The bearing insert below has been plastigaged. What can you determine by this observation?

When a bearing insert is plastigaged, it is assessed for its clearance between the bearing and the journal. This process involves placing a thin strip of plastigage material in the bearing before assembling it. After tightening the bearing cap, the width of the deformed plastigage gives a direct measurement of the clearance.

Determining journal taper involves examining the width of the plastigage at various points along the journal's length. If the width varies, this indicates that the journal is not uniformly sized along its length, which is characteristic of taper. This measurement is crucial, as it helps identify potential issues like uneven wear, misalignment, or manufacturing defects in the crankshaft.

Taper can affect engine performance and longevity due to abnormal bearing wear patterns, leading to potential engine failure if not corrected. Therefore, recognizing journal taper through detections made with plastigage helps ensure that any necessary repairs or adjustments are made to maintain the engine's integrity.

The other observations generally relate to different issues, such as bearing spread and roundness, which would be evaluated differently using the plastigage method. However, when evaluating the specific context of plastigaging and the indicated observation, identifying journal taper is a valid and insightful deduction from the process.