I know the process of changing the chains and tensioners has been covered many times on this site and others, but I thought I would share with you that you don’t need all the special tools to successfully complete the job, here's a pic of my version of the tools that I used to repair my 2001 XJ8 4L after the cam skipped a tooth one morning while trying to start her!
I had changed the tensioners about 3000 miles ago, using the cable tie method and noticed then that the chain still seemed to be slack after the new tensioners were fitted. So I knew that a complete front end strip would be needed, but I was forced into it when she skipped one Monday morning as I started her up, sounded like I’d flooded it at first, shut her off, and tried again, as you do, to a heart stopping sound of a very loud knock! Thought S**t, the valves had touched the pistons, but pulling the plugs, and turning over by hand nothing locked or knocked, so I started to get my hands dirty.
Anyway put just over 1000 miles since the rebuild and sounds better than it ever has, even if she has 127k on her.
Thanks to all who have posted their previous encounters with the tensioners, you've been a great help.
Cheers
Pete

 

So what was the cause of the slip - a lower chain tensioner failure? Your angle steel cam lock is very inventive!

 

to pd_regan -

I had been wondering if a piece of angle stock couldn't make a good tool for locking down the cam flats. Looks like the answer is yes! Nice trick.

But "the world now wants to know" what are the other tools, and how (or from what) did you make them? Thx.

 

Hey Pete, I admire your ingenuity in fabricating the necessary gear, they look pretty good copies of the Jag spec tools. Did they work just as well because you could have a market in making them! I know of a few members here that would benefit.

 

Cheers Guys, sometimes simple is best, and cheapest, there just seemed to be a lot of slack on the upper chain, I could get my little finger between the chain and the tensioner, so mayby that tension had stuck on startup allowing enough slack/slap to skip a tooth. The lower kit appeared all fine no splits in the tensioner bodies, but one of the guides did have a crack, as in the first pic below.

I made the tools from bits found around my manshed, sprocket locking tool started life as a shifter to remove the disks from a 9" grinder, the pins were the right fit for the holes in the sprocket but too short, so I drilled them out and replaced with a nuts and bolts.

the flywheel lock was made from a 19mm 3/4" bolt ground down to be a snug fit into the bellhousing and ground to fit into the elongated slot of the flywheel, this is just used to set the TDC for the timing, not designed to lock the crank from turning when you undo the crank pully bolt, this has to be done with a strong pry bar held on a jack. for me anyway. it was kin tight....

The other ground down bolt is the original pulley bolt i took off the car, used to center the puller so the pressure is put on the end of the crankshaft and not the thread or the taper washer that sits between the crank and the pully.

hope that helps, the puller is self is just a disk of 20mm steel with a 19mm nut welded on, if anybody wants the measurements to make their own just ask and i'll put the sizes on the pics

 

Kudos to you regan.

Its gotta be worth doing a detailed how to, with pics, sizes etc as I'm sure there are more than a few that would be interested to do this if you're up for it?

 

So you don't really know what caused the failure in the first place? Did you replace the chains, and if so, were the originals stretched any? When all done was the initial slack gone?

 

Hi pd,I want to know is there some noise(not loud) still there after you changed tensioner 3000 miles ago.I had a little noise after changing tensioner a month ago.Your situation can help me a lot! So please tell me!By the way,I made those tools too,I use square steel instead of angle one,I think it's stronger.

 

Reading between the lines:

 

Reading BETWEEN between the lines - the line you quoted was referring to the upper tensioner replacement he had done 3000 mi earlier.

So the question remains, Pd - Did the full chain/tenisioner replacement eliminate the slack that you still had after just the upper tensioner replacement, and if so, what do you think, from inspection of the old components, was cause of the slack - lower tensioners or chain stretch?

 

Sorry, but why would one start a car with slack in it's timing chains?
I'm surprised that the engine lasts for about 3,000 Miles at all!

When I changed the secondaries I paid special attention on two things:
That the timing was correct and that the tensioners are working as intended.
In no way I would have started my engine if one or the other was not perfect.

Have the new tensioners been defective or what was the reason that you had slack in the upper timing chain?

Just curious!


David

 

Thanks for sharing pics of your tools.

 

Did your engine knocking ever make you think you had a rod knock? Because I'm currently stuck determining whether I have a rod knock or a timing chain part failure until I take the valve covers off tomorrow.

