Why should the crankshaft taper and flywheel hub be clean and dry during installation?

The correct answer highlights the importance of maintaining a clean and dry crankshaft taper and flywheel hub to prevent the flywheel from being overstressed. When the surfaces are clean and free from debris or oil, it ensures that the flywheel fits snugly onto the crankshaft taper. If there is contamination, such as oil or dirt, it can create uneven pressure distribution when the flywheel is installed. This uneven pressure can lead to excessive stress on the flywheel during operation, potentially causing it to crack or fail. A secure and dry installation helps transmit torque efficiently and maintains the integrity of both the flywheel and the crankshaft components, contributing to the longevity of the engine and reducing the risk of mechanical failure.