ROP vs LOP

[Roger O]

Interesting discussion.  I wonder what the Mooney gurus like Don Maxwell recommend and why?

Roger

[KSMooniac]

Lead does lubricate and cool, that is why it is added to aviation fuel...

That's not true...it is an octane booster. Seeing cooler temps with leaded fuel versus unleaded is due to the differences in the combustion event from the octane difference. If you observe 100UL and 100LL you wouldn't notice any temp differences, but one of those would result in a much cleaner engine... In the past an unleaded 100 octane couldn't be easily made, so differences were observed with lower octane fuels. Those observations were attributed to lead, but for the wrong reasons.

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[Brian Scranton]

I found this nugget on lead: Another benefit that became known over time was that Tetraethyl lead kept valve seats from becoming worn down prematurely. Exhaust valves, in early model cars, that were subject to engine knocking tended to get micro-welds that would get pulled apart on opening. This resulted in rough valve seats and premature failure. Lead helped fuel ignite only when appropriate on the power stroke, thus helping eliminate exhaust valve wear and tear.

[gsxrpilot]

3 hours ago, Brian Scranton said:

My old school A&P trashes the idea of LOP ops...he says he's seen all the data from Mike, John and APS but he also has 40+ years of looking at lots of different engines that have been run lots of different ways. He believes that LOP have one major disadvantage, the loss of protection that comes with copious amounts of lead only found in copious amounts of fuel. He thinks by limiting the lubricating, protective aspect that 100LL has on the metals in a cylinder, we're doing far more harm on the life of the engine components. He agrees, LOP may be 50 degrees cooler, and he agrees that less fuel equals longer ranger and less $, but he's seen a shit ton of valve, ring and compression issues as a result. Ready....DISCUSS! 

I'm not going to try and teach the Advanced Pilot Seminar here. I'll just say that I enjoyed the class and as an Engineer with a background in science and math, I understand the scientific method, testing, peer review, and conclusions backed up by data as opposed anecdotal evidence backed up by old wives tales and "this is the way it's always been". Your old school A&P is speaking from a position of ignorance. And if he's seen all the data, he obviously didn't understand what he saw or read.

Take the course, see for yourself, draw your own conclusions... I'll be taking the course again in the fall to cover some of the stuff I missed the first time around. 

With that... I'm out.

[Shadrach]

On May 1, 2017 at 1:19 PM, N6758N said:

You may be referring to a fuel injected engine, to the OP who posted about a carbureted engine however, LOP is not a good idea. 

A setting that is good in an injected engine is just as good in a carbed engine. The trouble is that it may not be attainable with a carbed engine. LOP is a fine idea in any engine, again, it's whether it is attainable that is the question. Regardless of fuel delivery system, at 10,000' I'd likely be on the rich side of peak or peak unless I had a nice tail wind. 

Even if I had a carbed engine, I'd attempt mixture settings across the spectrum. I'd want to learn just what it was capable of.

 

[Shadrach]

14 hours ago, N6758N said:

Okay Paul, I'll risk sounding like an idiot here. I am not a huge Mike Busch fan (not that I discredit what he does) but besides that point, what is the 'red box'? I'm assuming its the danger zone of engine operation parameters?

The red box is a zone of high peak cylinder pressure. It generates the highes CHTs and puts the engine in a regime that has the lowest detonation margins.

[Brian Scranton]

11 hours ago, gsxrpilot said:

I'm not going to try and teach the Advanced Pilot Seminar here. I'll just say that I enjoyed the class and as an Engineer with a background in science and math, I understand the scientific method, testing, peer review, and conclusions backed up by data as opposed anecdotal evidence backed up by old wives tales and "this is the way it's always been". Your old school A&P is speaking from a position of ignorance. And if he's seen all the data, he obviously didn't understand what he saw or read.

Take the course, see for yourself, draw your own conclusions... I'll be taking the course again in the fall to cover some of the stuff I missed the first time around. 

With that... I'm out.

It's certainly on my list. And i've read all I can on LOP ops--I for one think it makes absolute sense. I wish I could get my engine there but I think I need to invest in some GAMIs. 

[gsxrpilot]

6 minutes ago, Brian Scranton said:

It's certainly on my list. And i've read all I can on LOP ops--I for one think it makes absolute sense. I wish I could get my engine there but I think I need to invest in some GAMIs. 

If you sign up to attend the course, plan to go to Ada, OK a day early or even just to arrive that morning. Jean-Paul from GAMI will be happy to go up for a flight with you in your plane and run the GAMI Spread Test for you. He'll either show you how to run LOP with what you have, or prescribe exactly the GAMI's you need to get LOP. They are not just trying to push GAMI's out the door, and will tell you if you don't need them. That service is usually free and net very valuable.

