So many threads on timing chains, and I know Jag updated the tensioners and timing chain width fairly early somewhere around 2013, but I can't find in all those forum pages when was the last update to the timing chains made for the XJ V8?

What would be the VIN and/or build date of that update? I am specifically interested in a May 2017 car with the V8.

 

I have tried to find this out and I "think" this is the answer?
My 2014 XJR is VIN V54xxx. Looking at many parts listing I find the XJ VIN cutoff is V58602. So bad for me as my car missed the latest revision by 4000 cars or so!
But I think it does show the last change was somewhere around 2014 for the XJ. So check yours but it being a 2017 it should have all the latest stuff?

Note this is different from when Jaguar dropped the early 6.35mm stuff and went to the 8mm stuff as you said in 2012-2013 time frame. These do not interchange and from what I have heard only the 8mm is available but did see some guys were still using the older 6.35mm timing components.
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For what it’s worth, I haven’t seen any 6.35 pitch chains on an XJ in the US. My US market 2010 XJ (built 2009) has 8mm chains and was the 207th XJ sent to the US. My understanding is the 6.35 equipment was largely installed on XFs and XKs.

 

A tech told me that the timing chain issues that remain are largely due to the soot deposited into the engine oil by the GDI process, which the oil filter is not able to catch. This is the reason we are supposed to change the oil more often than the factory recommended.

 

The latest oil specifications from all manufacters and SPI etc all have requirements for managing soot build up because of this.

https://blog.amsoil.com/help-prevent...with-good-oil/

People focus on oil weight and frequency of changes, but using the latest possible specification is a very good idea. All of the latest oil standards also include mitigation against low speed pre detonation, another common issue with DI engines.

Use an oil that meets the STJLR.03.5006 standard and change it at half intervals seems to be the sensible approach.

Part no changes to timing gear could just as well be a change of supplier, you're looking for patterns in tea leaves if you're using that to know if/when JLR did anything to mitigate chain issues.

 

Actually no. Read my post? The tensioners were upgraded depending on the VIN of the car. This is a fact and is easy to see as they are physically different. All the early 5.0L cars have tensioners problems. This was mainly due to a spring loaded steel pin that wore into the back of the Aluminum guide rail. Jaguar's fix was to start installing a metal "button" on the backside of the guide rail. We have had forum members post pictures of what failed and why. Also picture of the updated parts.

Chains were and are not the main problem. But it does bring up some questions on why they were changed? Several experienced mechanics have stated the original 6.35mm stuff is better than the later 8.0mm stuff. I can't say either way and Jaguar never stated why the change in the timing gear? One theory was cost cutting by Tata maybe the same reason why they started with Aluminum cooling pipes on the front of the engine but around 2011 they went to the failure prone plastic versions?

Here is a great picture from this forum showing the timing chain differences.



Timing gear issues become very rare after about the 2014 model year. Now it still can and does happen. The latest year I saw was a 2016 with tensioner problems. So we are never totally out of the woods!
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