borescope it look for impact marks it will save you a lot of effort. unless the original secondary chain snapped at speed they usually are fine

an aj27 that’s sat forever or flooded with fuel from multiple failed starting attempts will also flunk a leakdown test.

 

Thank you for the resource, this will be of great value to me.

 

Though the engine does not appear to have been disassembled prior, I cannot say that with certainty, and if it has been, that would explain the like new condition of the timing chain, guides and tensioners, and if the mechanic presumed as I did, that it should be timed at TDC #1, then we have a real possibility that we have just solved the problem. This would also explain why both banks are out of time the same amount. It also means that the engine was not at operating temperature and could not have been turning at any more than cranking speed when the valves got bent. This means there is a high likely hood that the heads, pistons and cylinders are undamaged. So I will pull the heads and if this is all true, I will order new exhaust valves and head gasket set. Can any of you think of anything else that deserves attention?

Additionally, the car had been inventoried before we bought it and one part had been sold from it, the throttle body, so if I am successful with the engine work, I will need to replace that. Are these throttle bodies known for failure meaning I should get a new one? Or, do they generally last the life of the engine meaning I can get one used?

 

The leakdown test showed airflow through the exhaust and none into the crankcase and was done with all four cam lobes in the fully closed positions.

 

The first engines to be fitted with the all metal tensioners was engine SN 0108130000 that would have likely been fitted to 2002MY cars.
Your 2000MY VDP was NOT fitted with the newer timing components unless a replacement was fitted since it left the factory.

I would set the engine/pistons to 45 ATDC, loosen the exhaust timing chain sprockets and set the cams correctly before a 'teardown'.
You might find that the valves are not bent but simply not closing at the correct engine positions?

The front cover of the engine can be left off and a leakdown/compression test performed again to verify findings.

You will have to remove the cover anyway so just a few hours extra to set it and know the results instead of guessing?

 

Thanks for this. I will post pics of the timing components as soon as I can get over there to take them and with your help, perhaps we can positively identify them. The timing chain cover is already removed and all components look perfect. I had hoped that the lack of compression was simply a matter of incorrect timing, but, as stated, I did a leakdown test with all four cam lobes in the fully closed positions, where all four valves are expected to be closed, and yet, unhindered airflow through the exhaust, I heard it and felt it on my cheek at the tailpipe. Unless I missed my guess, this can only mean bent exhaust valves. Replacing valves will certainly be less work and less expense than replacing the engine with a used one, and I will also know that I have a 70,000 mile engine that will last.

 

Make sure you're using the correct tool to hold the crankshaft in position as you set the camshaft timing. It fits into the flex plate in the correct position replacing the CKP. Remember not to attempt the tighten or remove the 24mm crankshaft pulley bolt using this tool to hold the crankshaft in place or the flex plate is going to be damaged.

 

Caution: Do not use JD 216, crankshaft setting peg, to hold the crankshaft
when tightening or loosening the center bolt of the crankshaft.

 

OK guys, time for an update. Apparently, I need new glasses, or new memory, or both. Better lighting and glasses show me that the timing chain components are NOT new, the guides are plastic and appear to have metal reinforcement. The plastic is cracked on at least one of them, and, the chain has a very slight amount of slack between the crank sprocket and guide, but not enough to cause a jump and I would expect the tensioner to take up that slack upon getting oil pressure. So this lets out the improper assembly/timing from a previous mechanic and supports the "not previously disassembled" theory I had initially. So we are back to the question of how did both banks jump time when they are completely isolated from each other?

I suppose my next step is to lift the car, align the flex plate for the 45 deg. position and check the flats again. If they are in line, then I have a mysterious leak down test result. If they are off, which I suspect will be the case, then I order exhaust valves, top end gasket set, timing chains, guides and tensioners.

Is there any reason I should not buy aftermarket parts for this project?

