Coopere
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- Feb 11, 2015
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Ok, so has anyone here had experience with replacing a cylinder on a lyco with regards to cht? So my aztec went into annual and I had to replace #5 on the left engine due to very low compression, looks like a leaking exhaust valve. I wanted a factory lycoming cylinder, but due to delivery issues in Canada and not wanting to be down for a month I was suggested and talked into a superior millennium cylinder. New of course.
They put the cylinder on and said " fly it at 75% power for no less than the first 2 hours. They ground ran the aircraft as per the breakin instructions by superior.
I flew it for 1 flight of about 25min at 75% power and about 12mim into the flight I got a high cht alarm from my jpi 760, cht was exceeding 450F, I immediately went full rich and verified the cowl flap was fully open, that brought the cht down to around 432f
My next coldest cylinder on that engine is 404f and they range down too 350f except number 6 that was the coldest at 290f
On my right engine they are all colder than 390F at the same power settings as per the book at 75%
Back too the flight, the alarm concerned me a great deal and as I was on with a terminal controler I informed them I needed to return to the field due to this alarm. Since I have never had any experience with cylinder replacement, I wasn't expecting to see such a hot temp.
After talking to my amo they inform me this is normal and the temp should reduce over a few hours. So with that said I set out the next day on a 2h 20min cross country. I was required on that flight to have the cowl flap mostly if not totally open to keep the temps in the 430-440f range on the new cylinder, and the others were below 390 except for 3 that was 404f and once again the next hottest cylinder I think it's picking up radiant heat off number 5
So now I have about 3 hrs on it or a little shy... I've been reluctant to fly again as I don't want to burn up a brand new cylinder. Ambient temps on both days were below -12c at alt
I also decided to look at my engine baffling, in some spots it's poorly sealed, it looks good but when u really look at it its not so hot. However I never had any issues prior to the cylinder replacement and temps were never above 395f even on hot summer days
Any suggestions? I'm thinking of replacing the engine baffling...
They put the cylinder on and said " fly it at 75% power for no less than the first 2 hours. They ground ran the aircraft as per the breakin instructions by superior.
I flew it for 1 flight of about 25min at 75% power and about 12mim into the flight I got a high cht alarm from my jpi 760, cht was exceeding 450F, I immediately went full rich and verified the cowl flap was fully open, that brought the cht down to around 432f
My next coldest cylinder on that engine is 404f and they range down too 350f except number 6 that was the coldest at 290f
On my right engine they are all colder than 390F at the same power settings as per the book at 75%
Back too the flight, the alarm concerned me a great deal and as I was on with a terminal controler I informed them I needed to return to the field due to this alarm. Since I have never had any experience with cylinder replacement, I wasn't expecting to see such a hot temp.
After talking to my amo they inform me this is normal and the temp should reduce over a few hours. So with that said I set out the next day on a 2h 20min cross country. I was required on that flight to have the cowl flap mostly if not totally open to keep the temps in the 430-440f range on the new cylinder, and the others were below 390 except for 3 that was 404f and once again the next hottest cylinder I think it's picking up radiant heat off number 5
So now I have about 3 hrs on it or a little shy... I've been reluctant to fly again as I don't want to burn up a brand new cylinder. Ambient temps on both days were below -12c at alt
I also decided to look at my engine baffling, in some spots it's poorly sealed, it looks good but when u really look at it its not so hot. However I never had any issues prior to the cylinder replacement and temps were never above 395f even on hot summer days
Any suggestions? I'm thinking of replacing the engine baffling...
