10. What's a stakedown kit and why do I need one for my XJ6?
The XJ6 6-cylinder Jaguar engine was designed in the 1940s, and when designed was a perfectly functional engine. With the advent of stricter emissions requirements, the operating temperature of the engine increased, particularly around the exhaust ports. As a result of the temperature increase, the exhaust valve tappet guides tend to work loose and rise up out of their seatings, and come in contact with the cam lobes. The cam quickly destroys the tappet guide, sending shards of metal through your engine at least, and potentially breaking the timing chain, which destroys the engine in a matter of milliseconds.
To combat this problem (which, by the way, Jaguar still refuses to recognize) the stakedown kit is installed to hold the tappet guides in place, preventing them from coming loose. Installation of this kit by a professional tends to run about $300-$400, but can be done by the handy home mechanic with a bit of care. It requires drilling into the cylinder head.
How do you know if you need one? If you have a pre-1988 XJ6, you need one. You may already have one installed, and if you take off the oil filler cap and peer inside with a flashlight, you should be able to see it if it's there. It is a bar that spans the distance between two tappet guides, just under the cam, holding both tappet guides in place. If it's not there, get one!
See our Jaguar Parts Store Catalog to order parts.