Caution - Religious discussion, click here only if you can handle this topic.

My mechanic has always encouraged ROP saying the extra fuel burned is cheaper than an engine.

Fair enough but but everything I know about engines tells me LOP should be better for the engine since excess fuel leads to carbon buildup. If I'm wrong I'm wrong but I don't think I've ever heard a good technical explanation of why and it just doesn't make sense.
 
Not touching any knob in the climb until you reach cruise is solid advice. Leaning in this configuration is a no-no.

Now, no LOP running? They need to provide data to support LOP ops are bad. I am certain they have tested this. Don't make general statements- show me data that supports your recommendations.
 
GLMS_NC said:
Not touching any knob in the climb until you reach cruise is solid advice. Leaning in this configuration is a no-no.
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Assuming you’re not going high enough for full rich to cause problems. Does Lycoming documentation really indicate that climbing to 10,000 feet or higher should be done full rich?

What I found doesn’t seem to…
On engines with manual control, maintain mixture control in the FULL RICH position for

rated take-off, climb and maximum cruise powers (above approximately 75%). However,

during take-off from a high elevation airport or during climb, roughness or loss of power can

occur from over-richness. In such a case, adjust the mixture control only enough for smooth

operation - not for economy. Monitor instruments for temperature rise. Rough operation due

to over-rich fuel/air mixture is most likely to be encountered at altitudes above 5,000 feet

(1524 meters).
Click to expand...
 
For those of you who operate LOP, do you do that with an engine as built by Lycoming, or so you modify and/or ensure that fuel flow to each cylinder is balanced?
 
How many of us are climbing to 10,000 on every flight?

Let's go see what Lycoming says:

According to the official Lycoming Operator's Manual and Service Instruction No. 1094D, the standard recommended procedure for a normally aspirated IO-540 engine during a climb from sea level to 10,000 feet is to maintain a Full Rich mixture setting.
However, Lycoming provides specific criteria and manual adjustments for high density altitudes as you climb higher.

1. Standard Climb (Sea Level to 5,000 Feet)
    • Setting: Leave the mixture control lever in the Full Rich position.
    • Reason: At high power settings (greater than 75% power), the excess fuel provided by a full rich mixture is structurally required to assist in engine cooling and prevent detonation.
    • Monitoring: Constantly monitor your Cylinder Head Temperatures (CHTs). For maximum engine service life, Lycoming recommends keeping CHTs below 435°F (224°C).

2. High-Altitude Climb (5,000 to 10,000 Feet)
As you pass 5,000 feet density altitude, the thinning air will cause a standard full rich mixture to become overly rich. This can cause engine roughness, spark plug fouling, and a significant reduction in climb power.
    • Adjustment: Lycoming specifies that for 5,000 feet density altitude and above, you may lean the mixture to smooth out the engine and regain lost power.
    • The "Target EGT" Method: Smoothly and slowly pull the mixture control back. Lean the engine just enough to re-establish the same average Exhaust Gas Temperature (EGT) values that you observed during the full-rich takeoff at sea level.
    • The Flowmeter Method: If your aircraft is equipped with a calibrated fuel-flow gauge or a placard, lean the control to match the specific fuel-flow target listed for that altitude at climb power.
 
That's all on the full power setting. Continental points out that as long as you are at the max cruise setting, you can set the mixture wherever you please from full rich to so lean the engine is misfiring and it won't hurt anything.
 
GLMS_NC said:
How many of us are climbing to 10,000 on every flight?

Let's go see what Lycoming says:

According to the official Lycoming Operator's Manual and Service Instruction No. 1094D, the standard recommended procedure for a normally aspirated IO-540 engine during a climb from sea level to 10,000 feet is to maintain a Full Rich mixture setting.
However, Lycoming provides specific criteria and manual adjustments for high density altitudes as you climb higher.

