🔍 Key Concepts

• Identify how the valves are actuated: do you see a camshaft directly over the valves (overhead cam), or do you see pushrods and rocker arms driven from a cam lower in the engine? • Look at the cylinder liner cooling arrangement: does the cooling water appear to touch the outside of the liner itself (wet liner) or is there a thick cylinder block wall between the liner and the water jacket (jacketed/dry liner)? • Study the connecting rods at the crankpin: is there one simple rod per crankpin (conventional) or a main rod with a secondary rod pinned to it (articulated/marine‑type)?

💭 Think About

• Trace the path from the cam area to the valves: is motion transmitted by long slender rods (pushrods) to rocker arms, or does the cam sit directly above the valves? • At the crankshaft throw shown, count how many separate rod ends or joints you can see. How does that compare with a simple automotive‑style rod versus a multi‑piece marine rod set‑up? • Look closely at the shaded blue cooling passages around the cylinders. Do they contact the liner’s outer surface directly, or is there a solid wall of block material between the water and the liner? What type of liner does that suggest?

✅ Before You Answer

• Be sure you can visually locate pushrods vs. an overhead camshaft before choosing between pushrod and overhead cam options. • Confirm whether cooling water directly surrounds the liner (wet) or only surrounds the block that contains the liner (jacketed/dry) by following the blue areas in the figure. • Verify whether the crankpin in the illustration shows one rod or a main rod with a second rod jointed to it, and then match that to the connecting‑rod descriptions in the answers.