Valve gear worn - how can you tell?

In my case the car was running rough, and the engine light came on, further investigation, showed cylinder number 5 misfire, it had good compression, spark and fuel. After removing the valve cover and intake they found a worn cam lobe causing, the cylinder 5 misfire.
That was at 150k miles.

Scotty

Thanks for that. 100k miles seems to be a common point.

What concerns is that the experts (RPI, eg) say that by the time the wear makes itself felt or heard, the cam lobe has worn enough to leave a trail of fine metal particles circulating the engine and causing damage .....

Is there a way to detect this wear without stripping the motor?

Actually, I guess it would be worth removing the intakes and having a look ...

Cam wear on the 4.6 is rare and are known to out last the life of the car but there are times when oil changes arnt carried out that the cam then does suffer.

Without being to negative on RPI side we need to remember they are a company selling goods for the Rover V8.......
Thuogh I would agree there must be a life limit somewhere Ive seen Rangies with 300 000ks plus and still running smoothly

The best way to find out what your oil contains is get a sample sent to an oil laboratory they will be able to tell you which part of your engine is detoriating the most.
Then you can make your own mind up of what to do next, wether it's a top end rebuild, crank and journals or just carry on changing the oil.
RPI are in the v8 market but they have a lot of experience and it does say "this section is not for the fainthearted"

Any wear on the engine results in metal coming off; that is why you filter the oil and change it regularly.

In fact if you really want to be technical it is also why the filter is after the pump and before the engine; not only is it easier to filter under pressure but if a lump comes off the oil pump it gets caught in the filter instead of going to a bearing.