tried LOP for the first time - have some questions

[jetdriven]

Pull to where you'd guess you are 50 LOP. then richen to peak to find it, then lean as planned.  In your buggy, around 8 GPH. Above 7K, a lesser value.

[carusoam]

201er

For lop you need to know "last cylinder to peak" or richest cylinder.

"Big pull" is a way to get from ROP to lop without dawdling and over heating things on the way.

Tradition has it that you lean from ROP through peak of all cylinders and then measuring deg lop from the last cylinder to peak.

Once you have done this, you can pretty much skip the time consuming hard work and heat by leaning using fuel flow instead.  

Of course you should use traditional method first to develop FF data for your setup.

Big pull is more valuable at low alts for NA engines or more important for turbo engines.

Either way it is the method of getting to an end point.  It is a lower temperature method, not an easier or more simple way of getting there.

Best regards,

-a-

[carusoam]

Byron,

How do you set the JPI for your method?

Do you set LOP mode, and pull slow enough for the JPi to register the cylinders in order?

This way you will be leaning to the last to peak.

 

The question being how do you lean to the richest cylinder?  

For lyc io360 it is always the same?  Just lean that one?

 

Best regards,

 

-a-

[John Pleisse]

I love you guys to death, but 10.8 @ 8.5k, 1365/375 never hurt a thing and made Lycoming 4-bangers legendary. Twist those knobs and fixate on the GEM all day!! 2.8 gph for two thousand hours= a factory new top. Either way, see you at TBO!!!!

I am still waiting for my POH supplement from Lycoming (holding my breath...turning blue....gasp.....). Great science and pertinent to big bore Continentals.

[carusoam]

N4352H 

Get big bore continental, breathe easy....lop data is in the POH.

At 2.8 gph for 2k hours you have nearly saved enough for a complete oh, no?

Best regards,

-a-

[Shadrach]

Quote: N4352H

I love you guys to death, but 10.8 @ 8.5k, 1365/375 never hurt a thing and made Lycoming 4-bangers legendary. Twist those knobs and fixate on the GEM all day!! 2.8 gph for two thousand hours= a factory new top. Either way, see you at TBO!!!!

I am still waiting for my POH supplement from Lycoming (holding my breath...turning blue....gasp.....). Great science and pertinent to big bore Continentals.

[Shadrach]

Quote: 201er

Could someone explain this "big pull" concept? I was just accustomed to pulling the mixture to where I'd guess 50ROP is and letting it stabilize. The slowly leaning with the vernier to peak and then either in or more out to get to where I want to be.

[Shadrach]

Quote: bd32322

Oh one more question - is there a red-line for peak EGT?

I saw 1500 in the flight i mention above at 3000 feet - and thought that was a pretty darn high number compared to what i usually see - so I took immediate action

[Shadrach]

Quote: carusoam

Becca is the only mooney driver cruising at 3k or below, right?  And she is running ROP.....

[jetdriven]

We have no JPI, we have a Masten Products engine monitor from 1991.  It measures all 4 CHT, EGT, and FF plus totalizer on a single line, 5 digit display.  You can only see one thing at a time, but it has an auto mode to monitor the hottest cylinder. When we bought the plane, I didnt like it. Now I do.

[jetdriven]

So they Lycoming rep stopped by the shop today to make his rounds. He remarked on my 201 sitting there with no prop or cowl on it, and asked how many hours it had on the engine. I replied 1500.  He informed me I only had "500 hours left if I was lucky".  I'm glad he reminded me when the engine is going to sieze up. I almost forgot.  better get my order in now.  He informed me for only 40K I can get an IO-390 on my airplane and gain 5 knots. Ok. Fine. Not for me. Roller tappets are cool, but my 1987 IROC had them and its nothing new. He claimed the airplane is "smoother and quieter" because of them.  Seriously. Roller tappets.

