Air cooled engine failure modes
 

Where are the most likely causes and results? Seems like catastrophic failures are less common than with the newer motors.

Well I guess if you get a coolant leak in the air cooled cars it is not nearly as serious as in the water cooled ones.

Some of the ones I have seen were due to improper down shifts. Results were see though crankcases :)

Ha ha. 14,000 rpm is bad?

Under normal use what are the most common catastrophic failures? It doesn't seem like there are many. Sure there are broken studs but even those motors soldier on and bring the car home. And the only water pump is for the windshield so a failure doesn't leave you on the side of the road.

On an older motor, if you are really careless about checking the oil level, you could start starving the bearings of oil on hard cornering. The engine can't withstand whole lot of that. But one of the shop guys would be best placed for listing customer blunders.