This operation is not a regular service and is only done when the car has high mileage, after having it overhauled or when trying to diagnose a noise or power decrease originating from the valve gear. Things are adjusted by taking out the camshaft and replacing the cam followers which can be in 26 different thicknesses of the scale ranging from 3.00mm to 3.50mm in steps of 0.02mm. Valve clearance is among the critical aspects of an engine and thus requires proper adjustment for efficient engine operation. To check the clearly, draw the outline of the engine on paper and number cylinders in such a way that number 1 must be at the timing chain end of the engine and mark the position of all the valves accompanied by the clearance permitted for it. Shake off the cylinder head cover, set No 1 cylinder at the top centre of its compression stroke. For the given set of valves, take distance between the cam base and the follower, and then note it down. Twist the crankshaft again to get back to No 4 cylinder and check the number of correct clearances for the rest of the valves, and the disparity of the real and required ones. For the adjustments, the followings are required: Micrometer or Dial gauge. If the valve clearance is out though, replace the cam follower with one of the correct thickness, which are listed on the follower. For any removed follower, take the measurement of the thickness to note the level of wear. For the purpose of ascertaining the follower thickness necessary, the calculations should be made on the basis of the value obtained in the clearance measurement whether it is lesser or greater. Remove the follower, fit a new oil to the new one and gently place the new one to the cylinder head. Resurface the camshafts then make sure of the thicknesses of the fitted followers for future use. With all the clearances adjusted, turn the crankshaft several times in order to put down the followers and once again, measure the clearances. Last of all, tighten all the components that were altered for the access of the cylinder head cover.