XKR Timing chain tensioners
Discussion
There is a lot of material out there on this, and a lot of much better informed people than me but what I would say is
1. Try XKEC website also
2. Have you seen the Nigel Thorley book?
3. These items were upgraded a number of times, so its not necessarily a one off cure but something that needs to be watched. Failure is very serious and immediate action if you think there is a problem is always recommended.
Hope some mechanically minded chaps will be along shortly
1. Try XKEC website also
2. Have you seen the Nigel Thorley book?
3. These items were upgraded a number of times, so its not necessarily a one off cure but something that needs to be watched. Failure is very serious and immediate action if you think there is a problem is always recommended.
Hope some mechanically minded chaps will be along shortly
Hi plasticpig,
Their are three generations of the V8 primary and secondary timing chain tensioners.
1st Gen, these are the plastic type and have no spring assitors on the secondary tensioners, these tend to crack along the body of the tensioner and lose oil pressure thus not tensioning the chain, or the slipper part breaks free and the chain runs ove the metal section, worse case is a snapped secondary chain and possible valve/piston/bore damage.
2nd Gen, these were brought out by Jaguar to combat the loss of oil pressure problem and to keep the secondary chain tensioned during start up, they simpley have a spring to maintain chain tension so not relying soley on oil pressure. These still break up and can cause the same problems as the original design.
3rd Gen, these are alloy bodied and were original fit in all 4.2 litre engines, from about 2003 Jaguar stopped supplying the second generation tensioners in favour of the alloy boddied 4.2 ones, they require four shorter hex bolts from Jag to fit them into the 4.0 V8's, their has been no reported sudden or unexpected failure of this version in either the 4.2 engines or when fitted to the 4.0 as an 'upgrade'.
As for the specific years when they were fitted generally the first gen is 1996-1999, second gen 1999/2000-2002, third gen was as said when they moved to the 4.2 engine mid 2002.
We have however had a few late 2002 4.0 cars in the workshop that have had third gen tensioners and chains (morse type) fitted as standard. I also have customers with early cars that had to have the second gen fitted due to the originals failing and are now requiring the third gens because the second gens have also failed.
HTH
Their are three generations of the V8 primary and secondary timing chain tensioners.
1st Gen, these are the plastic type and have no spring assitors on the secondary tensioners, these tend to crack along the body of the tensioner and lose oil pressure thus not tensioning the chain, or the slipper part breaks free and the chain runs ove the metal section, worse case is a snapped secondary chain and possible valve/piston/bore damage.
2nd Gen, these were brought out by Jaguar to combat the loss of oil pressure problem and to keep the secondary chain tensioned during start up, they simpley have a spring to maintain chain tension so not relying soley on oil pressure. These still break up and can cause the same problems as the original design.
3rd Gen, these are alloy bodied and were original fit in all 4.2 litre engines, from about 2003 Jaguar stopped supplying the second generation tensioners in favour of the alloy boddied 4.2 ones, they require four shorter hex bolts from Jag to fit them into the 4.0 V8's, their has been no reported sudden or unexpected failure of this version in either the 4.2 engines or when fitted to the 4.0 as an 'upgrade'.
As for the specific years when they were fitted generally the first gen is 1996-1999, second gen 1999/2000-2002, third gen was as said when they moved to the 4.2 engine mid 2002.
We have however had a few late 2002 4.0 cars in the workshop that have had third gen tensioners and chains (morse type) fitted as standard. I also have customers with early cars that had to have the second gen fitted due to the originals failing and are now requiring the third gens because the second gens have also failed.
HTH
Quote
3rd Gen, these are alloy bodied and were original fit in all 4.2 litre engines, from about 2003 Jaguar stopped supplying the second generation tensioners in favour of the alloy boddied 4.2 ones, they require four shorter hex bolts from Jag to fit them into the 4.0 V8's, their has been no reported sudden or unexpected failure of this version in either the 4.2 engines or when fitted to the 4.0 as an 'upgrade'
Hmmm, on the Xkec at least one member had failures of the 3rd generation tensioners when fitted to his car. Fortunately not catastophic. Note failures are not only to the tensioner body, the slipper can break up and the guides can fail. Yes the 3rd generation are better but you should still be changing them at about 100K miles if you want your engine to make it to 200K miles
3rd Gen, these are alloy bodied and were original fit in all 4.2 litre engines, from about 2003 Jaguar stopped supplying the second generation tensioners in favour of the alloy boddied 4.2 ones, they require four shorter hex bolts from Jag to fit them into the 4.0 V8's, their has been no reported sudden or unexpected failure of this version in either the 4.2 engines or when fitted to the 4.0 as an 'upgrade'
Hmmm, on the Xkec at least one member had failures of the 3rd generation tensioners when fitted to his car. Fortunately not catastophic. Note failures are not only to the tensioner body, the slipper can break up and the guides can fail. Yes the 3rd generation are better but you should still be changing them at about 100K miles if you want your engine to make it to 200K miles
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