How long have you been running LOP

[201er]

I see that a lot of guys have been trying LOP. It was a pretty novel concept a few years ago but is now common place. I wonder if enough people have flown LOP long enough to put to rest the myths about needing cylinders or premature overhauls. How many years and hours have you done of LOP flying? What kind of engine trouble have you run into in that span?

Edited May 1, 2017 by 201er

[gsengle]

There is another active thread on this as we speak.


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[Oldguy]

I would think many of us (myself and two other Mooney pilots I know as my entire sample) started after researching and listening to/reading about the results of the "early adopters" and, importantly, had an engine monitor covering all cylinders.

I've been through 3 annuals with no valve or cylinder problems, currently have 1500 on the engine, and expect to make it to TBO and beyond. Another Mooney pilot who works with me has put 1000 hours on his engine running lean of peak and is shooting for 2400 to do an engine O/H or replacement. He is currently at 1600. We both run oil analysis and are religious about oil changes on time or hours.

[Bob - S50]

I'm in the 100-500 hour range because that's all the hours I have on a piston.  Our mechanic loved the way the engine looked when he did the borescope at the last annual.  He said it was very clean and dry.  Then again, he also asked if we ever use the brakes on the plane.

[201er]

I have about 800 hours on the engine since overhaul. I've been running it LOP for 90%+ of the time. No engine/cylinder troubles yet. I was promised by mechanics to be needing new jugs within 300 hours if I would dare run LOP. I also had a few hundred hours of LOP on the previous engine.

I am curious if we have any Mooney pilots here who have gone TBO to TBO running LOP. Perhaps it may take a few more years till anyone has done it.

[gsengle]

I'm at 1980 hours or so...


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[1964-M20E]

well

I have about 1350 on my engine 450 of those I put on it.  6500+ hours TT on the plane.  I believe that this is the original engine since new maybe with some new jugs over the years but I do not have the logs in front of me.  I do not know how the previous owner ran the engine.  Couple of years ago we had some of the cylinder off to put new base o-rings on the bottom and they looked fine.

[David Medders]

Lycoming TIO-540-AF1B (M20M), 2,000 TBO, LOP since reman:

• First cylinder overhaul: 1,250-ish hours;
• Three more overhauls done at 125-ish hour intervals;
• Leaving two original cylinders on the engine at 1,850 hours.

A friend, now former-ROP operator, did his first cylinder overhaul at 800-ish hours on the same type.

[Cyril Gibb]

21 hours ago, 201er said:

I see that a lot of guys have been trying LOP. It was a pretty novel concept a few years ago but is now common place.

Ah 201er, you are so young.......

When I started flight training in the early 70s, I was taught to cruise LOP.  Every pilot and instructor I knew flew LOP.  I understand that the advantages of LOP was known and practiced in the 30s and 40s.  It ain't new.

I dropped out of aviation for forty years until a few years ago.  I couldn't believe that LOP/ROP was being argued.  Bizarre!

 

[gsxrpilot]

1 hour ago, Cyril Gibb said:

Ah 201er, you are so young.......

When I started flight training in the early 70s, I was taught to cruise LOP.  Every pilot and instructor I knew flew LOP.  I understand that the advantages of LOP was known and practiced in the 30s and 40s.  It ain't new.

I dropped out of aviation for forty years until a few years ago.  I couldn't believe that LOP/ROP was being argued.  Bizarre!

 

Yep, it was interesting in the APS class to hear the story of how ROP came back into fashion and now has to be debunked all over again.

[carusoam]

It was going to burn the valves!!!

Without open conversation via the internet, we couldn't have these conversations or share video of engines shooting flames past the valves running ROP.

Excess oxygen was going to burn things up as well.  Except all those things are some level of stainless and resist oxidizing.

The proliferation of engine monitors has been a great way for everyone to gain better knowledge of what is actually going on with their engine.  Familiarization leads to the ability to take on additional steps.

Having the LOP as part of the POH is incredibly helpful.  Having APS demonstrate their abilities with actual engines similar to our own is incredibly helpful.

What else can you get to help prove LOP works for your bird?

Exhaust parts have the most difficult life. ROP in a TC'd engine is pretty tough on the exhaust system.  LOP isn't going to be any worse.  The nice part about the NA engine is the release of exhaust pressure, thermodynamically drops the temperature significantly.

Best regards,

-a-

[Hank]

Carburetor? Yes. Doghouse? Fixed. Carb heat box? Fixed. Now LOP enabled, nice and smooth for at least 25°LOP. 

Engine monitor? Not yet. No LOP cruising, still ROP. Approx. 800 SMOH, only magneto, muffler and SoS problems unrelated to LOP/ROP.

But no running there until monitor selected, purchased on sale and installed with Avionics assistance.

Then I'll repeat previous failed experiments with reduced throttle, partial carb heat, etc. Maybe it will go leaner now.

[Shadrach]

Mooney clearly new about the advantages of LOP as far back as 1969. It's the economy setting that is described in the POH:

 

[201er]

30 minutes ago, Shadrach said:

Mooney clearly new about the advantages of LOP as far back as 1969. It's the economy setting that is described in the POH:

 

That's 25ROP, how's it any different than all the OWT?

[N6758N]

4 minutes ago, 201er said:

That's 25ROP, how's it any different than all the OWT?

