Like most used xj-s's out there, mine suffers from generally deferred maintenance.

My fuel hoses are dried and cracking and the plugs, wires, and distributor are all likely original to the car (66k miles). Also I discovered that my valve covers are leaking slightly.

V12performance.com sells nice fuel hose and ignition replacement/tune up kits so I am planning to do a major ignition system rebuild and replace all fuel hoses, have the injectors cleaned, and have parts such as the fuel rail anodized while they are off the car.

Now I am considering expanding this job to replacing the valve cover gaskets while it's all apart. I have never done such intensive work to a Jag V12 and it makes me a little nervous. Is this additional work worth it? Are leaky valve covers common and can I expect to fix the leaking by replacing the gaskets or is it one of those things where "they all leak a little"

I believe after 30 years such a service is necessary but what should I look out for? What problems can I expect (mainly with getting to the cam covers)?

PS: Changing the distributor cap and rotor doesn't affect the timing correct? (probably a stupid question)

 

It's a fair bet that the cam cover gaskets are leaking ....to some degree or the other...if they are original. There's a bit of labor in replacing them so the severity of the leak must be weighed against your enthusiasm towards the task. :-)

Personally I'd 'go for it', though. It's a perfect time to replace those fuel hoses, repair crispy wires, replace rotten vacuum hoses, replace plugs and wires, clean throttle bodies, replace throttle bushings, de-desize the distributor, etc all in one fell swoop. Do it all, do it once, forget about it for a few years.

There's lots of 'stuff' to remove to replace the gaskets. Just go slow, take tons of notes and pictures, and stay organized.

Cheers
DD

 

Correct. Just changing the cap and rotor won't alter the timing setting

Cheers
DD

 

Not a problem, just go through Kirby's book,(two, three, or four times) have Haynes as back up, label and take pictures.
Good Luck
Snowball

 

I'd classify myself as a novice and am currently in the process of doing major work myself (cam cover gaskets, water rail, and all the extra stuff that goes along with the job). It's very intimidating at first, but going slowly, taking pictures and notes and with the help of the good folks here, you can do it. And, it's really very fascinating getting to know the insides of your V-12.
Here's a photo of progress to date.

 

Digging into my V12 seemed intimadating. I have always done my own maintanance, but shyed away from the 12.
Reading this forums posts, educating myself, and reading Kirbys book, "as snowball said, over and over", I think this job is fairly simple.
Time consuming, but simple. While its down do it!
It is reasuring that if there are troublels, the people here will help in a heartbeat!
You have options of half moon seals, and gasket or no gasket. Reasearch it and decide whats best for you.
The steps you are planing are a huge step in the proper direction, get as much done as you can, while its apart!