has anyone else been getting high oil temps. i have to run 22'/2300rpm on warm days(>70f) to keep the temps under 200. if not, they climb to 210-215. my lycoming manual says to run the oil temps between 160-200f for longer life. i was thinking about running another skat tube from the oil cooler to it's own exit point, like a vent of some sorts. my cht's go up above 400 on those same days when i'm climbing more than 1000fpm. any ideas? or is this just an rv10 thing?????
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high oil temps
- Thread starter Jeffreymd
- Start date
gmcjetpilot
Well Known Member
New engine
What oil cooler? How is it mounted? 4" SCAT right (standard for the RV10 I think)? Is the engine new?Jeffreymd said:
f1rocket
Well Known Member
I can't comment on the RV-10 specifically, but I do run an IO-540. I have a hard time getting my oil temp up to 200 dF. Based on my experience, and what other Rocket owners have experienced, here are some suggestions:
1) First, previous posters are right in that a new engine will make more heat for awhile. I don't have the explanation, I just know that I found it to be true. So maybe do nothing for awhile. You can run your oil up to 220 to 230 and still be within Lycoming's limits. I see from your engine hours above that you are beyond the break-in period, so this is probably not the problem
2) The 4" SCAT tube is a very ineffective way to route air to the cooler. This only provides you with 12.5 " sq of airflow. Measure the face of your oil cooler. I don't remember the exact dimensions but I think its about 16" to 17" sq. So if you stay with this set up, you are not going to be able to move the maximum amount of cooling air through the cooler under any circumstances. I know you probably don't want to change this so you might try other things first. I mounted my cooler to the engine mount tubes and built a plenum chamber off the baffle. Pictures are on my website. Here's a key. I was told (don't know if its true) that if the lower and upper surfaces of the oil cooler plenum chamber diverge more that 12 degrees, a turbulence will be created right in front of the cooler, reducing its efficiency.
3) Having a really tight baffle seal to the cowl is important to both engine cooling and oil cooling. The higher the pressure, the more air volume you can push over the cylinders and through the cooler. Do you have a real tight fit with no gaps? I have a plenum chamber I built out of aluminum using Van's RV-10 baffle kit. I have zero air leakage.
4) On van's baffle kit, the ramp to the cylinders is abrupt. I smoothed this airflow out by inserting an aluminum ramp up to the cylinders. I also did the same on the top surface of the air inlets. Do you have the fiberglass inlet ramps installed? This change alone lowered by cylinder temps by about 50 dF. I learned my leason about have a smooth, un-interrupted air flow into the plenum.
Good luck on tracking this down. Fluid dynamics is a mind boggling subject. You think it works one way but find out it doesn't. Sometimes, I think its luck. I've tried to copy what has worked well for other builders and so far, its worked out for me.
1) First, previous posters are right in that a new engine will make more heat for awhile. I don't have the explanation, I just know that I found it to be true. So maybe do nothing for awhile. You can run your oil up to 220 to 230 and still be within Lycoming's limits. I see from your engine hours above that you are beyond the break-in period, so this is probably not the problem
2) The 4" SCAT tube is a very ineffective way to route air to the cooler. This only provides you with 12.5 " sq of airflow. Measure the face of your oil cooler. I don't remember the exact dimensions but I think its about 16" to 17" sq. So if you stay with this set up, you are not going to be able to move the maximum amount of cooling air through the cooler under any circumstances. I know you probably don't want to change this so you might try other things first. I mounted my cooler to the engine mount tubes and built a plenum chamber off the baffle. Pictures are on my website. Here's a key. I was told (don't know if its true) that if the lower and upper surfaces of the oil cooler plenum chamber diverge more that 12 degrees, a turbulence will be created right in front of the cooler, reducing its efficiency.
3) Having a really tight baffle seal to the cowl is important to both engine cooling and oil cooling. The higher the pressure, the more air volume you can push over the cylinders and through the cooler. Do you have a real tight fit with no gaps? I have a plenum chamber I built out of aluminum using Van's RV-10 baffle kit. I have zero air leakage.
4) On van's baffle kit, the ramp to the cylinders is abrupt. I smoothed this airflow out by inserting an aluminum ramp up to the cylinders. I also did the same on the top surface of the air inlets. Do you have the fiberglass inlet ramps installed? This change alone lowered by cylinder temps by about 50 dF. I learned my leason about have a smooth, un-interrupted air flow into the plenum.
Good luck on tracking this down. Fluid dynamics is a mind boggling subject. You think it works one way but find out it doesn't. Sometimes, I think its luck. I've tried to copy what has worked well for other builders and so far, its worked out for me.
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I have an aerosport built IO-540 too. I have a hard time seeing any temps over 190 in most conditions. Back when the engine was new, the highest I think I ever saw was 215 on a 90 degree day with an extended climb. The posts above though are right....make sure you have good baffle sealing, especially around the air ramps on the inlets, and make sure the air cant flow under (through) the inlet sideways.
Tim
Tim
