Henry Ford has been credited with saying, “Failure is simply the opportunity to begin again, this time more intelligently.”, it’s the “this time more intelligently” portion of the advice that many disregard. Not taking advantage of all the information presented during the postmortem of an engine failure may lead to repeat failure again and again. If every engine failure that ever occurred was accompanied by a high-resolution datalog from every sensor following the last minute of the engine’s life, determining the cause of failure would be much easier. In the real world, the datalog that is available after an engine failure is typically just the broken engine. While just about anyone that owns their own set of tools can disassemble an engine and tell “What” broke, the “How” and “Why” the part broke requires a much higher degree of intelligence and experience. To help you make more intelligent decisions, we will have assembled the basics of engine failure analysis to speed up your development process.
Within the engine, there are few parts that by themselves can often tell a tale of what happened during the failure. The spark plugs are about the only parts in an engine that are generally accessible before the teardown of an engine. Spark plug inspection can often determine if the issue is global or localized. If all of the side electrodes are intact but one that has been melted off, there is a fuel delivery issue to the cylinder that is home to the damaged spark plug. If all the spark plugs are relatively dry except one that is soaked with oil, there is likely an issue in the cylinder that has a wet spark plug. While not being able to identify a local issue, using a filter cutting wrench on the oil filter can provide some insight on if there was a lubrication issue. If the filter media is packed with bearing material, a spun bearing is likely to be found.
Failure analysis using technical knowledge and tools of fish bone diagram, existing data from past failures, technical documents of the engine, etc. are among the activities that have been going on in the Dinamotors Co. for years.