So I decided to finish him off and tell him we are running 30 LOP and burning 8-8.5 GPH.  His look of horror told all, he looked like I just killed a pack of baby seals, exposed myself in the park to some children, or cheated on his sister.  Seriously, shrinking away from me.   He informs me I am "burning my engine up", to which I reply, how is a 330 CHT burning anything up. At 75 LOP i am worried about enought CHT, its at 280. He says this is cooling "with air, and the extra oxygen and chemicals in the metallurgy, causes the cylinders to burn up."   No kidding.  Did he go to college?  I am laughing now. I suppose Continental has some special "LOP metal" cause some of their engines are only approved for LOP.

Anyways, He immediately inspects my cylinders for "burning" as the gray paint turns dark at 500 F.  All are nice gray.  He is quiet. He asks, how many hours we have ran it this way, (150 hours, enough fuel savings to buy an 1100$ overhauled cylinder already).  Nevermind the oil consumption is down to a quart in 12-15 hours or more vs. the quart every 5 hours when we bought it, clean oil analysis, no carbon or trash in the filter, and 75 hours on spark plugs that required no cleaning.  The engine tone is a little different but I think the engine is happy running this way.  perhaps I am crazt, betting 8K worth of angle-valve cylinders on it, but you, know what, I will take that bet.

[carusoam]

Roller tappets in the 87 Iroc were nice, but the valve guides were the wear item...As evidenced by the smoky starts and crusty deposits on the spark plugs.

Was that the L98 engine?

 

So, has the Lycoming guy been doing this a while or was he hopeful new guy who had been taught scare tactics as a primary sales tool?

Best regards,

-a-

 

 

[carusoam]

dp

[201er]

Quote: jetdriven

So I decided to finish him off and tell him we are running 30 LOP and burning 8-8.5 GPH.  His look of horror told all, he looked like I just killed a pack of baby seals, exposed myself in the park to some children, or cheated on his sister.  Seriously, shrinking away from me.

[John Pleisse]

Quote: jetdriven

Perhaps I am crazt, betting 8K worth of angle-valve cylinders on it, but you, know what, I will take that bet.

[KSMooniac]

Lycoming is their own worst enemy on this topic.  What a fool.

[John Pleisse]

Quote: Shadrach

John,

What you've said about LOP ops is a common misconception. However, LOP or "lean of stoichiometric" operations are pertinent to combustion propulsion science and engineering...period.  Just about every Modern/semi-modern injected internal combustion engine on the planet runs lean of stoic, depending on power demand. Lean air/fuel ratios and the technology that enables them has contributed largely to improved fuel economy in every machine that burns hydrocarbons.  The main reason auto technology is going towards direct injection is to enable autos to run extremely lean air/fuel ratios in excess of >50:1 which is far leaner than we could ever achieve with our constant flow port injection set ups.  It has nothing to do with Continental vs Lycoming. Ignited Avgas cares not about the name embossed on the rocker covers...

The genesis of Gami injectors was born out of Continental's intake design (log runner intake) and that systems inherent flaws with regard to fuel distribution (not air distribution, which is another common misconception). Gamis will benefit any Continental with a log runner intake system regardless of whether it is run LOP of ROP. While the owner of GAMI (George Brawly) is also involved with Advanced Pilot Seminars (APS) and also happens to currently operate a Continental, it does not mean that LOP operations are only "pertinent" to "big bore Continentals".

I think people should operate as they choose. However, I think it's better to be informed about how that choice affects the combustion event and its effects on CHT and EGT which in turn have an affect on both engine health and economy.

Lycoming has no incentive to revise it's POH (BTW, the power settings per the POH are recommendations, not limitations) and in fact has a legal incentive not to revise based on what they've been saying for the past 5 decades. They're tune changed at Oshkosh this year.

All of that being said, anyone with even a rudimentary knowledge of combustion science would have an impossible job reconciling lycoming's past stance that "peak EGT settings are safe, but LOP settings are dangerous".  It is an intellectually and scientifically unsupportable position.

