Hi everyone,
My 2001 XJ8 (3.2l) has done c120k and was running sweetly until last night.
Parked, and when I returned started engine which ran rough at tick over but seemed fine during normal driving.
Arrived home (c25 miles), got out of car to open garage, and heard noticeable clattering from engine. Can't hear this from inside so can't check if there while driving.
Haven't yet been able to remove engine cladding and try to pinpoint source area (screwdriver to ear thing).
My concern is that this could be timing chain slip/tensioner problems which would only result in expensive disaster if ignored.
Also concerned about costs so may have to consider doing this myself.
Have done plenty mechanical work and changed timing chains in the past but is there anything I should be aware of with a Jag or an available procedure?
Is there anything else this is likely to be? (Someone suggested air/fuel ratio control and that noise could be pinking, but seems unlikely to me).
Unfortunately I have a pre-existing amber engine warning light emissions condition that I have been trying to chase through from exhaust back to air/fuel control and ECU but not yet solved, so this light was already on.
I also need to buy an OBDll reader but this is separate topic.
Any advice/comments will be much appreciated.
Thanks in anticipation, John

 

It is possible that a tensioner has totally failed and the chain is rattling. Until this is resolved DO NOT ATTEMPT TO START THE ENGINE. You may have skipped a tooth on one of the exhaust sprockets, and if it skips again could result in bent valves. You need to remove the valve covers and inspect the secondary tensioners. There are many threads on inspecting and replacing tensioners. The link below is one of them:

https://www.jaguarforums.com/forum/x...ics-how-52653/

 

Thanks for this RJ237,

I note you refer to the secondary (plastic) tensioners as most likely cause and as suggested have checked a number of related threads. Sounds like my concern was well founded.

As such I will open valve covers and check tensioners, guides and chains carefully before buying full set unnecessarily.

There is a lot of info available out there and although many threads relate to different V8 series engine sizes it seems that the main difference in engine capacity is increased cylinder length, and I assume that the crankshaft/timing chain top end arrangement will be fundamentally similar to my European 3.2 litre version.

What is best way of resetting timing if a chain has skipped a tooth on one of the exhaust sockets? I assume there are adequate TDC type marks to aid resetting.
Regards,

John

 

Adequate timing marks, not in my opinion. To check the camshafts you can rotate the engine with a 24mm socket on the crankshaft bolt, turning clockwise from the front. Just in back of the first camshaft bearing there is a flat spot. The flats on the intake and exhaust should line up perfectly, as determined with a straight edge. If off by more than about 1 deg. They will have to be realigned. Check first one bank, then the other. Do that and inspect the tensioners, then tell us what you observe.

 

The 3.2L Jag V8 has a shorter stroke than the 4L, but the cam chains & timing are the same-it's only the crankshaft that has a shorter throw.

The engine warning light problem may well be the upstream front oxygen sensors-you can get a cheap OBDII fault-code reader off ebay to check these & reset the light. I carry mine in the glovebox all the time...

The quick procedure for checking the timing of the exhaust cam relative to the inlet cam is to make sure the flats on the cam line up. There is a special cam-locking tool used in the official procedure for changing the secondary tensioners. It clamps the cams stationary using these flats on the cams-so the cam timing is correct when the flats line up on both cams. The engine needs to be slowly turned by hand to line them up.

Rough running followed by a clattering sound is a very strong indication that the secondary tensioners have failed & the chain has skipped a tooth. It's also possible that the fault light may have come on due to a skipped tooth happening a while back, before the tensioner failed completely & caused the clattering sound.

As advised above-get the cam covers off before starting the engine again. As a rough guide to checking the cam timing without using the official tool, you can remove the spark plugs & crank the engine over by hand until you see both flats on the cams. Then lay a short, straight edge across them to see if they line up.

I would say that this should be done with extreme caution as a skipped tooth may result in direct piston-to-valve contact, so you'd have to crank the engine over very slowly with all the spark plugs removed, and stop at the first sign of any mechanical resistance.

 

Thanks guys, most useful info but will only have time to open up and inspect next week. I will keep you informed of progress.
In the meantime I keep thinking of extra queries.
I notice from various threads that unless there are signs of obvious damage to the other tensioners and guides many seem to get away with just changing secondary tensioners on each bank.
Assuming only secondary tensioners show sign of damage and chains, guides and lower tensioners look good do you think it safe to take this easier route rather than replace everything?
If I have to buy full set am considering Jaguar Spares Northeast at £195 + VAT + shipping, per this link:
Jaguar V8 Timing Chain Kit - Detailed item view - Jaguar Spares Northeast
Any experience with them or other recommendations?
Red October, I have replaced Lamda sensors and cat convertor but still showing emission problem, which I assume must be upstream of the exhaust system.
Any further suggestions to concentrate upon would be much appreciated as I keep throwing cash at this without success.

