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Found this video with a guy talking about the 5.0 V8 engine (in this case, in a Land Rover, but it's the same as in our Jaguars) and the problem with timing guide wear:
This was great because I never really understood where I should be looking for wear, but of course, I still have my old guides saved from my engine teardown, so I was interested to discover this:
This problem seems to be widely known about and discussed within the Land Rover world, with people recommending timing gear changes etc, but not so much here. Makes me wonder if we should be thinking about it more - it would certainly explain the intermittent clicking I often thought I heard from my timing gear.
Hi Dave ,
thanks for this vid . It gives a reasonable explanation
why these guides were updated in the past as mentioned in
my MY14 F-type workshop manual (see picture) .
I'd forgotten that diagram (I have the same one in the XF workshop manual). When I first removed the guides I thought they looked more like the new style in the diagram above because of the hole where the guide pin hit, I never realized the guides were supposed to be flat and the hole had been worn into it! I assume the blue circle is actually a piece of hardened material that's added on the redesigned guides. Once I've ordered replacement timing gear for my rebuild I can upload photos of it.
The TSB, which I've attached, describes the noise as a "rattling" or a "ticking" noise at the front of the engine. This is caused by reduced tension on the timing chain due to the fact that a hole has been worn in the back of the guide rail, meaning the tensioner pin doesn't push it out as far. The hole worn in my old timing chain guide rail is approx 1.8-1.9mm deep, and I guess this is enough to have an effect.
I should point out
This only affects engines built from 2010-2012
As far as I'm aware, Jaguar have never issued a similar TSB, despite the fact the 5.0 V8 engine found in the XF between 2010 and 2012 has the same tensioner design problems.
I had the timing chain, tensioners, pulleys etc (including a water pump and an oil change) done on my 2011 5.0. Luckily, my CPO warranty covered it, or it would have been about $6000. My service writer was the one that heard the noise when the car was hot. I had 86k on the car.
While working on my block during the rebuild I was interested to discover these signs of wear (block is currently upside down on a stand):
The only thing that passes through this area is the primary timing chain for that bank (the other side shows similar grazing).
This suggests that as a result of the wear on the timing guide, the chain tension was loose enough to cause it to wobble against the aluminium block and graze the edges quite significantly. I'm wondering if this might have contributed to my engine failure - as the chains wear against the aluminum block, metal particles end up in the oil before they can be filtered out by the filter, causing knock-on issues?
If I was you, before reassembly, I would de-burr all those possible “webbing” areas and passageways to clearance that a bit more.
Excellent, that was exactly my thinking too. I don't want any more aluminum particles in my oil, thank you!
I thought it was a great illustration of how bad things can get with the slack timing in this engine though - I'm astonished it didn't jump a tooth on the cams with that kind of movement. If you have the timing gear tapping on idle, save your engine and replace the valve guides, chains, and tensioners. You can change them with the engine in situ, although it's pretty tight and a LOT has to come off the front of the engine, including the crankshaft pulley which requires a serious amount of torque to remove (and special attention paid to the direction of the bolt by the markings on the top).
I did a lot of research on this as I wanted to buy a 2013 Range Rover HSE LUX and almost passed on one I liked. In fact I did pass.
I spoke to a RR service guy about the issue and he told me he had seen a "few" such examples and that his dealership would charge $8,500 to replace the tensioners etc.
After I confirmed that the RR I wanted was outside the TSB vin range of affected vehicles I went ahead with the deal at a better price than originally priced.
Found this clip at the end of a video I recorded of my car (by mounting a GoPro in front of the grille) a month after purchasing it in 2014, which (at the last few seconds) highlights the noise pretty well.
Found this video with a guy talking about the 5.0 V8 engine (in this case, in a Land Rover, but it's the same as in our Jaguars) and the problem with timing guide wear:
This was great because I never really understood where I should be looking for wear, but of course, I still have my old guides saved from my engine teardown, so I was interested to discover this:
This problem seems to be widely known about and discussed within the Land Rover world, with people recommending timing gear changes etc, but not so much here. Makes me wonder if we should be thinking about it more - it would certainly explain the intermittent clicking I often thought I heard from my timing gear.
Very interesting video. Especially since I do own a 2010 XF 5.0L.
11-06-2017, 01:18 AM
Interesting video about 5.0 timing guide wear
