If you find that the crankshaft rod journal has no taper but is smooth, what is the appropriate action?

When the crankshaft rod journal is found to be smooth and without any taper, this indicates that the crankshaft has maintained its proper dimensions and does not exhibit wear that would require modification or replacement. In this context, installing standard bearings is the appropriate action because they are designed to fit onto components that are within specifications.

Using standard bearings allows for optimal contact with the crankshaft surface, ensuring proper lubrication and performance during engine operation. The smooth surface also suggests that there are no significant irregularities that would necessitate the use of oversized bearings or grinding, both of which are reserved for crankshafts that show signs of wear or damage that would affect their roundness or thickness.

In situations where the crankshaft is still within acceptable specifications, simply replacing the bearings with standard ones is not only a best practice but also a cost-effective solution that preserves the integrity of the engine components.