I have looked at other threads but haven't found this issue address. Granted I live in a colder climate but I am hoping someone else has already had and addressed this issue. My oil temp is running to low. I have a YIO360M1B factory Lycoming with the Hartzel CS prop. I engine is the stock Vans installation and I have installed the oil cooler shutter. With shutter 100% closed I am running about 100 degrees above ambient temp. Suggestions.
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Oil Cooling
- Thread starter Berchmans
- Start date
Mike S
Senior Curmudgeon
Your cyl temps are related to oil temp---------the oil picks up the heat from the guts of the engine remember.
It sounds like you could neck down your cooling air flow (either intake or exhaust side) and get both temps up.
Restricting the cooling intake air is pretty easy, and you could make removable cuffs/chokes for winter use, remove them when the weather warms up.
As I recall, Bob Axsom and Alan Judy both had threads showing how they made cowl intake restrictors. Might be worth some time going through their old threads. Bob has passed on, and Alan is not very active so a PM is most likely not going to be worthwhile.
Both Bob and Alan were looking for speed mods, so keep that in mind.
http://www.vansairforce.com/community/member.php?u=1183
http://www.vansairforce.com/community/member.php?u=4492
It sounds like you could neck down your cooling air flow (either intake or exhaust side) and get both temps up.
Restricting the cooling intake air is pretty easy, and you could make removable cuffs/chokes for winter use, remove them when the weather warms up.
As I recall, Bob Axsom and Alan Judy both had threads showing how they made cowl intake restrictors. Might be worth some time going through their old threads. Bob has passed on, and Alan is not very active so a PM is most likely not going to be worthwhile.
Both Bob and Alan were looking for speed mods, so keep that in mind.
http://www.vansairforce.com/community/member.php?u=1183
http://www.vansairforce.com/community/member.php?u=4492
Burke I fly all year. First couple years I was blocking oil cooler inlet completely and barely got oil temp in the green. Then some smart dude (forgot who was it) suggested to block it from both sides. Gained at least 20 degrees.
I will start with blocking the aft side, seems easier than blocking/restricting all air flow. The CHT's and EGT's seem ok. Most of my winter experience has been with much slower aircraft and blocking the upstream side of the coolers seems to be all that's required. Might add a second shutter on the back side and interconnect the two so they work of a single push/pull cable.
Move south.
Sorry, I couldn't resist....
Sorry, I couldn't resist....
flyboy1963
Well Known Member
herding cats???
wouldn't most of this be solved if the engine stopped sending oil to the cooler to be overcooled????
someone very nice and smart once provided a nice chart here on VAF that showed exactly what the vernatherm does.
sounds like a couple of thin washers (add/subtract) to adjust the oil flow might be all that's needed, if it's functioning correctly.
wouldn't most of this be solved if the engine stopped sending oil to the cooler to be overcooled????
someone very nice and smart once provided a nice chart here on VAF that showed exactly what the vernatherm does.
sounds like a couple of thin washers (add/subtract) to adjust the oil flow might be all that's needed, if it's functioning correctly.
Mike S
Senior Curmudgeon
Professor Horton, as I recall. This maybe?? http://www.vansairforce.com/community/showthread.php?t=125378&highlight=vernatherm&page=5
Last edited:
704CH
Well Known Member
This is the exact thread I am looking for. Covered the rear of my cooler completely with aluminum sheet and my oil temps are only getting to 172.. My CHTs are only about 304-308 so I think I need to reduce the inlet.
Looking at the links below that I think you are referring to, it looks like the pics aren't available. Does anyone else have better links, or a recollection of what Bob/Alan did?
Bob: http://www.vansairforce.com/community/showthread.php?t=18858&highlight=oil
Alan: http://www.vansairforce.com/community/showthread.php?t=12633
Thanks
Looking at the links below that I think you are referring to, it looks like the pics aren't available. Does anyone else have better links, or a recollection of what Bob/Alan did?
Bob: http://www.vansairforce.com/community/showthread.php?t=18858&highlight=oil
Alan: http://www.vansairforce.com/community/showthread.php?t=12633
Thanks
BillL
Well Known Member
Engine Design-Oil cooler facts.
It is logical to think so, but the potential failure modes jump up and bite you. The actual issue, is that some engines once had this system where the oil cooler was completely blocked off. There were instances where it closed off completely and went to altitude a very cold temperatures and the oil gelled (below -20F) in the cooler. So, then returning to higher temps and needing the oil flow again, the cooler was essentially blocked and no oil cooling occurred. There was a failure and serious consequences. This is why the current designs use some flow through the cooler at all times.
It is logical to think so, but the potential failure modes jump up and bite you. The actual issue, is that some engines once had this system where the oil cooler was completely blocked off. There were instances where it closed off completely and went to altitude a very cold temperatures and the oil gelled (below -20F) in the cooler. So, then returning to higher temps and needing the oil flow again, the cooler was essentially blocked and no oil cooling occurred. There was a failure and serious consequences. This is why the current designs use some flow through the cooler at all times.
AlexPeterson
Well Known Member
Carl Froehlich
Well Known Member
One other thought. Talking with my neighbor that did the south then north pole in his Lancair IV, he had -30 degrees over the north pole. With all air shutdown to his oil cooler he still could not get oil temp over 90 or so.
After he got back I thought about the paths for heat to leave the oil. On his plane the special, oversize 16 quart oil sump presented a huge cooling area for the oil to dissipate heat. Here adding some insulation to the sump would have, I believe, significantly helped retain oil heat. Something like this: http://www.aircraftspruce.com/catalog/appages/koolmat.php?clickkey=183585
That said I would be surprised that any RV would need to resort to insulating the oil sump. My coldest run in either the RV-8 or RV-10 has been around 5 degrees. Closing the butterfly valve to cut off air to the oil cooler has always been adequate to keep oil temps at 180 or so.
Carl
After he got back I thought about the paths for heat to leave the oil. On his plane the special, oversize 16 quart oil sump presented a huge cooling area for the oil to dissipate heat. Here adding some insulation to the sump would have, I believe, significantly helped retain oil heat. Something like this: http://www.aircraftspruce.com/catalog/appages/koolmat.php?clickkey=183585
That said I would be surprised that any RV would need to resort to insulating the oil sump. My coldest run in either the RV-8 or RV-10 has been around 5 degrees. Closing the butterfly valve to cut off air to the oil cooler has always been adequate to keep oil temps at 180 or so.
Carl
Temperature update
Thought I would make some longer flights without varying power and altitude to see the results of installing shutter on upstream side of oil cooler and a blank plate on the downstream side and here is what I got.
OAT 15, CHT Spread 290 to 301, Oil Temp 145, Altitude 300 feet
OAT 30, CHT Spread 300 to 310, Oil Temp 150, Altitude 1500 feet
OAT 32, CHT Spread 311 to 318, Oil Temp 160, Altitude 4000 feet
Power was set at 65% running in LOP mode...all runs were at least 20 miles long...warmer, thinner air = higher oil temps.
Thought I would make some longer flights without varying power and altitude to see the results of installing shutter on upstream side of oil cooler and a blank plate on the downstream side and here is what I got.
OAT 15, CHT Spread 290 to 301, Oil Temp 145, Altitude 300 feet
OAT 30, CHT Spread 300 to 310, Oil Temp 150, Altitude 1500 feet
OAT 32, CHT Spread 311 to 318, Oil Temp 160, Altitude 4000 feet
Power was set at 65% running in LOP mode...all runs were at least 20 miles long...warmer, thinner air = higher oil temps.
