Timing Chain Tensioner Question ?

[Gary220262]

Hi All
I have a 99 3.2 Sport that according to service history had top tesioners only changed at 60,000 in 2006 now on 70,000 miles 6 years later and worrying about bottom tensioners and chains and also which tensioners would have been used in 2006, were latest ones available ?. the engine sounds really sweet and local Jag specialist says if it sounds ok it is ok but not sure any suggestions guys ?

[Brakebuster]

the revised metal tensioners were introduced with the 2002 4.2 V8 unit , and as such are the required ones to replace the plastic versions before them ,

however, the plastic versions were still available to buy , but i doubt it in 2006, as in 2007 i bought a set for my car and the latter metal ones were supplied ,

as for the lower tensioners and chains, i wouldn't worry if there is no noise or indication that they are causing trouble, and your mechanic monitors the situation , as these do not usually cause issues.

regular 3k mile oil changes are advised with an oil filer change every other fluid change ,

get in her, fill with premium petrol and enjoy

BB

[Gary220262]

Thanks for that BB always have changed oil/filter every 3 months on all my cars (although mainly diesels) interesting point about petrol though as at the moment ive used only ordinary unleaded (only filled up once yet !) will it pay me to use premium unleaded ?

Gary

[Brakebuster]

petrol is still cheaper than beer , pint for pint

and i know what i'd rather do.....


vroom vroom

BB

[J44EAG]

As said in the article, the only way to find out what tensioners are fitted in your engine is to remove one of the cam covers. There is no other way of seeing them. I would have thought it very unlikely that an engine that had tensioners fitted in 2006 would have the ali units fitted unless the fitter was knowledgeable that the ali types were then available.

I don`t think the new ali tensioners were fitted to 4.2 units until MY52. So the ali units would have been on the shelves in 2006 but whether they were fitted in 2006 to your car is the big question which only inspection will reveal. Perhaps another member can remember just when the ali tensioners first came to our notice.


As regards the primary tensioner and the two plastic slipper guides is concerned, although the slippers do crack, they do not suffer from regular and known failure be able to the same monotonous degree that the secondary or top tensioners exhibit. They are under vastly less stress than the secondary units and despite the odd crack are known to be good in most instances for well over 150,000miles. However there may be the odd exception to the rule.

Cracked V8 primary chain guide 162k miles.jpg (53.77KiB)Viewed 2618 times

There is only one plastic primary tensioner and four long plastic slipper guide arms in the primary timing gear. The tensioner survives without issues at quite high mileages. Although as just said, the slippers can crack and still survive to seemingly high mileages. Neville Anderson at North East Jag Spares has developed an aluminium based kit as an option for when high mileage engines need overhaul. If that mileage is ever reached with your car at that mileage, then you might consider replacing the tensioner and slippers with his kit.

It is very unlikely that on a V8 with only 70k miles run, that you would need to replace the primary tensioner and slippers at such a low mileage. My S has covered 77k miles and I have no intention of opening up my engine for at least another 77k miles before replacing the primary parts. I think you too can sleep easy on that score.

Finally just reverting to BB`s article in the July 2012 magazine once again, my comment at the conclusion is worth revisiting once again. A quiet front end on a 4 litre V8 means little unless fitment of the third generation secondary tensioner type is known. Plastic tensioners on even a quiet engine can fail in a split second and wreck an engine in the same time. There are often no early warning signs that such a disaster is about to occur although some owners have been fortunate and had some indication that something was not as it should have been.

Sadly, it is a case of bite the bullet and find out just what secondary tensioners are in your engine. If they are plastic then best advice is to replace with the aluminium units at the earliest opportunity. Again Neville can supply those items at good prices.

Mike

[Gary220262]

Thanks for another well written piece Mike, looks like another weekend of dirty hands instead of driving pleasure (wife will be pleased !) il take covers off in a couple of weeks and let you know, if anything to report il take a few pictures t post and see what they look like after 6 years but only 10,000 miles covered.

[J44EAG]

With only 10k miles covered, Gary, you will probably find that even with plastic tensioners fitted, they are almost certainly likely to be in almost perfect condition. That having been said, having removed the cam covers, the best advice again would be to remove them and replace immediately with the ali jobs. Can`t be too cautious with these known failure items!

My tensioners were well cracked at 44k miles but you should be ok to run on the plastic items if fitted for a while whilst you gather up new parts and buy or rent the special lock down tool. Annie Jenkins at our Tools and Spares Dept should be able to hire you the kit for the job.

Mike