| 摘要 |
A pair of valve-timing controlling oil passages leading to a second valve-operating characteristic changing mechanism are defined in a lower camshaft holder, and a valve lift controlling oil passage leading to a first valve-operating characteristic changing mechanism is defined between the pair of valve-timing controlling oil passages in a mating surface of the lower camshaft holder with a cylinder head. In an area where the width of the valve lift controlling oil passage is reduced in order to avoid the interference with the valve-timing controlling oil passages, the depth of the valve lift controlling oil passage is larger than that in the other positions, whereby a sectional area of the oil passage is secured. Thus, the oil passages leading to the first and second mechanisms can be formed compact in a camshaft support member.
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