Not a fan of locking the engine so it can't rotate to the least tension point for the exhaust cam lobes. Too many incidents in this forum where the caps were torqued down from the timed position and at start up the cam shaft broke.

But, again, the pros, not the DIYers are purists, as they should be. Either way, once you pull the cam covers, you need to look into the engine and determine whether the primary chain guides are worn: if so, bite the bullet and have it done right (complete primary and secondaries, new chains, et al).

If you decide to do the tie method like I did, and many others successfully, place a shop towel in the open space on the left bank to keep anything from dropping into the engine: be damn sure to pull the rag out when you are done or it will be sucked into the engine and clog your oil pump intake.

A 770's comment is maybe the best advise: don't touch it if you are not confident . . .

But get it done. You are on borrowed time.

 

Thanks, 770, but from all that I've read it seems easier, and just as safe if not safer, to use the zip-tie method rather than remove the sprocket.

I have been "working on" my own cars since 1969 (first car a Triumph Spitfire) and have not fouled anything up terminally yet, but sometimes have had to back off from a repair that I did not sufficiently understand (put it together again as it was). I just want to be as prepared as possible...

I enjoy working on my Jag myself, and would probably not be able to (and certainly would not dare) without the forum. So thank you all!

 

Go for it. It is actually easy providing no other issues are obvious . .

 

Thanks for the encouragement, as well as all the experience / expertise. I just spoke to Chris at Christopher Parts in NJ to order the tensioners, etc. (thanks to this thread) and he recommended replacing the upper chains too, with ones with a master link (that he supplies too). He said there was no issue of messing up the timing (assuming the old chain had not broken), no need for the special cam-holding tool: just line up the flats on all 4 cams turning the engine by hand, cut the old chains off and put the new ones around the sprockets. Sounds straightforward and easy, but made me wonder why there is so much discussion on the thread about keeping things in place during the work. Am I (or less likely, is he) missing something?

 

The timing is critical. I guess, too frequently people make a mistake and pull the cam shaft instead of just lifting them sufficiently to grab and take out the old tensioners and then can't put it back in the same spot.

It sounds like he is suggesting that the new chains should be done first, installed from the timing alignment position; then turn the engine to the least tension point to change the tensioners. Is that how you understood Chris' direction?

Back in late 13 early 14, danielsand (his user name) broke his chain; in about three threads he told how he replaced his chain. He too bought the parts from Christopher. Do a search and find those -- he had a great writeup and included replacing the chain. I can't seem to make the search function work. Might try google, as well.

I remember a thread on the XK8 forum, as well (same engine).

 

Thanks again! I think that Chris was suggesting leaving the cams in place and replacing the tensioners with the chains off (maybe with the pin in place to keep them in the compressed position?), but your question makes me aware that I should give him another call and ask, unless the information on danielsand's post make it clear. I remember reading the post, with a lot of good pictures, but I too have a hard time finding things again using the search function. Sometimes it is quicker to use google to find the right thread on the forum.

Do you concur that the secondary chains often suffer from stretching, too? Have you seen/heard of that much? I'm thinking of waiting till I have the engine open, and seeing how much play there is in them, and only then deciding whether or not to replace them.

(I would never have had the nerve to get a Jag without this forum!)

 

Using the search function at the top of the forum, I search secondary chain tensioners and found most of danielsand's stuff on the third page.

I only have experience with my car: didn't see any chain stretch, but not sure I would know it if I saw it.

But I would definitely check with Chris again. Rereading ds's final missive on this subject, it was not crystal clear what he was doing.

Not convinced the chains need replacing, but you won't know until it is unbuttoned.

 

I have 2 questions here - the how-to states that "BOTH pairs of cams MUST be locked off together, as any movement is fatal to the timing". I fail to see why this is necessary - how can the cams/chains on, say, the right bank move while working on (and locking down) the left bank? Also, what is the purpose of the sprocket spanner here - I am unclear as to what it is being done with it from the pics?

 

Thanks again, Jhartz. I think that if, when I have the covers off, the secondary chains are not looser than the range of the tensioner warrants, I will leave them and just sneak the new tensioners under the old chains. The car only has 55K miles -- I am in Naples Florida, a great place to buy a "little old lady"'s car after she passes (that's what this one was). Since I come from the Northeast, it is a joy to work on an engine with no rusty bolts, nuts, brackets, etc. etc. I'm used to rust making every job at least twice as hard.

One member on this site did say that after he replaced the tensioners, one secondary chain was still not under tension. If I see that, then I'll think about replacing the chain. Just as well to have the chains if I need them at that time; if I don't, the few extra dollars were still well spent -- not even a drop in the bucket compared to taking it to a shop.

