IO-360 Leaning during cruise climb

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arksat
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IO-360 Leaning during cruise climb

Post by arksat »

I searched the forum but couldn't find discussions so let me post.
(If this was a duplicated topic, please give me a pointer.)

My question is about leaning technique during the cruise climb, let's say 24MP, 2400RPM to 8000 MSL.
I know it's better to lean as I get higher, but I'm not sure what number (EGT, GPH) I should look for and adjust to. I believe it requires constant adjustments.
What do you guys with Lyc IO-360 do for leaning during climb?
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Rich
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Re: IO-360 Leaning during cruise climb

Post by Rich »

I use WOT and target 1300 deg EGT during climb. This is based on an old recommendation I once saw from John Deakins and seems to work well.
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Re: IO-360 Leaning during cruise climb

Post by p3dave »

I actually was looking for information on this topic and copied the below:

Diamond DA40 - CHT / EGT

RUN UP - While your at 2000 RPMs, lean until you can see all your EGT bars. Switch to mag 1 then to mag 2. Watch bars for a steady rise on 1 and return to baseline on both. If you see an EGT fall out completely then that plug is dead. If one rises way more than others you could have a partially fouled plug or if EGT is way higher than peek maybe a stuck exhaust valve. You can get a lot of info from your run up.


ECG COOLING - Climb full power, full rich (1000' msl). I make a mental note of my EGTs and CHTs. As I climb out and gain some alt. I will very slowly pull out some fuel every thousand or two feet to keep my EGTs at my original take off value. In other words, as you climb you will get richer and richer because of less air. If your too aggressive in the lean you will get the EGT close to peek and thus peek cylinder pressures which in turn will make your CHTs climb out of control. I also will try to keep CHT at 380 or below.


CHT COOLING - it is normal for the CHTs to change slowly - remember they are measuring the temperature of a large mass of metal that takes some time to change temperature - unlike the EGT, which is measuring the temperature of the exhaust gas and changes almost instantly. I would expect it to take many minutes for the CHTs to fall back into the normal range after you take corrective measures. The important thing with CHTs is to see that the trend is in the desired direction.

• Add fuel. This reduces pressures and thus heat
• Increase airspeed, this increases cooling flow over the cylinders
• Reduce manifold pressure, this reduces cylinder pressures as above.


Rules for Leaning –
1.) Delay leaning until the EGT's start dropping below 1300* F in the climb.
2.) Target 1250 for EGT
3.) Every Couple 1000ft of climb check CHT/EGT Lean as needed

POH RECOMMENDATION –

CHT – 400* Climb and 380*Cruise
Fuel
Mix
High Density Settings to Lean CHT/EGT – What are the normal Settings?


Pilot Recommendation
RUN UP –Set RPMs to 1800– Pull MIX until EGTs are showing EGT 1150-1300 Range
LOOK AT EACH CYLINDER reading that they are reporting across the board
Leaning should boost EGT to about 2000*

EGT is faster to monitor ( almost Real-time) than the CHT Temp (Large block heating /not real-time)


RUN UP - Ignition Magneto Test – Monitor Mag1 to both-Mag 2 to both – watch for steady rise in each cylinder, cooling on base (both magnetos)

• Non-Sparking Plug – Complete drop of EGT – Will run rough
• Partially Fouled - It's sparking but not well and the flame front is slower than the other cylinders. The burning gasses will pass out into the exhaust and continue to burn thus giving you a higher EGT in that one cylinder than the rest. You will be running rough. The EGT will be less than peek EGT.
• 150RMP Drop and 50 RMP difference is a crude way to know what is going on within each cylinder, there fore visually inspecting the ECG is smart.

CLIMB – CHT 380 / EGT - 1250
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maestretti
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Re: IO-360 Leaning during cruise climb

Post by maestretti »

Here are some other articles I have found on the forum re IO-360 performance and leaning. Trying to pull them together with the AFM, STCs, engine manual etc for our own ops guide. Additional pointers are appreciated.

Advanced Leaning Mike Busch
2200 or 2400 Cruise
Preferred Power Settings
How do you fly cross country
IO-360 Lean During Cruise Climb
Maximizing Climb Performance
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TAILspin38
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Re: IO-360 Leaning during cruise climb

Post by TAILspin38 »

Hey Dave, tried the run up procedure you posted the other day. Do you just leave the engine leaned while you cycle the prop as well and then just full Rich for t/o? Thanks for posting it, I am a low time pilot and NEW to the DA40. It makes me feel better about the condition of the plugs!
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Re: IO-360 Leaning during cruise climb

Post by Charles »

I cruise climb WOT at 90KIAS and, as a rule of thumb, set the fuel flow to match the MP. Full rich at takeoff, then I lean to 16gph passing 26MP, 15gph passing 25MP, 14gph passing 24MP, and so on. That keeps the CHTs around 380F. I will enrich a bit if CHTs approach 390F and lean a bit more if less than 370F. I don't look at EGT at all during climb (Deakin also said the absolute value of EGT is meaningless, it is only useful as a relative measure to peak EGT).
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Re: IO-360 Leaning during cruise climb

Post by perossichi »

Following up on Rich. I took the advanced pilot class some years ago from Deakin and Brally.

They say to lean to match EGT on take off from a sea level airport. That is about 1350 in my old 2002. Of course, you should check CHTs and enrichen if they get over 400.

I always climbed at WOT and full RPM since I had the hartzell composite prop which was STCed for full RPM.

It never makes any sense to reduce Mp on climb or even cruise. Reduce RPM and lean in cruise. On descent I never cut the throttle until absolutely necessary.

RIP John Deakin.
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Charles
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Re: IO-360 Leaning during cruise climb

Post by Charles »

Exactly. As he said (or was it Busch?), any flight above 6000 in a normally aspirated engine should start WOT and should remain WOT until descent. When I said to match fuel flow to MP during climb, I meant to leave the throttle WOT and lean as MP decreases due to decreasing pressure altitude. I did not imply to reduce throttle. The numbers I gave work for 2500rpm.
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Re: IO-360 Leaning during cruise climb

Post by p3dave »

TAILspin38 wrote: Sat Jan 22, 2022 1:26 am Hey Dave, tried the run up procedure you posted the other day. Do you just leave the engine leaned while you cycle the prop as well and then just full Rich for t/o? Thanks for posting it, I am a low time pilot and NEW to the DA40. It makes me feel better about the condition of the plugs!
That's what I do on the run up and rich for takeoff unless above 3000 feet MSL. The engine needs air based on air density so in higher elevations (or density altitude for that matter) you have to lean to get max power.
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