CHT again

[Lance Murray]

CHT's this high are a problem you need to correct either through maintenance, inspection/repair of the baffles or pilot technique. Something isn't right. 400 degrees is the number that you need to take action on immediately. What are your EGT's running at? If your baffles are in good condition then what is your ignition timing set at? Is it possible your timing is advanced? What is your leaning technique?

https://www.youtube.com/watch?v=fqe9j74qMdk

This whole conversation is...surprising. I just flew from Seattle to Austin and back -- 11 days -- in a variety of conditions. Most cruise was at 22/2200 or 22/2300; fuel burn ran to 7.5- 8.0. But the CHTs were, as always, in the low 400s the whole way, with #3 coming in the hottest at 430-440 most of the time (and up to 470 if I bumped up to 2500 on climb).

This is how this plane (2007 XL) has run for the 2.5 years I've owned it. I can't imagine how y'all are getting such low CHTs; we seem to be doing the same things, but I'm consistently getting a much hotter result. Thoughts on what might be different?

[Rich]

This whole conversation is...surprising. I just flew from Seattle to Austin and back -- 11 days -- in a variety of conditions. Most cruise was at 22/2200 or 22/2300; fuel burn ran to 7.5- 8.0. But the CHTs were, as always, in the low 400s the whole way, with #3 coming in the hottest at 430-440 most of the time (and up to 470 if I bumped up to 2500 on climb).

This is how this plane (2007 XL) has run for the 2.5 years I've owned it. I can't imagine how y'all are getting such low CHTs; we seem to be doing the same things, but I'm consistently getting a much hotter result. Thoughts on what might be different?

Sara, I can't find if you mentioned it, but do you have an electronic ignition (Electroair, LASAR, etc.). And what actual EGTs are you running? Do you have Powerflow exhaust?

[Chromer]

Good afternoon everyone,
I have a 2002 and had the same problem with my CHT for the past couple of years. It would run 420 on the climb out (2400 RPM) and then 410 (2400 RPM) at cruise. It made me a little nervous with this high temp. I noticed that a few on the forum have indicated that the problem may be worn baffles, I changed the baffles and this brought the temp down to around 370 at climb out (2400 RPM), and 380 (2400 RPM) at cruise. At times the temp would climb a bit but still ran cooler.
I was doing some research and found this video. The video is about running over square, https://www.youtube.com
/watch?v=A1fmNFWNHD4.
I tried this and I brought my CHT down to 366 on cruise at 2200 RPM still cruise at 130 knots. The video explains the reason for running over square. I only brought the manifold pressure up .3-.5 in Hg. This has made a difference for my plane. Might be worth a look.

[Rich]

Good afternoon everyone,
I have a 2002 and had the same problem with my CHT for the past couple of years. It would run 420 on the climb out (2400 RPM) and then 410 (2400 RPM) at cruise. It made me a little nervous with this high temp. I noticed that a few on the forum have indicated that the problem may be worn baffles, I changed the baffles and this brought the temp down to around 370 at climb out (2400 RPM), and 380 (2400 RPM) at cruise. At times the temp would climb a bit but still ran cooler.
I was doing some research and found this video. The video is about running over square, https://www.youtube.com
/watch?v=A1fmNFWNHD4.
I tried this and I brought my CHT down to 366 on cruise at 2200 RPM still cruise at 130 knots. The video explains the reason for running over square. I only brought the manifold pressure up .3-.5 in Hg. This has made a difference for my plane. Might be worth a look.

I believe this link will work better:
https://www.youtube.com/watch?v=A1fmNFWNHD4

[Chromer]

Thanks, I didn't notice it moved to the next line

[astaib]

Hi Daryl,

Your feedback is interesting for me. Can you tell me if the Baffle that you changed was the "non-Arizona" one, and if you replaced by the "Arizona" one? Did you change all the 4 baffles + the seals in the same time?

I also have a 2002 version that is equipped from the origin with "non-Arizona" Baffle for cylinder 1, and I just bought the "Arizona" version.
I will have it installed in the coming weeks, and I hope that it will help me to reduce the CHT.

Arnaud.

[Rich]

Hi Daryl,

Your feedback is interesting for me. Can you tell me if the Baffle that you changed was the "non-Arizona" one, and if you replaced by the "Arizona" one? Did you change all the 4 baffles + the seals in the same time?

I also have a 2002 version that is equipped from the origin with "non-Arizona" Baffle for cylinder 1, and I just bought the "Arizona" version.
I will have it installed in the coming weeks, and I hope that it will help me to reduce the CHT.

Arnaud.

Generally when you see "replace baffles" you should assume it means replacing the flexible strips along the top. Those components are subject to wear and loss of flexibility. Not expensive to replace, but kind of tedious, with really tiny, easily dropped and lost forever, machine screws attaching them to the rigid portions.

[Chromer]

Hi Arnaud,
Rich is correct, its the flexible strips. I talked with the engine shop and he suggested silicone instead of rubber. I have the original fiberglass baffle on the right side. I would be interested to see the difference and the total cost to replace it. Summers can get pretty warm here in the valley so I want to look at all of my options.
If you have any pictures of the new baffle it would be great to see.

Thanks
Daryl

[astaib]

Hello,

I was sure that Baffle means the rigid parts, and seals the flexible strips.
In my case, I already changed last year the seals that were old and worn, but it has no effect on my CHT's.
And now I'm about to change only one of the 4 baffle (rigid part) that has had an evolution compare to mine that was mounted on my early bird from 2001. This evolution is a bigger hole for air intake, I hope it will have an impact on the CHT's for that price!

@Daryl: I didn't knew that there was differents seals (silmicone or rubber), I don't know which one was mounted during the replacement last year.

Arnaud.

[blsewardjr]

Arnaud- In English, the rigid parts are the "baffles" and the flexible parts are the "baffle seals". See https://www.aopa.org/news-and-media/all ... ne-baffles

However, I suspect that since most aircraft never need the rigid parts replaced, American pilots tend to use the term "baffles" when they are really referring to "baffle seals."