 

John, if your camshafts are aligned correctly and you do not see a problem with the primaries, I would go with the zip tie method of replacing the secondaries. Working with a limited budget, as I am, one hesitates to invest in parts that may not be required, to say nothing of the additional labor.

 

Normally it's only the secondary tensioners which can cause the severe engine damage when they fail-so the cheapest option is to just buy the two 3rd-gen metal upper tensioners & the 4 shorter bolts which will be needed. The quick way to change them is the zip-tie method, which can be found on this forum.

The kit you've looked at is also for the primary tensioners & chain guides. It's a bigger job to do all that so for the moment the priority is the secondary tensioners.

Regarding your emissions problems & illuminated Check Engine light, the best method of diagnosis is to get a cheap OBDII scanner to read the actual codes. You can get them off ebay for less than £20 & keep it in the glovebox as it's small enough-I got an Autel Maxiscan MS300 for £17 off ebay. The socket on the car will be under the fascia, in the drivers's side footwell by the transmission tunnel on UK cars.

Literally just above & slightly to the left of where your left knee will be from the driver's seat-the socket points downwards

These cars have 4 oxygen sensors-2 for each bank of the engine. It's normally the upstream sensors that fail as their design uses a powerful heater which runs very hot & can fail with time-usually throwing up fault codes P1646 (driver's side-easy to change), and P1647 (passenger's side & pig to change as it's buried under the expansion tank).

It's usually the difficult one that fails (P1647), probably because it works in a more confined space & so runs a bit hotter.

 

Your trouble code may be caused by a cam jumping a tooth. If you find that to be the case, I would try to set it back to where it was and then zip-tie and replace tensioners and bolts. If you loosen the bolts holding the cam sproket to the cam, then you need to worry about getting the cam timing set again. That's the whole idea of the zip-tie method - to keep the chain on the sproket and to not change the orientation of the sproket to the cam.

 

Thinking about jumping a tooth. What's the problem with removing the caps and shifting the exhaust cam one tooth so that the intake and exhaust line up?

 

Well, that's what I was thinking. While you are swapping tensioners anyway, why not slip the chain back over a tooth so the cams will line up and replace tensioner and bolts and away you go.

 

This is a very feasible suggestion & should work, as it doesn't involve slackening the bolts which hold the cam sprocket to the camshaft.

The only really critical timing setting is the primary chain drive from the crankshaft to the inlet camshaft, as the exhaust camshaft timing is set relative to the inlet camshaft timing. Setting the exhaust cam timing to match the inlet cam timing is relatively simple as you just need to ensure the flats on the cams line up.

 

Good evening everyone.
Feeling very frustrated as I have just spent long time writing detailed feedback on this work and somehow lost it all.

Too late to reconstruct tonight but will provide fuller feedback when everything completed, hopefully later this week.

In brief, stripped open earlier this afternoon, found LHS secondary tensioner completely broken not cracked (managed to retrieve parts from lower down), but all chains, primary tensioner, guides, etc, inspected and looking in good condition. The camshaft flats on this side are obviously out of alignment but don't look slipped by more than one tooth.

Lucky, as on reflection I must have driven over 50 miles with at least three starts after first noticing that tick over was lumpy.

Everything looks good on RHS.

Have ordered 3rd generation metal secondary tensioners and new cam cover gaskets for both banks, and will do basic service while I'm at it, so have also ordered Air & Oil Filters and Spark Plugs. Hope to have everything Thurs.

A few, I hope simple, questions.
1. I notice blobs of some sort of sealant at the join of engine block to chain housing, obviously to seal against oil leaks at this point. Do I need to use anything special for this or can I use a standard gasket compound?
2. Can you tell me what the spark plug gap should be? I assume in the region of 40-50 thou" but only guessing!
3. What viscosity engine oil do you recommend? (5W30, 0W40, or ???)

Many thanks to everyone for all your sage advice.
John

 

You may be one of the fortunate few who caught the failure before destruction.
1. It is best to use high temp silicone seal at the joint of the timing case and head.
2.Spark plug gag is dependent on the plug you use.
3. You will get many recommendations. I use Mobil 1 10-40 high mileage in both of my cars, partly due to a slight rear main seal leak.

 

RJ- If you ever decide to do the cams "right", I will lend you the tools for a fee similar to(or exactly like) a cheap six pack.

 

Hi Gents,

My apologies for delay in updating but a lot has happened over the lastcouple of weeks.

