i changed my timing chain tensioners yesterday

[Antz0711]

Thanks for the excellent description BB. I plan on doing my secondary tensioners tomorrow. Can you tell me, is the exhaust sprocket located on the cam with a peg/spline/key, or is it by friction from the bolt?

Kind Regards

Tony

[rogerpalin]

Apologies to BB, thought if you are doing the job today I'd better butt in! The sprocket is held in place by friction, which accounts for the eye watering torque it needs. I set it by using a spring balance on the end of a one metre pipe on a conventional alan key. You need to keep the chain in tension on the driven side with either the special tool or a screwdriver carefully applied to the sprocket.

[Brakebuster]

bump....

for new members info

BB

[Mike1966]

Thanks to Brakebuster's brilliant posting I built the confidence to do my top tensioners last weekend. My car's a '97 model with a steel linered engine fitted in 2004. It had the second generation tensioners fitted and I caught one of them just in time - slipper just about to drop off the left side. Bodies on both were split. It was a straightforward job, but make sure you have a 10mm allen key which can deal with the torque on the sprockets - I broke two allen keys before buying a pro set fit for the job.

Anyway, I'm now paranoid about the bottom tensioners and guides, but don't have a £1000 to pay for the job to be done, so I'm thinking of stripping it down and replacing the lot for total piece of mind as the replacement engine has now done 45k miles.

The only bit scaring me is getting the bolt off the crank pulley - 370lbs torque! Has anyone managed to do this at home and if so did you do it manually or with an impact wrench? I don't mind buying a heavy duty impact wrench ( I have a compressor) if I know it will do the job without risk - any advice?
Finally, on the XK8 is it necessary to remove the radiator and air con unit to do the job as obviously that's more of a pain and expense for the air con?

Thanks
MIke

[Brakebuster]

top job......

its not that bad to do is it......

as for the bottom pulley bolt, use a bit of physics, double the length of the lever, and half the force to move the bolt

so get the bolt with a 600mm long ' knuckle ' bar on the socket.......firm and steady pressure will see it undone, however, i dont know if its left or right handed thread...so be careful

( if the pulley turns clockwise when the engine is running, then the bolt is a left handed thread, and visa-versa )

same with the serpentine belt tensioners.....one is left handed and one right handed , i found out the hard way

if doing this its recommended to fit a new seal and bolt......

and dont forget to remove the flywheel sensor and fit the locking bolt when doing the chains , or the timing will go to pot really quick...

BB

[Philmurphy]

Hello Brakebuster,
I am in the process of changing the timing chain tensioners on my 2001 XKR and have found your article very helpful however for some reason I can't access the photos, is there anyway of finding them ? I appreciate the article was published a while ago.
All the best, Philip

[J44EAG]

Sadly, we haven`t heard from BB for quite a while.

The thread that Vince created is quite an old one. It would appear that migration of images from our old site to this newer site format caused some images to disappear on the change over.I doubt if we can now recover them. Such is life.

The images were certainly detailed and highlighted exactly what is needed during 4 litre V8 motor conversion from plastic tensioners to the later uprated and almost bullet-proof metal units. I`ll have a word with James at HQ and see if we can recover the images. I`ll see what I can do.

Mike K

[J44EAG]

James thinks that these images were hosted using Photobucket. As some of us will recall, Photobucket suddenly changed policy and decided that those wishing to use the facility should pay for the privilege. This was not popular!

James will investigate with our web geeks and see if we can get the images recovered. That`s the best I can do at present.

Mike K

[Andy P]

Hi Phil,
Hope all is going well with your tensioner change,a job well worth doing.
If you are a club member I stumbled upon an in depth article on this work by David Marks in the club magazine just by accident the other day.
I think those two issues have just been made available because they were not there a few weeks ago.
Year 2012 Nov and Dec Issues.
You can only access these if you are a club member though .
Also here's a link to a file on my Google Drive which might be of use to you.
https://drive.google.com/open?id=1rh3d- ... 66Zkhx0paE
Hope that helps a bit.
Take Care.
Andy