 

Those timing components are original from the factory as the engine was built.(plastic)

 

Lift a bit one of the front corners just enough to slide under and fit the plug, it is easily accessible at the bottom front of bellhousing

 

Thanks much for the pictures and I do think the engine has had some care. I don't see the oil baked black into the Aluminum so it looks to have had regular oil changes.
I do think you have been lucky as those plastic tensioners have not disintegrated as so many have.

This is from a Lincoln LS but you can see how the engine has been baked with all the oil stains in the metal. Indicates poor maintenance for sure!


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When I worked at the dealer decades ago we had an S-Type 4.0 come into the shop with a 'chunk' of the head missing where the chain scrape marks are in the pic above due to the chain 'wadding-up' after it broke and pushed a section of aluminum out, breaking the head.

I can't remember if a new head or complete engine was installed but it was a 'warranty-job' so Jaguar paid for it.

 

It is possible for the exhaust camshaft(s) to 'jump' a tooth or two and become mistimed. If the chain 'jumps' three or more teeth, the exhaust valves are bent.

 

I like plenty of room to maneuver when under a car so I will be lifting at the center and supporting with jack stands. I ordered a timing tool kit four days ago but the seller has not shipped it yet, aggravating.

 

Yes it is quite clean inside, and this is one reason I favor repairing rather than replacing. Most of the replacement engines I found had many more miles and likely not had the level of care this one apparently has had, but yet, here we are doing a timing chain job. My Prius engine went 225k and never needed chain service, but I did replace it when it developed piston slap.

It seems to me that despite having done such a nice job engineering these engines, Jaguar really dropped the ball on the timing chain systems. At this rate, belts would have been a better choice, and I am a chain guy!

So, Lincoln used this engine in the LS, I had no idea Jaguar engines were used in anything but Jaguars.

 

The 3.9 liter engine Ford used in the LS and Thunderbird was very similar but there are differences.
The Ford/Lincoln 3.9 does NOT have VVT.
Many parts are not interchangeable but some are.

 

When the 4.2L was released by Jaguar Ford added a simple VVT system to the 3.9L at the same time. This was the 2nd generation LS built from 2003-2006 when LS production stopped. However the 1st generation 3.9L did not have VVT at all.

Jaguar got a nice continuously variable cam timing setup and the Lincoln made due with a system that had steps only and was not continuously variable. Still an improvement and that's why I waited before I purchased my 2003 Lincoln LS V8 Sport. Same idea as always when Ford owned Jaguar. Jaguar was the premium brand and got better upgrades including that nice 6 speed ZF which never made it to the LS. That would have been a great addition to the LS!

I think the Jaguar engine is worlds away from the little Prius stuff. Any DOHC engine will suffer from tensioner issues sooner or later. If you look at what the tensioner system has to go thru plus the rpm ranges we are turning these engines. The tensioners are just pounded too pieces. It's a rough life!
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As I'm sure we all know, the name of the game regarding the Prius is fuel economy. The engine doesn't work that hard because it works in tandem with the electric transmission which is the only variable drive that is worth a damn, because it works, it lasts, and it replaces the starter and the alternator. Not as fast or nimble as a Jag, but it's a great daily driver, and 50 mpg isn't hard to take when fuel is so pricy. Its timing chain is virtually trouble free so I'm sure if Jaguar, Ford, or whoever is in charge of development put their heads to it, they could design a cam drive system that lasts. I had the same criticism for American V8's. Why didn't they even have chain tensioners for all those years? We just had to suffer with timing that bounced around like a superball on steroids when the chain got sloppy.

I'm still waiting for the timing tool kit. I bought it on ebay and the seller appears to be lazy about shipping it.

 

Dropping fully plastic tensioners and guides into the engine is not an error but act of sabotage,
At some point CEOs did their flawed math and while toyota put on reliability and economy jaguar thought that little junk here and there means returning customer, either for repairs or a new car
" but hey, average jag customer is and idiot with a lot of disposable income so he won't care anyway" -thought retarded CEO projecting his own mind
As stupid and shortsighted as it is, both strategies brought their results, toyota is doing well and jag is on the verge of bankruptcy