No I don’t.

I know from the sensor location, and the way in which I run the engine, that the bottom of the green is about the right indication.

LB fair enough - so what does the redline indicate ?
I have no argument with multipoint EGT and CHT - have this on my RV. But many older aircraft just had basic CHT and EGT if any at all.
EGT is not the problem - Excessive CHT does the damage. I just lean to give smooth running with hottest cylinder CHT no more than my self imposed maximum of 380 degrees F - considerably less than manufacturers max. EGT is not relevant.
I like to keep it simple. IO-360 with one electronic and one normal mag using above gives me 26 l/hr at economy cruise 2200 rpm 140 kt tas.

I think the redline on the old CHT gauge is 460F (238C). My monitor alarm is set to 200C (392F) - a nice round number that is, like your 380, considerably less than the gauge redline. I’ve seen 210C once, on a very hot day just after take off, but anything over that I’m back on the ground, one way or the other.

Yes - EGT is not the problem, but rather CHT.

However, EGT provides some good reference points that assist in keeping CHT under control. Knowing when EGT peaks is very important, because 40 to 50F rich of that is the mixture at which you will give an engine its hardest (and unnecessarily hard) beating. And to return to the specific issue raised by this thread - knowing the EGT ‘balls to the wall’ at sea level on a standard day gives you the reference for leaning during the climb, as well as the reference to lean to when taking off from a field at higher density altitudes.

26lph and 140kts TAS: A beautiful set of numbers!

What aircraft type are you getting 140knots from at 26lph? almost sounds too good to be true unless you are pulling off LOP and you're quoting figures from 8,000ft+ for TAS.

I get get a TAS of around 135-140 at 9,500ft on 20-21 lph with a 400kg+ payload, just sayin' :-)

SWTT - RV9A And get 140 TAS from 4000 ft up.

So that's your cruise / low power economy setting?

SWTT - correct. I can also stooge around all day at 90 kts burning 18 l/hr (or less). Or go fast 155-160 at 29-30 l/hr.
Bit hard to beat a 9A.

thepilotadviser,

Although I fully agree with the above posters re the usefullness of having a multi-cylinder engine monitor, I gather that you are mainly flying rented club or school aircraft that don't always have an egt gauge fitted? Assuming you don't have a turbocharger, the short answer to your questions 1 and 2 are "yes", to both. On a normally aspirated, fixed pitch aircraft at a high elevation field on a hot day, you won't hurt a thing by leaning until you see the RPM peak. Don't do that down low or with a turbocharged engine though.

What speed were you flying? Flying too fast will also greatly decrease climb performance. If climb performance was an issue, you probably should be targeting around 70-75 KIAS, or even slower e.g. 65 for best angle to clear terrain.

Is there evidence to support the idea that the same mixture always gives the same EGT? (Actually we know it doesn't - one ignition inoperative will raise EGT, detonation will lower EGT, but lets ignore malfunctions.)

I would be slightly surprised if the EGT was always the same - my guess would be that lower RPM, lower manifold pressure and lower air density would each lower EGT to some extent. That is just a guess though, I would be very interested in actual data.

Ah, back in time your single point EGT was adjusted by a screw on the back of the gauge.
You'd turn that to get your particular engine to peak at the star on the gauge face as you're leaning.
Only then does your gauge accurately reflect 25 degrees per division, and only at that point on the guage.
It's probably not like that now. Everyone is so much smarter these days.

Well obviously you’ll get different EGTs for the same mixture if you change MP or RPM (or timing or turn off a mag).

The data comes from the engine monitor and comparative climb performance.

If you take off in an aircraft at sea level with a normally aspirated aero engine at mixture full rich, pitch full fine and throttle wide open, and touch nothing during the climb, the mixture will become more and more rich as you climb, because the manifold pressure becomes lower and lower. The further rich you go the less power you are producing (on this part of the power curve). There is no doubt or controversy about this.

If you instead take off and touch nothing, other than the mixture so as to lean during the climb to get around the same EGT as you got at sea level on take off, you’ll get more power out of the engine than you would if you’d stayed full rich. The CHTs will remain nice and cool. The CHTs on the engine monitor and the rate of climb compared with full rich shows this.

I see it every time I take off and climb to a ‘decent’ height. SOP is I don’t touch the throttle or RPM (unless it’s early in the morning and near a populated area, in which case I’ll pull the RPM back a bit until I’m clear) and lean every minute or so during the climb to get back to the ‘target’ EGT. If I go full rich during the climb, the rate of climb goes down compared with the rate of climb when the mixture is set to achieve the ‘target EGT’.

PS: One correction to the above. Some engines have an altitude compensating fuel pump which automatically leans to match the density altitude. It does, automatically, what I’m trying to do by leaning manually to the ‘target’ EGT.

andrewr -
I was climbing out at about 70-75 knots. Climb was still positive and from memory at least 300 - 400' per minute. As it was quite windy and not head on I wanted to keep some airspeed up my sleeve. I was positively climbing, albeit slower than normal due to terrain also increasing my density altitude.

I have a digital EGT / CHT in my aircraft. I'll give Desert Goats approach a try and see how I go.

In reading these comments which are very helpful thanks, I have noted that I am perhaps not paying enough attention to my CHT on climb out. The old dial is always in the green but my digital one does indicate over 400f regularly on climb out. Perhaps I'mm climbing too hard too regularly?

If you have a look at the article that Centaurus linked: https://www.avweb.com/news/pelican/182084-1.html you’ll see near the end a graph and some discussion about the relationship between strength of the material cylinders are made of and temperature. Protracted periods above 400F are not good for cylinder longevity.

Are you getting those temps even with the mixture full rich?

Thanks Lead Balloon. I plan on reading that article in detail this weekend. Yes, I'm seeing plus 400 with full rich. Ignorantly I have not been monitoring this closely so cannot say for how long or exactly how high I have seen this. Will definitely be paying attention now. Again, in training it was ful throttle, full rich and away you go until you reach altitude. As I now have a new digital CHT to compliment my old dial I am seeing more accurate read outs I guess. The old dial one never gets too close to the red.

Are your head temps sitting above 400 on all cylinders regularly, or just one?

On my aircraft engine, mixture has absolutely ZERO affect on CHT. CHT is about airflow, thus angle of climb and airflow. No matter how lean I set it, the CHT's do not rise, in fact they sometimes drop.

Is this not the norm for a Cessna?

Are you saying that your CHT stays the same whether the mixture is set e.g. 20c ROP versus e.g. 100C ROP? That would be an extraordinary outcome.

The data show that if you continue to lean from around 20c ROP your CHT will start to reduce. That could explain why they “sometimes drop”.

What probe/monitor brand do you have?

It's an MGL TC03 12 channel with high grade sensors.

Hmmmm. And the engine and aircraft type?