Hey,All

I have a 1999 jaguar xj8 VDP.I changed left side secondary tensioner three weeks ago,and got noise(when started it ,got 50 second sound,then gone,but after the car getting hot,noise come back).I locked down the cam flats,but I didn't lock the flywheel.did it cause the problem?Need you guys help!

 

I would bet yes. Assuming everthing else is right, I suspect you have mistimed the cam.

 

If I had mistimed the cam, how can I adjust them? Intake cam can adjust? how?or I have to move exhaust cam.What is VVT position when engine stop?

 

You need to read and follow the timing chain setting procedure. Look inthe faq section about 1 screen down:
https://www.jaguarforums.com/forum/s...ad.php?t=20090
If you have questions before, or during check back. Plenty of experience on here on this topic.

 

I am getting set to do the same job.

I did not plan on locking down the crank, just leave it in park and put on the brake. As I am only doing the secondary tensioners and chains, only the valve covers come off as I understand it. If so, how would you lock down the crank in this condition?

I got the chains with the missing link... and the link with the clip.

I see a fellow renting the lock for the cams on ebay for $75 (3 weeks). I have access to a welder and was planning on cooking up my own. Any advice in this area?

Thanks!

 

Tomjagxj, I thought a bit more about your description, and the only thing that comes to mind is that one of those tensioners may have been defective. If the car is not running rough (and I think you would have mentioned that), then I doubt your timing is off. However, these tensioners are hydraulic, and yours may be bleeding out overnight, and it takes that minute to pump it back up in its defective state. When it gets hot, the oil is thinner and if the unit is defective in maintaining pressure, it would lose pressure at that point and the chain would contact the guides and make noise. Perhaps a good amount of noise.

I am a Jag newbie, but have owned a Lincoln LS with this motor for some time. I love it in the LS, and it has been trouble free (knock on wood) and running strong at 140K miles. I have no direct experience with this issue (yet), so this is only my WAG, but thought I would throw it out there. Sometimes parts are not good, and you don't know unless you test this with a proper test rig, but stuff does happen. Maybe "just" a bad part.

 

While I did lock my crank I cannot see that it is really necessary as long as the cam flats are locked down. The relationship between the intake and exhaust cams is the only thing you are disturbing.

Did you use the shorter bolts required for the metal tensioners? The bolts used with the plastic tensioners are about 1/8" longer and bottom out before you have a good seal at the tensioner oil port.

Here is a link to a thread that has the dimensions of the cam locking bar:

http://www.jag-lovers.org/snaps/snap...?id=1242243983

Why only one side?

 

The problem is with chain slack. If you locked the cams and assured that you did not move the crank at all, and was careful to pull the primary and secondary chain slack up in the right direction, I would agree. But I do not see how you could be sure of all that practice. I do agree the mounting bolt dimensions are a concern.
And I am in disagreement with many posters on the issue of not worrying about the VVT being in it's unadvanced position while tightening the chains. It naturally should go to that position due to the spring, but the manuals clearly define a procedure for biasing it to that position, there is a tool called out to do it, and as I recall on my MY 2002, there is the possibility of moving it off that position as you tighten the sprockets.


BTW, on the 2002 ecu, I believe you can read the cam timing feedback position on autoenginuity. I haven't looked at wds, but I assume you can read it there too. I do not know if earlier year models AJ27 engines support this feature or not.

 

Thanks guys.I made my story too short,in fact I changed two tensioners on this side.First one I put in(with short bolts) totally no working.I pulled out and found it come to parts,I think it's a bad one,then I asked the shop(they order the tensioner for me),they told me the part is ok,maybe I didn't put some oil in it first.I install it again with oil,but same thing.I open my cover again and get it,I bring it to the shop ask them change one for me.They don't,they still think it's good one,maybe I made a mistake.They said I have to buy another one, if new one working fine then they can return my money(ca$120).No choose,I bought another one and put in and it's working like that,much better.I used the tools were made by myself ,they are pretty good.I thought about oil too,I put 1.5L Lucas in for increase oil pressure, not work,do I need change oil from 5w30 to 10w40? The car runs smooth and just has 90k kms on it. Any ideas!

 

IMO, it's a mistake to try to mess with the camshafts without locking the flywheel. (A mistake I made myself.)

Here's a link to my fiasco:

https://www.jaguarforums.com/forum/s...ad.php?t=49955

There's probably nothing applicable to your situation till post #11.

The only thing I didn't include regarding my solution was how I got the sprocket bolt loosened on the mistimed camshafts. Basically, it required that I carefully shim the flat on the offset exhaust camshaft flat so that the camshaft lockdown tool took the bolt torque load rather than the chain. I was pretty careful also to avoid allowing the aluminum lockdown tool to directly take pressure from any of the sharp edges of the camshaft flat.

However, once you get the intake camshaft out of the picture, it's a direct timing connection from the crankshaft to the exhaust camshaft sprocket which makes things easy from that point... timing chain tensioner mandatory.

