Hi CHT with 0.0 gami spread


Andrew Anunson
 

My Bendix injected Lycoming O-360 (COZY MKIV, built to plans, 1 LSE EI, 1 mag) is running hi CHT's on the #4 cylinder (see CHT and OIL TEMP image).

On the ground, not moving, the CHT's are all pretty close (see GROUND CHT image).
During taxi and climbout, the #4 leaves 1, 2, and 3 in the dust (see TAXI and CLIMB image)

The GAMI lean testing shows a spread of 0.0 to 0.5 gph (see images GAMI 1 and GAMI 2 images)

It appears to be an airflow balance issue.
What are the first steps to take?

Open up baffling for #4 cylinder?
Tighten baffling for #1, 2, and 3?

Air deflectors?

Thanks,
Andrew Anunson
Cozy MKIV #1273
Pound, VA


Roch LaRocca
 

You probably just need a ramp in the cowling or similar.  I have  a ramp for my #3 cylinder as well as a short “wall” that channels some other air flow.  Sometimes you have to work with it.  
Rock L.

On May 18, 2022, at 18:53, Andrew Anunson via groups.io <macleodm3@...> wrote:


My Bendix injected Lycoming O-360 (COZY MKIV, built to plans, 1 LSE EI, 1 mag) is running hi CHT's on the #4 cylinder (see CHT and OIL TEMP image).

On the ground, not moving, the CHT's are all pretty close (see GROUND CHT image).
During taxi and climbout, the #4 leaves 1, 2, and 3 in the dust (see TAXI and CLIMB image)

The GAMI lean testing shows a spread of 0.0 to 0.5 gph (see images GAMI 1 and GAMI 2 images)

It appears to be an airflow balance issue.
What are the first steps to take?

Open up baffling for #4 cylinder?
Tighten baffling for #1, 2, and 3?

Air deflectors?

Thanks,
Andrew Anunson
Cozy MKIV #1273
Pound, VA
CHT and OIL TEMP.PNGGROUND CHT.PNGTAXI and CLIMB.PNGGAMI GROUND.PNGGAMI FLIGHT.PNG


Steve Rothert
 

Andrew,
At what speed do you climb out?  Try climbing about 10mph faster and see how the temps behave.

If you have a NACA inlet, do you have a "diffuser" to slow down the air?   After a lot of "encouragement" from Terry Schubert and others, I built one for my 0-320 Long-Ez.  The CHTs balanced out.  #3 and #4 CHT did not rise as fast on climbout.

My $.02 worth
Steve


Tim Andres
 

Start with a CHT probe calibration. Put all 4 in boiling water .  
Also I believe #4 is almost always the hottest cyl on these planes. 
Look for anything under that area that might trip the airflow, something that might create turbulence.  I had a bracket for my cabin heater that I believe was leaking a disturbance in the force” A redesign of that helped in my case. I would also  try opening up the gaps in the cyl head baffles. 
Good luck, doesn’t look too bad overall though. 
Tim Andres

On May 18, 2022, at 11:53 AM, Andrew Anunson via groups.io <macleodm3@...> wrote:


My Bendix injected Lycoming O-360 (COZY MKIV, built to plans, 1 LSE EI, 1 mag) is running hi CHT's on the #4 cylinder (see CHT and OIL TEMP image).

On the ground, not moving, the CHT's are all pretty close (see GROUND CHT image).
During taxi and climbout, the #4 leaves 1, 2, and 3 in the dust (see TAXI and CLIMB image)

The GAMI lean testing shows a spread of 0.0 to 0.5 gph (see images GAMI 1 and GAMI 2 images)

It appears to be an airflow balance issue.
What are the first steps to take?

Open up baffling for #4 cylinder?
Tighten baffling for #1, 2, and 3?

Air deflectors?

Thanks,
Andrew Anunson
Cozy MKIV #1273
Pound, VA


skovbjerg
 

I will suggest one action at a time.
Open below cyl 4 and be sure to close around the head on top. Then onto the others.
This is what I am looking at right now.
WOT / ROP climb to 8,500, then lean to LOP around 65% cruise:


On May 18, 2022, at 11:54, Andrew Anunson via groups.io <macleodm3@...> wrote:


My Bendix injected Lycoming O-360 (COZY MKIV, built to plans, 1 LSE EI, 1 mag) is running hi CHT's on the #4 cylinder (see CHT and OIL TEMP image).

On the ground, not moving, the CHT's are all pretty close (see GROUND CHT image).
During taxi and climbout, the #4 leaves 1, 2, and 3 in the dust (see TAXI and CLIMB image)

The GAMI lean testing shows a spread of 0.0 to 0.5 gph (see images GAMI 1 and GAMI 2 images)

It appears to be an airflow balance issue.
What are the first steps to take?

Open up baffling for #4 cylinder?
Tighten baffling for #1, 2, and 3?

Air deflectors?

Thanks,
Andrew Anunson
Cozy MKIV #1273
Pound, VA
<CHT and OIL TEMP.PNG>
<GROUND CHT.PNG>
<TAXI and CLIMB.PNG>
<GAMI GROUND.PNG>
<GAMI FLIGHT.PNG>