hi,
cant help with VVT issues, but if you are concerned about the cam sprockets id like to suggest the following.

My belief is that the sprockets have to go on a certain way. this is I think because the centre is tapered so when the bolt is torqued they lock on to the camshaft.

staveeasy

 

I can't work on it till the weekend anyway. but i will check for any taper in the cam sprockets that may tell me which way round is correct for locking in to the camshafts.

XKRacer you must have posted your kind offer yesterday while i was still writing my waffle below it, hence the lack of a prompt response.

Was i correct with regard to the phasing in so far as lining the sprocket centres up level on a lateral line with the secondary chains fitted, and if the teeth on the sprockets are out of phase, the chain links will keep their orientation through fitting and tightening?

From the sizes of the VVT and cam sprockets it looks like about 2 to 1.
IE: the VVT turns 2 teeth for each tooth of movement in the cam sprocket.

And i saw no mention in blackonyx's article with the XJ8 about retarding the VVT's, with or without a special tool.
Do i need to get this tool and retard them?

Are the VVT's and cam sprockets interchangable for each bank?

And lastly, is it right that i don't need the backing plates from the old primary tensioners when fitting the new tensioners?

I guess the above is a summary of everything i'm not sure about.

 

OK Here goes.... 1st don't worry about loading up the VVT, you dont have to, they only load up so to speak at around 1300 rpm they are in there natural state and can be bolted on and off accordingly, in theory it should not matter if you have swapped the sprockets over they are both the same but like most including myself when an engine has run for so many miles, it beds itself in and you like to put things back where they came from but like I said should not really matter. Using the C spanner with a ratchet in the square drive load up the chain, then you need to tighten the VVT on torque up to 120-125nm, you then , but you do this the opposite way the spanner would seem to work, this is why you often bend them and then torque up the exhaust cam sproket to 120-125nm

You will not require the backing plates

 

I just tried ringing you XKRacer, although it's 8:30pm and i didn't realise it was a shop i was ringing
I'll try again tomorrow.

I thought the VVT's advanced something as the engine warms up or the revs rise, so i would imagine i'd need to "unload" (retard) them.

I also thought that the c spanner was held still with a breaker bar in it's square slot while i torqued up the VVT bolt, which i don't think would bend it.
And i assume that "loading up" the chains means putting tension on the drive side of them via the sprocket tightening procedure.

With the phasing of the sprockets, i didn't explain myself very well.

What i meant was, to take the sprockets off the car, get a piece of flat board or wood, and draw a line on it with a pencil.
Then make sure the pencil line passes through the middle of the hole in each sprocket with the secondary chains fitted ( to make sure the sprockets are level, or "in line" with each other).
If one of the cam sprocket teeth points in between two of the VVT sprocket teeth while both sprockets are level with each other, and the chains are fitted, the theory is that i should be able to fit them as a 3 piece unit, and they'll be out of phase as they should be.

Just a novices idea of ensuring the sprocket teeth are out of phase, and i've got no idea if it would work.

As i said, i've give you a tinkle tomorrow

Edit:

I think you may be assuming i have a greater degree of familiarity with mechanical terminology than i am actually in possession of. Hence my continuing cluelessness.

 

Hi this is leroy1. I have a 02 xj8 107xxx my tensioner on the passager side broken made the chain jump on the exhauts cam how do i set it back in time it still run but run rough in idol. Code p0301 p0302 p0303 p0304 p1000 p1316. Chang tenisioner but timing is off do you have link that i can print out the timing guide

 

Hi Leroy,

to set the timing you'll need some "special tools".

You can see them in the first picture.

The little plug at the top left is the crankshaft setting tool, that goes in the hole normally occupied by the crank position sensor, which is under the car, back of the engine and centre, in the forward face of the flywheel housing.
It locks the crankshaft, so you can set the timing of the camshafts in relation to the crank.

Bottom left is the camshaft setting tool, which will fit into slots in the exhaust sprocket and hold it still, with the chains and tensioners in place, while you tighten up the sprocket bolt.

On the right are the camshaft locking tools, which will line up with flats on the (forward-most) cam lobes of each cylinder bank, and hold the camshafts in position.

I'm in England, and you are in the states, but the guys in America seem to be able to hire these tools quite easily, so no doubt someone will tell you where you can hire them from.

Once you've got them. with the crank setting tool in place, you'll need to remove the valve covers, undo the exhaust sprocket bolt on the bank where the tensioner failed and remove the sprocket from the secondary chain.
You can then put the bolt back in and use it to turn the camshaft to line up the flats.
Having done that, lock them in positon with the tools, put the sprocket back in the chain and refit it.

The second and third pictures show the camshaft locking bar in position on each bank, behind the sprockets.

Then you use the camshaft setting tool (with the hooked end) to hold tension on your secondary chains while you tighten the exhaust sprocket bolt.

If you've had a chain jump a tooth and not do any damage, you've been luckier than many, and if one secondary tensioner has failed the other one will likely do the same shortly.

I'd change both tensioners, or next time you could trash your engine.

That's the basics, others on this forum may give you more, and better, advice shortly.

 

A few more things.

Don't even turn the starter again until you've fixed it.

If the chain has slipped one tooth it could slip another one, and the secondary tensioners are there to take slack out of the chains when starting.
These are interference engines, meaning the valves and pistons occupy the same space in the cylinder, but at different times. . .normally.

The next sound you hear if you try to start it, could be your engine going crunch.

I kid you not, you are tempting fate to even turn the key before you've fixed it.

XKRacer was kind enough to answer my questions by phone, so if you read my second from last post where i asked about VVT sprocket/exhaust sprocket phasing, it's not an issue when changing chains and tensioners.

The phasing issue is with the VVT sprocket and INLET cam sprocket, but the latter is attached to the back of the former, and their phasing is locked unless they are seperated from each other.

Seperating them would only be done in the event of a VVT issue, or inlet cam sprocket issue, such as renewing one of them.