Jeff,

 

Let me add my congratulations on your first flight.

 

 On the subject of thermostats, I have been using a non-Mazda thermostat in my 13B powered RV6A for over two years with good results: Hypertech 160 Degree Thermostat  H1008.  This thermostat operates properly with the Mazda bypass system.  Here in Laramie, WY we often see temperatures similar to those you saw on that first flight.  Under most conditions, the thermostat is only partially opened and is controlling the coolant system temperature.  When this is the case, I see pressures of over 30 psi between the water pump and thermostat.  At the same time, on the downstream side of the thermostat I see pressures that can be slightly negative.  These pressures are gauge pressures relative to ambient.  I have always used a 14 psi cap on the expansion tank and it has never vented as long as there is an air cushion.  Depending on where the connection is made between the expansion tank and the rest of the cooling system, and also depending on where the coolant pressure measurement is taken, it is not unreasonable to see a pressure reading significantly greater than the pressure rating of a properly working pressure cap on the expansion tank.  It also has been my observation that the temperatures seen at the thermostat location are usually about 10 degrees lower than the temperature at the other stock temperature sensor location on the engine block when operating at cruise to max power settings.

 

I have also successfully used an impact wrench to remove and reinstall nuts retaining alternator pulleys.  Just don’t get carried away with the impact wrench settings and times.  Those threads have always been right hand on the alternators I have worked on.

 

Just some additional data points to consider.

 

Sincerely,

 

Steve Boese

 

RV6A, 1986 13B NA, EC2, RD1A