 

I was down in st pete late Jan: saw an "old lady's" 03 XJR with 35000 miles for $7k. Thought about parking mine and pulling the tags off it.

Next task on mine is changing front rotors; really dreading breaking the 15 and 17 mike mike bolts holding the calipers on. Rust on 14 year old cars is thrilling.

 

Saw this forum item was still bubbling along and thought I would repost the photo of the tools I made for the job I did on my car in 2006 for those who want to save a few bucks on the tools. Easy to make & worked just fine.

I also have a copy of the write-up on the job I sent many other forum members when I did the job if anyone is interested (although it seems that there is lots of info on the forum since I wrote it that parallels it, so it is mostly redundant)

 

Wish that '03 XJR was still around -- sounds great. I thought I did well with an '01 XJ8 (almost showroom) with 40K miles for $8K, but that one beats it hands down (and my wife could use an upgrade). I'll keep my eyes open down here for something like that.

Good luck with the caliper bolts!

 

yes and no, I do these in less than 2 hours total. I dont use the tools as if one pays attention to what they are doing, its quite easy. for each head, line up the flat spots on the cams. now, (left or right) use a plastic tie to tie the chain to the sprockets for the exhaust cam. The intake cam doesnt have the holes so I just wedge a plastic piece i cut for this job alone up against the chain. Now carefully on the exhaust cam ONLY start removing the cam holders starting from middle out each way. The cam will jump up a bit when all cradles are removed, if not just bump it a bit, Now unbolt the tentioner and remove, install the new one and push the exhaust cam back in place. (as a side note I also mark the chain to each sprocket in case something slips) Torque as per specs and pattern the cam, remove the tentioner lock pin cut the plastic tie, both cams should still be in the same place. I use this method on a lot of ford dual cam motors as well with great success. You do not need that whole toolkit if you are only doing the top tensioners. And I prefer not to disturb the cam gear bolts on these types of jobs. You will never loose the actual timing with this method. True, this method is not for everyone if they are not mechanically inclined. There are youtube videos of this method as well.
And yes, if you open that engine and see plastic tentioners, CHANGE them!

 

Having read all the posts on this replacement that I could fine, I still have a question or two. There is some disagreement on whether to do the tensioner replacement with the cams in the horizontal-flats position, or in the "relaxed" position with where the pressure from the valves is the least. Any advantage to doing it in the "horizontal" position? Also is it necessary to wedge or fix the intake cam sprocket at all? Most posts don't mention it.

 

Using the tie method I tied both intake and exhaust: not sure it matters.

Some folks report broken shafts from torquing caps from the timed position: didn't see any reason to chance it. Just two additional steps: turning crank to low spot before tying cam and turning back to check timing after torquing. No big deal, no apparent down side.

Same idea behind pulling the fuel pump relay to pump up the tensioner; an extra step, but just wasting two minutes to be safe seems worth it.

 

relaxed is easier, heres video of this method...
Fair warning, relaxed or not, After the cam is bolted back in place. turn motor over just enough to make sure both flat spots are still flat with each other. During the jiggling around on a ford once, I bolted it back down and was off one tooth! So always double chack and your fine...

 

Well, I wish I had seen this video before beginning to do the work of replacing my tensioners today. I only got to the left bank; in the end I did replace the valve cover and related gaskets, but I could not get the old tensioner out because the camshaft was "impossible" to lift, even after removing all the caps. The tension from the chain kept it stuck in place. Did you place the end of a stick of wood under the unpolished part of the cam and lever it up? Any more advice on loosening a stuck camshaft?

I still have to do the right bank, if I have luck with it I may open up the left bank again. Anything to be particularly cautious about?

This is a little more ambitious than most of what I have done on my cars over the past 40 years, which have tended to be exhausts, brakes, alternators, distributors (remember those), electrical problems, etc. This is my first time messing with cams and timing chains, but I would love to get past the hump.

The good news is whew, the car still runs and sounds fine, now that I have it back together.

Thanks again!

 

It is the oil surface tension that keeps the cam in place.

The solution, if you are using the relaxed spring pressure method, is to place the zip tie so that you can rotate the crankshaft/cam just enough to cause a rising cam lobe to pop it loose.

 

Were you able to see the condition of the tensioner?

I simply pried the cam up. Been so long ago, not sure what I used; most likely a heavy piece of wood. But it wasn't a sticking point.

 

I used a small block of wood and yes, make sure the tentioner mating surface is CLEAN and torque properly! I always soak my tenstioners for a couple hours in oil before installing and as far as too much tension to pull out the tensioner, Just push down on it with the bolts out to relieve pressure... And like I said, After install rotate motor to get the flat spots on the cams to to the top and make sure they are even across.