Here's my youtube of my sound:
http://www.youtube.com/watch?v=LUAQ77hS3yQ

Because your case has my hope really high that its just my timing chain gone wrong and not a lower end failure after you described a "very loud knock"

 

hi

@chinny

It did make a knock like that, but for the short time I ran it for, it was missing like hell, so my "knock" could have been due to the timing being out, yours sounds like its firing on all cylinders but with a pronounced knock, take the valve covers off and check that the flats of the cams are lined up, at least that would eliminate the cam slip, but it would also, unfortunately, point at small/big ends. Good luck

@davidN
When I replaced the top tensioners the first time, the chains weren’t "that" slack, just seemed to me that the chains could have been tighter, and using the cable tie method, you cant "nip" up the chains because you cant access both sprockets without taking the front cover off, which at that time, I didn’t have the "tools", the parts or the time as the car is a daily driver. Also when the chains have been set up correctly and you continue to rotate the engine manually through all 4 strokes, you notice that the chains do go slack at the point when there is no tension from the valve springs, this is what the oil pressure part of the tensioner takes up, which is lost when they have cracked. So there’s no need to be sorry for your lack of knowledge of my circumstances.

@Quad
Yes the full replacement did sort it, due to the fact that new chains were fitted and set correctly which I couldn’t do due to... see above.

@tomjagxj
There was still a slight noise from the chains after the initial plastic tensioners were changed, which were both cracked, but it did sound a lot better, but to be honest, I didn’t notice the noise getting any louder in the last 3000 miles before the slip.

So in essence, I guess, IMHO, change the tensioners using the cable tie method, as a quick fix, especially if you find that they had cracked, as mine had, but if your going to keep the car, do the full replacement. As the whole point of the original post was to show you dont have to spend a fortune on the "special tools" to do the job.

Thanks for all the encouraging comments, hope I’ve helped a few.
Cheers
Pete

 

Chinny, that doesn't sound good, but it's really hard to tell where the knock is in the video. I was lucky and found a video that could have been my car. In the video yours sounds a bit more metal to metal than what I had. You are also focusing on the center of the engine in the video - which leads me to believe that's where you think the noise is coming from. I know from research and first hand experience (I'm waiting on a few parts now to finish a full timing component replacement), that the knock associated with tensioners is most recognizable at the front of the engine. Passenger side secondary tensioner is the one that appears to get the most abuse and in my case and as described by others is usually the first to go and in the worst shape. Use a stethoscope or a screwdriver to the ear and see if you can pinpoint the location of the knock. The secondary chain and tensioner are about an inch beneath the bell on the front of your valve cover. If you've got a pronounced knock from this area- I'd say that a good bet would be a tensioner failure. From a first hand point of view - if you head down the timing component road - its a bit more work but take the time and effort to replace all the timing components. All the OEM tensioners and guide rails were made of the same plastic. I found significant failures in every one of mine (RH secondary was just the beginning). The OEM waterpump has a plastic turbine in it as well. New parts have all been upgraded to metal instead of plastic. I've been taking pictures as I've gone along, but I want to get some really detailed shots of the tensioner failures, but I'll be posting shots soon.

 

Pete,

no offense from my side !!!

I turned the engine (by hand) after the change and the tension of the chains was okay.
Not that strong as with the original plastic tensioners, but good enough to keep the chain from slipping.
And I noticed no slack when the valve springs are "relaxed".

One additional Q:
When you did the "full job" did you change the secondaries again?
Or did you keep the ones you installed using the zip-tie method?

I'm asking b/c I heard of new tensioners that came defective.
(Aftermarket parts though.)

David

 

Hi David,
No, replaced all with new, if you have a look at the pic in the original post, you can see the amount of slack that was there before it was stripped, there was no where near that amount after the cable tie job, no way would i have tried to start it if it was like that.
I havent checked the cable tie tensioner, I'll see if I can dig it out of the bin and check it out, guess it could have been faulty, but as I was replacing I was'ent looking for a fault.

All sorted now, and not as a difficult as I thought it would be and as always be much easier next time with the past experiance.

Cheers
Pete

 

Can anyone tell me what the hole spacing is (bolt circle diameter) for the harmonic balancer puller and what the thread spec is for the holes in the balancer? (M10 maybe?) I am thinking of making up one of these with extra holes for attaching a reaction lever, so that locking the crankshaft would not be necessary.

 

Hi boom,
The bolts are 8mm thread so thats a 13mm head on the bolts in the pic, just checked my puller and their 84mm centres.

 

pd -
Thanks! 84 mm bolt circle diameter doesn't seem like any sort of obvious round number, either in mm or inches. Well, it's not always easy trying to get into the heads of the Jaguar engineers.

Pictures of damper pulling tools in this forum show a sort of button or bearing to fit on the center of the crankshaft, presumably for the center bolt of the puller to push against without damaging the end of the crankshaft. Can you give a description of this extra bit?

Given how much force it takes to get the damper off, I'm almost surprised that only two 8 mm bolts are strong enough.