2001 VDP 4.2 NA 87K miles. I bought this car in 2017 with bad secondary tensioners. Replaced the tensioners immediately, but didn't get it on the road until a year later, after a new fuel pump, new tires, and new fluids. 3000 miles later the engine fails after mild acceleration from a stoplight. Flatbedded home to my driveway, 7 months later I finally get into the engine to see what's up. Passenger side shows a broken secondary timing chain and no sign of the plastic bed from the tensioner. This is my second tensioner replacement job, so I'm confident of my skills, but certainly shocked at the early failure. What happened to the plastic? Ground to bits by a faulty chain? Any sage advice about next steps would be welcome.
Could the camshaft stop in a neutral position where no fouling of the piston occurs? I looked into the spark plug holes with a scope, and couldn't see any recent damage to the pistons, but with all the carbon buildup, it's still early days on that score.

Left side is fine

Right side tensioner is incomplete, chain is broken

Chain damage

 

the poorly fitted slipper broke off the base and jammed the chain.

it’s basically the same failure mode as the original type. the metal ones just happen to break off on the fixed end whereas the old style can really only break off on the piston side.

chalk it up to bad luck with aftermarket parts 🤷‍♂️

 

I had a similar failure about 9 yrs ago, only I was lucky and only the neoprene came off, ...it looked like the neoprene dislodged and the chain threw it.
I was lucky to the point I was keeping a hard ear on it and didn't have but 40ish miles on it yet. As axlty stated, aftermarket parts...

 

This posting really paints "after market" parts into a horrible frame. It seems that "original"
Jaguar parts may well be worth the exponential price.

 

Well there are also a wide range of aftermarket parts. Some people sell full timing chain kits (all chains, all guides, 4 tensioners) for like $150 on ebay. Personally I wouldn't trust that. I went with Eurospares, which seems to have a decent reputation and I feel confident in my decision.

I think the point is that you can use aftermarket parts but makes sure to buy reputable brands from good sources, especially on engine critical parts.

 

the ones i buy on ebay are supposedly genuine tsubaki never an issue but they can always lie lol.


i’ve even reused secondaries from a car that blew an oil cooler line and ventilated the block. stick a paper clip in it and good to go for the next job.

 

Question for the PO - did you use the original secondary tensioner bolts to fit the new ones? There is a difference in length. The plastic tensioner bolts are longer than the alloy version.
When these are used they seal the oil galleries so the tensioner isn't pressurized and tensioning the secondary chain. Anything can happen, OEM or aftermarket.

As a side note for me it has to be OE parts from reputable agents, if not Jaguar themselves if it's drivetrain related that's a non negotiable and most pro techs are the same. Buy cheap, do twice.

 

I am with you Sean.

 

Yes, the alloy tensioners came with new bolts, and yes, I used them. Never had a quibble about aftermarket parts before, but this is indeed an"engine critical part.

 

I always used Ford/ Lincoln tensioners, much cheaper. Sometimes they even came in a Jag box.

 

Hmmm I wish I had a database of all the equivalent parts which are attributable to these cars.
The real problem is having to guess whether the part is of high enough quality.

 

I replaced the right side tensioner in question, and the chain (since it was broken and damaged) and buttoned it up, curious to see the result. It's been sitting almost a year since the car broke down, and took a week of trying every morning to start to fire completely and run at all. It almost fired on the first day, but not quite. Day 6 or 7, it started and ran, with a tappet noise, so I assumed a bent or sticking exhaust valve. Been driving it almost every day, and the tappet noise has disappeared. Idles smoother now, but still a bit uneven in Drive at a stoplight, for instance.

I checked the compression on the right side, and all gave me 115-120 lbs.

I'd forgotten how snug the passenger compartment of the X308 is, since I've been using X350s for daily driver duty. I have to be much more precise to maneuver my knee-replacement left leg into the car after I'm in the seat. This would be much easier if I lived in England or New Zealand since the offside entry starts with the bum leg first, followed by the rest of my carcass.

 

Result! I think that's a sign you should do the lottery, that could have easily been a toast engine.

Eye on engine temps for a while, and report back with some mileage on it!

 

Very nice Pete! Glad you are back in the passing lane.

 

I have an ‘02 XJR with 90k miles. I changed the secondary tensioners right away when I bought the car nine years ago when it had 50k miles. I haven’t replaced the chains.

When is replacing the chains recommended?

 

When you have slack in them...they should be fairly tight...my secondaries were horribly slack, I had about 3-4 mm in them. My acceleration was off and once I replaced them and the guides, it was a new world of performance for my gal.
You can count on about the same issue with slack secondaries.

 

I use the tensioner of eBay but not the chains because ebay chains very weak . Christopher rebadge ebay tensioners and sell it as ford original parts

 

Yes, on these cars only the highest quality chains would be recommended.

 

When I replaced the tensioners 2 years ago, I reused the original factory chains. The evidence seems to show that the new tensioner failed, causing the chain to snag on the works and be yanked apart. I had to order a replacement chain this time, from a reputable source, but I must have misquoted the VIN number or engine number, and when I got the new chain, it was 10 or 15 links too long. Since chains are made by man, they can be "altered" by man, and I've done motorcycle, bicycle and machinery chains before. I pulled out a couple of dusty chain vises, made a minor adjustment to the chain bed on one, and duplicated the original. Works like a champ now.

 

Yes, I remember doing that with a Kawasaki I used to own. The stock chain replacement came
way too long, however, was easy to rectify.