Symptoms:
My car ran perfectly with no excessive noise. (Well other than the supercharger coupling that sounds like a can of marbles bouncing around in my supercharger)
I parked the car for about an hour. Came out, started the engine and noticed immediately valve train clatter and a rough running engine. Right away restricted performance kicks in and I make the short drive home. Once home I pulled codes for misfires, cam and crank correlation. Typical for timing problems. I am an experienced mechanic and I knew about the timing issues on the JLR 5.0L engines, so I tore down the engine. To my surprise, I found updated chain guides and what looked to be new tensioners. I was also surprised and disappointed to see a lot of carbon buildup, sludge, and gunk. All typical of neglected oil and lots of blow-by.

Findings:
So why the hell did my timing chain jump on the drivers side? Chain was tight and the infamous chain guides have already been replaced.
When I removed the tensioners, I found quite a bit of sludge behind them. There is a perfect place for it to accumulate behind the tensioners. I can only hope that this was from missed oil changes and poor maintenance rather than a design flaw. This buildup is a problem. The tensioners essentially have two pistons. One is the spring loaded, ratcheting piston that keeps constant tension on the chain guides. The second, encases the first piston and is hydraulically actuated by engine oil. So the design is to apply light tension continually and significant tension immediately when the engine is started. If you have never dealt with timing chains on other cars, you would assume that this tensioner holds enough pressure on the chain to be sufficient. In reality, typical timing chain tensioners hold an impressive amount of force on the chain guide.
Obviously restricted oil to the tensioner would allow the timing chain to slack and jump at engine start, as mine did. Incidentally the miss timed ignition created enough detonation to blow out the rings on the driver side 4 cylinders.

Here is the tensioner as you would find when the engine is off.

Here is the tensioner in the fully extended position as it would be when the engine is running and oil pressure is present.

This is the hole on the back of the tensioner where oil is fed.

Here is the small grove that would allow oil to drain from the tensioner when the engine is off.

 

So only the outer piston is ratcheted and the inner piston is free to extend/retract under oil pressure? If that's the case, when the tensioner is first installed, the ratcheted position of the outer piston would be set and forever thereafter stay in that position and any additional tension on the guide would be provided by the inner piston (oil pressure). Is that correct, or is there a mechanism for the outer piston to continue to ratchet out over time to avoid the inner piston continuing to extend?

Thanks in advance for providing details on this. Without actually doing the job it's hard to visualize what happens. Any additional info on how to remove the bottom pulley and did you go for the zip tie method when removing the tensioner and guide or did you lock the cams?

 

The oil driven piston is free floating. It is fully retracted when the engine is off and deployed when the engine is on. The spring driven piston is always out once deployed initially. However, if you compress it once it has been deployed, then you will need to compress it just past the fully compressed position to get it to deploy again.

I used the loan a tool balancer puller to remove my balancer pulley. No issues.

 

As for removing the pulley, I removed the actual pulley from the hob first. Simple remove the 5 or 6 bolts that secure it to the hub.

Second, I held the hub with pipe fitters vice grips. See photo. The I used a tensioner bolt as a stop for the vice grips while I loosened the crank bolt.

Third, I used a simple harmonic balancer puller to pull the hub. Also worked well for installing the hub. See photo.

I had to check my timing so I purchased the cam locks.

I clamped this around the hub to hold the crank while I removed the crank bolt.

This puller worked just fine for removal and install of the hub.

 

Sorry for all the questions but this kind of experience is hard to come by. How was the crankshaft bolt tightness? Others have reported it's murder tight so did you use any special tools etc? I'm guessing that since you're a technician, this kind of thing is everyday work to you. Those of us less familiar with these larger jobs tend to worry more, especially given the cost of repairs and our limited access to tools and facilities.

 

The key is holding the crank still so the bolt can be loosened. Once you remove the pulley from the hub, the hub is easy to clamp with pipe fitters vice grips. Once you lock down the crank, it’s all a matter of getting leverage on the bolt. Use a piece of metal pipe to extend your leverage. I use vice grips like these but not with the cutting chain.

 

Sad to see troubles after having updated tensioners and guide rails fitted.
Sean, can you supply us with the part code for the hydraulic tensioners you have fitted, i am interested to know if yours were the Slovenian made tensioners or the German ones.

By the comment regarding the sludge build up it sounds like neglectful oil changes and engine oil flush procedure at oil change intervals, i can only hypothesize that sludge has been dislodged and blocked the gallery feeding the hydraulic piston leaving quite insufficient chain tension on start up.
After cylinder ignition it quite possibly would have been at that exact moment where the lack of tension upon firing the timing gears sudden acceleration being the point where the timing has jumped.
Regarding your pistons, if you can find a bore to match, just make sure your wrist pin height to piston crown is correct, hopefully your wrist pins on the coyote and the jag rods are a match for sizing.
Reminds me of when i was a teenager hanging out with the strip guys working strokers, looking through literally hundreds of pistons and a set of calipers looking for a match to pin height and bore, good luck, give ebay a good scour, i have seen some shells, oversize and std genuine parts around, also some pistons oem, dont forget to search range rover or landrover in your ebay searches you may be pleasantly suprised what you find.

