🔍 Key Concepts

• Bearing crush and why insert bearings are made slightly oversized • What happens to heat transfer, fit, and movement if a bearing shell is loose in its housing • Relationship between bearing fit and the tendency to move, pound, or change lubrication characteristics

💭 Think About

• Think about what ‘crush’ means in a bearing: is the shell slightly bigger or smaller than the housing, and why is that important? • If the bearing does NOT have enough crush, what physically stops it from moving when the crankshaft turns and loads change? • Would lack of crush make the bearing surface carry load more smoothly, or cause instability and movement under load?

✅ Before You Answer

• Be clear on the definition: crush = interference fit of the bearing shell in the housing cap and saddle • Ask: without enough crush, can the bearing still stay absolutely fixed in the housing under all operating loads? • Consider whether lubrication generally improves or worsens when the bearing fit is loose and can move relative to the housing.