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Here is an image of one of my guide rails. Generally it looks like XJsss' photos. There shouldn't be a circular dent in this guide rail; all of that is damage. You can even see the metal burrs around the edge of the dent.
Here are my tensioners. Note how far out the tensioner pins are, suggesting I was getting near the end of their range.
Yikes! Well I received all my parts today. I will be dropping my car off on Monday. Hopefully everything goes smoothly as planned.
The tensioners pistons are at there full extended position by there looks You can see the shiny marks on the piston it looks like that was the operating position.The pistons are spring loaded, if they are released will go to full out position.If you push the piston back in it should lock in its detent.
The tensioners pistons are at there full extended position by there looks You can see the shiny marks on the piston it looks like that was the operating position.The pistons are spring loaded, if they are released will go to full out position.If you push the piston back in it should lock in its detent.
Too smart cwalkey; that makes sense. Though by that logic I presume the non-shiny part on the tensioner on the left is the amount of tensioner travel used during regular vehicle operation, correct? That is still a fair amount of chain stretch.
Its hard to know where the pistons position was at the time of removal.The piston is supposed to lock in detent not to move in and out. It extends to keep the chain tight and lock. When the chain stretches, the piston will extend to a new detent the problem is the detent fails the piston moves in and out hens the shiny marks on the piston. When i removed my tensioners there was a long distance from the tensioner body to the chain about 5/8 in.That is enough space for the chain to slip the cam teeth when the piston detent fails This is a design fault along with the guild made off aluminum with out wear inserts.
The good thing is that you changed the parts before the motor was damaged.What was the final cost for the repair?.
The cost was approximately $5k. Half labor, half parts (all the parts listed above). The car sounds much quieter and idles better too.
I am wondering if the tensioner detent/ ratchet failure might be related to the guide rail problem. It seems that denting of the guide rail could change the angle that the tensioner piston engages the rail. I’m thinking if the piston is pushed in the rail and isn’t pushing exactly straight the ratchet mechanism could fail. Thoughts?
I believe there a several problems with the design The guide is one of theme. Where its mounted on the pivot bolt there is a lot of play in the opposite direction allowing rocking force on the piston when it embeds itself in to the aluminum guide. If the guild had an hard insert the piston could slide across the surface like the new style guild. This would help stop the piston from rocking on the detent causing it to fail. All so the quality of tensioner detent is in question. As i stated before we had to replace the timing system on a Land Rover with the new tensioner and guides the piston had collapsed and locked closed causing the chain to slip and bend valves.So i do not trust the new tensioners
Our family car is an old school 1995 X300 and my daily driver is an XJS but I've been eyeing off a few 5.0L X351s recently to bring us up to the current century.
But how depressing it is to read this thread and discover there are still timing chain tensioner issues on the 5.0. I thought all this had been addressed after the initial problems with plastic tensioners in the 4.0/4.2L motors. Reminds me of the regular tensioner replacements required on my AJ16. Yet on my old V12 the tensioner/chain hasn't been touched in 30 years.
I thought buying an X351 might relieve my weekends of DIY repair works jobs but perhaps not
I just changed the timing parts on my 2011 XJL supercharged over the winter. It is quite an experience for the first time on this car. The information is limited.to what you have to take of to reach the heads to remove the valve covers.Just before starting the job i helped my friend do the timing on a 5.0 land rover supercharged that had the timing changed 75 K with the updated timing kit new style tensioners and tension guide blades with the steel inserts. The tensioner piston lost its mechanical locking ability, an was forced in where it stuck. The chain slipped the cam gears and bent the valves. This happened on the right [drivers] side head. This will happen with all the 5.0 old or new tensiones, they will fail its only when will the fail. This is the third timing kit in this Land Rover. I cut the tisioner piston apart to see how it works,its made of two stage piston the first stage has the oil check valve the second stage is spring extended with a round circlip that locks into detent grove in the firs stage. This cerclip detent system is the mechanical lock that fails.It is the same lock that is on all the tensioners old or new.From what i have seen there may be several factors that cause the tensioner to fail, one is the tensioner guild blade. There are guild on the new blade that hit the side of the piston rocking it side ways this is because the pivot bolt has to much clearance witch will allow the blade to move side to side. Second the piston when no oil present [like on start up] gets slammed back into the housing hitting the circlip against the detent witch over time makes the cerclip lose. here are two photos of the failed new style tensioner. So i decided to make my own tesioner and modify the blade.So far all is working good.
I know this is an old post but what did you use for instructions/guidance on this job? How many hours did it take you?
You can follow this post, it’s for the XF with the same engine. This is the zip tie method that is a little quicker because it only changes the faulty tensioners and guides leaving the timing chains alone. I don’t think chain replacement is really necessary.
It's seems Jaguar still have issues when it comes to the timing gear. The design of lower guide positioning of the lower tensioner acting upon it is near one end, putting too much pressure on the metal of the guide despite inserts.
When chains become stretched on these supercharged V8s they become loose on the VVTS and if the chain is allowed to rattle along with the hole in the guide and over extended tensioner piston ( above 40k miles ) then there is a greater risk primary timing chains can ride the VVT and drop a tooth. (Finer inverted teeth and chains (quiet chains) on later V8 ls in general). So hear a clicking from timing, then it is well worth getting it investigated before extensive head damage as valves hit pistons.
I would like to see a separate blog on Jaguar Design issues as a record of known faults on all Models and whether solved in latet models.
Like putting coolant expansion tanks above coil packs (X308) and havIng long central spark plugs tiunnels that could be prone to oil and water flooding if seals were leaking was for me a loose design. Remember easy rocker box covers and spark plus assessed via the actual cylinder head was so much easier to get at.
Why are engine some much more difficult to work on now. Plastic covers hiding vital parts to be maintained and not left easily accessible. Numerous special tools. Why couldnt the harmonic damper be held by smaller three bolts rather than one at such massive torque wrench settings like newer VVTS.
Sideways wear on secondary tensioners (X308/XJR up to 2006?) compared to later XF guides between VVTS set up. Always though the early XJ6 striaght 6 that had the idea of a eccentric middle cog that could tension chains and could be adjused periodically and was easy to get at was a good way of keeping timing chains taut.
This design fault on later V8s of primary tensioner too near one end of the guide it is acting upon, drill a hole through excessive pressure and wear.
How fill sealed gearboxes when access is from under the car unlike earlier Jaguars that had a tube into gearbox. Tube could still be on the car and either just capped with a sealing bolt or old dip stick arrangement with a seal. Why hide these parts under the car.
I am sure there are plenty design faults or assess issues and/or potential solutions that other members could recall that could be held in a separate blog.
If Jaguar or other car makers though of locking Harmonic Damper by resigning it to take a sideways slot to engage with crankshaft end or take a sideways pin there would be the need to secure it with 270nm torque. It could be held in place and not able to rotate by a machine slot and the shalf inline bolt held by a more reasonable value. Most high range torque wrenches on the marketplace only go uo to 350nm anyway. With a slot or key the damper could still sit flat on the crankshaft end and not cause any in balance issues.
My mechanic seems to have sheered off two of the timing chain guide bolts in the midst of my timing chain service.. I have found what I believe may be the part under a Land Rover part number (LR011064G), but I'd rather ask here to find the specific part number that I need. Can anyone shed any light onto this. Thanks, Greg
phenomenal info in this thread!!! thanks to all that contributed.. Im having an issue with my non-S/C 5.0V8 and hoping its still repairable. Anyone in South florida do this job yet?
07-16-2019, 04:55 PM
