Slightly Off - topic

Aggressive Leaning

Some time back I wrote a small treatise on the wonders of agressive leaning. Until my SR 20 comes I am flying a Cessna 210 owned by a couple of doctors. It’s a Turbo Centurian II and very nice. Well kept, well mainatined, etc.

When I first started flying the beast last year I was sent an article from one of the owners on leaning lean of peak. Since the plane has an engine analyzer and Gami injectors, it was believed that you could lean 75 degrees lean of peak EGT and the plane would work fine. The article on leaing was very convincing with charts and scientific data etc.

The problems is that we are now replacing the top end of the engine at 800 hours. Culprit? Exhaust valves so burnt that some were sticking open. Lot’s of evidence of extremely high temps.

Before we gorunded the plane I was the last to fly it. It ran very well after a 100 hour. Except is was blowing out about 4 quarts of oil an hour through the new oil / air separator we installed. Apparantly, the stuck exhaust valve(s) were allowing gasses to pressurize the crank case above tolerances which led to the blowing of oil out of the crankcase point where there is supposed to be no pressue (return area for the separator).

I spoke with the mechanic about what I had been doing (leaning practices) and he nearly flipped. Told me to fly rich of peak (75 degrees) and ignore all the other recomendations.

Anyhow, I was wondering if anyone else has had a similar experience flying lean of peak. Not being the only pilot of the plane, I don’t know what the other guys are doing. Also, the plane was purchased used so the history is not well known either.

Mark

PS - For those of you wondering how the plane flew with valves stuck open, the mechanic has guessed that the turbo pressurized the cylinders enough to get some power. A normally aspirated engine would not have worked at all…

John Deakin, a columnist at Avweb, has much to say on leaning. He’s a proponent. He flies his IO-550 Bonanza at full throttle, 2100 rpm, and 50-degrees LOP. His technique violates all known wisdom. But Deakin says his JPI engine analyzer supports his unorthodox technique. He’s running cool and quiet, and what could be better?

Be very interesting, of course, how the Deakin strategy plays in the long run.

Aggressive Leaning

Some time back I wrote a small treatise on the wonders of agressive leaning. Until my SR 20 comes I am flying a Cessna 210 owned by a couple of doctors. It’s a Turbo Centurian II and very nice. Well kept, well mainatined, etc.

When I first started flying the beast last year I was sent an article from one of the owners on leaning lean of peak. Since the plane has an engine analyzer and Gami injectors, it was believed that you could lean 75 degrees lean of peak EGT and the plane would work fine. The article on leaing was very convincing with charts and scientific data etc.

The problems is that we are now replacing the top end of the engine at 800 hours. Culprit? Exhaust valves so burnt that some were sticking open. Lot’s of evidence of extremely high temps.

Before we gorunded the plane I was the last to fly it. It ran very well after a 100 hour. Except is was blowing out about 4 quarts of oil an hour through the new oil / air separator we installed. Apparantly, the stuck exhaust valve(s) were allowing gasses to pressurize the crank case above tolerances which led to the blowing of oil out of the crankcase point where there is supposed to be no pressue (return area for the separator).

I spoke with the mechanic about what I had been doing (leaning practices) and he nearly flipped. Told me to fly rich of peak (75 degrees) and ignore all the other recomendations.

Anyhow, I was wondering if anyone else has had a similar experience flying lean of peak. Not being the only pilot of the plane, I don’t know what the other guys are doing. Also, the plane was purchased used so the history is not well known either.

Mark

PS - For those of you wondering how the plane flew with valves stuck open, the mechanic has guessed that the turbo pressurized the cylinders enough to get some power. A normally aspirated engine would not have worked at all…

The SR20 POH recommends operating at either 75 degrees rich of peak or 50 degrees lean of peak.

Another good technical article that favors aggressive leaning: http://www.avweb.com/articles/pelperch/pelp0018.html

I’d like to hear what you conclude.

