2000 XJ8, Car started hard on first crank then started and went into big time missing (engine and car shake). Read codes and it says "misfire on cyls 1,2,3,4". There is a noticeable knock on the right side cyl head. Not too loud but, noticeable. As far as I know, no one replaced the cam chain tensioners. I think it slipped a tooth on the cam chain sprocket. What do you guys think? I need to look at the cylinder numbering. If 1,2,3,4 are on the right side it must be that. Oh, it has 140k miles on it.

Thanks Will

 

Pull the valve cover off on that side and take a look at the tensioner. 1234 are on right, passenger, side. You can tell if it's bad. Do not try to start the car again if you jump another tooth you lose the motor.

 

This is what can happen if you try to start it again. The guy I bought the car from had the same problem you do. He took it to a local shop that didn't know anything about Jaguar's. They keep cranking it to try to start it. Eventually it jumped another tooth and this is the result. It's an XK8 convertible that the guy just bought a couple of months earlier for $3700 and I bought it from him for $800. Let us know what you find out.

 

If your lucky enough and the tensioner broke during startup and skipped only one tooth, there's a 50/50 chance that you can just replace the tensioners and be ok. From my experience dealing with broken tensioners, if it was kept under 1500 RPM's, then you should be alright. Good luck!

 

In the first post he reported a knock while it was running, so I suspect there is a valve already bent from contact.

 

The noise I hear is coming from the cam chain area on the top front of the motor, not back in the head area. It is a very small noise and I located the source area by using a long screwdriver and putting my ear on the end of it (stethoscope).

 

Are you still running the engine without removing the cover and checking the tensioner and chain?

 

My thoughts exactly RJ. You need to remove cam cover to see what is going on. If you keep starting the engine you will be posting I now have a louder noise from my engine or the motor is froze. And our response will be to sell the car for nothing or get a replacement engine for $1000 to $1500. For your own good before you do anything else take the cam cover off and then we can go from there.

 

No, I am definitely NOT starting the motor again. I checked it before I turned it off. I disconnected the battery just in case of brain fart.

 

GREAT!!!!
When you get the covers off let us know what you find. I'm just as curious as you are. I don't know if you have taken covers off these engines before, but when you you do there are two bolts inside the coil cover that are easily missed.