I've taken on the tensioner replacement challenge, and am currently in the process of pulling out the little hair I have remaining. I've rebuilt a number of engines over the years, so this task seemed pretty straightforward, but there have been some complications I did not foresee and hope that I can get some guidance here.

I decided to go with the the manufacturer's recommended replacement (JTIS) procedure, but wish that I had just removed the exhaust camshaft while keeping the timing chain engaged... I'd be done and driving the car by now.

After reviewing the JTIS procedure and this very helpful thread on the Jaguar Forums ( https://www.jaguarforums.com/forum/s...ead.php?t=4747 ), it seemed pretty clear to me (perhaps wrongly) that aligning the timing mark on the flywheel was pretty secondary to the process, and that if I aligned the flats on the two camshafts, things would be where they needed to be and locking down the camshafts would allow me to get the job done properly. I was somewhat encouraged by the statement in the manual after the part about installing the crankshaft setting peg, "install the camshaft locking tool to camshafts, aligning the shafts slightly as necessary." I mean, if you have to adjust the camshafts anyway, why not use them as primary for this procedure?

So after turning the engine with a wrench on the crankshaft pulley bolt, I was able to get the left hand bank camshaft flats aligned. It actually took a number of rotations to get it so both flats were perfect because a number of times, they were off by a few degrees... plus the VVT assembly would sometimes shift the intake camshaft significantly. Anyway, I got a turn where the flats aligned, so I locked them down and replaced the tensioner, unlocked them, and buttoned that side up.

Same procedure with the right side, but much to my dismay, when I unlocked the camshafts, they rotated forward a few degrees. Just to double-check my work, I tried to rotate the engine until I got the flats aligned again, but they always seem to be a few degrees off from each other now. It wasn't obvious to me earlier, but it seems as if the camshaft lock only locks the exhaust camshaft sprocket... the intake valve sprocket can move when the intake camshaft is locked due to the intervening VVT mechanism.

So, I thought I'd try to time the system from scratch by finding the timing mark on the flywheel and working forward from there. Unfortunately, I've watched the flywheel go around many, many times and have yet to see the triangular arrow indent that's supposed to be there. It's almost impossible to see the flywheel through the access hole, but with the help of a mirror and someone else to turn the engine, I was able to inspect the flywheel closely. Makes me wonder how they timed the engine at the plant. As an aside, the manual diagram shows a hex head bolt holding the timing sensor in place, and my car has a nearly inaccessible torx head bolt. (Just mentioning this as another (albeit small) difference from the manual along with the apparent missing triangular timing mark.)

So, basically, I'm wondering how bad off I am, and if I need to take corrective measures, what should they be?

For the record, both original secondary tensioners looked to be in tip top shape, but I'm looking forward to having the opportunity to drive around without thinking about them anymore. Any insights that can be provided will be greatly appreciated.

Thanks,
Tim

 

OK, Tim
Take a chill pill. Basically, what you are probably missing is that there is some play in the timing chain system. You have to pull up all the slack on the primary and secondary chains to the "slack side". In other words, when the engine is running, the chain is tight on the side that the crank pulls the cams. So, the procedures are to mimic that effect, and tighten the cam bolts in their proper position relative to the crank, WHILE the "tight side" of the chain is tight. Now, add the complication of the VVT, as you have figured out. It must be in the "non advanced" position. while you get the chains tight then tighten the sprockets. I am just going through all that to try and define WHY the procedure is as it is. As to the peg in the hole, I suspect you have an AJ27 engine, and the pickup is mounted differently from the AJ26. It also has no triangle, as shown on some AJ26 procedures. you should find the special hole at approximately the point where the cams show flat. It happens every turn of the cams. In fact, it happens twice per cam turn. Just turn the engine by hand, slow down just before your cams show flat and look for the slightly elongated hole.

Pay attention to the procedure for holding the VVT in position.
Have a look at the files JaginBlack posted :

https://www.jaguarforums.com/forum/s...ad.php?t=48932

Look down the thread for his second posting of several links.
The ''winding the VVT'' is explained in detail.