Aggressive Leaning

Some time back I wrote a small treatise on the wonders of agressive leaning. Until my SR 20 comes I am flying a Cessna 210 owned by a couple of doctors. It’s a Turbo Centurian II and very nice. Well kept, well mainatined, etc.

When I first started flying the beast last year I was sent an article from one of the owners on leaning lean of peak. Since the plane has an engine analyzer and Gami injectors, it was believed that you could lean 75 degrees lean of peak EGT and the plane would work fine. The article on leaing was very convincing with charts and scientific data etc.

The problems is that we are now replacing the top end of the engine at 800 hours. Culprit? Exhaust valves so burnt that some were sticking open. Lot’s of evidence of extremely high temps.

Before we gorunded the plane I was the last to fly it. It ran very well after a 100 hour. Except is was blowing out about 4 quarts of oil an hour through the new oil / air separator we installed. Apparantly, the stuck exhaust valve(s) were allowing gasses to pressurize the crank case above tolerances which led to the blowing of oil out of the crankcase point where there is supposed to be no pressue (return area for the separator).

I spoke with the mechanic about what I had been doing (leaning practices) and he nearly flipped. Told me to fly rich of peak (75 degrees) and ignore all the other recomendations.

Anyhow, I was wondering if anyone else has had a similar experience flying lean of peak. Not being the only pilot of the plane, I don’t know what the other guys are doing. Also, the plane was purchased used so the history is not well known either.

Mark

PS - For those of you wondering how the plane flew with valves stuck open, the mechanic has guessed that the turbo pressurized the cylinders enough to get some power. A normally aspirated engine would not have worked at all…

Apparantly, the stuck exhaust valve(s) were allowing gasses to pressurize the crank case

This sounds very dodgy to me - wouldn’t pressure in the crankcase be more likely to be blow-by over worn or cracked rings? How could a leaking exhaust valve do it?

PS - For those of you wondering how the plane flew with valves stuck open, the mechanic has guessed that the turbo pressurized the cylinders enough to get some power. A normally aspirated engine would not have worked at all…

That sounds like complete rubbish. A engine that fails a static compression test can easily produce close to full power, because of the dynamics of the gas flow when the engine is operating. Rough running is likely to be the first symptom.

Mark,

Two issues here:

  1. In a turbo Continental doing a top overhaul at 50% of the TBO is typical - especially if its run at 75% a lot, or run high/hot a lot. TBO of the TSIO520 is 1600 hrs, so a top at 800 hrs is about right. It should be budgeted into the hourly reserves on the engine usage.

  2. The TSIO520, even with GAMI’s has a mixed reputation on running lean of peak. Most of the talks on running this way revolve around the IO550 engine, which is of course not a turbo, and has a different induction system as far as I have read. I think this makes it a candidate for running lean of peak, rather than the turbo TSIO520.

Best,

…Warren

Aggressive Leaning

Some time back I wrote a small treatise on the wonders of agressive leaning. Until my SR 20 comes I am flying a Cessna 210 owned by a couple of doctors. It’s a Turbo Centurian II and very nice. Well kept, well mainatined, etc.

When I first started flying the beast last year I was sent an article from one of the owners on leaning lean of peak. Since the plane has an engine analyzer and Gami injectors, it was believed that you could lean 75 degrees lean of peak EGT and the plane would work fine. The article on leaing was very convincing with charts and scientific data etc.

The problems is that we are now replacing the top end of the engine at 800 hours. Culprit? Exhaust valves so burnt that some were sticking open. Lot’s of evidence of extremely high temps.

Before we gorunded the plane I was the last to fly it. It ran very well after a 100 hour. Except is was blowing out about 4 quarts of oil an hour through the new oil / air separator we installed. Apparantly, the stuck exhaust valve(s) were allowing gasses to pressurize the crank case above tolerances which led to the blowing of oil out of the crankcase point where there is supposed to be no pressue (return area for the separator).

