Engine Oil Temps

[Runtoeat]

I flew Ziggy (N9922Z) yesterday in hot (95F) temps for the first time. On climb out to 5500' my oil temp was approaching redline. It appeared that I the temps would probably stabilize around the redline but I didn't want to test this theory so I throttled back to keep temps around 240F. What do you guys out West do? You fly constantly in this environment for most of the year, don't you? My CTSW is a 2006 and does not have thermostats for oil or coolant.

[Ed Cesnalis]

Dick,

 

I have had the same oil temp issue for years. (my EFIS overheats as well. recently the EFIS overheated just from sitting on the ramp in the sun. I had to use its cooling fan to bring it down to temp during pre-flight)

 

The big question is; are these high readings correct? I'm still not sure in fact I think the gauge is at fault.

 

If ambient temps are above 70F I will see oil temps in the yellow. I have learned that I spend less time warm/hot if I just climb to the cooler temps and get it over with.

 

My CT does seem to stabilize a few degrees below redline. Worst case was departing North Las Vegas when over 100F on the ground, climbing away from the runway at redline over the city is un-nerving.

 

I've planned on putting a digital thermometer sending unit in my oil tank and then running the display in the cockpit and comparing temps on a hot climb.

[Ed Cesnalis]

Roger,

 

My CHT temps run nice and low even when oil temps get high. Also I fly regularly at high altitude, I realize that rich is relative but I wouldn't want to get overly rich. Lastly my plugs always look good.

 

If my CHT was high as well the extra fuel would make more sense to me.

 

 

 

[Runtoeat]

Charlie Tango and Roger, good thoughts on this subject. I remember jetting my Husqvarna's (250 wide ratio enduro) bing carb to get proper mixture and forgot how effective this can be in regulating engine temps but CT has a good point regarding good CHT temps indicating that mixture might not be the cure. CT, I like your idea if putting a remote temp sensor in the oil reservoir. If you placed the sensor in the return flow, the oil temps you see should be pretty close to the internal engine oil temps. Let me know how this works for you.

[Ed Cesnalis]

my EGT (like my CHT) is always in the green and always on the cool side. before the rotax i used EGT as a guide for mixture and given the cool temps i get i would be leaning not enriching.

 

my big picture calls my hot oil readings into question.

 

 

 

[sandpiper]

Summer has finally arrived here. Two days ago my radiator was still taped and It was almost impossible to get 220 oil temp. Now, tape off, level with 5000 rpm it sits at the bottom of the yellow which is 230. OAT was 88 degrees.

[207WF]

I have the high oil temps similar to Ed, and we have discussed this a lot on the other forum. I have recently found that if, instead of throttling back like I used to do, if I keep full throttle in and raise the cruise climb speed to about 95 knots, then I can keep the temps around 240 on a hot climb. - WF

[207WF]

One idea on the oil temps that I think someone has tried and which seems interesting: The heater shroud around the muffler exits on the top front side, where a big wad of heater hose wiggles around to the heater intake on the back. If we could relocate the output on the heating shround on the muffer to the back part, there would just be a short piece of hose taking it to the heater intake, I bet the oil radiator would get better air flow and help with this issue. We have been having temperature inversion in LA lately: 60F on the ground and 90F at 3000 feet. I have been hitting 240F on temp the oil by 2500 feet in the climb. WF

[Brucegoose]

We are seeing late 80's on the ground just lately and into our hot season. Air is very dry and hot and I'm also finding it difficult to keep my oil temps below 250F. I looked at what you are saying and it makes sense.

My question, is why do most other Rotax installations have the oil cooler seperate from each other?

I have checked the return to the oil tank and the pipe was hanging a bit onto the odd up in the air straight in to the tank. I think this should at least have a 90 degree elbow for ease of routing.

 

Regards

 

Bruce

[Brucegoose]

I have a Neuform three blade constant speed and set 5500 for take off. Flat and level at 5500 I run high at about 240F. I keep to 500fpm at 80kts.

I,m sure your temps in Arizona get hotter than ours, we see an absolute high in the shade of 115F. Last summer we had a DA of 9000ft at a field of 3700ft. Only good for lying in the pool with a cold beer I guess! So yes we are at the start of spring and that is why I'm trying to get better cooling before it really heats up.

 

Bruce

[Brucegoose]

Thanks for the reply Roger,

 

I'm going to try that and move the clips down another notch. Will let you know the outcome.

 

Regards

 

Bruce

[207WF]

Ed has always questioned if is oil temps are reading right. I have the same problem as his: high oil temps in the climb but chts stay cool. By now I have switched out the oil temp. sender and the oil temp guage in the panel and I get the same readings. I think in my case they are real. WF

[207WF]

Here is an idea. Our "choke" is an enricher circuit. Suppose I applied the choke in a full power climb to bring in more fuel and cool that way. What do you suppose would happen? WF

[207WF]

Will the needle clip trick make things richer at all rpms, or just in a range? WF

[207WF]

OK, so if the problem, like mine and Ed's is hot oil temps (and normal CHTS) in the climb, normal to slightly elevated (say 240) oil temps in cruise, this may not make much difference. Still looking for a magic bullet on this problem. WF

[207WF]

I will let the oil get to 250F in the climb, and it will hit and even exceed that on a hot day (30C OAT or so) even in a 100 knot flaps -6 slow climb (which is over 5300 rpm the way my prop is set). Last week doing it that way, at 28-26C OAT, it took me 30 minutes to get to my 8500 foot cruise from sea level. At 250F on the oil I power back, level off for a while and step climb once it cools back to 240. This works, but it sure would be nice to just climb on up to altitide at 85 knots. It still puzzles me why some of us have this problem and others do not. WF

[207WF]

Oh, to complete that: I use AV-9 from Cal Power systems and Rotax oil filters from the same source. WF

[GlennM]

I would not use a K&N if I lived in a dusty area. The K&N passes more dirt than the paper filter. On the ground in diesel trucks, the turbo impeller leading edges get worn and the cylinders get scored from dirt passed by K&N filters. I would never buy a truck with one previously installed. I would think an airplane would not have so much trouble with dirt while flying, but they have to be on the ground eventually.

[207WF]

I have the K+N filter and the prop is set to run 5600 rpm WOT at sea level. So, maybe a different oil will help. I run a mix of 100LL and autogas, running more mogas in town and 100LL when travelling. WF