So I took my Jag to mechanic last year who knew the history on the Jag I purchased for a diagnosis of engine noise which I suspected to be related to the timing chain and tensioners. He told me the upper tensioners go bad on these and need an updated metal part and he'd have to replace them. He also said the primary chain doesn't need to be done on these Jags.

I authorized the work to be done and after the job I asked about the repair and what all was replaced and he told me he only the upper tensioners and some various gaskets, etc. The primary tensioners were not touched. I also asked about the chains and he said he wanted to save me money and didn't replace them. I was disappointed, but knew I'd be back for the primary tensioners soon enough and I'd probably get the lower SC pulley upgrade at that time(spoiler alert: I did).

So I finally had the primary tensioner job done by a different mechanic and he found all the usual symptoms(cracked tensioner and rail bits in the oil pan, everything worn to hell). Problem is my new mechanic also found the upper tensioners to be damaged and in need of repair. Apparently the chain that wasn't replaced had been previous sharpened by the old upper tensioners and had since cut into them ruining them. Mechanic stated "sharp as knives".

My question here is has anyone heard of this before? Should my first mechanic have known to replace the chain or is this a very rare occurrence that he couldn't have foreseen? Only other possibility in my mind is that my new mechanic is wrong about what happened,...

Thank you for your help!

Cheers,
Erick

 

You are asking for judgement by (mostly) non experts, without any physical evidence in front of them to settle a dispute between two "experts". You may get interesting answers, but you will have no valid data.
Plenty of us have changed tensioners without changing the chains with no apparent ill effects. Apparently your old tensioners had actually failed and were rubbing metal on metal. I assume that could cause the chain edge to sharpen or could raise some bits that would damage the new tensioners. And.. the previous mechanic should have checked the chains for any signs of wear or deformity, but for the added price of approximately $150. you are out buying new tensioners, I would not loose too much sleep over it.

I guess the lesson you have helped others of us with is to be careful to check the chains if our old tensioners have actually failed and caused metal to metal contact with the chain. Thanks!

 

Agree with Ross. Apparently price isn't a significant concern: first tech should have asked and given you the option to do a full up replacement. It would be useful to know the mileage and whether this car is raced.

 

One of the plastic shoes was missing on mine when I replaced the secondaries, but the chain appeared to be okay. It's been over three years now, so I should probably take another look, but I'm not losing sleep over it.

 

just joined. I picked up a 99 xj8 last week and I'm planning on doing the secondary tensioners asap. I ordered the parts ($100 on amazon, both tensioners and secondary chains included). however the bolts are not included. partsgeek says the size is 6x35mm($3.99ea).... Is this the correct size for the new style???thx. also planning on using the zip tie method, has anyone had any problems doing it this way?

 

I'm not sure how you are going to change the chain with the zip tie method, but I suppose it can be done. That seems like a very low price for including the chains, I hope they don't fail.
I don't recall the bolt length, and one car I helped do didn't have new ones, so I just ground 3mm off the old.

 

Jaguar Land Rover 3 2 3 5 3 7 4 0 4 2L 4 4L Camshaft Crankshaft Timing Lock Tool | eBay

Just buy the right tools. You'll thank us later.

 

Yeah, and despite the raves for the zip tie method (I have done one that way and it IS simpler), the fact is that the old and new tensioners have slightly different dimensions, resulting in a different length for the tight side path, so perfectionists would want to re-time using the tools.

And RJ is correct. How do you zip tie a chain you mean to replace? Count the teeth, I suppose, but that sure is not truly "zip tie"!

 

The shorter bolt for the newer tensioner design is
M6 x35mm.


Don't see why people would claim ignorance of the zip tie method.

It's all over the forum.

Using the tools mandates removing the sprockets. No thanks.

 

99 xj8 74k. Thanks for the input. I don't intend to replace the chains unless needed. If that's the case I'll have to get the timing tool kit. The tensioners were $75 each if I purchased them separately ,but only $100 for both with chains as a kit for some reason. Has anyone had an experience with getting bad/ poor quality tensioners?

 

I believe all tensioners come from the same source.

** Edit-
I did not notice this question was not from the OP!

 

tensioners don't come from the same place.i bought the last 3 pairs off of EBAY $150 a set from japan[they've come a long way].I also found cheaper ones that were made in Taiwan,[no thanks].steve

 

My new tensioners are from FAI (a British parts manufacturer).

 

Hmmh. I haven't bought any in a few years, but mine all had the same casting marks whether from Ford (Lincoln), Jaguar, or Brithish Parts.