I spoke with the mechanic about what I had been doing (leaning practices) and he nearly flipped. Told me to fly rich of peak (75 degrees) and ignore all the other recomendations.

Anyhow, I was wondering if anyone else has had a similar experience flying lean of peak. Not being the only pilot of the plane, I don’t know what the other guys are doing. Also, the plane was purchased used so the history is not well known either.

Mark

PS - For those of you wondering how the plane flew with valves stuck open, the mechanic has guessed that the turbo pressurized the cylinders enough to get some power. A normally aspirated engine would not have worked at all…

Can some current Cirrus owners let me know what the company’s recommended leaning procedure is for the 20/22? Deakin certainly has a lot of experience. His columns suggest that the standard 75 degrees rich-of-peak setting is about the worst place to be, esp. at power settings north of 65%. I’ve checked the Continental web-site and there doesn’t seem to be any information there on recommended leaning techniques.

John Deakin, a columnist at Avweb, has much to say on leaning. He’s a proponent. He flies his IO-550 Bonanza at full throttle, 2100 rpm, and 50-degrees LOP. His technique violates all known wisdom. But Deakin says his JPI engine analyzer supports his unorthodox technique. He’s running cool and quiet, and what could be better?

Be very interesting, of course, how the Deakin strategy plays in the long run.

Aggressive Leaning

Some time back I wrote a small treatise on the wonders of agressive leaning. Until my SR 20 comes I am flying a Cessna 210 owned by a couple of doctors. It’s a Turbo Centurian II and very nice. Well kept, well mainatined, etc.

When I first started flying the beast last year I was sent an article from one of the owners on leaning lean of peak. Since the plane has an engine analyzer and Gami injectors, it was believed that you could lean 75 degrees lean of peak EGT and the plane would work fine. The article on leaing was very convincing with charts and scientific data etc.

The problems is that we are now replacing the top end of the engine at 800 hours. Culprit? Exhaust valves so burnt that some were sticking open. Lot’s of evidence of extremely high temps.

Before we gorunded the plane I was the last to fly it. It ran very well after a 100 hour. Except is was blowing out about 4 quarts of oil an hour through the new oil / air separator we installed. Apparantly, the stuck exhaust valve(s) were allowing gasses to pressurize the crank case above tolerances which led to the blowing of oil out of the crankcase point where there is supposed to be no pressue (return area for the separator).

I spoke with the mechanic about what I had been doing (leaning practices) and he nearly flipped. Told me to fly rich of peak (75 degrees) and ignore all the other recomendations.

Anyhow, I was wondering if anyone else has had a similar experience flying lean of peak. Not being the only pilot of the plane, I don’t know what the other guys are doing. Also, the plane was purchased used so the history is not well known either.

Mark

PS - For those of you wondering how the plane flew with valves stuck open, the mechanic has guessed that the turbo pressurized the cylinders enough to get some power. A normally aspirated engine would not have worked at all…

Can some current Cirrus owners let me know what the company’s recommended leaning procedure is for the 20/22

For the 20, it recommends 75 rich of peak or 50 lean of peak. From experience, the LOP setting is smooth, but at least 5-8 knots slower than the ROP setting, so the reduction in fuel burn is partially offset by reduced speed.

The SR20 POH recommends operating at either 75 degrees rich of peak or 50 degrees lean of peak.

Another good technical article that favors aggressive leaning: http://www.avweb.com/articles/pelperch/pelp0018.html

I’d like to hear what you conclude.

Aggressive Leaning

Some time back I wrote a small treatise on the wonders of agressive leaning. Until my SR 20…

Gary,

Thanks for the link. I have printed the article and will read it this evening.

One of the things I want to be careful of is falling into the trap of a non-sequiter. In other words, I am not sure the conclusion (burnt valves in C210 Turbo) follows the premise (agressive leaning).

As I mentioned in the post, the plane was used when the owners bought it and it is flown by two other pilots. I believe their skill level is up to task but I don’t know for sure.