[N6758N]

11 hours ago, gsxrpilot said:

I'm not going to try and teach the Advanced Pilot Seminar here. I'll just say that I enjoyed the class and as an Engineer with a background in science and math, I understand the scientific method, testing, peer review, and conclusions backed up by data as opposed anecdotal evidence backed up by old wives tales and "this is the way it's always been". Your old school A&P is speaking from a position of ignorance. And if he's seen all the data, he obviously didn't understand what he saw or read.

Take the course, see for yourself, draw your own conclusions... I'll be taking the course again in the fall to cover some of the stuff I missed the first time around. 

With that... I'm out.

His A&P certainly is a little ignorant, however he has eons more experience working on engines than someone like Mike Busch. There are definitely two sides to this argument and I do not think either one is 100% right. My biggest issue with Mr.Busch is he is more pilot than mechanic. His suggestions are usually sound and backed by his experience in the cockpit, however his maintenance pedigree is relatively small in the grand scheme of things ( like Brian's A&P with 40+ years experience turning a wrench) . Most of us on here have only owned a few different airplanes and our experiences are a grain of sand on a very large beach, I think we have to give some considerations to our mechanics who have spent decades working on these engines and have seen everything and anything that can happen.

I believe in the debate of ROP vs LOP you have to do what you are most comfortable with and what works for you, if you engine runs smooth and happy at LOP then fly it like that, and vice versa. Most importantly keep an eye on your CHTs and EGTs and do routine oil/filter analysis and you should get a long service life out of your engine. 

[gsxrpilot]

With all respect...

Science is in the business of debunking theories and beliefs that have been held in error for eons. I completely agree with your point about Busch. But the guys at GAMI are in a different category. They are scientists who test, measure, and either confirm or debunk long standing theories based on real data.

Mariners who had spent their entire lives at sea were absolutely sure the earth was flat until science proved them wrong. It's interesting to me that over on the Beechtalk forums, anyone disputing that LOP operations isn't settled science, is considered in the same boat as the flat-earth folks.

Doing what is most comfortable for you is just that, comfortable for you, and no more. It has nothing to do with the health or harm to your engine.  There's nothing wrong with doing what's comfortable, it just can't be equated to engine health. 

[cnoe]

18 hours ago, bonal said:

So to be clear and since I am not using a fancy monitor I use the lean to rough then rich to smooth and that results right at 20 to 30 degrees based on what the incraments on my factory gauge represent per my POH so I am LOP and was just wondering about running at peak which according to the tables shown in this thread am still better off than being ROP. My cylinder temp #3 in cruise is around 360 degrees. The reason I wondered about running at peak is it makes for a very simple process since I only have the factory EGT gauge (easy to tell) when I reach peak temp. But I would have to say that my carb engine is very smooth at just lean of peak. Different opinions here so I will just keep what makes the most sence a smooth running engine which just happens to be a tad LOP

With all due respect, in the absence of an engine monitor that displays the EGT of EACH INDIVIDUAL CYLINDER you have no idea whether you are running LOP or not. Sure, your factory gauge might show an EGT drop, but the other 3-5 cylinders may all be running 50 ROP. More likely you may be running one cylinder at 20 LOP, another at peak, another at 20 ROP, and the fourth at 50 ROP. There's simply no way to know without a good monitor. I suspect that this is the exact reason why LOP operations gets such a bad rap by many old-school mechanics; the pilot THINKS he's LOP while in fact he's got one (or more) cylinders that are still in the red box.

As mentioned before you've got no worries at high altitudes or low power settings (65% or less), simply lean for best power or best economy and be done with it.

 

 

[201er]

1 minute ago, gsxrpilot said:

With all respect...

Science is in the business of debunking theories and beliefs that have been held in error for eons.

With all respect, the Gami guys did it in a lab. Mike Busch has done it in a real plane.
 

As you can see from the results in our how many hours of LOP poll, pretty much nobody has done it TBO to TBO enough times to have any say in the long term maintenance ramifications. We do have about a dozen guys that have gone about half TBO to at least demonstrate that LOP isn't going to cause short term catastrophic problems. Back when I started flying LOP in 2011, the number of Mooney guys with over 500 hours LOP was virtually non-existent. It looks like it's going to take another 5 years until those guys start reaching TBO and sharing their experience about going TBO to TBO flying predominantly LOP and what it has done for the life of their engine. If all things are equal and they get exactly the same lifespan out of the engine as ROP, they will already prove it worthwhile by paying for their overhaul with the gas savings.