I finally took the car for a test drive today because it was the first day that wouldn't involve driving through mud and slush. Took the engine almost up to 5K rpm, and it was as smooth as could be. Of course, it's possible that the valves are smoothly burning up, but I take comfort in not hearing any nasty noises, to include the engine seizing up.

I'm curious about your tensioner bolts... test point's comment about the length should be paid attention to. [edit: oops, started composing reply before your last post; posted after you did]

 

FWIW, I don't know if this is your problem, but if you're concerned about the camshaft timing, this would be a way to work your way out of it.

 

Hi test point - this is what I thought too, but this is what I found out the hard way: when the crankshaft is not locked, and the exhaust camshaft sprocket is released, there's nothing holding the engine in any particular position, including the locked down intake camshaft. The reason is because the VVT mechanism does not lock the intake camshaft sprocket to the intake camshaft... the whole chain system is essentially floating free of the camshafts at that point.

I don't know that anything moved while I was installing the tensioners, but when I went back to check on the exhaust camshaft timing after locking the crankshaft, I found both sides out of timing, the left side by a little, and the right side by more.

So I agree with you... the job should be quick and easy and shouldn't put anyone off, but everyone should do what you did: lock the crankshaft before doing anything else.

 

So, if I read all this correctly, the XJR won't have this issue, as there is no VVT on that model. I do not see a reason to lock the crank, if in park and brake applied. I spoke to a parts guy at Motorcarsltd in Houston, and he said the only tool required was the cam lock, after discussing with his techs (they sell parts, tools and do service). It seems if the cams are locked, the tool will take all the torque, not the crank shaft. Once I get the old ones off, I put the sprocket back on, put the chain on, and re-assemble.

I got the chains with the masterlink. I plan on eyeballing the existing chain to determine which side the slack was on, and the duplicating that with the new chain.

Am I courting disaster with this XJR? Thanks for the help.

 

If there's no VVT then I don't see why your plan wouldn't work, but that's assuming everything else about the engines are the same, although I'm not sure that eyeballing the chain for slack is something to depend on.

 

You're a gambler, right?

Do yourself a favour and spend $10? on the lock tool for the piece of mind.

 

Sean, point noted, but yea, all my life. Risk taking is unavoidable, and I don't have a garage full of specialty tools. The tool looks to be over $40, and while that is not a lot, this job just keeps adding up. I know, what did I expect when I bought a Jag? I have done DOHC head jobs in the past, always seemed to manage.

Still, if you know where I can get one for less, I might reconsider!

 

Well. line up the hole and clamp the flywheel with a C clamp.
Folks whom I generally respect opinions from are apparently adament about not needing to set all the positions per the manual, so I have to wonder about my assumptions BUT I am pretty sure I am right, none the less. I ask those who say that you do mot need to "unwind" the VVT and lock the crank a few simple questions to help me understand your position on this.

Are you saying, the VVT cannot move itself from the maximum retarded position while you have the cams Locked in position? If that is true, I concede your point, if that is true. BUT, why can it not move?
If your contention is that it is not important for the VVT position to be at retard when the sprockets are tightened, then the VVT position is indeterminite when the relative cam to cam position is locked (by the tools). If the VVT position is indeterminate, then the cam to cam position is indeterminate with respect to the VVY position when the tool is removed and the cams are not correctly timed.
Inquiring minds ...

 

With respect to the engine I worked on which most definitely had a VVT (apparently unlike michaeldeanrogers' engine), my position is that you DO need to lock the crank and DO NOT need to unwind the VVT when timing the exhaust camshaft (assuming nothing was unfastened on the intake camshaft). I can explain it if I'm one of the folks you're questioning.

 

Ross, not sure if this is directed to me, and am a bit sheepish as I inserted my car into a VDP thread, but the XJR does not have VVT, so I THINK the point is moot. I am saying that with the cams locked on an XJR (can't say on anything else) there should be no force put on the crank when removing the cam gears to remove the old chain, or to re-install. As a new guy here, I really don't have much credibility, and though I have worked on my Lincoln LS with essentially the same motor a fair bit, I don't have ANY Jag experience (and none with these timing chains).

So I take your heads up very seriously, and will look into this further before doing anything. Thanks for the warning, as I have a history of doing a job twice... once to learn what I am doing, the second to fix what I screwed up. Then I am an expert, never to do it again!

 

I am not sure we are even arguing the same point.
My hypothesus is- To set the cam timing (on one side) on a XJR, it is necessary for the crank and both cams to be at the correct absolute positions. It is further necessary that the primary and secondary chains be pulled up tight on the tight running side. We need all of these things to be true after we have tightened the sprockets to the camshafts. Do we agree on these points? If we do, we can argue the best / easiest way to do that. If not, well...
Now, for the NA engine, we further need the VVT to be in the retarded position at the timed position. Right?
If I am wrong, please explain.