The engine analyzer indicated that all was well with regards to EGT on all six cylinders. It sometimes takes a bit to find peak EGT and other cockpit chores (onerous in a 210 single pilot IFR when it is bumpy and nasty)can take your attention away from the analyzer for longer than you should while you are trying to dial in the correct mixture.

Other opinions would help. Thanks again for the article. I had not read this one.

Mark

George Braly the co-inventor of GAMI’s regularly posts on the Bonanza list. His articulate description of the benefits of “properly” running lean of peak are worth reading but unlike most aviation pundits, he backs his words with money so here is a snippet regarding running lean of peaK. Jim McKeith

I can show you a Turbo 210 owner who operates the engine LOP 100% of the

time, at very high power settings. Hell, just for the “shock effect” …

I’ll let you in on a little secret: He even does climbs, lean of peak.

He has been doing this since he replaced the engine, about 1100 hours back.

Engine is perfect, in every way.

BEFORE he changed and started operating lean of peak, he had the normal TCM

set of engine problems.

I can show you a turbo C310 owner that is now at 2800+ hours since overhaul

on both engines. He has been operating lean of peak since 1500 hours.

The problems this T210 is experiencing is a lot like the problems the Malibu

owners experienced with the TSIO-520BE some years back… when they were

told to operate it 50 LOP… but they didn’t believe it and they ended up

operating it at peak or 25 ROP, because they thought (wrongly) that would be

“cooler”. They cratered a lot of engines, prematurely.

I teach approved A&P and IA renewal seminars for the FAA on engine

management. I have been through about 500-600 mechanics, so far this year.

In my experience, from quizzing the folks in those classes, they are at

least 90% very, very badly misinformed about the effects of operating lean

of peak. Many of them are almost in shock when they see TCM’s own data that

shows that CHTs get cooler when operated lean of peak… because they have

been telling pilots the “wrong” information for so many years.

The most important information you received from the SR-20 driver was the

fact that:

  1. He had no idea what the previous operation of the engine was like; and

  2. He had no idea how the other pilots had been operating the engine.

Last, 800 hours is considered good for a lot of T-210s, when operated as

TCM and Cessna recommends.

I have seen a bunch of them lunch engines before 500 hours.

 I have a standing offer to pay anybody $1000 bucks, if they can show me hard

data that establishes anything to the contrary to the following:

 At a given horsepower, in an otherwise apples-to-apples comparison:

 1) LOP operation results in lower peak cylinder pressures;
 2) LOP operation results in lower cylinder head temperatures;
 3) LOP operation results in lower ring blow-by;
 4) LOP operation results in cleaner oil at oil changes;
 5) LOP operation results in 10% or more fuel savings;
 6) LOP operation results in cleaner combustion chambers;
 7) LOP operation results in cleaner piston faces;
 8) LOP operation results in cooler exhaust valves;
 9) LOP operation results in cleaner exhaust valve seats;
 10)LOP operation results in fewer valve guide deposits;
 11)LOP operation results in cleaner spark plugs;
 12)LOP operation results in 90+% reduced carbon monoxide...

As compared to operation of the same engine at the same horsepower at 75F

ROP fuel/air ratios.

Regards, George

Two issues here:

  1. In a turbo Continental doing a top overhaul at 50% of the TBO is typical - especially if its run at 75% a lot, or run high/hot a lot. TBO of the TSIO520 is 1600 hrs, so a top at 800 hrs is about right. It should be budgeted into the hourly reserves on the engine usage.
  1. The TSIO520, even with GAMI’s has a mixed reputation on running lean of peak. Most of the talks on running this way revolve around the IO550 engine, which is of course not a turbo, and has a different induction system as far as I have read. I think this makes it a candidate for running lean of peak, rather than the turbo TSIO520.

