Oil temperature control and thermostat temperature selection for Rotax 912, what a daunting task! There seems to be more confusion and opinions here than should be the case. Rotax is remiss for not giving us more guidance for such an important topic.
Following is from official Rotax information.
The following is from the Rotax 912 Operators Manual:
• The oil temperature sensor for reading of the oil inlet temperature is located on the oil pump housing.
• Oil Temperature:
• Avoid operation below normal operation oil temperature (190-230° F) as possible formation of condensation water in the lubrication system badly influences the oil quality.
• To avoid possible accumulated condensation water, at least once a day 212° F must be reached.
And the following is from Rotax SL-912-012 Use of an Oil Thermostat for Rotax Engine Type 912 and 914 (Series):
• If the aircraft manufacturer of owner thinks that the oil temperature is too low during engine operation, an external oil thermostat can be installed.
• Opening temperature must be between 82° C and 90° C (180-194° F)
Discussion: My maximum and cruise oil temps (measured at the low temp point where Rotax put the thermocouple) with a Perma-cool thermostat and the stock 180° F wax stat is under 180° F in autumn air temps. How seriously should we take the requirement to “at least once a day 212° F must be reached”? How seriously should we take the “avoid operation below normal operation oil temperature (190-230° F)? Right now (cool fall air) I do not meet either criteria, best I can tell. Given that Rotax draws our attention to the fact that we are measuring the temperature at the coolest point in the oil’s journey, does this mean we need to add a thermocouple to the engine outlet or tank inlet to see if we are reaching 212° F. Has anyone done this? Ideally it seems we want the oil at some point to reach 212° F. Plus we need to know if at the engine oil pump inlet it is within operating limits. Do we add additional complexity to the oil’s travel to raise the temperature to 212° F if that is not happening? Or is this simply a requirement that we take with a grain of salt and keep flying.
Here is what I am thinking. I am planning to raise the Perma-cool temperature by replacing the 180° F wax stat with a 195° F, as well as measure the temperature coming into the oil tank with temporary instrumentation. I think my inlet temperatures are way too low this time of year. I am speculating that even with the 195° F, I will not come anywhere near 200° F, let alone the recommended 212° F in cool weather.
Obviously there are some high time 912s out there doing fine. What are you guys seeing in the way of oil temps?
Any ideas? Help?
Dennis
Following is from official Rotax information.
The following is from the Rotax 912 Operators Manual:
• The oil temperature sensor for reading of the oil inlet temperature is located on the oil pump housing.
• Oil Temperature:
- o max 285° F
- o min 120° F
- o normal operating temperature 190-230° F
• Avoid operation below normal operation oil temperature (190-230° F) as possible formation of condensation water in the lubrication system badly influences the oil quality.
• To avoid possible accumulated condensation water, at least once a day 212° F must be reached.
And the following is from Rotax SL-912-012 Use of an Oil Thermostat for Rotax Engine Type 912 and 914 (Series):
• If the aircraft manufacturer of owner thinks that the oil temperature is too low during engine operation, an external oil thermostat can be installed.
• Opening temperature must be between 82° C and 90° C (180-194° F)
Discussion: My maximum and cruise oil temps (measured at the low temp point where Rotax put the thermocouple) with a Perma-cool thermostat and the stock 180° F wax stat is under 180° F in autumn air temps. How seriously should we take the requirement to “at least once a day 212° F must be reached”? How seriously should we take the “avoid operation below normal operation oil temperature (190-230° F)? Right now (cool fall air) I do not meet either criteria, best I can tell. Given that Rotax draws our attention to the fact that we are measuring the temperature at the coolest point in the oil’s journey, does this mean we need to add a thermocouple to the engine outlet or tank inlet to see if we are reaching 212° F. Has anyone done this? Ideally it seems we want the oil at some point to reach 212° F. Plus we need to know if at the engine oil pump inlet it is within operating limits. Do we add additional complexity to the oil’s travel to raise the temperature to 212° F if that is not happening? Or is this simply a requirement that we take with a grain of salt and keep flying.
Here is what I am thinking. I am planning to raise the Perma-cool temperature by replacing the 180° F wax stat with a 195° F, as well as measure the temperature coming into the oil tank with temporary instrumentation. I think my inlet temperatures are way too low this time of year. I am speculating that even with the 195° F, I will not come anywhere near 200° F, let alone the recommended 212° F in cool weather.
Obviously there are some high time 912s out there doing fine. What are you guys seeing in the way of oil temps?
Any ideas? Help?
Dennis
