It has always concerned me that the maintenance schedule for my 2009 Ford Focus CC with a 2.0 Duratec petrol engine does not say when valve clearances should be checked. Some Ford mechanics claim they are hydraulically operated, but both Haynes and the Ford technical department say this is not the case. However, no explanation was given as to why no maintenance was advised. They suggested checking them at 100,000 miles, but why is this not in the official schedule?
As you are probably aware, the valve clearances on your Focus should be set to 0.25-0.31mm for the inlet and 0.30-0.36 for the exhaust and the clearances should be checked with the engine cold.
One of the main reasons that the clearances are no longer included in the routine service schedule is because it is deemed that they no longer need to be. With modern motor oils, the wear on the valvetrain components is now minimal and a regular check is no longer necessary. The direct action of the cam lobe onto the top of the valve with only a shim and follower in between means there is little to wear. This is also the reason that the gap will more likely close than become greater, due to wear on the valve seat (without lead in petrol, valve seats are at greater risk of wearing, although they are hardened to compensate for this).