1. Standard Climb (Sea Level to 5,000 Feet)
    • Setting: Leave the mixture control lever in the Full Rich position.
    • Reason: At high power settings (greater than 75% power), the excess fuel provided by a full rich mixture is structurally required to assist in engine cooling and prevent detonation.
    • Monitoring: Constantly monitor your Cylinder Head Temperatures (CHTs). For maximum engine service life, Lycoming recommends keeping CHTs below 435°F (224°C).

2. High-Altitude Climb (5,000 to 10,000 Feet)
As you pass 5,000 feet density altitude, the thinning air will cause a standard full rich mixture to become overly rich. This can cause engine roughness, spark plug fouling, and a significant reduction in climb power.
    • Adjustment: Lycoming specifies that for 5,000 feet density altitude and above, you may lean the mixture to smooth out the engine and regain lost power.
    • The "Target EGT" Method: Smoothly and slowly pull the mixture control back. Lean the engine just enough to re-establish the same average Exhaust Gas Temperature (EGT) values that you observed during the full-rich takeoff at sea level.
    • The Flowmeter Method: If your aircraft is equipped with a calibrated fuel-flow gauge or a placard, lean the control to match the specific fuel-flow target listed for that altitude at climb power.
Click to expand...
For some of us, every flight is 10K or higher.....wait, if I'm only going to Pueblo for lunch, then I'm at 9500. Things are finally cooling off around here. After all, my ground is higher than Lycoming's "high altitude climb" instructions. Right now, DA at KAPA is 8,050 feet MSL.
 
Let me throw this hand grenade into the room and leave...

ROP had always been the default strategy but pilots have been flying LOP for many years and many hours now. Has anyone ever actually seen or known anyone who had an engine problem or premature failure from running LOP? Because it seems to me if it made more than a marginal difference we'd know by now. Perhaps the very reason why it's still so contentious is it's really not making much of a difference at all and everyone is just going on gut feeling.
 
Just one owner's data point:
-- have run my Lycoming IO360 (one real mag, one EIS; constant speed prop) in cruise always LOP with WOT
-- at 2800 tach hours with original engine and original cylinders, completed first and only top overhaul
-- now at 3200 tach hours, same SOP and same happy engine
 
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Bill said:
Is he really giving you what is best for the engine, or what is best for selling engines?
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A "self-sealing" conspiracy theory is a belief system structured so that any evidence against it is reinterpreted as proof of its truth, making it completely immune to disconfirmation. The term describes the closed-loop, circular logic that seals the theory off from external reasoning or factual correction.
 
I wonder about the prop setting. Down low, fixed pitch prop won't get anywhere near the RPM that a constant speed prop will. So why not dial it down a bit for the sake of the neighbors?
(granted, this is more for O-360 pilots as higher HP engines typically aren't paired with a fixed pitch)
 
Bill said:
It boils down to: Is he Mike Busch really giving you what is best for the engine, or what is best for selling engines subscriptions to his services? Who knows, crap shoot.
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FIFY.

One side makes and sells engines and carries the risks thereof. The other doesn’t make engines, doesn’t do any bench-level testing that I know of, and makes a profit from aggregating (cherry picked) data they didn’t personally do the research to create plus a relatively small N of personal experience. That is, one is an expert in their product and the other is more or less SGOTI on steroids.

Now THAT’s a religious statement! ;)
 
Llewtrah381 said:
FIFY.

One side makes and sells engines and carries the risks thereof. The other doesn’t make engines, doesn’t do any bench-level testing that I know of, and makes a profit from aggregating (cherry picked) data they didn’t personally do the research to create plus a relatively small N of personal experience. That is, one is an expert in their product and the other is more or less SGOTI on steroids.

Now THAT’s a religious statement! ;)
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Mike B/Savvy's original position might have been based on the AFP Class that George B and others held at GAMI. But I think the situation has changed. At this point, considering the number of subscribers to Savvy Aviation, and a large percentage of those subscribers upload engine data on a regular basis. I would surmise that Savvy actually has more data to back their position than Lycoming.

