Filtered Content: This photo may not be appropriate for work.

As Fall returns full-force, the morning temperatures drop, and it's time the fleet of Corvairs have working heaters again. Since Corvairs are air-cooled, it's necessary to control the amount of air flow that crosses my engine fins. To accomplish this, GM designers put in sheetmetal that encloses the bottom of the two volumes that contain the engine's cylinder and head fins and added two thermostatically-controlled doors. The doors are closed when the engine is cold, thus restricting air flow, and once the engine is up to temp the thermostats expand opening the doors to allow air-flow.
The thermostats are quite expensive to replace, so many Corvair owners remove them and the associated sheetmetal during the warmer months when engine heat-up happens without restricting air flow. The heater in a Corvair works by ducting the heated air bottled up in the closed volumes and directing it into the passenger compartment. Therefore, without the sheetmetal, the heater is useless.
So, the re-installation of the thermostats has become a Fall ritual around our house. First, it was my oldest daughter’s ’64 a couple of weekends ago, followed by the ‘61’s last weekend. Finally, my ‘63 got hers installed yesterday.