Proper lubrication of the main bearings is more easily obtained in a single acting four-stroke cycle diesel engine than in a single acting two-stroke cycle diesel engine because __________.

Correct Answer: Option A — bearing pressure in a four-stroke cycle single acting diesel engine is continually reversed

Four-stroke cycle engines experience continuous reversal of bearing loads between the power and exhaust strokes, which aids oil film replenishment compared to unreversed loads.