So, I think you need to take a deep breath, approach the beast with confidence, and vanquish the foe! Good luck.

 

Hey Ross, thanks for the moral and technical support.

No worries... just had to vent (I had just snapped off the coolant return hose from the radiator (the one that goes to the expansion tank) when my wrench came off the crankshaft pulley bolt and I fell into the engine compartment. )

Will take some time to digest this, but can give you immediate feedback that it should be an AJ27 engine (2000 model year), that I did tension the secondary chain, and that I'm not sure I want to take off the timing cover to wind the VVT. Will post progress and questions as they develop.

Thanks again!

 

Tim:
I did not remove the timing chain cover on my MY 2002 when I did mine. I just do not remember what I used to hold the front of the VVT in place whilst tightening it. Hopefully Gus or Brutal or someone who has done a few will chine in. As to the coolant hose, I have broken several. In fact, I believe there is still a "temporary" rubber hose section with two clamps on either side still on my wife's car!

 

LOL.

Ok, I have locked the flywheel in place. Your insight to the AJ26/27 difference was a key revelation for me. FWIW, for others who have yet to do this, another difference between the AJ-26 diagram and AJ27 configuration is that the flywheel position sensor is on the opposite side of the access hole on the AJ 27 as compared to the AJ 26 diagram.

The intake camshaft is now slightly advanced, as might be expected of one that hasn't had its VVT wound back to the fully retarded position. I cannot see any way to do the wind without taking the timing chain cover off, because the assembly that's bolted on the end of the VVT mechanism (which also holds the solenoid) only has 1/8" clearance from the inside of the timing chain cover, and the diagrams indicate that there's a part of it that goes significantly farther than that into the VVT mechanism (where one would put the wind up tool).

How does the following sound for a work around procedure? With the flywheel locked in the proper position, the camshaft sprockets should also be in the correct position. The absolute position of the intake camshaft flat is not critical, but with the sprockets in the proper position, I can loosen the exhaust camshaft sprocket bolt, move the exhaust camshaft flat to the proper position, and retighten, ensuring that the secondary chain is properly tensioned.

The intake camshaft flat is only slightly out of position, and I believe I can shim between the chamshaft flats and the lockdown tool so that things are held with an even force.

 

Did I miss something?

I just locked the flywheel, locked down the cam flats, removed the exhaust sprocket, changed the tensioner, tensioned the chain and tightened the sprocket bolt.

Didn't mess with no stinking VVT winder. Shouldn't the VVT be in the correct position with no oil pressure on it?

 

I may have introduced a problem by not locking down the flywheel for starters and just locking down the cam flats. That being said, now that I do have the flywheel locked, the intake camshaft flat is 10-15 degrees away from where it needs to be to be locked down... and there's no way anything I've done to this point would have caused that. So it comes back to the VVT.

Tim

 

I ended up using my workaround on the right side, then went back and redid the left side. Just for insurance, I cranked the engine two turns by hand to ensure nothing would collide with anything else inside, then started it. Seems to be running like a top.

Will try to post a couple of pictures later this weekend showing the shim arrangement. And if I run into any problems down the road, I'll report back.

Ross... thank you for your help.

 

testpoint:
I believe the only thing you missed is that if you are not carefule, you can move the vvt while tightening it. But if you lock the cams, lock the crank and tighten the cams in the right order, I THINK that should not happen.

 

Referring to an earlier comment about winding the VVT without taking off the timing chain cover, I've attached a picture showing that area. The assembly that holds the solenoid and goes into the front of the VVT mechanism (don't know its name) has very little clearance with the cover. I could see no way to pull it out, given that there's a part of it that extends into the VVT mechanism and would pin the whole assembly in place. If I was desperate, I might have given it a try, but I had the workaround I thought would work (and I didn't have a windup tool either).