It came out a long time ago with multiple people stating employees at Lycoming will privately tell you the Lycoming position is not based on engineers but on lawyers. However, because of the lawyers, no one from Lycoming will ever publicly admit it. Fun catch 22 situation.

Lastly, Cirrus in the newer SR20 has a Lycoming engine; guess what the manual states, run LOP....

Tim
 
Ed Haywood said:
A "self-sealing" conspiracy theory is a belief system structured so that any evidence against it is reinterpreted as proof of its truth, making it completely immune to disconfirmation. The term describes the closed-loop, circular logic that seals the theory off from external reasoning or factual correction.
Click to expand...

Just stirring the pot, man!
 
Don’t trust busch or savvy. they charge a fortune for service that is completely automated. also have had too many a and p’s i respect tell me lop is quickest way to burn out an engine.
 
tspear said:
I would surmise that Savvy actually has more data to back their position than Lycoming.
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True. And kinda proving my point.

I’m a physician and was taught since medical school to understand the nature of the study making a point and to know its limits. We did a lot of research “journal clubs” to look past the assertion of an article’s title and see if the study proved the assertion.

He has gathered a lot of data from uncontrolled sources. Engine monitors don’t know, let alone report, stuff like ambient temperature, altitude, weight of the aircraft (so, load on the engine) and a host of other parameters. His borescope library is equally uncontrolled for those and more parameters.

He talks about the “red fin” and running a “high” CHT. Has he done any tests on engines in a test cell where variables are controlled, to back up his gospel-like assertions? Not to my knowledge but I’m happy to be shown I’m wrong.

He probably has a TON of data. But was it collected in a way that reliably controls for relevant variables? My impression is no. And to my knowledge he hasn’t taken the data, formulated a hypothesis from it, and then proven/disproven it in the lab. Just packaged what he could scavenge from others, pontificated, and sold it.

Don’t get me wrong: his stuff is good food for thought, IMHO. But he’s still SGOTI compared to people who actually have skin in the game.
 
I’m not a MB fan but I see the benefits of LOP in my Conti. I tried it in my IO-540/C 182 but it ran too rough past 15 F LOP to utilize. Until I completed the GAMI Advanced Pilot Seminar on LOP operations, I was hesitant to try it in a TSIO-520. I can run 70-72% power at 13.6-14 gph 40 F LOP and have lower CHT’S and still get 165-170+kts depending upon altitude and OAT. My cylinders and exhaust valves look great and no lead/carbon buildup on my plugs. Plus, my range increases dramatically as I have to burn 21+ gph at 70-72% power to keep #5 under 380 F.

Understanding how LOP operation affects the timing of peak internal cylinder pressure and how it improves efficiency of the power stroke will reveal why it is beneficial when done correctly. I highly recommend the course if one is LOP curious. Many have been able to operate injected Lycos LOP but many just wont run smoothly enough in that realm. My 182 would not (factory nozzles) unless I pulled the power way back and ran near peak….however, I did not buy the plane to fly 172 speeds.
 
Many modern engine avionics contain things like altitude, GPS track, etc. They probably have temps too. I know my G1000 has this info, and it's barely modern anymore. In Ada, OK - where GAMI is located - there is an excellent test cell with sensors in all sorts of places. They have done a ton of testing with it. The best part is, they are completely open with it. I went there many years ago to balance my injectors, and they gave me a tour of the place and answered any questions I had. It was really amazing.

I've been running LOP for the past 20 years and have been very happy with it. Mechanics that don't understand LOP like to blame it for all kinds of issues, including things that can't happen when LOP.
 
Llewtrah381 said:
He talks about the “red fin” and running a “high” CHT. Has he done any tests on engines in a test cell where variables are controlled, to back up his gospel-like assertions? Not to my knowledge but I’m happy to be shown I’m wrong.
Click to expand...

