Hello Every one i am new here and just got a 98 XJR with 120k but it has a pretty loud rattle from the right side timing area . I noticed that the cover has a small crack where the chain has probably worn through over time . I have not taken it apart yet so i am not sure if i should order all the chains and tensioners or maybe just the tensioners and have the cover repaired ? I have been doing some reading using the search button but wanted some more opinions and what special toold i might need . The car runs fine just underpowered and makes noise .

 

Switch the engine off, and when it is cooled down remove all the front timing chain covers and replace everthing you can lay your hands on. Don't drive the car any further until you have done it, because if one of those chains snaps and you're lucky, you will only bend a few valves, dent a couple of pistons, and do only a couple of grand's woth of damage. However, if both the top chains or the primary chains stop holding links, it will probably be cheaper to buy a second hand engine.

Check the forum links, look for whiteXKR's thread, he has the part numbers for the top chain tensioners to buy from Ford online. My suggestion is that you get replacement chains from any engineering workshop supplier in lieu of buying from a Jag Dealer, someone in the Forum suggested "Morse" chain as a quality brand. I'm so old I refer to "Reynolds" chain, since this was the brand used in the original XJ6 through the life of the engine. (It was double link, and lasted for half an eternity). "Quality is like good sleep, the benefits remain long after the price has been forgotten".

Having said all that, the other thing I would suggest is that you do a compression test on the motor first. Your observation that it is 'underpowered' is a definite worry. I'm assuming that it is a V8, and '98 means that it may well have a 'Nikasil' engine. If the compressions are down, then you are probably headed for replacing the engine anyway. The problem with the Nikasil lined bores was that fuels with higher sulphur content took the lining off the top of the bores, resulting in compression failure, and there is no cure other than replacement or rebuild. Jaguar stopped using the Nikasil lining after April 2000, but even then some April 2000 cars that had engines replaced under warranty were fitted with engines that still had Nikasil bores. (god alone knows how many blocks were in the warehouse when production of Nikasil engined cars was stopped, and they were looking for ways to get rid of them other than the furnace).

Welcome to the Forum and I'm very sorry to sound like a pessimist, but someone had to speak up and it might as well be me.

Reguards,

Languid

 

The loss of power could also be the result of timing chain being one notch off due to failed tensioner(s). In any case, don't run the engine...

 

Jussi is right, it could be. That's why I suggest a compression test first. If the compressions are good, then fix the timing chains. But if the compressions are bad, you will have to make a decision about the engine, and there is no point in spending several hundred dollars on the timing chain problem if the engine isn't good.

Cheers,

Languid

 

why have we got two exact same posts?

Forget the compression test, you've bigger problems

DO NOT START THE ENGINE - TAKE THE TIMING COVERS OFF TO CONFIRM BROKEN SECONDARY TENSIONER - then locate the tool set and replace the tensioners and chains and guides.
TOOLS
Laser Timing Tool Set Jaguar, Landrover 4.0, 4.2 V8 foam and metal case | eBay

 

Yeah ! ! ! ! !

 

The worst I have seen was the secondary chain tensioner failed, the chain snapped and 'wadded up' in the outer corner of the cylinder head and broke the aluminum head and front timing cover at that point.

We installed a NEW cylinder head and cover, the customer WAS NOT HAPPY!! (out of warranty)

bob gauff

 

Everyone thanks for your input . I am not running the car anymore it runs smooth tho and no cel on . I will be doing a compression test and if thats good then take the covers off and do the chains . But the right side cover towards the middle of the V has chain marks where the primery chain was hitting . I will take my time as i am not in the hurry to fix it but i want to feel the power this thing is suppose to have .

 

Although we said don't run the car, I bet most of us would not recommend cranking it either, which is required for a normal compression test. Just in case you have not already crashed the valves to the pistons, you will be saving an immense amount of work if you don;t crash them now.

 

The car ran fine so i think the compression is fine . I am going to start by taking the valve covers off even tho the noise is from pass side and check the tensioners . But i will have to take the front cover off to check the primery guides due to the damage on the pass side on the primery chain to cover area and have the cover repaired as well . Any place i should get the whole timing kit from if i need it ? I saw a couple of listings on ebay but not sure about those kits .

 

My experience is that the kits are more expensive than buying the parts. You MAY need chains, but most of us have found that our chains shuw no measuable wear and the sprockets and chains can be reused just fine. Your case might be different since you have apparently had a rub. Front covers are available on fleabay most of the time.

The best price I have found on secondary tensioners is from the Ford dealer network. The tensioners are the same as 3.9 liter lincoln v-8 from years about 2003. Any nuber of internet sites source primary rails and tensioners of the third generation.

BTW, when ou get conflicting recommendations, I suggest you consider the likely qualifications of the source.