REFLECTOR: Oil Temperatures

Fred Anderka fred at holohil.com
Fri Jan 20 12:45:21 CST 2012


Nick:

The oil temperatures I see in the summer (+20C OAT) can vary from >240 during climb out to 220-225 in cruise.  I often level off for a while when the oil temp. is high (and the oil pressure low <30) then resume my climb when it comes down.  Unless there are mountains to cross after takeoff I climb at a slow rate (300 f/m) and maintain a higher air speed for cooling.  Maintaining a rich mixture does not seem to affect the oil temperature very much, only the EGT's.  You may consider placing some VG's ahead of the front cooler NACA to enhance air flow.  Putting 2 VG's ahead of each of the top NACA's has done wonders for keeping the engine cool in the summer, unfortunately it keeps the engine way too cool in the winter.  Will try some duct tape over the VG's on my next flight until I get to warmer latitudes.

I opted for a diesel combustion heater as I was also concerned about having 100LL burning in front of my feet even if the heater has all sorts of safety interlocks.  Diesel on the other hand has such a high flash point, I feel much more comfortable should a leak or some other mishap occur.  

Fred



Fred, forgive me for straying from the cabin heat subject but this is somewhat related. I too have an IO-550 and I am interested in you cooling setup. You say you don't have any air going to the engine oil cooler mounted on the engine. I have completely removed the oil cooler from the engine and only have the forward oil cooler with an inline vernatherm. I have been concerned that this may not be adequate in warm temps. My thought is that because the front cooler is getting abundant ram air that this may be enough to keep the engine cool. You say that you have trouble keeping the temps up in the winter during cruise, I was wondering what temps you see in summer?

Best regards,

Nick and Connie Jones
Velocity XL-RG
N10CN
99% done 90% to go



All modern piston twins have combustion heaters. They are large, heavy, expensive and difficult to maintain. I had a Janitrol in my C-310 and was a nightmare to work on and had several recurring ADs. I wouldn't consider deliberately install one if a viable option exits.

Best regards,
Nick


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