[Kurt in NJ]

It’s in the installation,not using worn parts,the bolts can’t be worn and loose in the threads,the flywheel teeth have to have proper shape along with the pinion gear .
the locks have to be new each time, the bolts tight,the spring tight and not distorted,
45 years untouched on my car,has survived driving out of the garage on the starter,starting in gear many times when the clutch was stuck etc.
First starter I rebuilt 50 years ago,original to the car
the original generator has be more reliable than the chevrolet alternator in my truck (3 rebuilds in 40 years)