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Oil temps

S

steveciha

Well Known Member
I fly a 7a with 180 hp lycoming. oil cooler is baffle mounted per Van's fwf kit. Oil temps are usually below 210 but on hot Iowa days, it will top out at 220 degrees. Some people say this is no problem, but i am concerned about what temps would do if i venture into warmer still places, such as desert southwest usa. I know that cylinder head temps have been lowered by placing the spacer on the rear baffle areas. Has anyone noticed any decrease in oil temps by doing this? Theory being higher air flow and perhaps a change in air flow patterns at the cooler location. One thing i notice is that the lower part of the cooler is in the airflow location that would first cool the cylinder head and then go through the cooler. Does not seem like the ideal situation.

Steve Ciha
 
This is not unusual. Sounds pretty typical for my RV8 here in the desert southwest....which has been getting a lot of rain lately. Kinda neat.

Anyway, you didn't mention if your engine is new, fully broken in, or if this is suddenly a new problem after years of flying with lower temps. A tight, new engine is going to run hot, as will a worn out engine that is blowing by leaking rings. Is cylinder head temperature also high? Try to correlate as many data points as you can to narrow down what is going on. Try mixture adjustments too. Every lycosaur/RV combo has it's unique pulse....how it likes to breathe and run. Your plane may just like to run on the warm side.
 
Plane is 3 years old. second rv built. 140 hours on new engine. oil temp problems only on hot days. cht's all below 400 degrees in cruise. I may try bumping the oil pres up to 90 to see if that makes a difference.
 
Lyc Ops Manual

From Lycoming Ops Manual
Oil Inlet temperatures.
Temperature for Longevity 176?F
Maximum 244?F
Pete
 
Stewart Warner

steveciha said:
I fly a 7a with 180 hp lycoming. oil cooler is baffle mounted per Van's fwf kit. Steve Ciha
Click to expand...
What oil cooler? You can expect to drop temp with SW (Stewart Warner) oil cooler. The preferred part number is 8406R. Yes it is well over $400, but you get what you pay for. If you have another brand cooler the SW will lower temps noticeably. One builder say 18F lower oil temp going from a Aero Classic to a SW oil cooler.

http://www.rvproject.com/20040519.html (read flt test comments towards bottom)

Something to consider. Oil temp you have is not horrible but I like it in the 190F-200F range for max oil temp in cruise. Good Luck. I am a cheap skate but I am willing to spend double for the top of line cooler. Some (not all) of the other coolers are OK, but they don't cool as efficiently. They are fine for 320's and RV-4's**.

**( The RV-4 seems to be universily the best cooled RV, if anyone can tell me why they think that is so let me know; it's a mystery to me).
 
Last edited:
Thanks to all for the input. My cooler is the 7 row that Van's puts in the fwf kit. I assumed it to be a Stewart Warner clone. Perhaps i am wrong?
 
CLONE? Yea you don't have a SW

steveciha said:
Thanks to all for the input. My cooler is the 7 row that Van's puts in the fwf kit. I assumed it to be a Stewart Warner clone. Perhaps i am wrong?
Click to expand...
Operative word is clone. It is not a SW in anyway. It is like a Rolex you can by on the streets of NY for $40. Yes you have a "bargain" value priced unit. If you go to SW you will see a significant reduction in oil temp. Clone just means it is about the same size as one of the SW models. Performance wise they are very differnt.
 
Bad Analogy

Bad analogy, George.
The copy Rolex you buy on the street in NY or HKG will be much more accurate than the genuine article.
But we know what you mean.
Pete.
 
After reading the article on the linked site that Gmcjetpilot referenced, I am convinced that changing oil coolers is a step in the right direction. It contained some really good information. The cost does not scare me really. I just was not aware that there was such a vast difference in performance between the two units. Will stop by the hanger tonight and make sure i get the steel AN fittings as well and do it up right. I will change things out and report back.

steve ciha
 
Another oil cooler air flow option.

Steve,

I have an RV-9A with an ECI Titan 160 HP O-320 in it built by Penn Yan Aero Service. I know it runs cooler, but....

Look at the third photo on this web page for a simple idea that may help your situation.

http://www.n2prise.org/rv9a073.htm

I got this tip from another RV builder and put it in my airplane while it was still under construction to aid in the flow of the air to the oil cooler. I also thought about putting my oil cooler higher on the back baffle, but quickly discovered why Van's wanted it mounted lower.

The little modification also allowed my air seal fabric to run straight across the back baffle to meet up with the upper cowl.

My typical oil temperature at cruise is 180 degrees F or less depending on altitude, etc. Above 10,000 feet, full power at 2,300 RPM and C/S prop gives 160 MPH TAS on about SIX gallons per hour. My hottest CHT is around 370 degrees F up there. Below 8,000 feet, I still run at reduced throttle settings to maintain 160 MPH and a low fuel-burn rate. I could run at full power below 8,000 and get up to 180 MPH, but the fuel burn goes up around 8 GPH. With the reduced power settings, I figure that I will get longer engine life as the guy quoted above from the Lycoming manual.

Jerry K. Thorne
East Ridge, TN
RV-9A N2PZ
189.6 Hobbs Hours
 
Nice mod to the baffles, Jerry. I can see where it would make running the cowl seal material easier, but i am not sure that it would facilitate better air flow through the cooler.

I ordered goodies from Spruce yesterday. . will put the new cooler on next week and report back if there is noticable improvement.

steve
 
oil temp issue solved

Thanks to everyone who replied with advice on what i perceived as higher than desired oil temps. I bought the 6 row Stewart Warner and installed it a couple weeks ago. Both the trip to Oshkosh and the trip home happened on 90 degree days. Highest oil temp seen was 205 degrees. I believe that i have seen an honest 15 degree improvement.
 
engine temp on my rv4 is always a going concern for me[320 160hp] 0n hots days this time of the year 180 dgs but the winter time i plate my oil cooler and cover half of my cowl intakes and its still hard to get up to temp.
 
First oil temp alarm: Ripon/Fisk Arrival @ 90 knots.

I was tooling along over Fisk Boulevard heading for runway 36L when the red warning light came on and this time, it was not switch the fuel tanks. After a long slow run up from Ripon/Fisk, etc. the oil temp finally reached 213 degrees for the first time. I realized that with my heavy load of camping gear and my hangar mate in the right seat, my angle of attack and low speed was not helping my cooling. By the time we reached home-built camping and turned off the engine, the temp said 217 degrees as I switched off the avionics master.

On the way home Wednesday, the alarm tripped again when we diverted around the west end of the big line of storms spread from Saint Louis to Chicago. It was really hot at our fuel stop near Brookfield, MO. The oil temp alarm went off during the climb to altitude. Up above the scattered layer at cruise altitude and speeds, all was fine as usual, around 180 degrees F.

My Oshkosh photos and text begin at this web page http://www.n2prise.org/rv9a219.htm#Osh2006 and end on my page 227.

Jerry K. Thorne
East Ridge, TN
RV-9A N2PZ Hobbs hours = 202.5
 
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