CHTs - What is acceptable?

Nobody here can give you the correct CHT for your aircraft.
The engine manufacturer can, although it's like pulling teeth trying to
get it.

As a general rule, if you hold climbout to a max of 380CHT/1425 EGT and
cruise max at 350 CHT/1380EGT you won't seize or damage anything - that
is not to say that you will be at your most efficient - only that you
won't damage anything.

The most knowledgeable people I have found on this topic are Advance
Pilot Seminars. Walter Atkinson is one of their instructors and he is
often available at Cessna Owner Organization Forums.
I learned more about this subject from him than anyone else.
He teaches ROP leaning on carbs and LOP leaning on Gamis.
He really knows his subject and is the person that I recommend to answer
your question.

HTH

Tony
--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE


In article ,
(TripFarmer) wrote:

What is an acceptable CHT in cruise? How hot can one stay in extended cruise
flight? I've got 6 new ones and want to take care of them.


Thanks in advance.


Trip

TripFarmer,

What is an acceptable CHT in cruise?


anything below 400F. Have you read Deakin's columns on engine
management at www.avweb.com?

--
Thomas Borchert (EDDH)

"Stan Prevost" wrote in message ...
\ I have seen this but never understood it. Why does the maximum allowable
CHT depend on the airframe?


Not so much the airframe but where the CHT probe is located relative to the actual
head temperatures.

Yes. The redline on my Skylane is 450F, but I aim for no higher than 400,
and usually manage to keep them in the 370 range.

-jav

"Mike Rapoport" writes:

Isn't that above the melting point of aluminium?

Mike
MU-2


"Paul Tomblin" wrote in message
...
In a previous article, (TripFarmer) said:
What is an acceptable CHT in cruise? How hot can one stay in extended
cruise
flight? I've got 6 new ones and want to take care of them.

Our club instructors caution people not to lean the Lance to anything
higher than 1400 degrees.

--
Paul Tomblin http://xcski.com/blogs/pt/
Every fleeting thought you've ever had in your life, no matter how
bizarre,
is someone's lifelong obsession. And he has a website.
-- Skif's Internet Theorem

Stan Prevost wrote:
"john smith" wrote in message
...

TripFarmer wrote:

What is an acceptable CHT in cruise? How hot can one stay in extended

cruise

flight? I've got 6 new ones and want to take care of them.

I asked those questions to each of the Lycoming and Continental reps at
AirVenture a couple of weeks ago.
The answers I got were, it depends on the engine and the airframe in
which they are installed. You need a copy of the engine manual for your
airframe. A range will be given in that reference.
I was asking about Continental TSIO-360FB in a 1979 P28T and a Lycoming
I0-520K1G5 in a 1978 PA32.



I have seen this but never understood it. Why does the maximum allowable
CHT depend on the airframe?
Baffeling and type of cooling (upflow, downflow, gills, cowl flaps).

"TripFarmer" wrote in message
...
What is an acceptable CHT in cruise? How hot can one stay in extended
cruise
flight? I've got 6 new ones and want to take care of them.


Thanks in advance.


Is yours a turbo? What displacement?

Check out John Deakin's "Engine Series" at
http://www.avweb.com/news/columns/182146-1.html (specifically #'s 8, 18, 43,
63-66).

Never more than 400 degrees and typically at 370-390.

I just don't buy that "airframe" stuff. A cylinder head can only take
so much temperature for so long before it gives in. 400 degrees is
400 degrees no matter what airframe it's in. If I'm wrong please tell
me why.........

I've got about 15 hours on 6 new Superior Millinieums and just put in my
first quart of oil since 2TT. I have a range of temps at cruise from
320 - 380. They dropped a lot after about the first 30 - 60 minutes of
break in and seem to have stabilized since to these numbers. The hot one
will run 400-410 in a full power climb in my PA28 235.


Trip

In article , says...

TripFarmer wrote:
What is an acceptable CHT in cruise? How hot can one stay in extended cruise
flight? I've got 6 new ones and want to take care of them.

I asked those questions to each of the Lycoming and Continental reps at
AirVenture a couple of weeks ago.
The answers I got were, it depends on the engine and the airframe in
which they are installed. You need a copy of the engine manual for your
airframe. A range will be given in that reference.
I was asking about Continental TSIO-360FB in a 1979 P28T and a Lycoming
I0-520K1G5 in a 1978 PA32.

I just printed them all out to read at home.

Thanks.


Trip

In article , says...

TripFarmer,

What is an acceptable CHT in cruise?


anything below 400F. Have you read Deakin's columns on engine
management at www.avweb.com?

--
Thomas Borchert (EDDH)

TripFarmer wrote:
I just don't buy that "airframe" stuff. A cylinder head can only take
so much temperature for so long before it gives in. 400 degrees is
400 degrees no matter what airframe it's in. If I'm wrong please tell
me why.........

I agree the temperature a cylinder can tolerate probably doesn't depend on the
airframe, but the method of measurement might. Where is the CHT probe on the
cylinder? Don't know, but maybe Piper puts the probe in one hole, and Cessna in
another.

"TripFarmer" wrote:
I've got about 15 hours on 6 new Superior Millinieums and just
put in my first quart of oil since 2TT. I have a range of temps
at cruise from 320 - 380. They dropped a lot after about the
first 30 - 60 minutes of break in and seem to have stabilized
since to these numbers. The hot one will run 400-410 in a
full power climb in my PA28 235.

I have the same cylinders in a LYC O-360; they have 500+ hours on them. In
order to keep mine below 380 deg., I have to keep the cowl flaps wide open
in cruise in summer at 75% power. I can lean the engine in climb for better
performance, but it takes careful attention to the mixture to keep the CHTs
under 400.
--
Dan
C-172RG at BFM