I fault no one for following the POH, but those recommendations are not always the best course of action. For those that know what they are doing, deviating from the "cook book" can enable them to enhance performance and also be kinder to their engine, for those that don't, running per POH is certainly not going to hurt anything...most of the time. 

 

 

[KSMooniac]

GAMI's (if needed), a modern GEM and fuel flow instrumentation are *great* upgrades for any plane, no matter how the engine is operated.  It is a fallacy to think all of that is required for LOP any more so than for ROP ops.  In fact, there is a great argument to be made that it is *more* important to have a GEM for ROP ops since the engine can still be smooth when there is an induction leak or clogged injector.

Lycoming's stance on LOP ops has been repeatedly shown to be at odds with the science and data, and their position is not defensible from a technical standpoint.  They've gone so far down the road of anti-LOP that to suddenly change their tune might trigger some confusion and perhaps their legal department continues to advise them to spread misinformation.

There are an infinite number of LOP power settings to choose from if you believe that engines somehow get damaged from running one power setting. (which isn't true)

Even 1 GPH over a 2000 hr TBO run adds up to more than $10k at average fuel prices today.  That is significant to me!  Not to mention that running LOP will very likely keep your engine in great condition to run past TBO if you choose, and even overhaul your cylinders instead of replacing them, which is an additional $4k of savings for the angle valve jugs.

In light of all the benefits, I ask why would anyone run their engine ROP?  

[John Pleisse]

Quote: KSMooniac

It is a fallacy to think all of that is required for LOP any more so than for ROP ops.

Absolutely, but helpful.

Lycoming's stance on LOP ops has been repeatedly shown to be at odds with the science and data, and their position is not defensible from a technical standpoint.  

Absolutely false.....Lycoming has always  beleived the science of LOP ops to be worthy and viable. Where they disagree is pilot workload and the likelihood of pilot error in engine management. While this could be dismissed as arrogant, they readily point to the narrow margins at 50 degrees LOP and heavy GA workloads. While you may not like it, it is their warranty and perogative. Again.....GEM's are the modern catylist behind the movement. 

There are an infinite number of LOP power settings to choose from if you believe that engines somehow get damaged from running one power setting. (which isn't true)

Ah yes....but most under 69%, realistically.

Even 1 GPH over a 2000 hr TBO run adds up to more than $10k at average fuel prices today.  That is significant to me!  

Scott, I would never dismiss fuel savings, only quantify them vs. alternatives.

Not to mention that running LOP will very likely keep your engine in great condition to run past TBO if you choose, and even overhaul your cylinders instead of replacing them, which is an additional $4k of savings for the angle valve jugs.

Prove it.

In light of all the benefits, I ask why would anyone run their engine ROP?  

It is proven to be safe for the engine and provides a known reliability.

The LOP movement, while based in science, seems fixated with Lycomings stubborness at almost heratic levels. It's not the science, it's the pratical applicabilty and proven reliability. In Lycoming 4 bangers, all the margins are more narrow, including fuel savings.

[KSMooniac]

Actually I have run LOP power settings from 50% (actually a bit less) all the way up to 85% power.

Regarding Lycoming, just a few posts above jetdriven (Byron) posted an exchange he had with a Lycoming rep that wandered into his hangar and spouted off some very erroneous info regarding LOP ops.  

LOP ops result in lower peak internal cylinder pressures and cooler CHTs, which yields a much longer fatigue life (ie less chance of cracking).  This means that is is highly likely that 2000 hrs of LOP ops will leave a cylinder in great shape for an overhaul whereas ROP ops might lead to cracking due to the higher pressures and temperatures.  Angle valve jugs are sole-source Lycoming, and they cost twice as much as parallel valve jugs that have aftermarket competition.  This means a potential savings of $4k on a set of 4 if you choose to overhaul instead of replace.

One more fact... the detonation margins at 50 LOP are MUCH greater than they are at 50 ROP.  Detonation needs high temps and high pressures, and 50 ROP is far more prone to detonation than 50 LOP!

