Which method is best to check clearance in a diesel engine main bearing?

To accurately check clearance in a diesel engine main bearing, the lift check is considered the best method. This technique involves lifting the crankshaft by applying force and measuring the vertical movement at specific points. The clearance is understood by observing how much the main bearing allows the crankshaft to lift, which directly indicates the spacing between the bearing surfaces and the crankshaft.

While the feel method, digital calipers, and micrometers can provide measurements in various contexts, they may not accurately reflect the specific operational conditions within a diesel engine. The feel method relies on tactile senses and can lead to subjective interpretations, while digital calipers and micrometers are better suited for measuring static dimensions rather than the operational dynamics of moving components. Therefore, the lift check method stands out due to its ability to simulate engine conditions more effectively, providing a clearer picture of bearing clearance as it pertains to engine performance.