[N6758N]

4 minutes ago, gsxrpilot said:

With all respect...

Science is in the business of debunking theories and beliefs that have been held in error for eons. I completely agree with your point about Busch. But the guys at GAMI are in a different category. They are scientists who test, measure, and either confirm or debunk long standing theories based on real data.

Mariners who had spent their entire lives at sea were absolutely sure the earth was flat until science proved them wrong. It's interesting to me that over on the Beechtalk forums, anyone disputing that LOP operations isn't settled science, is considered in the same boat as the flat-earth folks.

Doing what is most comfortable for you is just that, comfortable for you, and no more. It has nothing to do with the health or harm to your engine.  There's nothing wrong with doing what's comfortable, it just can't be equated to engine health. 

Very true Paul, I love the quote by Neil Degrasse Tyson, " The funny thing about science is it is true whether or not you believe in it" The folks over at GAMI are for sure in a different category. I'll be honest, if I was a continental guy and I had GAMIs, I would be LOP all day long! My point is it is different for different engines, All things else equal, a carb'd engine versus an injected engine with GAMIs are not going to perform the same when operated at the same LOP/ROP setting. 

[gsengle]

With all respect, the Gami guys did it in a lab. Mike Busch has done it in a real plane.
 
As you can see from the results in our how many hours of LOP poll, pretty much nobody has done it TBO to TBO enough times to have any say in the long term maintenance ramifications. We do have about a dozen guys that have gone about half TBO to at least demonstrate that LOP isn't going to cause short term catastrophic problems. Back when I started flying LOP in 2011, the number of Mooney guys with over 500 hours LOP was virtually non-existent. It looks like it's going to take another 5 years until those guys start reaching TBO and sharing their experience about going TBO to TBO flying predominantly LOP and what it has done for the life of their engine. If all things are equal and they get exactly the same lifespan out of the engine as ROP, they will already prove it worthwhile by paying for their overhaul with the gas savings.

I don't get credit for 1980 hours, no issues? I'm hearing more pilots here flying lop, and I'm hearing no issues. I'm going past TBO and will overhaul on condition.


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[gsxrpilot]

4 minutes ago, 201er said:

With all respect, the Gami guys did it in a lab. Mike Busch has done it in a real plane.

Actually not true...  The GAMI guys have done their experiments both in the lab... past TPO hours on many different engines. (They happen to have the best lab in the world for these engines, as acknowledged by both Lycoming and Continental.) But they've also demonstrated this in several different airplanes with different engines, going well past TBO. Mike Busch has demonstrated his method in his one airplane, (it does have two engines though). And then has anecdotal evidence from customers of Savvy. But it's only anecdotal as the engines are instrumented beyond EGT/CHT/TIT.

The GAMI guys are flying fully instrumented engines for their tests. And that includes many probes and sensors that aren't available to the rest of us. But that's how you get data.

It was interesting to see their Champion and Tempest spark plugs that had been modified to accommodate a pressure sensor in the plug its self. This way they can measure Internal Cylinder Pressure in real time while flying, and over the span of an engine run from new to past TBO.

[gsxrpilot]

13 minutes ago, N6758N said:

Neil Degrasse Tyson, " The funny thing about science is it is true whether or not you believe in it" 

One of my favorites :-)

[peevee]

11 minutes ago, gsxrpilot said:

Actually not true...  The GAMI guys have done their experiments both in the lab... past TPO hours on many different engines. (They happen to have the best lab in the world for these engines, as acknowledged by both Lycoming and Continental.) But they've also demonstrated this in several different airplanes with different engines, going well past TBO. Mike Busch has demonstrated his method in his one airplane, (it does have two engines though). And then has anecdotal evidence from customers of Savvy. But it's only anecdotal as the engines are instrumented beyond EGT/CHT/TIT.

The GAMI guys are flying fully instrumented engines for their tests. And that includes many probes and sensors that aren't available to the rest of us. But that's how you get data.

It was interesting to see their Champion and Tempest spark plugs that had been modified to accommodate a pressure sensor in the plug its self. This way they can measure Internal Cylinder Pressure in real time while flying, and over the span of an engine run from new to past TBO.

they offer the class online now, I think it's either new or I just haven't noticed it before. Has anyone taken the online? It's $395 but more importantly the in-person class is always over a weekend and I work weekends, making it challenging to attend.

[gsxrpilot]

I took the live class, but it includes access to the online course as well.  It's recommended that you go through the online course first so that you're better prepared for the live course. The online course is excellent as long as you're willing to accept their instruction as the truth. But if someone is skeptical, the live class is a chance to sit in the room as challenging questions are asked and hear the responses. It's also a chance to get see the test lab and watch while an engine is put through it's cycles while data is collected in real time. You can watch detonation happen, and what happens when in the "red box". 

