Valve clear­ances

Car Mechanics (UK) - - Help! - David Bliss

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).

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