Yes. In fact MB provides reference data (or used too). WW2 studies. GAMI Advanced Pilot Seminars where GAMI has what was likely one of the most advanced engine monitoring dyno stands in the world. Look for Pelican Perch for more examples.
Basically, Mike B. George B. J Dean. and many others gather the data, did the studies and proved the that LOP is actually less stressful on the your engine. Where all the OWT come from is many people believed they were LOP when they were still ROP and in what has been called the red fin.

As for money. Considering the cost of fuel. The savings by running LOP vs ROP in a Cirrus SR22 N/A; actually more than covered the expected reman costs. Basically, the fuel savings pay for a new engine. Not sure about anyone else, but that makes me pay attention.

Tim
 
It's amusing, but not at all surprising, to see this topic come up again after the recent discussion here.

As I pointed out in my post to that thread, modern LOP procedures have been popularized by George Braly's GAMI Inc. Braly built a test cell and did extensive research with real engines, resulting in a methodology and procedures that allow pilots to operate LOP safely and reliably. Flyingcheesehead posted a good (and much appreciated) follow-up.

Regardless of which side of this religious schism you choose, it's incorrect to assert that LOP is a dogma that is not founded on science and data.

As for Lycoming, they have publically rejected LOP operations in favor of ancient, tried-and-true ROP procedures. My hunch is that their policy is based on the obvious fact that many pilots are unable, unwilling, and/or ill-equipped to learn, and properly adhere to, the procedures necessary to safely operate LOP.

Llewtrah381 said:
I’m a physician and was taught since medical school to understand the nature of the study making a point and to know its limits. We did a lot of research “journal clubs” to look past the assertion of an article’s title and see if the study proved the assertion.
Click to expand...
Okay Doc, go do your homework, and say hello to Charles Lindberg for me.
 
cowman said:
My mechanic has always encouraged ROP saying the extra fuel burned is cheaper than an engine.
Click to expand...
That's only true if he can demonstrate that the engine's longevity is significantly affected by running LOP/ROP.

cowman said:
Fair enough but but everything I know about engines tells me LOP should be better for the engine since excess fuel leads to carbon buildup. If I'm wrong I'm wrong but I don't think I've ever heard a good technical explanation of why and it just doesn't make sense.
Click to expand...
That's why I run LOP: The folks who brought us LOP before anyone knew of Mike Busch knew their stuff and backed it up with data and explained exactly why it's better to run LOP. The folks who say to run ROP cannot provide any evidence or explanation as to why you should do so.

GLMS_NC said:
Not touching any knob in the climb until you reach cruise is solid advice. Leaning in this configuration is a no-no.
Click to expand...
Not true whatsoever. Pulling back the prop is done for the airport neighbors, not to avoid wear and tear in the climb.

Also, pulling back the mixture in climb to keep the EGTs roughly where they were at takeoff is the only way to keep power where it should be. Lycoming's 5,000 foot thing is absolute nonsense. If you shouldn't lean in the climb below 5,000 feet, then your engine isn't running rich enough on takeoff either, because you're getting richer as you climb unless you start leaning.

FWIW, my plane has an EGT gauge with a green "CLIMB" range on it about 50ºF wide. There is a significant, noticeable increase in climb performance if I lean slowly in the climb to keep the needle in that range, even as low as 2500 feet. Probably lower too, but field elevations in my area are around 1000 so I'm just not paying as much attention to such things below 2500.

MauleSkinner said:
For those of you who operate LOP, do you do that with an engine as built by Lycoming, or so you modify and/or ensure that fuel flow to each cylinder is balanced?
Click to expand...
And here, I think you may have hit on the reason Lycoming has to get religious about this. I run LOP on my *Continental* IO-550-G, without GAMIjectors. In fact, it's book procedure for best economy in my 1997 airplane, before APS or Mike Busch became well known. Why? Because it has a balanced induction. My "GAMI Spread" is about 0.3 gph with my bone stock factory engine. Runs LOP beautifully.

While not all Continentals (and not even all IO-550s) have balanced inductions, I don't know if any Lycomings do. Maybe that's why they don't want people running LOP?