It was all just theory to me until I attended the live class and saw it "proven" live and in person.

[Shadrach]

5 hours ago, N6758N said:

His A&P certainly is a little ignorant, however he has eons more experience working on engines than someone like Mike Busch. There are definitely two sides to this argument and I do not think either one is 100% right. My biggest issue with Mr.Busch is he is more pilot than mechanic. His suggestions are usually sound and backed by his experience in the cockpit, however his maintenance pedigree is relatively small in the grand scheme of things ( like Brian's A&P with 40+ years experience turning a wrench) . Most of us on here have only owned a few different airplanes and our experiences are a grain of sand on a very large beach, I think we have to give some considerations to our mechanics who have spent decades working on these engines and have seen everything and anything that can happen.

I believe in the debate of ROP vs LOP you have to do what you are most comfortable with and what works for you, if you engine runs smooth and happy at LOP then fly it like that, and vice versa. Most importantly keep an eye on your CHTs and EGTs and do routine oil/filter analysis and you should get a long service life out of your engine. 

Combustion science couldn't give two shits what you are comfortable with. I am pretty sure that Mr. Busch is in the same camp. You seem to be long on opinions and short on understanding. My recommendation to you is that you read up bit on subjects before commenting on them. Reading Mr. Busch's CV would be a good start. Indeed he may be more of a pilot than mechanic, but then he's more mechanic than most mechanics.  

Why don't you post your CV so we can see how you stack up?

[peevee]

3 hours ago, gsxrpilot said:

I took the live class, but it includes access to the online course as well.  It's recommended that you go through the online course first so that you're better prepared for the live course. The online course is excellent as long as you're willing to accept their instruction as the truth. But if someone is skeptical, the live class is a chance to sit in the room as challenging questions are asked and hear the responses. It's also a chance to get see the test lab and watch while an engine is put through it's cycles while data is collected in real time. You can watch detonation happen, and what happens when in the "red box". 

It was all just theory to me until I attended the live class and saw it "proven" live and in person.

I really don't care about the theory as much as I'm looking for the technique.

[N6758N]

Just now, Shadrach said:

Combustion science couldn't give two shits what you are comfortable with. I am pretty sure that Mr. Busch is in the same camp. You seem to be long on opinions and short on understanding. My recommendation to you is that you read up bit on subjects before commenting on them. Reading Mr. Busch's CV would be a good start. Indeed he may be more of a pilot than mechanic, but then he's more mechanic than most mechanics.  

Why don't you post your CV so we can see how you stack up?

I don't need to post my CV here Ross. I'll be the first to admit I don't have the experience Mike Busch does, however I'm not publishing articles telling people to keep running their engines past TBO or to run LOP either. Not all aircraft owners are as savvy as most of us on the forum here, what about those that read his articles and think, "gee Mike Busch said so, so it must be true. Let me go ahead an run the bottom end of my engine to 4,000+hrs and ignore what my mechanic is telling me."

 I think I've been clear with my posts that my 'understanding' of the topic of LOP is limited, however I do know the basics. The fact is that a carbureted engine does not distribute the air fuel ratio as well as an injected one and thus running LOP is much more difficult, but that doesn't mean it is impossible and that people don't do it. Mooney Space is full of opinions and short on understanding in general, so I could really care less about your personal attack on my credentials. But in case you were wondering...I have a Bachelor's in aviation maintenance technology from the Pennsylvania State University, I have my IFR/commercial fixed wing, and I have several aircraft owners as well as Mooney drivers that can attest to my skills as I work on their airplanes in my free time. I am young and often dumb, but I am happy to admit when someone knows more than me.  So, that being said, whats your CV like? How many years have you been an IA, or have you just read all the right articles on the subject and now you're an expert? Cheers!

[Marauder]

30 minutes ago, N6758N said:

I don't need to post my CV here Ross. I'll be the first to admit I don't have the experience Mike Busch does, however I'm not publishing articles telling people to keep running their engines past TBO or to run LOP either. Not all aircraft owners are as savvy as most of us on the forum here, what about those that read his articles and think, "gee Mike Busch said so, so it must be true. Let me go ahead an run the bottom end of my engine to 4,000+hrs and ignore what my mechanic is telling me."

