| 摘要 |
A method is disclosed for assembling a valve operating system for opening and closing a poppet valve mounted on an engine cylinder head. The valve operating system comprises a camshaft 18 having two coaxial cams 14 and 16 for operating the valve 12, a summation lever 20 coupled to followers 24,26 of the two cams 14 and 16, a control spring 40 acting on the summation lever 20 to urge one of the cam followers 26 into contact with the associated cam 16, and a valve actuating rocker 30 pivotably connected to the summation lever 20 and acting on the valve 12 to open and close the valve in dependence upon the sum of the instantaneous lifts of the two cams 14 and 16. The method comprises the steps of journaling the camshaft 18 in a carrier 50, securing the cam summation lever 20 to the carrier 50 by means of the control spring 40, and securing the carrier 50 to the engine cylinder head, the control spring 40 and the carrier 50 serving to maintain the position of the cam summation lever 30 during assembly such that the valve actuating rocker 30 is aligned correctly to engage with the valve 12.
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