easyski
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- Apr 11, 2016
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This isn't really a post about a problem, but a solution; figured this might help some people in the future and maybe current
1999 Saratoga II TC TIO-540 AH1A (1700 hours TT if that matters)
I installed an engine monitor this spring and CHT on number 2 was always significantly higher than the rest (by 20 degrees for the next hottest to around 60 degrees to the coolest). On climb out, full power, full rich, I did everything I could to keep the CHT below 400. It easily reached 400 on climb at 110 kias and full power unless I pushed the nose over to 120 kias and reduced power slightly.
Recently had a high oil temp issue where it was found that the engine cooler on the right side was not sealed properly to the rear baffling causing inadequate cooling. I was able to keep the oil temp down by running almost full rich and about 55% power. My mechanic sealed some of the baffles with black RV silicone. I decided to take it upon myself to ensure it was a perfect job of sealing and with his blessing (and materials) went to work.
Almost every baffle had a pencil sized hole in the bottom corner when it met the next baffle. That made about 8 pencil sized holes along the back baffling. There were also significant gaps where baffling was bent around the rear engine mounts. Sealed those. Large gaps in the bottom corners where the baffling meets the upper and lower cowl. Also a large gap where the front baffle (by the prop) bends and is cut around the engine case. Sealed those.
Took a test flight today, full power (full rich) to 9500 ft highest CHT (still #2) never went over 370. Put into cruse setting at 80% power and leaned out to ROP 1600 TIT, hottest CHT climbed to 390 and held steady.
My typical setting when I fly is LOP 33" 2300 RPM fuel flow 14.1 to keep TIT < 1590 as anything above that TIT that would cause CHT # 2 to hover around 400 or exceed. It runs ok there, but not amazing, just not perfectly smooth. Today, was able to increase FF to 15.5 with TIT around 1620 (LOP) and CHT #2 was steady at 370 and was crusing around 10 kias faster (165 vs 155 TAS). OAT during all this was 21 Celsius on ground, 10 Celsius at altitude.
CHT for all cylinders at these settings were:
1: 346
2: 370
3: 302
4: 351
5: 315
6: 295
If you have any questions, feel free to ask. Only took me about an hour - 1.5 hours to seal everything. Obviously allow to dry for a day before you fly. Used a flash light in a dark hangar to ensure all gaps are sealed.
TLDR: Seal your baffles with RTV high temp silicone, be anal about getting every single leak and watch your CHT drop 30-40 degrees.
1999 Saratoga II TC TIO-540 AH1A (1700 hours TT if that matters)
I installed an engine monitor this spring and CHT on number 2 was always significantly higher than the rest (by 20 degrees for the next hottest to around 60 degrees to the coolest). On climb out, full power, full rich, I did everything I could to keep the CHT below 400. It easily reached 400 on climb at 110 kias and full power unless I pushed the nose over to 120 kias and reduced power slightly.
Recently had a high oil temp issue where it was found that the engine cooler on the right side was not sealed properly to the rear baffling causing inadequate cooling. I was able to keep the oil temp down by running almost full rich and about 55% power. My mechanic sealed some of the baffles with black RV silicone. I decided to take it upon myself to ensure it was a perfect job of sealing and with his blessing (and materials) went to work.
Almost every baffle had a pencil sized hole in the bottom corner when it met the next baffle. That made about 8 pencil sized holes along the back baffling. There were also significant gaps where baffling was bent around the rear engine mounts. Sealed those. Large gaps in the bottom corners where the baffling meets the upper and lower cowl. Also a large gap where the front baffle (by the prop) bends and is cut around the engine case. Sealed those.
Took a test flight today, full power (full rich) to 9500 ft highest CHT (still #2) never went over 370. Put into cruse setting at 80% power and leaned out to ROP 1600 TIT, hottest CHT climbed to 390 and held steady.
My typical setting when I fly is LOP 33" 2300 RPM fuel flow 14.1 to keep TIT < 1590 as anything above that TIT that would cause CHT # 2 to hover around 400 or exceed. It runs ok there, but not amazing, just not perfectly smooth. Today, was able to increase FF to 15.5 with TIT around 1620 (LOP) and CHT #2 was steady at 370 and was crusing around 10 kias faster (165 vs 155 TAS). OAT during all this was 21 Celsius on ground, 10 Celsius at altitude.
CHT for all cylinders at these settings were:
1: 346
2: 370
3: 302
4: 351
5: 315
6: 295
If you have any questions, feel free to ask. Only took me about an hour - 1.5 hours to seal everything. Obviously allow to dry for a day before you fly. Used a flash light in a dark hangar to ensure all gaps are sealed.
TLDR: Seal your baffles with RTV high temp silicone, be anal about getting every single leak and watch your CHT drop 30-40 degrees.
