Which type of lifting component is used on overhead cam engines to directly actuate the valves?

• A. Bucket lifter
• B. Solid lifter
• C. Hydraulic lifter
• D. Rocker arm

Answer: (A)

In overhead cam engines, direct valve actuation is achieved with a bucket lifter that sits between the cam lobe and the valve stem. As the cam pushes the bucket upward, the bucket transfers that motion straight to the valve stem, opening the valve without any intermediary rocker. This design minimizes the gap between cam and valve and allows direct, precise control of valve timing and lift.

Other options involve components like rockers or hydraulic mechanisms that insert an extra link or cushion between the cam and the valve, so they don’t provide direct actuation. The bucket lifter, specifically, is the piece that directly pushes the valve in certain OHC configurations.