Cam Timing
 

I have read several articles in preparation for checking timing on my car. I think I understand all that's required but the one thing I've not found. If timing is off how and when do I align cams to install blocks?

Blocks?

Pull up a thread on replacing the tensioners.

Lock the flex plate though the sensor port.

Observe the cam flats. They should be parallel. If not, the alignment will need to be adjusted but that is not a common problem. Due to cam pressure the right side will be slightly tilted to the center of the cams. Left side should be close to parallel.

If not aligned, loosen the 10mm Allen bolt on the exhaust cam while locking down the cams with the Jaguar special tool. With the flex plate locked in place and with the cam flats locked down with the tool everything is in time.

Tighten the 10mm exhaust cam bolt.

That was the clarification I was looking for. Thank you so much

The tool for the flex plate is the key- once you have it in place, the cams should line up. If not, see above.

I have all the tools. Just did not understand how and when to change but I believe test point cleared it up

I am in the middle of this process. My right side exhaust camshaft is a few degrees off of flat, while the intake camshaft is flat. The bolt that holds the exhaust cam to the sprocket is loose, but the bolt that holds the intake cam to its sprocket is tight. Tightening down the adjustment bar (that spans the two flats) will not rotate the exhaust camshaft to the flat position. I believe that the best approach will be to remove the tensioner (which in my case is new, but not tightened into place), slide the sprocket and chain out of the way (perhaps with a tie wrap attached so it doesn't get out of phase), then tighten the sprocket bolt into the camshaft. At this point, I believe I will have to rotate the cam 360 degrees (actually more like 357 degrees), then secure the camshafts with the adjustment bar - for good measure as much as anything.

Am I missing something or is this the correct procedure?

Thank you

The exhaust camshaft must not be loose enough. You should be able to rotate the camshaft without the sprocket moving when the bolt is loose. You do have the crankshaft locked don't you? The tensioner should be tight and torque and the pin removed to release the tensioner before timing cams.

:icon_banana:With the last two posts I think I have the confidence to go ahead with mine. Have one other project in the works(installing led light strips on my trailer and rain forecast for the next several days). Soon as I'm done with that I'm tearing into it

Still in the middle of the project and I will tell you soon what I have discovered. But here is a WARNING I came up with after sleeping on my mid-project predicament.

WARNING: Do not rotate one camshaft 360 degrees to set timing because it may interfere with a piston and you could bend a valve.

Now, this may or may not happen, but it is possible, so just don't do it !

I'll post again shortly as I gain "experience."

If the crank is LOCKED with the special tool in the torque converter drive plate, there is NO PISTON high enough in a bore to contact a valve!!!!!

BOTH 1A and 2B are 45 degrees ATDC. All others are somewhere lower in their bores.

bob

Thank you for that Bob...I'm going to be safe anyway and not spin the cam, even though the crank is locked down...But I will say, listen to the two Bob's above and lock the crank before you do anything else...well at the point in the instructions where you are instructed to do so...which is early on...Again, I'll share my woes soon. I don't think my woes are going to Whoa! my project, but I've made more than one easily avoided amateur mistake.

Fixing Mistakes
 

This reply pertains to timing the cams/valve on a 1997 Jaguar XK8 with the front cover plate over the primary timing chains removed, along with the cam covers removed.

I did not replace the timing chains, primary tensioners and guides because they were brand new (but did replace the secondary tensioners and one of the chain bush/guides, which was broken). Which led me to believe I could get away without locking the crankshaft. Big mistake.

Here is how I fixed my mistakes, after making a mess. Hopefully it helps someone.


1) Re-read instructions. (I am using the 1999 repair manual and this Tmingi chain and tensioner replacement
website for instructions.)

2) Install crank locking mechanism. Very easily done with car safely jacked up or on a lift. The special locking slot appears about an inch past the arrow in the window. Use the harmonic balancer bolt to turn the crankshaft. An inch is just a scoche of rotation. If you miss, keep turning until the arrow re-appears.

3) Moving to the camshaft...having loosened the sprocket on the passenger side, I found the camshaft flats to be lying unevenly, instead of flat, as is the goal. Tightening the bar that crosses the flats did not turn the exhaust cam. Instead there was a snap as I broke the bolt. I fixed the problem with a, drill, tap and die and a lot of labor. Don't break the bolt. Don't try to turn the cam flat with the tool.

4) Turning the cam: It turns out that my cam turns freely. (And I squirted some motor oil on the cam lobes to make sure.) The problem is, the special tool does not exert force at the correct angle to push the cam flat. Adding to the problem, one or some of the lobes is pushing against a valve spring at this point so tightening the cam tool isn't going to move the cam. However I found that I could turn easily the cam with a pair of channel locks on an un-machined part of the camshaft (don't put your wrench on the smooth part!) I know the cam is hollow and fragile, but this is the best I could do, especially as I had to turn the cam counterclockwise and couldn't use the cam sprocket bolt to help. Having moved the flat to the flat position, I locked it in place and (tomorrow morning, because I'm now done!) will torque everything back in place.

