Check the cam lobes and bearing surfaces for abnormal wear and damage . Replace camshaft as required. If camshaft is replaced due to lobe wear or damage, always replace the lifters.Measure the lobe actual wear (unworn area - wear zone = actual wear) and replace camshaft if out of limit. Standard value is 0.0254 mm (0.001 in.), wear limit is 0.254 mm (0.010 in.).