Best,

…Warren

Aggressive Leaning

Some time back I wrote a small treatise on the wonders of agressive leaning. Until my SR 20 comes I am flying a Cessna 210 owned by a couple of doctors. It’s a Turbo Centurian II and very nice. Well kept, well mainatined, etc.

When I first started flying the beast last year I was sent an article from one of the owners on leaning lean of peak. Since the plane has an engine analyzer and Gami injectors, it was believed that you could lean 75 degrees lean of peak EGT and the plane would work fine. The article on leaing was very convincing with charts and scientific data etc.

The problems is that we are now replacing the top end of the engine at 800 hours. Culprit? Exhaust valves so burnt that some were sticking open. Lot’s of evidence of extremely high temps.

Before we gorunded the plane I was the last to fly it. It ran very well after a 100 hour. Except is was blowing out about 4 quarts of oil an hour through the new oil / air separator we installed. Apparantly, the stuck exhaust valve(s) were allowing gasses to pressurize the crank case above tolerances which led to the blowing of oil out of the crankcase point where there is supposed to be no pressue (return area for the separator).

I spoke with the mechanic about what I had been doing (leaning practices) and he nearly flipped. Told me to fly rich of peak (75 degrees) and ignore all the other recomendations.

Anyhow, I was wondering if anyone else has had a similar experience flying lean of peak. Not being the only pilot of the plane, I don’t know what the other guys are doing. Also, the plane was purchased used so the history is not well known either.

Mark

PS - For those of you wondering how the plane flew with valves stuck open, the mechanic has guessed that the turbo pressurized the cylinders enough to get some power. A normally aspirated engine would not have worked at all…

Thanks for the information -

Since I last posted my message, I have personally seen the engine in the 210

The number four cyl exhaust valve is shot. The number 2 stuck and scored the rocker arm bearing so that oil quit flowing thru the are with a resulting ugly valve.

Number 6 was stuck but is salvagable.

It seems that only one cylinder needs to be replaced. # 4. The rest should be okay with a reeming of the valve guides.

Talked to the meachanic some more about the possible causes. He still thinks that high heat was the culprit. However, when I was running LOP I could see a significant decrease in temps (EGT and CHT) at 75 degs LOP. The engine ran good and I only lost a little bit of RPM.

The mechanic has now told me that he thinks the problem is occuring during climb. For takeoff, we have been going full throttle to about a 1000 feet then pulling the throttle back to get the MP in the green. The mechanic says we should advance the throttle to an inch below the top of the green then reduce the RPM’s when we get cleaned up. After we reach the altitude we want, level off and trim, we should then set the prop, throttle and mixture according to the manual for 65% power and using the fule flow meter as the primary reference. EGT and CHT be damned.

Hmmm. I am really confused now and I am looking forward to having my own bird without worrying about other pilots. The good news is I am just “renting” this plane from the two owners. God knows what they do…

Mark

George Braly the co-inventor of GAMI’s regularly posts on the Bonanza list. His articulate description of the benefits of “properly” running lean of peak are worth reading but unlike most aviation pundits, he backs his words with money so here is a snippet regarding running lean of peaK. Jim McKeith

I can show you a Turbo 210 owner who operates the engine LOP 100% of the

time, at very high power settings. Hell, just for the “shock effect” …

I’ll let you in on a little secret: He even does climbs, lean of peak.

He has been doing this since he replaced the engine, about 1100 hours back.

Engine is perfect, in every way.

BEFORE he changed and started operating lean of peak, he had the normal TCM

set of engine problems.

I can show you a turbo C310 owner that is now at 2800+ hours since overhaul

on both engines. He has been operating lean of peak since 1500 hours.

The problems this T210 is experiencing is a lot like the problems the Malibu

owners experienced with the TSIO-520BE some years back… when they were

told to operate it 50 LOP… but they didn’t believe it and they ended up

operating it at peak or 25 ROP, because they thought (wrongly) that would be

“cooler”. They cratered a lot of engines, prematurely.

