The uninspected fishing trawler to which you are assigned is fitted with main propulsion diesel engines of the type shown in the illustration. In terms of valve operating gear, cylinder liner type, and connecting rod type, what statement is true? Illustration MO-0005
• 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)?
• 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?
• 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.
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