The sprocket on the intake camshaft for the primary chain is an integral piece with the sprocket for the secondary chain, meaning the exhaust camshaft sprocket has for all intents and purposes a direct connection with the crankshaft. Bottom line here is that if the flywheel is in the right position, and the VVT is not messed with (and I never touched it), the exhaust camshaft can be timed with no concern for the position of the intake camshaft.

See the next post for the actual workaround.

 

Since the intake camshaft was not lining up properly because of the VVT and I didn't have a good way to adjust it, I did my exhaust camshaft timing while bypassing the intake camshaft.

The main problem here was that since the intake camshaft was in an advanced position, the flat was not in the right place and the edge of it was higher than the exhaust camshaft flat. Therefore I could not tighten the camshaft lock tool down the way it needed to be.

To get around this problem I took a sheet of plate aluminum, 1/8" thick (something I had lying around), and cut out six shims roughly 1" x 1/2" in size. I stacked them in pairs and taped them together, leaving a long masking tape pigtail so the shims would not end up somewhere they didn't belong. This left me with three 1/4" (nominal) shims. The thickness can be adjusted to need, depending on the degree of offset on the intake camshaft flat.

Referring to the picture, I put one shim under each end of the locking tool, and one between the tool and the exhaust camshaft flat (you can see this third one peeking out the right side of the tool on the camshaft). I could then tighten the tool down, assured that the exhaust camshaft flat was properly restrained.

This involved more hands than I had by myself, so a helper was invaluable. It also involved having to turn the exhaust camshaft with a very large set of channel lock pliers to put the flat in the right orientation. (The valve springs are beefy enough that this took a bit of strength and effort.)

If you happen to look closely at the photo, you can see a deformation of the locking tool above the intake camshaft flat. This was present when I got the tool and was completely incidental to the whole operation... the tool never touched the intake camshaft.

With the exhaust camshaft locked down tightly, I was then able to tighten the bolt for the sprocket (it was loosened at the beginning of the operation using a slightly different shim configuration with the lock down tool). Pulling on the tensioning tool simultaneously tensioned the secondary chain and the primary chain, since the pair of sprockets on the intake camshaft are a single unit. While holding the tension, 120 Nm of torque was put on the sprocket bolt, and presto, the exhaust camshaft was timed.

After redoing the other side of the engine and buttoning everything up, I was able to start the engine. I let it idle and revved it a bit as well, but won't be taking it for a drive until the replacement expansion tank hose arrives. Overall, I'm pretty comfortable with where things stand, but will be very attentive to any clues that indicate things aren't quite right.

 

For all those contemplating replacing their own tensioners please ignore the previous post and see post #6. It is not that hard.

 

I'm glad it worked out so well for you.

I'm sure that most of the time the procedure is simple and straightforward, but I managed to get myself into a bit of a pickle. Since I got into the situation and asked for help online, it seemed that to be a good citizen I should post what turned out to be the solution for me.

Hopefully, no one will ever need to use this solution, and will be fully satisfied with the thread I linked to at the beginning of this thread if they have the misfortune of happening upon this one first.

As a side comment, I wonder how often people run into the same problem I did. The camshaft locking tool I rented was significantly chewed up on its camshaft flat contact surfaces, just as if it has been tightened down multiple times when the intake camshaft flat was out of alignment.

 

Yeah, I did mine also.... wasn't that hard. This is definately the hard way to do it :-)

 

Lol. And I was thinking it was the easier way compared to tearing the front end of the engine off!

FWIW, the left side went as slick as you guys said it should, but when I went back to check it after my right side fiasco, the exhaust camshaft was a few degrees off. I needed to do a little shimming to loosen the sprocket, but no shimming to tighten it back up.

Consider it a cautionary tale to lock the flywheel before doing the job. If that step is done (as it's supposed to be--my bad), I would expect it to be easy as you say and anyone contemplating the job should not be put off by my little detour.

 

If I remember correctly the way you went about it was the first version of the "offical" jaguar procedure. Later they came out with the revised procedure using the cam locking tool etc....