5) Experts may disagree with my procedure. Please do so if necessary. If I had locked the crankshaft in place first, I probably wouldn't have had to do the other stuff. But I think the most important thing I found is that if the cam flats are off and the special tool won't turn the cam, don't force it. Gently turn the camshaft with a pair of channel locks, then tighten the special tool.

I always turn the motor manually in a clockwise direction using the crankshaft bolt before I put timing cover back on. I will then lock the crankshaft down again and recheck the flats to make sure they are aligned. It will take a few minutes to recheck but can save hours if they are off and you have to tear it back down to correct the timing.

Be aware that the arrow you refer to is ONLY on the AJ26 torque converter drive plate. None of the other plates have that mark.

bob

Loving all these hints I'm finding as I'll be doing mine shortly. I've had a slight setback as I slipped on my wet top step yesterday and fell hurting my back pretty good but doc says a few days rest and I'll be fine. Now, I'll just go crazy next few days not being able to get out

Sorry to hear about your injury and speedy recovery.

As for you saying that you will be going crazy sitting around it reminds me of myself last January. I had knee replacement surgery. They said I would be laid up for a couple of months. Before I had the surgery I set my 99xk8 that needed A drum repair. I put it on the lift and had my tools and parts set up. Saw the doctor after 2 weeks and told him what I was going to do. He said go ahead because I was going to do it anyway. He said just don't put any weight on that knee.

Raised the car with the lift just high enough and did work while sittig in my office chair. When I had transmission loose I used transmission lift to remove it from car. Did the drum repair reinstated transmission. Car has been working like a champ until it stalled on freeway a couple of days ago.

Howdy, fellow cam timers. Well, everything is together, but the cover plate is still off and everything is locked into place.

However, the right (passenger) side primary chain on the flat sided chain guide, opposite the tensioner, seems a bit loose. These instructions say this can happen when the cams "walk." Tmingi chain and tensioner replacement
But my cams haven't walked anywhere.

Will the tension even up when I rotate the engine during my final check before buttoning the motor up? Or should I loosen the intake cam again, collapse the primary tensioner and re-adjust the curved guide?

I know from reading past threads that the fellows who have commented here have vast experience and await your advice with many thanks in advance.

Follow the procedure on page 26 of engine assembly section.
http://www.jagrepair.com/images/Auto...Code%20168.pdf

Trying to picture what you have I think you need to loosen the intake cam and exhaust cam. You need to make sure Vvt is retarded, counter clockwise looking from front engine, then tighten intake cam.Then using the tool retard the exhaust cam then tighten. That should take the slack out of the chain. Remove cam locking bars and crank locking tool. Rotate the engine manually at the crank pulley in clockwise direction at least a couple of times. Reinstall crank locking tool then using the cam bars slide them over the flats to see if engine is in time.

I'm doing this from memory so if I missed something I encourage correction. This is why I encourage rotating the engine a couple of times to ensure that the engine is in time.

The valve spring tension on the cam lobes will try to advance the camshaft a little. If you can pull it back into place the tensioner should try to take up the slack but will not hold it without oil pressure.

Strong pliers should be able to move the cam back a little.

bob

Here is what I did to tighten the flat side of the chain:

First loosened the intake sprocket bolt. Chain snapped to attention (not a big snap, but noticeable). Then I went back and forth, tightening the bolt slowly. No luck. Finally, I re-compressed the tensioner (tip: you can pull back the ratcheting latch with your thumb, then compress the spring with your fingers) locked it in place with the pin from the "official" tool kit, used the chain tensioner wedge to tighten the chain and tried again. It worked a little better. Then I realized that the tensioner is ratcheting. So, I pulled a little bit on the blade and the chain tightened up.

Not sure what is involved in retarding the VVT. I'm hoping it's just a big cylinder with a bunch of user unfriendly parts inside that work no matter what.

We'll find out if everything went together right in a couple of days.

I do have one more question (forgive me, I feel like I have hijacked this thread) and that is, I found what appear to be brand new all aluminum chain blades/guides in the car and these look like the photo in the "black onyx" photos. The guides I purchased, have a plastic insert, but don't appear as sturdy. Am I correct that some aluminum guides do not get a plastic insert? (It wouldn't be the first part that someone has installed in this car haphazardly.) I would prefer to leave the all aluminum guides in place.

All for now. I will await advice, thank all participants in advance and pop up again in a couple of days.