EGT and CHT red line

[MichRV10]

In reguards to the limits on the cht and egt what is recomended redline for the IO-540?
When I lean the engine out i goes above 1400 for egt's. I have never pulled the mixture out far enough for the engine to run rough to find peak.
Cht's are all around 360 and below.
What is too hot for each?

3135F

[w1curtis]

Originally Posted by MichRV10

In reguards to the limits on the cht and egt what is recomended redline for the IO-540?
When I lean the engine out i goes above 1400 for egt's. I have never pulled the mixture out far enough for the engine to run rough to find peak.
Cht's are all around 360 and below.
What is too hot for each?

3135F

EGT maximums are largely irrelevant as long as the CHT is kept below a maximum. Lycoming recommends a maximum CHT of 420 for continued cylinder health, my personal maximum is 400 and my engine analyzer is programmed to begin alerting me at 380. As you lean your EGT can rise to something about 1600 while on the rich side to a peak and then fall back as you move to the lean side of the curve. As long as you don't operate per longed within 25 degrees of the peak on the rich side, it doesn't really matter what the actual temperature is.

[airguy]

Within reason - turbo inlet temps do have limitations

[Mark]

It's essential to keep all CHT's at or below 380 deg. during cruise to achieve good cylinder longevity, and 350 deg. is even better.

Mark (N410MR)

[Kahuna]

Originally Posted by MichRV10

In reguards to the limits on the cht and egt what is recomended redline for the IO-540?
When I lean the engine out i goes above 1400 for egt's. I have never pulled the mixture out far enough for the engine to run rough to find peak.
3135F

Your waisting a lot of fuel. Why would you not lean to peak? It sounds like you might want to retain another pilot with experience to to walk you through the leaning process so you get your desired LOP or ROP operations.

[Jeffreymd]

what series and hp io540 do you have. i have the i0-540-"d4a5", 260hp. i had the 9.2-1 pistons installed which makes it a 280hp. these #'s come straight out of the lycoming operator's manual. here's mine....max cht is 500f or 260c. general rules- for max svc life, cht's should be maintained below 435f or 224c during high performance cruise operation and below 400f or 205c for economy cruise powers. leaning egt's- normally aspirated engines with fuel injectors or carbs. 1) max power cruise(approx 75% power)- never lean beyond 150f on rich side of peak egt unless aircraft operator's manual shows otherwise. monitor cht's. 2) best economy cruise(approx 75% power and below)- operate at peak egt. i run 20f rich of peak on my hottest cylinder which comes out to about 1450f. hope this helps, jeff

[Randy DeBauw]

I would suggest you download Lycomings "Key Reprints". It is on their web site and it will answer a lot of questions for you. Randy 40006

[ScottSchmidt]

I've been told that the absolute max is 500 degrees. I have mine set at 470 even though I've never seen anything close. Although I have heard of some F1 Rocket guys hitting 500 on hot days while they were climbing out at max rate of climb. I've also been told that you will start to lose propeller control when oil temps start approaching 240 to 250 F.