CHTs - What is acceptable?

Wish I did. I have an old analog 6 cylinder anaylzer.

If you want to protect your investment it would be HIGHLY recommended to
get
a good engine analyzer.

I'll second that motion. It's a tiny percentage of what your engine just
cost, and it provides invaluable data.

Trip and I have the same engine, both in PA28-235s. In my experience, after
observing my new engine with a JPI EDM-700 for several hundred hours, CHTs
of over 400 degrees are WAY out of normal range. I keep mine below 350, and
have no problem doing so.

In cruise they will settle into the 315-320 range. EGTs can range from 1350
to 1500, depending on leaning.

Now if you have only one cylinder out of line, it could be a sensor/probe
problem, or it could be a baffling problem. I sealed all visible holes in
my baffling with high-temp RTV, and saw my CHTs drop slightly, but
noticeably.

Good luck!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Our club's Skylane has one CHT gauge with a big 'ol green range & no
temps
on it. Any recommendations on how to use this rather "useless" gauge?

That's what both our Warrior and Pathfinder had in the panel when we
obtained them. They were almost worse than useless, in my experience.
Using them for reference meant nothing, as leaning "by ear" turned out to be
easier and just as "accurate" (meaning not accurate at all).

As you may have noticed, we've got the one from our Pathfinder on display in
our lobby, along with a whole bunch of other "spare parts."

Heck, it's not even a good doorstop!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Dan Thomas wrote:
: http://www.airweb.faa.gov/Regulatory...e?OpenFrameSet

: These are the Type Certificate Data Sheets (TCDS) for US made
: airplanes, engines, propellers and appliances (equipment such as
: Carbs, seat belts and so on).
: Engine TCDS give CHTs and a lot of other stuff. The statement by
: the engine guys that the airframe manufacturer sets CHTs is
: misleading.

: Dan

While the TCDS might contain the max CHTs and such, many people believe that
they are insane. The metalurgical changes that occur when you run a cylinder up to
the "approved" TCDS limit of 500 degrees are significant. Remember that once a TCDS
is approved, it's basically gospel and can never be changed.... in other words, it's
guaranteed to be wrong forever.

Different airframes' engine limits shouldn't be compared directly, but I know
I would try to take the lowest of all of them as a recommendation. The guys who know
engines say that running over 400 in cruise is bad.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering Ph.D. Graduate Student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Jay,

I'm still running mineral oil. I do expect the CHTs to drop when
I go to Aeroshell. I've got 15TT since TOH now. One quart in last 13 hours.


Trip


In article TUHVc.59500$TI1.36466@attbi_s52, says...

Wish I did. I have an old analog 6 cylinder anaylzer.

If you want to protect your investment it would be HIGHLY recommended to
get
a good engine analyzer.

I'll second that motion. It's a tiny percentage of what your engine just
cost, and it provides invaluable data.

Trip and I have the same engine, both in PA28-235s. In my experience, after
observing my new engine with a JPI EDM-700 for several hundred hours, CHTs
of over 400 degrees are WAY out of normal range. I keep mine below 350, and
have no problem doing so.

In cruise they will settle into the 315-320 range. EGTs can range from 1350
to 1500, depending on leaning.

Now if you have only one cylinder out of line, it could be a sensor/probe
problem, or it could be a baffling problem. I sealed all visible holes in
my baffling with high-temp RTV, and saw my CHTs drop slightly, but
noticeably.

Good luck!
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"