I was going to tackle the upper timing chain tensioners this weekend and was wondering if anyone had a picture of the breakdown so I could see what I was getting into before I start. I understand the whole job can be accessed by taking the valve covers off. I have no probelms with any kind of mechanical work I just wanted to see if I should do it in my driveway or take it to my shop.

 

I have a few pictures but it is really a simple job. Remove everything necessary to remove the valve covers and there they are. You will need the cam locking tools but what's a few degrees among friends (just kidding). Just don't drop anything down inside the front chain covers.

Four hours including detailing the engine bay while in progress.

 

this should tell you everything you need

http://www.jag-lovers.org/cjw/#0104a

 

Is there anyway to do this If I cannot gain access to the cam locking plates? I mean the sprokets only fit on the cams one way correct. So from what I can see in the pictures the biggest problem is how to loosen and tighten the exaust sproket bolts, and how to align the exaust cam if it does move while apart.

 

you have to remove the front cover to get at the tensioners, this means following the printed instructions to the letter , it's long job, the hardest part is removing the bottom pulley as it requires a special puller and is very very tight.

you really need the cam locking tool, a friend and I tried doing mine with mole grips and brute force but in the end I bought the proper tool which made it much easier.

we did it without having ever seen the inside of a jaguar engine so if you're mechanically competent it's not hard just time consuming

mine was on a 4.0 XK8 the XKR might be different

 

Mine is an 2002 xkr with 50k on it, so I am doing the secondary tensioners only. I understand from the dealer that this is all I have to do. This is preventitive maintenance at this point as I have no noise. I am a mster tech for Nissan. With that being said on our cars we have hexes on our camshafts to turn /hold them while doing this proceedure. Anyone know where I may rent the tools from, or has anyone made there own?

 

The sprocket to cam connection is a flat surface, infinitely variable connection held in place by a very large bolt. A degree or two out of alignment makes a lot of difference at 5k rpm. Due to the cam pressure on the valves, the two cams try to be out of alignment so must be held in place by the bolt down alignment tool.

Secondary tensioners do not require removing the front cover or crank pulley. That is reserved for the primary ones.

When I replaced mine at 48k on a '02 XK8 one of the tensioners had a 3/8" crack in it. With the spring assist introduced in October '98 the 'rattle' went away but not the tensioner failure.

 

sorry I misunderstood, we did all the tensioners and the chains

 

so if I am reading what you are saying correctly, the cam sprocket and cam dont have anything but the bolt keeping them in time? No dowel pin's, serrations, anything?

 

That's correct. Much like a Morris taper on a drill press. Surprised me too!

That is probably why the requirement for the '******' Allen wrench/socket to allow for using a torque wrench. While a 10mm Allen wrench with a pipe extension will very adequately loosen and tighten the bolt, without the 'knob' allowing a slight angle you cannot get a torque wrench in there.

Not having one and seeing the size of the bolt I just put a LOT of torque on the pipe extension of the Allen wrench.

Also why you must have the cam lock down tool to completely lock the cams in place for alignment and tightening.

And you are probably correct, the Lincoln LS valve cover seals probably will not fit the XKR as the LS never had a 'R' version to my knowledge.

 

I couldn't stand it so had to go look it up. According to the 1998 Technical Description Updates on the AJ27 engine the valve covers are the same on the NA and SC except the SC does not have the opening for the VVT valves. Another forum member used the Ford valve cover seals on his AJ27 so apparently they are valid for both.