i changed my timing chain tensioners yesterday

[Brakebuster]

yup,

after sourcing all the right tools for locking off the cams , and the crank pulley remover along with the flywheel ( torque converter ) locking tool , and after buying all the right parts from my local Jag dealership including all new gaskets for the cam-cover ( outer seal, spark plug seals , bolt seals , variable cam sensor sealing ring etc etc ) i plucked up the courage to take the engine apart
http://www.talkphotography.co.uk/galler ... 4a87_3.jpg

my catalyst for this job was two-fold,

firstly , i had minor oil leaks from a few places on the cam cover and the variable sensor seals, i didnt like this at all

secondly , the tensioners them selves, as they were an unknown quantity and i had just reached 90k miles in my 1999 Nikasil engined XJ8 Sov ( successful blow-by test recently carried out 19ltrs/ per something or other ?? )

with spanners in hand i removed all the cover trims and the spark-plug coil covers on both cams, and carefully replaced all the bolts back in their holes as not to loose any ( i did this all the way through he job), removed the coils and wiring and tucked out of the way , and proceed to remove the cam-covers , was a little surprised at having to guide the cover up and over the cam sensor on the front of the engine, the seal broke away as i did it, all the rubber/plastic seals were flat and pretty much U/S , thats why i had a full new set ( £78 ), did this on both sides
http://www.talkphotography.co.uk/galler ... Small_.JPG

once all the top is removed you can easily see the secondary timing chain tensioners, they are the orange parts in the pictures, they start off as white, but with the oil and the heat they go orange and deteriorate and eventually split or loose a slipper against the chain
http://www.talkphotography.co.uk/galler ... Small_.JPG

i then proceeded to set up the cams, this is done by turning over the bottom crank pulley by hand with a 24mm socket an a large ratchet , i did this until i reached TDC and the two pairs of cams ' flats ' were parallel to each other, this was checked with a steel straight edge ruler , once in this position i installed the locking tools and bolted them down very tight , while remembering it was into aluminium!!!
the picture below shows the cam locking tool, with the sprocket spanner and a 10mm Allen key for removal of the sprocket nut and washer
http://www.talkphotography.co.uk/galler ... Small_.JPG
BOTH cams MUST be locked off together, as any movement is fatal to the timing ,

undo the two 8mm bolts holding down the old tensioner,

the exhaust sprocket can now be removed , the bolt is very long , and be sure not to drop anything down the covers !!!

while holding the sprocket and chain in one hand, remove and lift out of the way and remove the old tensioner, then drop in the new tensioner and replace the sprocket onto the cam shaft , screw in the cam bolt hand tight at this point, straighten up and fix down the new tensioner , then remove the spring retaining pin to tension the chain , then tighten the sprocket bolt to 70 lb feet with a torque wrench

do the same on the other side, ensure everything is tight and then check again , and then when feeling brave remove the cam locking tools , nothing should move at this point
this picture shows the new tensioner fully in place and tightened up after removal of cam tools
http://www.talkphotography.co.uk/galler ... Small_.JPG


now for the results ...........

the original tensioners looked fine in place, but when they came out i could see that all the work was worth the effort ,
the right bank one had a 1mm split starting on it, but worse then this the bottom ( spring ) slipper was severely worn and gouged out, showing ' bubbles ' in the original plastic moulding wearing through
http://www.talkphotography.co.uk/galler ... Small_.JPG
the left bank one showed hardly any wear to the slipper, but the shank had a 4mm split in it ,
so all in all a top job methinks, the new aluminium tensioner can be seen in the background ,
BTW, the new tensioners require four new SHORTER bolts to fix them down, and £0.96 each....
http://www.talkphotography.co.uk/galler ... Small_.JPG

it took me four hours on Saturday to strip the engine , and four hours on sunday to complete the job

all the mating surfaces were cleaned of oil and old gasket, and the engine was put back together,

i then ( with heart in mouth) turned her over to see if it was asucess ?
voila!!( sp ) she lives, muhahahaha

drover down to bristol and back today , very gingerly with the radio off, lol

but not a beat was missed

new oil next week and a new water pump and thermostat to fit

BB ( anyone want to buy the set of cam tools from me ??? )

[D_Doran]

Fantastic job, and a very thorough review with pics.

[xk82002jaguar]

Good Job and great pics. I will be doing mine in the fullness of time, my XK8 has only done 46K though. I will only be changing the secondary tensioners too. Might give you a shout when the time comes if you want to sell on the locking tools.

regards
Mick

[jagdaveh]

Planning on doing my tensioners in the next couple of months - should I do the whole job (secondaries, primaries & chains) or just go for the secondaries?? Obviously I'm interested in the tools: how much?

