"In April 2025, Jaguar sold only 49 vehicles in Europe, a 97.5% drop compared to the 1,961 sold the previous year, according to DesignRush and Yahoo! Autos. This significant decline occurred during Jaguar's transition to an all-electric brand, where they eliminated most of their existing models. Year-to-date sales from January to April were also down 75.1%, with only 2,665 cars sold across Europe. While global sales figures for Jaguar in 2025 are not fully available, Statista projects Jaguar's global sales to reach 87,900 units. "

 

The V8 pushrod engines favoured by the US manufacturers have short timing chains that can be easily replaced with the engine is situ in most cases.

The main issue with any overhead cam layout is weight of reciprocating mass plus wear factors. Adding a double row chain also increases the length of the engine, which causes packaging issues for the designers. The AJ33/34 has a different timing chain system with metal bodied tensioners, but I have seen those fail as well on rare occasions.

 

the second gen 3.9 has the same vane phasers are the 4.2. every update to the engine mirrors the 4.2

 

Have seen your post Cable Guy and couldn't agree more

 

Whoa! What happened to posts # 44, 45, and 46?

 

Someone must have strong affiliation to said community and went on sad facts erase rampage

 

I deleted those posts because they were irrelevant to the topic at hand and veered into politics, which are not allowed in the model forums. If you want to discuss Jaguar's current business strategies, look for one of the relevant threads in the Off Topic forum. This thread is about your timing chain issues.

Cheers,

Don

 

Thanks xalty I checked and yes they are the same. I had read back when I had my LS that the Ford version had a simpler VVT setup because of cost.
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Respectfully Don, I feel that the downward trend I eluded to is directly responsible for the timing chain issue I am now dealing with, but, it's your forum.

 

Well Gentlemen, I finally got to working on the VP again. After inserting the locking pin into the flex plate, I found that the flats of the cams are inline, indicating, of course, that timing has not changed on either bank. I did notice a little slack in the primary chains that had escaped me initially. The tensioners are most definitely plastic, but before I replace them, I need to know why I have no compression on any cylinder.



Due to my workload, I'd really like to avoid pulling the heads if at all possible, and at this point can only speculate stuck exhaust valves, however, the cam followers are returning to the closed positions as the lobes turn away from them so I don't see how that can happen without the valve closing. Burnt valves crossed my mind, but all 8 cylinders at the same time? Not so likely. What else could cause a complete loss of compression through the exhaust? Unless you guys can come up with a magical solution, it would appear that I am condemned to pulling heads.

 

0 in all holes on the nikasil engines is the lack of oil film to seal the rings. just dump oil in the bores and crank it until they seal. this happens from sitting, extended cranking or being shut off during cold start enrichment

 

xalty this is a bad case of bore wash?
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Now that would be a truly magical solution! In all my years I have never run across this, even with engines that have sat for decades as in the case of some of my Amphicars. These cars would end up getting parked because of lack of parts during the late '60s and '70s, or if they rusted to the point where they would no longer float dependably and owners could not afford to have them fixed. Their little Triumph Herald engines always come back to life easily, usually needing no more than a carb cleaning and points clean and adjust.

But, remember, there was absolutely no compression whatsoever and compressed air through the spark plug hole during the leak down test showed air coming out the exhaust and none going into the crankcase or the intake.

 

Assuming that engine compression was tested at top dead center instead of crankshaft position, here may be the reason why it let air through
At this point you have not much choices left, either threat it as bore was, drop some oil and try to start or inspect it with the boroscope camera, given your timing is intact there is nothing wrong with just starting the car

 

Remember, valve and timing chain covers are removed and the engine has no throttle body. That was removed and sold before we bought the car. I'll buy another one if I can get compression and all else looks good. So that precludes simply starting the engine. And since the compressed air exited the cylinder only through the exhaust when the cam lobes were off the lifters, this indicates an exhaust valve problem which led me to the bent valve thesis. Now with the timing not a factor, this leaves stuck exhaust valves as the only possibility, but, there's a problem. As the cams rotate, the followers go down and come back up all the way. Presuming the valve springs are pulling the valve stems up, and the end of the stem is pushing the follower, this would seem to indicate normal valve function.

I had considered gasket failure, but all 8 cylinders? Not a chance. So, unless you guys come up with something new, I'll be pulling heads.

 

Put some oil in all the cylinders through the (removed) spark plug holes and spin it over.
Now repeat the compression test with plugs left removed.

 

Sounds logical but all of them both banks without a jumped chain?
Other wild guess, nikasil lining got stripped due to severe engine overheat.
Me thinks cheap boroscope will save you time and mind bending over the thing

 

The bent valve thesis was because I initially thought the timing had jumped because I didn't know about the 30 degree crank angle for cam timing. Again, the leak down test had no air coming from the crankcase, only the exhaust. However, I only checked one cylinder. Since there was no compression on any cylinder, I figured they are all from the same reason. I would expect that if it was a nikasil problem, I would have air going past the pistons to the crankcase. I don't see how oiling the cylinders with help this problem, but it will probably be a good thing to do anyway. I can see that I will be pulling heads on my next work session.

 

If you have never experienced bore wash it will surprise you! I have seen engines refuse to start no matter what. A little oil in the cylinders and possibly a burst of starting fluid got them going. The thing with bore wash is IF you can ever get the engine started it will fix itself.
Hard to believe but true.

Sad they sold parts off that car before you purchased it. Hope they did not sell too much stuff!
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They only sold the throttle body because we found the car before more of it could be sold.

I have had engines that had totally dry cylinders that would at least show some compression, but never 0 psi. And I've never seen an engine with good gaskets, pistons, rings and valves fail to compress, at least something. But this engine blew 0.00.

In the next work session, I will recheck compression after oiling, as you recommend, because even though I hold little faith that it will remedy the problem it will at least lube up the cylinders so I don't have to feel guilty for checking all 8. And, if I get lucky, it may just free stuck valves, if that turns out to be the problem. I'm thinking Marvel Mystery Oil is a good choice. It works well in my air tools and is thin enough to flow quickly around parts.