problem with the original tensioners was that they had plastic bodies that aged and cracked.
Remember that when the motor is operating the chain tensioner is charged with oil under pressure which keeps the chain tight and counteracts your observation that the valve timing floats, as log as the tensioners are in good condition.

Regarding the chain(s), hold both top and bottom sides of the chain to keep it tight on the sprockets.
The try to lift the chain off the sprocket at the 90* positions ( horizontal position). If the chain is loose and can be pulled away from the sprockets then it has probably stretched (There is a specification for this gap).
If it is is firm around the sprocket then the chain pitch is the same as the sprocket pitch and it is unlikely that the chain has stretched or that the sprockets are worn.
If you are still concerned change them for piece of mind, they are not that expensive but does seem like a waste if there is no sign of stretch or wear.
But you do need to make sure that the active side of the tensioner is expanding against the chain when it is loose,
If the oil galleries are blocked or the tensioners fouled then you have real problems but you would probably observe a very poor performance and a significant rattle when the motor is operating.
DaveR