[John Pleisse]

Quote: jetdriven

So they Lycoming rep stopped by the shop today to make his rounds. He remarked on my 201 sitting there with no prop or cowl on it, and asked how many hours it had on the engine. I replied 1500.  He informed me I only had "500 hours left if I was lucky".  I'm glad he reminded me when the engine is going to sieze up. I almost forgot.  better get my order in now.  He informed me for only 40K I can get an IO-390 on my airplane and gain 5 knots. Ok. Fine. Not for me. Roller tappets are cool, but my 1987 IROC had them and its nothing new. He claimed the airplane is "smoother and quieter" because of them.  Seriously. Roller tappets.

So I decided to finish him off and tell him we are running 30 LOP and burning 8-8.5 GPH.  His look of horror told all, he looked like I just killed a pack of baby seals, exposed myself in the park to some children, or cheated on his sister.  Seriously, shrinking away from me.   He informs me I am "burning my engine up", to which I reply, how is a 330 CHT burning anything up. At 75 LOP i am worried about enought CHT, its at 280. He says this is cooling "with air, and the extra oxygen and chemicals in the metallurgy, causes the cylinders to burn up."   No kidding.  Did he go to college?  I am laughing now. I suppose Continental has some special "LOP metal" cause some of their engines are only approved for LOP.

Anyways, He immediately inspects my cylinders for "burning" as the gray paint turns dark at 500 F.  All are nice gray.  He is quiet. He asks, how many hours we have ran it this way, (150 hours, enough fuel savings to buy an 1100$ overhauled cylinder already).  Nevermind the oil consumption is down to a quart in 12-15 hours or more vs. the quart every 5 hours when we bought it, clean oil analysis, no carbon or trash in the filter, and 75 hours on spark plugs that required no cleaning.  The engine tone is a little different but I think the engine is happy running this way.  perhaps I am crazt, betting 8K worth of angle-valve cylinders on it, but you, know what, I will take that bet.

[John Pleisse]

Quote: KSMooniac

Actually I have run LOP power settings from 50% (actually a bit less) all the way up to 85% power.

Regarding Lycoming, just a few posts above jetdriven (Byron) posted an exchange he had with a Lycoming rep that wandered into his hangar and spouted off some very erroneous info regarding LOP ops.  

LOP ops result in lower peak internal cylinder pressures and cooler CHTs, which yields a much longer fatigue life (ie less chance of cracking).  This means that is is highly likely that 2000 hrs of LOP ops will leave a cylinder in great shape for an overhaul whereas ROP ops might lead to cracking due to the higher pressures and temperatures.  Angle valve jugs are sole-source Lycoming, and they cost twice as much as parallel valve jugs that have aftermarket competition.  This means a potential savings of $4k on a set of 4 if you choose to overhaul instead of replace.

One more fact... the detonation margins at 50 LOP are MUCH greater than they are at 50 ROP.  Detonation needs high temps and high pressures, and 50 ROP is far more prone to detonation than 50 LOP!

[KSMooniac]

Quote: N4352H

 One more time Scott.....

Absolutely false.....Lycoming has always  beleived the science of LOP ops to be worthy and viable. Where they disagree is pilot workload and the likelihood of pilot error in engine management. While this could be dismissed as arrogant, they readily point to the narrow margins at 50 degrees LOP and heavy GA workloads. While you may not like it, it is their warranty and perogative. Again.....GEM's are the modern catylist behind the movement. 

[John Pleisse]

Quote: KSMooniac

 One more time Scott.....

Absolutely false.....Lycoming has always  beleived the science of LOP ops to be worthy and viable. Where they disagree is pilot workload and the likelihood of pilot error in engine management. While this could be dismissed as arrogant, they readily point to the narrow margins at 50 degrees LOP and heavy GA workloads. While you may not like it, it is their warranty and perogative. Again.....GEM's are the modern catylist behind the movement. 

[KSMooniac]

Quote: N4352H