[Brakebuster]

reasons for changing all the timing chains and both sets of tensioners or just the secondaries can depend on many things, but the most important one is the condition of the upper ( secondary chain ) tensioners to start with ,

if they are in deteriorated but essentially ok condition, then just replacing them will be ok,

however

if they have lost a slipper it means that metal has been rubbing on metal and the chain will need replacing, and the part that fell off the tensioner will be in the bottom of the front case and will need taking out,

this means taking off the bottom crank pulley , and will need a new seal to re-install. and 24 bolts to take the front off the engine, the tools i have will do the whole front off the engine job, and actually has the bottom pulley removal tool,

you will also need a 10mm allen key socket with a torque wrench that does 70 lb feet for the uppers and 370 lb feet for the pulley , and a decent socket set

the job should take no more than eight hours to do carefully,


as for the tools , pm me off board, they will be resonably priced, and cheaper than getting them from Jaguar, and you can sell on again , if required

hope ths helps

BB

[mike020150]

Great description and pics! Mike.

[vinniexkr]

Hi,
Great Article,

I have just bought a 2002 XKR and wondering if the same problem will happen to mine , and if it does when should i get them done.

Best Regards Vince

[mike020150]

If you have a 4 litre car and there is nothing in the service history to indicate that the tensioners have been changed for the 4.2 litre versions you need to have the job done. It's a lottery as far as the earlier versions of the tensioner are concerned. There is no way of knowing if or when they will let go. What is certain is the cost of a new engine if it happens at speed! Mike. Ps It's quite therapeutic. Despite the cost of the job you will sleep easier afterwards.

[painter]

very brave and great photos. Job done. I think for me it would have taken 8 days. Can you access the VVT's whilst doing this work? they were pointed out by dealer today as the most likely cause of a noise on startup after cold for several days, and I nodded knowingly, but not fully appreciating where they hide. I assume they adjust the valve timing under differing throttle openings (or revs?)

[mike020150]

The VVT units can fail and have been known to produce odd noises. The units are mounted on the front ends of the inlet cams and use oil pressure to impart a twisting motion to the camshafts to change the timing. Needless to say, it's the engine ECU which gives the orders to open the valves controlling the pressurised oil feeds to the units. Mike.

[rogerpalin]

Hi,

Thanks for the very helpful post. Have just done my tensioners - replaced second generation fitted to a 96 XK8. One slight concern (since the engine won't start!) It looks as though the tensioners can go on either bank, so I have assumed that the spring loaded bit goes uppermost on the B bank (passenger side with oil filler) and facing down on the A. This would seem to fit with the cams rotating clockwise seen from front of car. Is this correct?

[Brakebuster]

the tensioner do mount as you state,

however,

they are not the same , they are handed and should be fitted as such ,


to be honest it would be very hard to put in upside down, as the bracket shouldnt fit

did you use the newer shorter bolts to fit them with ?

did you ensure the timing wasnt moved ?

did you pull the ' red pin ' to tension the chains after the tensioner was fitted , but before the exhaust cam sprocket was tightened ?

did you remove the fly-wheel locking bolt after finishing... ?

have all the sensor plugs been put back properly ?

did you break any of the vacuum hoses on the top of the cam covers ?


try cranking the engine over by hand by the lower pulley using a large spanner, if it moves freely, then you have a vacuum or electrical problem,

good luck

BB

[rogerpalin]

Thanks very much for the comprehensive checklist! Looks like I got 5 out of 6. Completely forgot to lock up the crankshaft

Will get the timing reset and hopefully that will be it.

[rogerpalin]

Timing checked out OK - I guess you don't need to lock the crank unless you are disturbing the main chains

Engine was just flooded so disconnected fuel pump, dried out plugs and dribbled a bit of engine oil into the cylinders. With a freshly charged battery it started OK.

Definitely worth doing though - one tensioner plastic body had a crack about 3mm long in the same spot as BB's, so looks like these second generation tensioners have a definite design fault.

[Brakebuster]

good news,

you are correct about the crank bolt, but if the main chains are being removed you MUST use the locking bolt,

as for the flooded engine, its a common problem, and especially if the battery is getting a little weak , this can happen if the boot or doors are left open for any substantial time, and you have the radio on while doing the work on the engine etc, lol

there is a genuine Jaguar starting procedure for just this problem, but a fresh or new battery is required.....

start the car as normal, but floor the throttle pedal and keep it there till the car splutters to life , this can take quite a while,

by flooring the pedal your telling the ecu to stop fueling during the initial startup procedure, but keep cranking and firing, until the cylinders have been cleared of unburned fuel, things should go back to normal after this..

one other problem is the cylinder bores can become ' washed ' with petrol, making the oil wash away and loosing some compression temporarily,
the above starting procedure deals with this scenario to

BB