 

Sorry double post

 

Thanks for this post. I didn’t realize that the ratcheting position was completely dependent on spring tension when the car is off. I thought the hydraulic pressure helped push it into its next position as necessary. This definitely clarifies why oil type and change frequency are so important.

I keep looking at your pictures of the tensioner and for some reason the pistons look weird. Just for reference here were my old ones post removal.

 

My tensioners look exactly the same as the new ones that I purchased. Im sure this is because they were replaced at some point.

Here is the full piston removed. It simply slides out.

Here you can see down the bore.

 

Here is a better picture of the part number.

 

Thanks for the added pics.

It may be the angle but I don’t see a nub on the end of the piston like in the picture of my old tensioner where it engages the guide. Was that eliminated in the new tensioner?

To to be honest I never looked at the new style tensioner before it got put in my car.

Thanks again

 

I have not had much luck with LR parts or Jag parts. Interestingly enough, you can purchase rebuilt engines, so obviously the parts are out there.

My objective is to rebuild my engine better than factory. I feel that these engines are not built as well as everyone wants to believe. Especially the forced induction engines. Blow-by can be better controlled with stronger pistons and rings. There also needs to be some sort of oil pressure monitoring. It’s asinine that the oil pressure is not monitored at all. All that being said, having custom parts made is not a reasonable option. Rebuilding a typical engine yourself does not cost more than $2k, including machine work. This should be possible if Ford parts will work in this engine. Especially considering the amount of aftermarket support and affordability of coyote parts.

 

There are no numbers on the piston. Only the body.

The weak link here is the engine oil. It cannot be neglected as I assume mine was. I dis clean a bunch of sludge from the oil passage in the engine feeding the tensioner.

 

Great pictures too!
Please let us know if any 5.0L Ford stuff fits. Even though it has FoMoCo on the parts nothing interchanges so far.
It would be great if you could find more parts supplies.

Have you read Dave Tibbs thread on his engine rebuild?
He got into it very deep.
5.0L Rebuild
.
.
.

 

Yes, his posts are very informative. He took a very determined approach. I’m looking to find a more traditional engine rebuild approach. Something that can be easily duplicated by others.

I know that the part numbers do not match between Ford and JLR but I have a sneaking suspicion that some parts are equal.

 

Subscribing as your methodology is methodical and precise. Something I used to teach the techs on my team. Your posts are really informative!

 

I did a heap of reading lastnight on the coyote, the aftermarket performance parts are as you would expect and heavily geared toward street/strip level performance, which is great for the pony buffs. Well the blocks between the AJ133 and the Coyote5.0 share literally nothing, even the liners are hugely different, not so great.
Interestingly a company called MMR make all kinds of gear for the coyote, including timing tensioner kits and guides, aftermarket demand is obviously far above JLR, even aftermarket VVT setup, and wow the $ compared to jag for this race gear, well yeah Jag tax, all those dollars does not mean better quality.
The MMR timing tensioner assembly is upside down on the Coyote compared to the AJ133, and we cant use Coyote hydraulic tensioners as the mount and gallery reservoir simply does not match, kind of expected that.
The MMR tensioner is actually built the same as our current stock tensioner from JLR in that it uses a twin ratcheting and sprung piston, and they are half the price of stock JLR with a nice billet anodised look. The stock Ford tensioner and Ford high performance version uses a external ratchet acting on the outside of the outer piston, commonly known to fail in the same way as ours, the flaws seem to be common between all engineering concepts of this design, where the inevidable failure of the ratchet will occur no matter where its put.
I have not had anytime to dig into the crank journal measurements and big ends or any of the reciprocating assembly for parts match.
Sean is right though, an engine rebuild, line hone, decked and squared, full balance of rotating assembly is cheap compared with the price of JLR parts, you could even cc port match intake and exhaust, 3 angle valve job, the list goes on, while the AJ 133 is a great base to work from, its a bloody stretch by JLR to ask top fueller prices for factory stock parts, it is what it is i guess.

 

The block, heads and all external accessories including fuel and ignition components are different. It’s interesting the approach Ford took for the VVT and timing chains. Same layout as the JLR engine but instead the chain runs around one cam sprocket. This means a shorter chain. Seems simpler.

Once I get a piston out of the engine, I can compare to aftermarket.

Imagine having Hypereutectic pistons, and steel rings in the JLR engine. This seems like a no brainer for forced induction engines. Its not uncommon to have a built up engine that run high rpm’s, high boost and have virtually no blow-by. Improvements in oil circulation , engine and oil cooling and strong internals are typically easy to achieve with the aftermarket. We will see if this can be done reasonably with the jaguar engine.

 

https://www.jaginfo.org/showthread.p...g-chain-rattle this OP got compensation of sorts