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
my catalyst for this job was two-fold,
firstly , i had minor oil leaks from a few places on the cam cover along with the spark plug wells 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
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
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 bolt and washer
BOTH pairs of 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
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
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....
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
BB ( have already sold on the tools to another Jag owner who has also now done the job himself ......third time so far.....)