gmcjetpilot
Well Known Member
Solve High CHT with Timing
EDIT: Meant High CHT
I found this YouTube channel Savvy Aviation, Mike Busch. These are webinars hosted by the EAA over the last few years. See video link below. It's about pre-ignition but he specifically talks about RVs and timing. Every video is fantastic, they're long but chalked full of great information on engines. Starting at 58:00 in video below he starts to talk about 25 degrees BTDC, before top dead center, being a little aggressive and the cause of high CHT in Lycomings. He spacifically talks about RVs. If you go back to the beginning of the video or the beginning of the Q&A there's all kind of good information. Lycoming later issue revised timing on IO360's to 20 degrees before top dead center.
https://youtu.be/bZLxcWAk9Nc
The topic of detonation, pre ignition, and engine self-destruction is pretty fascinating. He's a proponent of setting 380?F as your yellow or warning CHT. He goes on to say for Lycoming you might push that to 400?F but anything above that is abusive. Agree that has been my policy. This is below Lycs recommend temp limit. Lycoming has a red line of 500?F. That temperature is unacceptable. If I see 400-420?F I am going to take action (enrich mixture, lower power, reduce climb or level off if climbing). He also points out that spark plug ring CHT probes read about 40?F low. All the videos are amazing.
EDIT: Meant High CHT
I found this YouTube channel Savvy Aviation, Mike Busch. These are webinars hosted by the EAA over the last few years. See video link below. It's about pre-ignition but he specifically talks about RVs and timing. Every video is fantastic, they're long but chalked full of great information on engines. Starting at 58:00 in video below he starts to talk about 25 degrees BTDC, before top dead center, being a little aggressive and the cause of high CHT in Lycomings. He spacifically talks about RVs. If you go back to the beginning of the video or the beginning of the Q&A there's all kind of good information. Lycoming later issue revised timing on IO360's to 20 degrees before top dead center.
https://youtu.be/bZLxcWAk9Nc
The topic of detonation, pre ignition, and engine self-destruction is pretty fascinating. He's a proponent of setting 380?F as your yellow or warning CHT. He goes on to say for Lycoming you might push that to 400?F but anything above that is abusive. Agree that has been my policy. This is below Lycs recommend temp limit. Lycoming has a red line of 500?F. That temperature is unacceptable. If I see 400-420?F I am going to take action (enrich mixture, lower power, reduce climb or level off if climbing). He also points out that spark plug ring CHT probes read about 40?F low. All the videos are amazing.
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