Initial Fix said:
And yet the contental folks had an entire talk on running LOP and doing it correctly.
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Huh. How about that.

Llewtrah381 said:
One side makes and sells engines and carries the risks thereof. The other doesn’t make engines, doesn’t do any bench-level testing that I know of, and makes a profit from aggregating (cherry picked) data they didn’t personally do the research to create plus a relatively small N of personal experience. That is, one is an expert in their product and the other is more or less SGOTI on steroids.
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While Mike Busch didn't personally do the testing, he is good friends with George Braly, who *DID* do a lot of testing. George is the researcher, Mike is the PR department. Plus, Mike likely has more access to GA engine data than anyone else via Savvy Analysis.

wellknow said:
Don’t trust busch or savvy. they charge a fortune for service that is completely automated. also have had too many a and p’s i respect tell me lop is quickest way to burn out an engine.
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Yeah, I've had plenty of A&Ps tell me I'd never make TBO with my IO-550. I've also had plenty of A&Ps tell me that I shouldn't run LOP. And yes, they're guys that I respect that do fantastic work.

However, I don't listen to them on the subject of LOP or whether or not my engine will make TBO, because I've been running it at 65% LOP for 14 years now, and it's up to nearly 2500 hours.

Llewtrah381 said:
He has gathered a lot of data from uncontrolled sources. Engine monitors don’t know, let alone report, stuff like ambient temperature, altitude, weight of the aircraft (so, load on the engine) and a host of other parameters.
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Au contraire. Any of the Garmin systems, at least, DO store OAT, altitude, airspeed, fuel flow, and lots of other stuff that's interesting when it comes to analyzing engine temps. They don't know weight directly, but weight has no affect on "load on the engine" in a propeller powered airplane - The load on the engine comes from the air, the performance one gets out of the airplane is what varies with weight.

Llewtrah381 said:
He talks about the “red fin” and running a “high” CHT. Has he done any tests on engines in a test cell where variables are controlled, to back up his gospel-like assertions? Not to my knowledge but I’m happy to be shown I’m wrong.
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Mike himself hasn't, but his good friend George Braly, founder of GAMI and Tornado Alley Turbo (among others), has.
 
flyingcheesehead said:
Also, pulling back the mixture in climb to keep the EGTs roughly where they were at takeoff is the only way to keep power where it should be. Lycoming's 5,000 foot thing is absolute nonsense. If you shouldn't lean in the climb below 5,000 feet, then your engine isn't running rich enough on takeoff either, because you're getting richer as you climb unless you start leaning.
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Completely agree on 5,000 being nonsense. It's an arbitrary number. Once at some arbitrary number then its ok to start leaning? Ok... How much should I lean? Shrugs.

Why not pick an arbitrary number after takeoff and look at your egt and chase that egt... Whatever it was

I don't understand those that discourage leaning in climb. Like you say, by keeping the egt as close to what it was at takeoff, you're still rich of peak. But you're fuel air ratio is staying more constant thus making sure your engine is making the most of the air that's available.

As far as pulling back on the blue knob. Aside from keeping neighbors happy. It also minimizes friction hp loss.

I think Lycoming says what they say out of simplicity. It's far easier to make blanket statements to cya. Your engine is making less than full power because you're overly rich at 4,999 feet. But you're still safe as opposed to the hamfisted operator that doesn't understand how to lean in climb and nukes a cylinder by leaning past the rop
 
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RyanB said:
I pulled this from a Facebook group. Lycoming’s take on LOP, per their reps at OSH. Would it void a warranty? The reps take and my mechanics opinion are in alignment here.

View attachment 153821
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if God had meant man to Fly Lean Of Peak he would have given him……… ???
 
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Racerx said:
As far as pulling back on the blue knob. Aside from keeping neighbors happy. It also minimizes friction hp loss.
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While this is true, and is the reason I cruise at 2300 and change (the minimum recommended by Conti for my engine), and is more efficient, it still results in less power.

