207WF Posted September 12, 2012 Report Share Posted September 12, 2012 We used to use auxilliary oil coolers on VW powered dune buggies back in the day. I wonder if anyone has ever seen one on a 912? Maybe that would solve the high oil temperature problem on some CTs? WF Link to comment Share on other sites More sharing options...
Admin2 Posted September 12, 2012 Report Share Posted September 12, 2012 Any high oil temps aren't an engine design issue or even a standard CT issue or we would all have them. You need to find the root cause. It could be a slow flow from a little garbage in the oil cooler. I would personally change the routing of the oil return line off the bottom of the engine. It's too short and makes too sharp a bend. Any slow oil flow will make the temps rise. Too course a prop pitch will do it or a reduced radius coolant hose. Link to comment Share on other sites More sharing options...
207WF Posted September 13, 2012 Author Report Share Posted September 13, 2012 All those ideas have been checked off, so I am looking for some new ones! WF Link to comment Share on other sites More sharing options...
Admin2 Posted September 13, 2012 Report Share Posted September 13, 2012 Have you changed and lengthened the bottom engine oil hose that returns to the oil tank? Have you removed the oil cooler and flushed it? Anti freeze in use? Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 13, 2012 Report Share Posted September 13, 2012 Have you changed and lengthened the bottom engine oil hose that returns to the oil tank? Have you removed the oil cooler and flushed it? Anti freeze in use? I have done those things. I have never confirmed that my gauge reads correctly though. Link to comment Share on other sites More sharing options...
Mike Posted September 13, 2012 Report Share Posted September 13, 2012 In the UK we have a job to get them to 100 deg we have to tape up the cooler rad even in the summer Mike Link to comment Share on other sites More sharing options...
FredG Posted September 13, 2012 Report Share Posted September 13, 2012 Do all aircraft using the 912 locate the oil cooler directly behind the coolant radiator? Seems like a poor way to exchange heat from the oil into the airstream. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 13, 2012 Report Share Posted September 13, 2012 Depending on the plane the oil and coolant may be separate and in a completely different location. Link to comment Share on other sites More sharing options...
Jim Meade Posted September 13, 2012 Report Share Posted September 13, 2012 Depending on the plane the oil ans coolant may be separate ans in a completely different location. What is your experience with these separate layouts as far as oil temperatures is concerned? Link to comment Share on other sites More sharing options...
Adam Posted September 14, 2012 Report Share Posted September 14, 2012 I have never seen a CT that doesn't have oil temp problems? (on climbout) I have owned 2 and flown at least 5. Everyone of them in the climb quickly goes from green to yellow and if you persist without a little power management will keep right on going to red. I'm with Wayne on this one. Global warming, hot outside air temps, western USA, whatever the cause, our little oil coolers or the designed placement of them are inadequate. I simply back off on the throttle and manage the climb to keep it at the top of green. Once to altitude and level then I can increase power (after a few minutes of cooling) and keep it green in the cruise (most of the time). Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted September 14, 2012 Report Share Posted September 14, 2012 I used to do the throttle management routine but now I realize that the quicker I get to less than 72 degrees outside air temp the sooner I willl be be back in the green. That is the line for me 72 OAT. Adam a typical departure for me that gives me oils temp issues is departing Van Nuys headed north for Mammoth. In that 20 minute climb, in the summer I am going to be hot no matter what and wandering around avoiding the climb creates its own issues. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 14, 2012 Report Share Posted September 14, 2012 Hi Adam, None of the 6 CT's in Tucson ever have high oil temps. Most of the ones that come in here don't have high oil temps. I would expect the OAT's to be at 100F+ to get very far into the yellow. The yellow starts around 230F and I wouldn't be overly concerned about 240F-245F in a take off climb. 250F is getting too warm and it should be addressed and should be able to be fixed. If you have a poor ground it will read higher than it should. I said poor, not gone. I can take off at 105F OAT and not have any over temps. It will see the yellow at 230F maybe even 235F, but that's normal and okay. When I pull back to cruise at 5100-5200 then temps come back to 215F-220F on a hot day. Prop pitch and grounds are major players for oil temp. Even with the comments above all engines and CT's are individuals and having a 10F-15F difference would be considered very minor. The guys that only get 5500 WOT flat and level tend to see higher temps than I do with a 5700 WOT setting. Less load. I also have a better ground than a factory CT and when I had just the factory ground my oil temps were higher which is what Dynon predicted. There are fixes, you just have to find which one is causing you grief. For fluctuating oil temps: The guys with the D120 Dynon we have another tool we can use to help with the oil temp fluctuation. Go into setup and select the oil temp under sensors. The FD factory has the sensor type 1 selected. It is an unfiltered setting and allows the temp to bounce around under 3 degrees of temp. Select the #4 sensor type and that is filtered and won't fluctuate as much unless you have larger temp swings. It won't fix everyone's issues because you have to take care of other issues first like poor grounds, but it does make a difference. Link to comment Share on other sites More sharing options...
