Easy to follow guide describing how an automotive engine starter motor works,
this information pertains to most vehicles.
A starter motor is used to rotate an engine to begin the combustion process.
A flex plate or flywheel is connected (bolted) to the rear of the crankshaft, these
unit are fitted with a ring gear which enables the starter to be activated. If the
flywheel is worn it can cause a grinding noise when the starter is operated.