 I think I've been clear with my posts that my 'understanding' of the topic of LOP is limited, however I do know the basics. The fact is that a carbureted engine does not distribute the air fuel ratio as well as an injected one and thus running LOP is much more difficult, but that doesn't mean it is impossible and that people don't do it. Mooney Space is full of opinions and short on understanding in general, so I could really care less about your personal attack on my credentials. But in case you were wondering...I have a Bachelor's in aviation maintenance technology from the Pennsylvania State University, I have my IFR/commercial fixed wing, and I have several aircraft owners as well as Mooney drivers that can attest to my skills as I work on their airplanes in my free time. I am young and often dumb, but I am happy to admit when someone knows more than me.  So, that being said, whats your CV like? How many years have you been an IA, or have you just read all the right articles on the subject and now you're an expert? Cheers!

Would you happen to be talking about me? Once I helped you understand the "Righty Tighty, Lefty Loosey" concept, everything went great!  Not like the other guy who I had show the difference between an open end wrench and a pair of pliers.

I'll have you know that the mag wires and spark plugs you installed still haven't fallen off the plane! Good job!

[Shadrach]

6 minutes ago, N6758N said:

I don't need to post my CV here Ross. I'll be the first to admit I don't have the experience Mike Busch does, however I'm not publishing articles telling people to keep running their engines past TBO or to run LOP either. Not all aircraft owners are as savvy as most of us on the forum here, what about those that read his articles and think, "gee Mike Busch said so, so it must be true. Let me go ahead an run the bottom end of my engine to 4,000+hrs and ignore what my mechanic is telling me."

 I think I've been clear with my posts that my 'understanding' of the topic of LOP is limited, however I do know the basics. The fact is that a carbureted engine does not distribute the air fuel ratio as well as an injected one and thus running LOP is much more difficult, but that doesn't mean it is impossible and that people don't do it. Mooney Space is full of opinions and short on understanding in general, so I could really care less about your personal attack on my credentials. But in case you were wondering...I have a Bachelor's in aviation maintenance technology from the Pennsylvania State University, I have my IFR/commercial fixed wing, and I have several aircraft owners as well as Mooney drivers that can attest to my skills as I work on their airplanes in my free time. I am young and often dumb, but I am happy to admit when someone knows more than me.  So, that being said, whats your CV like? How many years have you been an IA, or have you just read all the right articles on the subject and now you're an expert? Cheers!

My CV is focused on banking and corporate finance, I turn wrenches for fun. I also apprenticed as a shop rat while getting my PPL. It does not matter though, I'm not the one making ignorant comments about a renowned maintenance technician, pilot and author. It's fine to have an opinion, it's off putting when you just state it without supporting information.

You seem to have a problem with running a bottom end to 4000hrs. Why? Indeed it is ok if the owner wants to do so. Neither you nor anyone else gets to dictate what an owner does with his or her engine. Make a recommendation, if the owner says no, get over it.  If the owner is uncomfortable, they are welcome to rebuild it whenever they like, maybe every 500hrs is safer? You have that option, by all means.

Of the 10 or so engines I've been involved in tearing down ( to include several motorcycles, autos and aircraft), not a single one showed significant bottom end wear. If my memory serves, every crank of every case I've seen split has been at or near new limits.  Most ground based recips see in excess of 6000hrs without skipping a beat. I give Busch credit for not being afraid to question the conventional thinking with data. I believe he has been very articulate in terms of what he's done and why. Aviation MX is full of anecdotel information, tribal knowledge and a tremendous amount of "recommended" make work. There are even a few facts here and there. Bottom ends rarely catostrophically fail and when they do fail it's typically due to a lubrication issue. Barring that, they run like the energizer bunny. Do you have data to the contrary? Have I missed the rash of crashes due to seized cranks and spun bearings? 

I know a number of credentialed IAs and I can say that only a handful have a reasonable knowledge of combustion science. That knowledge is typically derived from something outside aviation (race cars, motorcycles etc...). The ones that don't are at a huge disadvantage on the diagnostic side. 

[Shadrach]

2 minutes ago, Marauder said:

Would you happen to be talking about me? Once I helped you understand the "Righty Tighty, Lefty Loosey" concept, everything went great!  Not like the other guy who I had show the difference between an open end wrench and a pair of pliers.

I'll have you know that the mag wires and spark plugs you installed still haven't fallen off the plane! Good job!

This place is a collection of unsavory characters with questionable judgement!

[N6758N]

Just now, Shadrach said:

This place is a collection of unsavory characters with questionable judgement!

That sums it up pretty accurately. It is a shame to argue on here about differences of opinion, I think 90% of us would get along great if we meet in person. I am willing to admit my knowledge of combustion science is limited to textbook basics. We are all free to do what we like with our airplanes, my point was that with the wealth of information on the internet, some may be tempted to follow something blindly while ignoring other facts being presented to them.