CHT's

mikefitz · #1 06-02-2010, 04:56 PM

I have an 0-320 in a -6 with a Flightdek D-180. Cylinders 1 and 2 have similar temps but 3 is the hottest and 4 is the coolest. I moved probes 1 and 2 back to 3 and 4 and the gap narrowed but confirmed 3 is hotter than 4. The oil cooler is behind 4 so there may be a higher exchange of air on that side. Thoughts and #'s you see would be appreciated.

Mike
RV-6 N12M

asav8tor · #2 06-02-2010, 05:00 PM

CHT differences are caused by 2 different things, fuel distribution and airflow distribution. You did not mention if you have FI or carb? If you have FI you would want to balance that first before attacking airflow.

mikefitz · #3 06-02-2010, 07:03 PM

It's a carb. Vans cowling and baffle kit with a good fit.
Mike

N941WR · #4 06-02-2010, 08:07 PM

Mike,

Go to the hardware store and get some aluminum tape and use it to put a small air dam in front of #1 & #2 cylinders. Place the tape so about an inch sticks up in front of the cylinders. This will work to push some of the air up and over the cylinders, raising their temps and lowering #3 & #4.

Kyle Boatright · #5 06-02-2010, 08:35 PM

Quote:

Originally Posted by mikefitz

I have an 0-320 in a -6 with a Flightdek D-180. Cylinders 1 and 2 have similar temps but 3 is the hottest and 4 is the coolest. I moved probes 1 and 2 back to 3 and 4 and the gap narrowed but confirmed 3 is hotter than 4. The oil cooler is behind 4 so there may be a higher exchange of air on that side. Thoughts and #'s you see would be appreciated.

Mike
RV-6 N12M

I have the same engine and had the same issues. A 1.5" or thereabouts cylinder head blocker in front of #1 really evened things out.

mikefitz · #6 06-03-2010, 04:59 AM

The baffle kit I have included the air dams. Early in the climb, I see temps in the mid to high 300's on 1 and 2. 3 will blow right past 400 without a power reduction. #4 is low 300's. Again, I think there is some error in probes. When I moved 1 and 2 back to 3 and 4, the spread narrowed some and maybe the temps were a little lower.This is with a cruise climb to keep up the flow. I'm mostly curious as to what temps others see and what is a max time and temp.
Mike

Kyle Boatright · #7 06-03-2010, 05:19 AM

Quote:

Originally Posted by mikefitz

The baffle kit I have included the air dams. Early in the climb, I see temps in the mid to high 300's on 1 and 2. 3 will blow right past 400 without a power reduction. #4 is low 300's. Again, I think there is some error in probes. When I moved 1 and 2 back to 3 and 4, the spread narrowed some and maybe the temps were a little lower.This is with a cruise climb to keep up the flow. I'm mostly curious as to what temps others see and what is a max time and temp.
Mike

With an air dam on #1, #3 is still my hottest cylinder and will go to ~410 in an extended steep climb. In a normal climb, it peaks at around 400F. The others are 15-25 degrees lower. In cruise, I see temps between 340 and maybe 370, depending on power settings, ambient temps, etc. #3 is slightly higher (5-10 degrees) than the other 3.

mikefitz · #8 06-03-2010, 05:38 AM

The engine is a fresh overhaul with 8 hrs now. Don't you think the temps will decrease some? If so, how much?