Maybe they've all been running ROP this whole time thinking they were LOP! 

[Shadrach]

1 hour ago, 201er said:

That's 25ROP, how's it any different than all the OWT?

It's not written that way. Read both paragraphs and tell me what's different about the them.

[N6758N]

Yes it is 25 ROP, that is for best economy, for best power the next paragraph says 100 ROP for best power. Either way they are both ROP as it states, "enrich the mixture"

[Shadrach]

13 hours ago, N6758N said:

Yes it is 25 ROP, that is for best economy, for best power the next paragraph says 100 ROP for best power. Either way they are both ROP as it states, "enrich the mixture"

If one wants to get from 80LOP to 30LOP they must "enrich the mixture", so I hardly see how that phrase means anything without knowing where you're starting from.

My post was meant to be tounge and cheek, given how poorly worded the POH is, one could easily read it as a LOP setting (indeed 25LOP produces about the best BSFC possible in a Lyc 4 banger).

The first paragraph says to lean "temp peaks and starts to decrease" and then to enrichen to 25 degrees below peak. Second paragraph says to lean only to peak and then enrichen to 100.

The only reason I mention it is because I know that some of the factory pilots were running that way long before it was mainstream.  Mr Lopresti completed the 1985 CAFE 400 @75% and 50LOP.  This type of running was not unusual to the factory or the CAFE foundation in the 70s and 80s.

 

 

 

 

 

[Shadrach]

1 hour ago, bluehighwayflyer said:

Good stuff, Ross!  Thanks for posting. I'm surprised Roy climbed so high in a closed course. I would have probably stayed down low. But he is the expert and legend. 

He was low considering the surrounding topography!  It seems they were using "natural" pylons.

St John mountain = 6745'

Latour Butte = 6737'

Bully Choop Mountain = 6978'

Link to the complete article here. 

[Marauder]

We had a discussion awhile back about the long term effect running LOP has had on an engine's longetivity. I would love to see data from engine overhaulers who have seen and worked on these engines firsthand before drawing a conclusion.

Not having a problem with an engine could be more about the metallurgy of the engine rather than if is run LOP or ROP.


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[201er]

58 minutes ago, Marauder said:

We had a discussion awhile back about the long term effect running LOP has had on an engine's longetivity. I would love to see data from engine overhaulers who have seen and worked on these engines firsthand before drawing a conclusion.

Not having a problem with an engine could be more about the metallurgy of the engine rather than if is run LOP or ROP.


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A big problem for gathering useful data is that I think few pilots run the same engine from overhaul to overhaul (and especially the same way the whole time). When a plane goes through multiple owners (or even partners) through the life of an engine, there is far less opportunity to point to how it was flown specifically.

On the flip side you get guys buying a midtime engine airplane and flying it LOP since purchase. Doesn't really make it clear if the recent LOP flying or the way it was previously flown is the culprit or the savior.

The only meaningful scenario is when the same engine is flown overhaul to overhaul by the same owner. The biggest issue with this data is that most likely this is someone who flies a lot and regularly so it will be hard to separate whether it was the LOP that helped the engine or the frequent flying.

Edited May 3, 2017 by 201er

[N6758N]

12 minutes ago, 201er said:

A big problem for gathering useful data is that I think few pilots run the same engine from overhaul to overhaul (and especially the same way the whole time). When a plane goes through multiple owners (or even partners) through the life of an engine, there is far less opportunity to point to how it was flown specifically.

On the flip side you get guys buying a midtime engine airplane and flying it LOP since purchase. Doesn't really make it clear if the recent LOP flying or the way it was previously flown is the culprit or the savior.

The only meaningful scenario is when the same engine is flown overhaul to overhaul by the same owner. The biggest issue with this data is that most likely this is someone who flies a lot and regularly so it will be hard to separate whether it was the LOP that helped the engine or the frequent flying.

Not to mention whether or not flaps were used on takeoff for the life of the engine, don't forget that Mike!

[DXB]

Despite claims to the contrary, I remain skeptical that anyone with an O-360 can run lean of peak on more than one or two cylinders at a time.  That doesn't seem to count, so I didn't vote. But if it does, then yeah sure I run LOP all the time.

[Godfather]

I replaced fewer cylinders in the 2000 hrs hrs I flew the plane than the original owner did in the first few hundred. So yes, good engine management utilizing LOP has paid off over the long term. Looking for another 2500 hrs of low maintenance bliss...

[Marauder]

A big problem for gathering useful data is that I think few pilots run the same engine from overhaul to overhaul (and especially the same way the whole time). When a plane goes through multiple owners (or even partners) through the life of an engine, there is far less opportunity to point to how it was flown specifically.
On the flip side you get guys buying a midtime engine airplane and flying it LOP since purchase. Doesn't really make it clear if the recent LOP flying or the way it was previously flown is the culprit or the savior.
The only meaningful scenario is when the same engine is flown overhaul to overhaul by the same owner. The biggest issue with this data is that most likely this is someone who flies a lot and regularly so it will be hard to separate whether it was the LOP that helped the engine or the frequent flying.

I think what you pointed out is why all of this remains theoretical. A controlled study would help go a long way to prove whether or not running LOP actually improves engine reliability and/or has no effect on engine wear.


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