SUMMARY
The discussion centers on calculating rod bearing load when a 90 ft-lbs torque starter motor stalls, revealing a calculated pressure of 61,703 PSI on the rod bearing, which raises concerns about the bearing's ability to withstand such loads. Participants emphasize the importance of considering the crank advantage and the opposing forces of cylinder pressure and starter torque. They conclude that the load on the rod bearings is determined by the lesser of the starter torque and the cylinder pressure at TDC, suggesting that higher torque starters may not be a solution for engines already experiencing damage at lower torque levels.
PREREQUISITES
- Understanding of torque calculations in mechanical systems
- Familiarity with engine compression ratios and their effects
- Knowledge of starter motor operation and characteristics
- Basic principles of thermodynamics, specifically adiabatic and isothermal processes
NEXT STEPS
- Research the effects of crank advantage on starter motor torque requirements
- Study the relationship between compression ratios and cylinder pressure at TDC
- Explore the mechanics of starter motor ratings and performance under load
- Investigate shock loading and its implications for bearing failure in engines
USEFUL FOR
Engine designers, automotive engineers, mechanics, and anyone involved in performance tuning or troubleshooting starter motor issues in internal combustion engines.