I have A 1998 JAGUAR XJ8L 90,000 Miles, due to the noise at start up I replaced
tensioner's to new upgraded, I have replaced timing chains new gaskets, guides, vvt sensor, now after putting the car back together the mechanic say's it is still ticking and that its the upper primary sprockets because the chains are still loose, can someone please help because I really thinking he is just guessing and the bill is adding up, the sprockets looked find to me, what else could it be? any suggestions would be grateful!

 

The VVT units themselves have been reported to make noise. In fact, I believe the "upper primary sprockets" are integral to the VVT units. The noise is apparently not from the chain teeth, but from the innards of the VVT.

Some folks have reported success by using 20 W 50 oil, others by adding a can of Restore. Are you sure they replaced the upper timing chains themselves?

 

If the secondary chains are still loose, something was installed incorrectly. This may sound like a dumb question, but did he remove the pins from the new secondary chain tensioners ? If the primary chains are still loose, it's a little more complicated.