Mooney Bravo CHT #2 Cylinder

[Nick G]

5 minutes ago, LANCECASPER said:

What power settings are you running at in climb ad in cruise? 

34/2400 in climb

30/2300 in cruise 

[Nick G]

1 minute ago, Nick G said:

34/2400 in climb

30/2300 in cruise 

Also, I’m curious as to how much of a potential problem having an exhaust slip joint directly above that CHT probe that’s pumping out 1500 degree heat would cause the CHT to rise more than cylinders without it. 

Edited November 17, 2025 by Nick G

[LANCECASPER]

18 minutes ago, Nick G said:

I’ve been talking with the previous owner as well and he said #2 was always hotter but not that bad. I’ll see if I can figure out that baffling test as well. Thx!

There's actually two ways to cool that engine, air and fuel.

Make sure on a turbo-charged engine that you aren't leaning in the climb. On that engine in particular you need the cooling of the fuel to keep it cool.

Until you get it figured out even in cruise I would keep enough fuel flowing (don't lean as much) to keep those CHTs under 400

[LANCECASPER]

4 minutes ago, Nick G said:

Also, I’m curious as to how much of a potential problem having an exhaust slip joint directly above that CHT probe that’s pumping out 1500 degree heat would cause the CHT to rise more than cylinders without it. 

That probe is screwed into the cylinder. It's not being affected by that slip joint.

[IvanP]

Cyl #2 in my Bravo is always the lowest temp in all phases of flight. Recent baffling (3 yrs), CHTs stay below 400F in climb at 110-120 KIAS. In cruise on high power, I need to crack open the cowl flaps a bit to keep CHT on my hottest cylinder (#5) below 400F. I run ROP - too chicken for LOP.

[Nick G]

4 minutes ago, LANCECASPER said:

That probe is screwed into the cylinder. It's not being affected by that slip joint.

Hmmm. I’ve had two people tell me it could so I’m not sure what to attack. 

[LANCECASPER]

7 minutes ago, Nick G said:

34/2400 in climb

30/2300 in cruise 

34/24 can be used in a cruise climb, as long as you keep the Indicated Airspeed at 120 to keep plenty of air coming on over the cylinders and provided you aren't leaning the mixture in climb. I preferred full power (and of course full rich) - it gets you to cooler air and cruise altitude faster and if you do the math you actually burn less total fuel for the entire flight since you're getting up to your most efficient altitudes sooner.

30/23 works fine for cruise. On all three of the Bravos I had 29/24 was a little louder but smoother (less vibration). If you lean to 1600 or below (I kept mine at 1580) your cylinders can last as long as the engine does - provided you get everything figured out to be able to keep CHTs 380 or below.

[LANCECASPER]

1 minute ago, Nick G said:

Hmmm. I’ve had two people tell me it could so I’m not sure what to attack. 

Send a picture if you get a chance of not only that but a few of your whole engine

 

Also on some engines I've see it where the inter cylinder baffles either weren't there or where installed incorrectly.

[LANCECASPER]

8 minutes ago, IvanP said:

Cyl #2 in my Bravo is always the lowest temp in all phases of flight. Recent baffling (3 yrs), CHTs stay below 400F in climb at 110-120 KIAS. In cruise on high power, I need to crack open the cowl flaps a bit to keep CHT on my hottest cylinder (#5) below 400F. I run ROP - too chicken for LOP.

You probably know this already but the cowl flaps should be set up so that the "closed" position is open at least 1/2 inch. Not only does it keep the cylinders cooler, but it's actually faster. If the air pushed into the engine can't go anywhere the lack of airflow acts as a speed brake.

[LANCECASPER]

9 minutes ago, Nick G said:

Hmmm. I’ve had two people tell me it could so I’m not sure what to attack. 

I would do the flashlight test first, then if necessary swap the CHT probes, then if you get that far have someone that knows these engines look at the intercylinder baffles (metal with "springs" between the cylinders).

[Nick G]

4 minutes ago, LANCECASPER said:

I would do the flashlight test first, then if necessary swap the CHT probes, then if you get that far have someone that knows these engines look at the intercylinder baffles (metal with "springs" between the cylinders).

Sounds like a plan. I don’t remember seeing the intercylinder baffles but not sure what they look like. We’ll look at those as well

Edited November 17, 2025 by Nick G

[IvanP]

3 minutes ago, LANCECASPER said:

You probably know this already but the cowl flaps should be set up so that the "closed" position is open at least 1/2 inch. Not only does it keep the cylinders cooler, but it's actually faster. If the air pushed into the engine can't go anywhere the lack of airflow acts as a speed brake.

I will have to check the flap alignment in closed position as I never have the flaps closed on the ground. Thanks for the tip. 

[LANCECASPER]

Sounds like a plan. I don’t remember seeing the intercylinder baffles. You sure that motor had them?

100% - you see them from below the engine

Items 16, 17 & 18 below

[LANCECASPER]

5 minutes ago, IvanP said:

I will have to check the flap alignment in closed position as I never have the flaps closed on the ground. Thanks for the tip. 

Mooney discovered that trailing position on the flaps being faster on the flight testing for the Mooney 252. But in the field if a maintenance shop or owner doesn't know that they think the rigging is off so they adjust it to fully closed on the "closed" position.

[Nick G]

5 minutes ago, IvanP said:

I will have to check the flap alignment in closed position as I never have the flaps closed on the ground. Thanks for the tip. 

Seems like mine are about that when closed. I can never come close to closing them in flight 

[Nick G]

11 minutes ago, LANCECASPER said:

100% - you see them from below the engine

Items 16, 17 & 18 below

Awesome. Thx! Would have time for a quick conversation by phone? 512-820-6612

[Gee Bee Aeroproducts]

Baffle seal

correct thickness 

cut from a sheet, not a roll 

fiberglass reinforcement 

ams3320.093 spec 

die cut to original spec