所以阀门能完全关闭，气门间隙在操作机构内是必须的。

So that the valves can close fully some clearance is needed in the operating mechanism.

youdao

所以阀门能完全关闭，气门间隙在操作机构内是必须的。

So that the valves can close fully some clearance is needed in the operating mechanism.

youdao