End result is my XJ8 is just back on the road and running smoothly, possiblybetter than ever. About 100 miles of cautious driving so far and all seemswell.

In short here is summary of my saga.

RH Bank A
Removed everything necessary to enable access.
Removed spark plug cover plate, unclipped and removed ignition units, removedspark plugs - oil collecting in wells and dripping into cylinder head.
Removed cam cover.
No obvious signs of damage to secondary tensioner.

LH Bank B
Stripped as Bank A.
Could immediately see problem with secondary tensioner.
Chain tensioning plate broken off and secondary chain very slack.
Signs of chain hitting outer casing.

Used crankshaft pulley bolt to rotate engine carefully clockwise.
No obvious signs/feel of valve/piston collision. LH cam flats definitelyout of alignment but as best I could see chains, guide rails, primarytensioners, etc, looked undamaged.

Used cable tie method and carefully undid cam caps, quite easily manoeuvredcamshaft to slip a cog tooth and realign flats, and replaced both secondarytensioners with new metal bodied 3rd generation/shorter bolts.

Slowly hand rotated engine to check smooth running and cam alignment, andnoticed immediate problem with LH secondary chain/tensioner which was notrunning smoothly.
Closer inspection of chain identified one link had stretched side plate leadingedge causing hole to enlarge allowing chain to distort off centre under tension.

Decided that as long as bottom end primary chains were retained in placeon their drive cogs (positions white marked as back up) I could always realigncam flats, and with extra pair of hands to help tried to juggle camshaft to seeif I could remove primary chain and then secondary without having to stripfront end and remove chain case cover.
Tried every combination but not possible to get enough play on primary, sobit the bullet and stripped front end.

This is the point where everyone will scream.
Having done all the work to get in there I should have replaced fullchain set but had already bought tensioners, gaskets, plugs, filters, oil, etc,and cost is a major consideration when you are running on a tight (pension) budget,so very carefully checked all chains (link by link), guide rails andprimary tensioners OK and made calculated decision to only replace LH secondarychain to save considerable extra expenditure on full set.

Get ready to scream again.
I didn’t have the (necessary?) timing tool set to lock crankshaft, camflats, tension chains, etc, so had to improvise

I rationalised that as long as I correctly aligned/levelled cam flats onboth sides I could retain timing position by locking engine rotation at thatpoint (I wedged a crowbar between the drive plate on the engine and the torqueconverter via the transmission access hole, and white marked sprocket/casingpositions as back up).
I could then remove chains as it didn’t matter where the primary locatedand the secondary could be easily adjusted to restore level cam flats.
I removed tensioners and with a friend helping carefully manoeuvred LH camshafts to remove both chains, replaced secondary, and with a bit of jugglingrestored both chains, tensions and cam flat levels (slipping a cog tooth bytooth until it pulled everything into correct position).
This way I didn’t have to remove the variable valve timing bush carrier,cam sprockets, etc.
A trial and error process but if there are two of you it’s not too bad, didn’ttake long and worked very well.

With this completed and camshaft caps carefully refitted I released tensioners androtated engine by hand. Everything turned smoothly, chains pulled up nicely andcam shaft flats aligned perfectly.

Checked, double checked and closed everything up using new gaskets, plugs, etc, ready to restart.
Now, the moment of truth.
She’d been sitting there for over 2 weeks!
Oil leaked into cylinders when Iremoved plugs!
Reasonably confident in what we have done but what if???

Switched on and she fired first time.
Slight clatter initially but no worse than expected, and as oilcirculated settled to quiet and smooth tick over.
Smoky exhaust which soon cleaned up as the spilled spark plug well oilburned off.
So far so good.

Dashboard warning readout advised that boot (trunk) and door open soclosed both, and was left with readout saying Restricted Performance.
A little alarmed but hoped that the ECU was still stabilising after initialproblem/oil burn off/high exhaust emissions/reset timing, etc, so left idlingfor a few minutes and then drove her round the block.
Ran sweetly at low revs but couldn’t accelerate past about 2800 rpm. Aftera few minutes this readout light went off and she ran smoothly through fullrange.
Stopped for a few minutes, restarted and warning returned but went offwithin a few seconds and hasn’t returned since.

Done about 100 miles of mixed heavy traffic and highway cruising but haven’thammered it, and she has been running at least as smoothly if not better thanbefore.

The only problems during this work were mostly smaller things or of my ownmaking.