Were I equipped with the 310hp/2700 RPM version of my engine instead of the 280hp/2500 RPM version I'd probably pull back to 2500 after takeoff. As it is, I'm already at 2500 so I just leave it there and it's reasonably quiet but still giving me full rated hp.

Racerx said:
I think Lycoming says what they say out of simplicity. It's far easier to make blanket statements to cya. Youre engine is making less than full power because you're overly rich at 4,999 feet. But you're still safe as opposed to the hamfisted operator that doesn't understand how to lean in climb and nukes a cylinder by leaning past the rop
Click to expand...
Tell that to the guy who was at 3000 feet so never leaned it out and ran out of fuel because the performance charts also assume you lean for cruise...
 
murphey said:
For some of us, every flight is 10K or higher.....wait, if I'm only going to Pueblo for lunch, then I'm at 9500. Things are finally cooling off around here. After all, my ground is higher than Lycoming's "high altitude climb" instructions. Right now, DA at KAPA is 8,050 feet MSL.
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But are you leaning to re-establish the average EGT values that you observed during the full-rich takeoff at sea level? :dunno:
 
iamtheari said:
But are you leaning to re-establish the average EGT values that you observed during the full-rich takeoff at sea level? :dunno:
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I’ve never had the opportunity to fly at sea level. Not in 26 years with the Cherokee. Like I said…my ground is higher than Lycoming’s 5000 ft definition of high altitude. First thing newbies learn out here is how to lean.
And after 26 years of flying, I know my O360 A4A prefers cruising at 2400 rpm and leaned to about 365-385 temps on the JPI 730 engine monitor.

Engine just feels more smooth.
 
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GLMS_NC said:
Not touching any knob in the climb until you reach cruise is solid advice. Leaning in this configuration is a no-no.

Now, no LOP running? They need to provide data to support LOP ops are bad. I am certain they have tested this. Don't make general statements- show me data that supports your recommendations.
Click to expand...

So if I am located at an airport with a density altitude of 6000 MSL, do you advocate I don’t lean for takeoff and what the difference between a full power take off and a climb at 6000 feet?
 
RyanB said:
I pulled this from a Facebook group. Lycoming’s take on LOP, per their reps at OSH. Would it void a warranty? The reps take and my mechanics opinion are in alignment here.

View attachment 153821
Click to expand...

Let me rephrase the question submitted to the Lycoming rep. If I take one of your engines and install after market injectors (GAMI), can I operate your engine lean of peak?

The best response from Lycoming is no. We don’t test another manufacturer’s product, make recommendations concerning the use and safety of other products and don’t have any quality control of that product. We don’t recommend this practice using our injectors based on our testing. Lycoming only recommends original Lycoming parts and reject claims made by untrained people promoting after market products and making operation recommendations for our engines.

Further, any injector patent GAMI held has long expired and Lycoming could easily copy the design and make their own LOP recommendations. If Lycoming has tested GAMI injectors, and I’d be shocked they haven’t, they aren’t required to release data and for what ever reason reject LOP.
 
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flyingcheesehead said:
While Mike Busch didn't personally do the testing, he is good friends with George Braly, who *DID* do a lot of testing. George is the researcher, Mike is the PR department
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My point exactly. George has done the original research and has skin in the game. Mike is the salesman with no real risk exposure
 
murphey said:
I’ve never had the opportunity to fly at sea level. Not in 26 years with the Cherokee. Like I said…my ground is higher than Lycoming’s 5000 ft definition of high altitude.
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That was my joke/point. I have done 4 sea level takeoffs. Most of us, at least between the Appalachians and the Cascades, aren’t going to get a lot of use out of a technique where the first step is virtually never available to us.
 
Ed Haywood said:
A "self-sealing" conspiracy theory is a belief system structured so that any evidence against it is reinterpreted as proof of its truth, making it completely immune to disconfirmation. The term describes the closed-loop, circular logic that seals the theory off from external reasoning or factual correction.
Click to expand...

You just described hims…
 
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