Adam Posted September 14, 2012 Report Share Posted September 14, 2012 Hey Roger, I guess we need to define "high". To me, "high" is out of the green range and into the yellow. I'll have to look at my Dynon Skyview range settings. If I remember right (not in my plane, rather on my sofa!) at 230 my Skyview goes from green to yellow. At 250 it goes to red. If you say 240 to 245 is ok in a climb that means I'm climbing in yellow. 245 is closer to red than green. I have been backing off throttle a little bit at 235 and have not been letting it go that high. Lately OAT's here at the ocean have been in the low 80's. At 100 I'd be the failure (not the plane)(I know, its a dry heat, I used to live in Scottsdale). Perhaps I will try to climb and see if it stabilizes at 240 or keeps going up. In my case prop is set so that WOT straight and level is about 5500 to 5600. I have yet to put the ground mod on (have the 8 gauge aviation wire, waiting on the crimp lugs to deliver) Reminds me... My plane always use to go yellow on voltage too (at like 13.8). I got tired of it, 13.8 is far from high on charging so I changed the setting on the Skyview to stay Green to 14.0. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 14, 2012 Report Share Posted September 14, 2012 Hi Adam, Voltage change was a good idea. The yellow temps are nothing. Just a caution area to get your attention so you will pay attention and know you are getting closer to that 250F red mark. If all you are seeing is the yellow at 230F-240F then don't worry about it. The engine is perfectly okay there. I usually change peoples CHT low temp yellow and red since you can't do anything about it anyway except warm the engine up or just look at the numbers. I do the same with EGT's on the low side too. They are what they are. I care about the actual number not whether it's yellow in color. No offence intended here! I'm talking about other people in their cars. The colors are kind of like the idiot lights on a car panel. Most people don't know what the numbers are or even mean so they just put a light there so they will hopefully notice and do something about it. Fat chance on that for some. Most don't know what the real Rotax numbers should be, the range or how they're interconnected so they have colors on the panels to get peoples attention. It helps people without all the training get an idea when things are headed the wrong way. Link to comment Share on other sites More sharing options...
FredG Posted September 15, 2012 Report Share Posted September 15, 2012 I switched oil temperature sensor ID to #4, and my oil temp immediately displayed a temperature 15 degrees F higher than the temperature indicated when #1 was selected. That is a reproducable difference, when switching between sensor type 1 and sensor type 4. According to the table on page 5-9 of the D120 Installation Guide (for software version 5.4), Rotax factory sensors are #4. So, which temperature is correct? How does one ascertain "true" oil temperature? And, why does FD deliver these planes with Sensor ID #1 selected when Dynon documentation recommends #4? Fred Link to comment Share on other sites More sharing options...
Doug G. Posted September 15, 2012 Report Share Posted September 15, 2012 Rotax, the Marvel Mystery Motor! Link to comment Share on other sites More sharing options...
FredG Posted September 15, 2012 Report Share Posted September 15, 2012 According to the April 2010 Rotax 912 Operating Manual, the maximum operating limit for oil temperature is 266 degrees F. The "normal operating temperature" (for oil) is "approx." 190-230 degrees F (see page 2-5). I find no Rotax statement or recommendation about temperatures between 230 degrees F and 266 degrees F. Fred Link to comment Share on other sites More sharing options...
Roger Lee Posted September 15, 2012 Report Share Posted September 15, 2012 In the operators manual it has 120f - 266f is the mi and max with 190 - 230f as normal. 230 to 266 is within the operational limits. The CHT's may be part of a limiting factor. If you use a 50/50 coolant mix then 248f coolant temp is the limit which might keep you from seeing a 266f oil temp. Link to comment Share on other sites More sharing options...
Roger Lee Posted September 15, 2012 Report Share Posted September 15, 2012 The switching from oil temp sensor type was a direct Dynon recommendation. A few others should give it a try and see what results they have. They stated the the #4 sensor type had a filter and won't recognize a small 3-4 degree change which should make it stead. If we as a group find this to be incorrect then we can call them. Link to comment Share on other sites More sharing options...
FredG Posted September 15, 2012 Report Share Posted September 15, 2012 Regarding setting the oil temperature sensor ID to #4, Dynon made the same recommendation to me this past week (D120 equipped 2006 CTsw, software version 5.4). Since switching to #4, my oil temperature fluctuations have gone away. Oddly, when I switch back to #1, it no longer fluctuates on that setting, either (I know, it makes no sense). But, as noted above, the temperature values are 15 degrees higher. I was having the known problem with fluctuating oil temperatures, especially above 200 degrees, but careful attention to grounding minimized it (but didn't make it go away entirely - I was still having fluctuations of +/- 2-3 degrees F). Still, a lot better better than the 20 degrees F variability that I had before making sure all grounds were tight. I would be very curious what others observe by entering the sensors menu of the Dynon D120 operating system and switching from sensor #1 to sensor #4. Is the indicated temperature difference of 15 degrees a universal observation? My questions, above, remain - 1) how does one ascertain "true" oil temperature? and 2) why does FD deliver these planes with Sensor ID #1 selected when Dynon documentation recommends #4? I can ask FD USA the answer to the second question. One thought I have regarding measuring true oil temperature is to run the engine up to temperature on the ground, with no cowling, shut down the engine (but keep the D120 energized) and then measure with a non-contact thermometer ("laser thermometer) the temperature of the housing into which the oil temperature sensor is attached (and compare to the D120 value). Of course, that is surface temperature, not internal temperature, but with the prop stationary, they may be close. Another approach might be to measure the temperature of the oil in the tank. Any suggestions? Fred Link to comment Share on other sites More sharing options...
Roger Lee Posted September 15, 2012 Report Share Posted September 15, 2012 Hi Fred, Cameron from Dynon has been talking to both of us. I have a long flight home tomorrow and I'll switch back and forth and see which works best. Cameron stated the the #1 were basically the same except that the number 4 sensor setting has a filtering mechanism to stop small fluctuations of a few degrees. Link to comment Share on other sites More sharing options...
FredG Posted September 15, 2012 Report Share Posted September 15, 2012 Roger, thanks, should be interesting. fg Link to comment Share on other sites More sharing options...
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