1. Oil dipstick tube (LH Bank). The retaining clip is really difficult to remove with very limited access to retaining nut on extended cam cover bolt, and when you finally get it off you have to use considerable force to bend the clip over enough to force it off as the tube doesn’t pull out (short of going into destruct force mode).Once off I split the clip ring to facilitate return,and was able to move the tube sufficiently to the side to be able to work.
2. Plastic coolant tubes (with quick release fittings) across top of LH Bank cover. I found these were fragile and one fitting broke (reservoir to radiator).I removed whole tube and replaced with half inch reinforcedheater tubing held by jubilee clips at each end.
3. Breather tube (LH Bank). This had become brittle and broke at quick release fitting end, and I made short term repair with cooling hose amalgamating tape, but will monitor and replace if necessary.
4. Crankshaft pulley bolt removal. A job for a strapping lad, requiring a surprising amount of force applied on the end of a 3ft extension bar (engine locked as previously described).
5. Crankshaft pulley removal. No universal harmonic balance remover so made what I thought was a very strong tool. Wasted a day bending heavy plate and bolts with lotsa frustrations. Borrowed UHBR from mechanic friend. Removed pulley inminutes (it fits onto a tapered shaft with a slit liner that compresses when pulledtight).The bottom line is don’t improvise in this area,borrow or buy the right tool. Returned UHBR to friend to ensure he remains one.
6. Replacement cam cover gaskets were more substantial than originals, didn’t fit into grooves as snugly and kept dropping out when positioning cover. Had to use high temp silicone to hold them in grooves.
7. Like an idiot I left rag in the spark plug holes when I refitted the cam covers and only realised when I tried to fit new plugs!

Never having worked on a Jag before this was a cautious process. As soonas I opened everything up the chain/tensioner/camshaft relationships andworkings were clear and logical.

Whilst it would have been ideal to have the correct setting tools anexperienced engineer can improvise almost everything, particularly withan extra pair of hands to help.

My thanks to everyone on this thread for their invaluable direction andadvice.

To anyone considering working on an XJ8/X308 with timing chainproblems I highly recommend looking at:

http://jaguar.blackonyx.net/tech/timingchain.htm

This is a definitive grass roots step by step guide with excellent photosat each key point. I referred to this where necessary and it provided excellentsupport for deciding on my improvised actions.

There are many links available for cable/zip tie method of changing secondarytensioners which will immediately identify on any internet search.

To anyone sourcing Jag spares in the UK I received excellent service andassistance from Alex at SNG Barrett, who can be contacted on 0746 765432.
If you don’t know them, they are a Jag Specialist and Authorised Parts Distributor, stocking genuine Jag parts and alternative cheaper OE and Aftermarket parts.
Iordered parts as I identified need and always received them by courierearly the next morning.

Again, my thanks and best regards to everyone.

John

 

Nice update daG. So pleased that you now have your Jaguar up and running again.

 

The only thing that worried me is your method of locking the crankshaft. As to your procedure for replacing the chain, that is further proof that this is not rocket science. All it takes is careful observation and a good dose of logic. I wouldn't have replaced everything, either.

 

would your tools work on a xk8 2001 owned by an old fart EE from texas?
On starting the engine I heard the dreaded noise and now I am stuck on the crankshaft nut part of the job.

 

From my research on this site I believe that both engines and drive trains are basically the same with the main differences being in the gearbox and ECM programming.

However, this is not speaking from personal experience so I recommend that you get more expert confirmation.

However, if they are the same I repeat my recommendation that the most comprehensive write up I have found, which includes good pics at every stage, is:

Tmingi chain and tensioner replacement

This goes into much detail that you don't necessarily need but is most useful in those trickier areas like getting that crankshaft pulley bolt out. From personal experience you will need to jam the engine stationary and use a lot of force on the end of a 3ft long bar.

You will then have to remove the pulley which needs a universal harmonic balance remover, two 8mm bolts with ~60mm shaft length and hardened washers.
This still took some force but came off OK using the right tool.
Try to clean out the two bolt holes/threads as much as you can before using to ensure you get maximum thread grip, but be careful you don't use too long a bolt and tighten it right through onto chain case housing and damage it.
I tried to improvise and make up an extractor but just couldn't strengthen it enough, wasting a day in the process.
Don't try to lever off from the back or you will almost certainly damage both pulley and chain case cover.

As you are doing the full front end strip rather than just replacing the secondary tensioners I assume that you are replacing all of your chains, tensioners and guides, not just your secondary.

If you follow recommended procedures you will need the full cam alignment, tensioner, locking plug, etc, tool set .......
unless you decide to improvise like me, which I found worked well but needed careful forethought and reasoning with two of us to handle for delicate chain position and camshaft adjustment.
I wouldn't recommend this unless you are confident in your own abilities.

Whilst I am happy to share my knowledge/experience, if you need further specialist or detailed input you will get a much better coverage by starting a new thread.
Good luck.
John