Re: CHT & EGT per cylinder
Posted: Sat Nov 14, 2020 10:45 pm
The only thing i can tell you is that the CHT difference is related among other parameters to the position of each cylinder relative to the airflow.
Nearly all the engines used in GA aircraft are flat four or six cylinders either from Continental or Lycoming, carbureted or fuel injected (not talking about the more exotic ones used in ultralights or VW conversions which is a different story)
The two frontmost cylinders usually run more cooler than the rearmost ones, since they catch only the airflow that enters the cowling and progresses to the back, while the back cylinders ( #1 & #2 iirc) are hotter since they also get hot air from the frontmost cylinders. A CHT difference between front and back cylinders of around 40-100F is not uncommon. And each engine has it's own "hotter" cylinder, due to slight mechanical differences in valves, springs, piping, etc...but you know that better than me.
As per EGT, it is commonly admitted to have a difference around 100F between the hottest and coldest cylinder for carbureted engines, and up to 150F for injected engines. What I saw on your video seemed right to me, but I think that cyl or 4(6) should be hotter than the others, as these cylinder are the rearmost ones.
Jacques
[EDIT]: upon research, it seems that the numbering of the cylinder is different between Lycoming (frontmost are 1 & 2 counting towards the rear) and Continental (3(5) & 4(6) counting from the rear of the engine), the even numbers being on the left side!
Nearly all the engines used in GA aircraft are flat four or six cylinders either from Continental or Lycoming, carbureted or fuel injected (not talking about the more exotic ones used in ultralights or VW conversions which is a different story)
The two frontmost cylinders usually run more cooler than the rearmost ones, since they catch only the airflow that enters the cowling and progresses to the back, while the back cylinders ( #1 & #2 iirc) are hotter since they also get hot air from the frontmost cylinders. A CHT difference between front and back cylinders of around 40-100F is not uncommon. And each engine has it's own "hotter" cylinder, due to slight mechanical differences in valves, springs, piping, etc...but you know that better than me.
As per EGT, it is commonly admitted to have a difference around 100F between the hottest and coldest cylinder for carbureted engines, and up to 150F for injected engines. What I saw on your video seemed right to me, but I think that cyl or 4(6) should be hotter than the others, as these cylinder are the rearmost ones.
Jacques
[EDIT]: upon research, it seems that the numbering of the cylinder is different between Lycoming (frontmost are 1 & 2 counting towards the rear) and Continental (3(5) & 4(6) counting from the rear of the engine), the even numbers being on the left side!