I teach approved A&P and IA renewal seminars for the FAA on engine

management. I have been through about 500-600 mechanics, so far this year.

In my experience, from quizzing the folks in those classes, they are at

least 90% very, very badly misinformed about the effects of operating lean

of peak. Many of them are almost in shock when they see TCM’s own data that

shows that CHTs get cooler when operated lean of peak… because they have

been telling pilots the “wrong” information for so many years.

The most important information you received from the SR-20 driver was the

fact that:

  1. He had no idea what the previous operation of the engine was like; and
  1. He had no idea how the other pilots had been operating the engine.

Last, 800 hours is considered good for a lot of T-210s, when operated as

TCM and Cessna recommends.

I have seen a bunch of them lunch engines before 500 hours.

I have a standing offer to pay anybody $1000 bucks, if they can show me hard

data that establishes anything to the contrary to the following:

At a given horsepower, in an otherwise apples-to-apples comparison:

  1. LOP operation results in lower peak cylinder pressures;
  2. LOP operation results in lower cylinder head temperatures;
  3. LOP operation results in lower ring blow-by;
  4. LOP operation results in cleaner oil at oil changes;
  5. LOP operation results in 10% or more fuel savings;
  6. LOP operation results in cleaner combustion chambers;
  7. LOP operation results in cleaner piston faces;
  8. LOP operation results in cooler exhaust valves;
  9. LOP operation results in cleaner exhaust valve seats;
    10)LOP operation results in fewer valve guide deposits;
    11)LOP operation results in cleaner spark plugs;
    12)LOP operation results in 90+% reduced carbon monoxide…

As compared to operation of the same engine at the same horsepower at 75F

ROP fuel/air ratios.

Regards, George

Two issues here:

  1. In a turbo Continental doing a top overhaul at 50% of the TBO is typical - especially if its run at 75% a lot, or run high/hot a lot. TBO of the TSIO520 is 1600 hrs, so a top at 800 hrs is about right. It should be budgeted into the hourly reserves on the engine usage.
  1. The TSIO520, even with GAMI’s has a mixed reputation on running lean of peak. Most of the talks on running this way revolve around the IO550 engine, which is of course not a turbo, and has a different induction system as far as I have read. I think this makes it a candidate for running lean of peak, rather than the turbo TSIO520.

Best,

…Warren

Aggressive Leaning

Some time back I wrote a small treatise on the wonders of agressive leaning. Until my SR 20 comes I am flying a Cessna 210 owned by a couple of doctors. It’s a Turbo Centurian II and very nice. Well kept, well mainatined, etc.

When I first started flying the beast last year I was sent an article from one of the owners on leaning lean of peak. Since the plane has an engine analyzer and Gami injectors, it was believed that you could lean 75 degrees lean of peak EGT and the plane would work fine. The article on leaing was very convincing with charts and scientific data etc.

The problems is that we are now replacing the top end of the engine at 800 hours. Culprit? Exhaust valves so burnt that some were sticking open. Lot’s of evidence of extremely high temps.

Before we gorunded the plane I was the last to fly it. It ran very well after a 100 hour. Except is was blowing out about 4 quarts of oil an hour through the new oil / air separator we installed. Apparantly, the stuck exhaust valve(s) were allowing gasses to pressurize the crank case above tolerances which led to the blowing of oil out of the crankcase point where there is supposed to be no pressue (return area for the separator).

I spoke with the mechanic about what I had been doing (leaning practices) and he nearly flipped. Told me to fly rich of peak (75 degrees) and ignore all the other recomendations.

Anyhow, I was wondering if anyone else has had a similar experience flying lean of peak. Not being the only pilot of the plane, I don’t know what the other guys are doing. Also, the plane was purchased used so the history is not well known either.

Mark

PS - For those of you wondering how the plane flew with valves stuck open, the mechanic has guessed that the turbo pressurized the cylinders enough to get some power. A normally aspirated engine would not have worked at all…