Question 26Motor Plants - 1st Asst/Chief

The correct answer is C) prevent sludge and dirty oil from entering the crankcase. The piston rod scraper box in a two-stroke cycle, crosshead diesel engine is designed to prevent sludge and dirty oil from the cylinder area from entering the crankcase. This helps maintain the cleanliness of the engine's crankcase and lubricating oil, reducing wear and extending the engine's lifespan. The other options are incorrect because: A) the scraper box does not eliminate the need for an oil scraper ring, which serves a different purpose; B) the scraper box does not directly prevent side thrust or cylinder scoring; and D) while the scraper box does help remove some deposits, its primary function is to prevent contaminants from entering the crankcase, not to scrape the cylinder walls.