Conti TSIO 520-R Cylinder problems

Conti TSIO 520-R Cylinder problems

I own a T-210 N with a conti fact. reman. TSIO 520 R.
Now 5 years installed, 488 hrs.
Five of 6 Zylinders failed now the compression test. The shop says due to
worn exhaust valves (seems to have run too hot) and some scratches in the cylinder wall at upper TDC.
The engine is closly monitored (trend monitoring), oil analysis, TIT, 6 channel CHT and EGT and never got too hot.
Oil consuption was stable at 1 quart / 50 hrs.
We fly usually at 60 - 65 % at slightly rich of peak EGT (plus 3 liters fuel flow on rich side of egt) with maximum 1550 TIT (allowed is 1650).
CHT are then about 400 and oil 200.
Now my questions:
If POH allows peak EGT operations up to 70% power setting how can be peak egt to hot for the valve - i mean peak egt is always as hot as peak egt is. and if peak egt is approved - why is then too hot? epecially at 60-65% with 3 liters rich of peak?
Any ideas how to operate this engine in the future ? lean of peak ?
or 80% cruise with horrible fuel flow to cool with fuel??
Or proceed and buy every 450 hours 6 new zylinders ?

Any ideas are appreciated.
Friedrich Renner

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Re: Conti TSIO 520-R Cylinder problems

Friedrich,

Have you tried to run this engine at LOP? The reason I ask is we have a few good examples with folks running TCM IO-550N Lean of Peak, and one with 2200 hours TT on it only barely needing a TOP OH - no failed cylinders the entire 2200 hours, and a clean bottom end. The 550, if run ROP will barely make 700 hours WITHOUT a TOP Overhaul.

That gives us operating the TCM-IO360s and IO550s longer life, 20% fuel savings, lower cylinder temps and pressures. I'll copy and paste items from our Engine Operations section on COPA that would be of use to you.

But a couple of notes - 400* CHT is too hot. You lose 30% of the cylinder strength when you are at 400. What did your oil analysis come up with? Was it elevated levels of nickel? Do you use an EDM-700 with fuel flow or any bells and whistles?

Drop me an email and I can direct you to a few folks who know you TSIO-520 basket case. But the bottom line is this - if you want longevity, you gotta learn Lean of Peak. A note on the diagram - the RED FIN, is an area where engine damage will occur. There is a Rich of Peak Side and a Lean of Peak side.

Regards,

Alexander Wolf
wolfala @ gmail . com


Notes begin....


NOTE: The specific fuel flow values listed below are for the IO-550 installed in the SR22. Different values are appropriate for the IO-360 installed in the SR20.
Contents
[hide]

    * 1 TAXI
    * 2 TAKEOFF
    * 3 CLIMB
    * 4 LEVEL OFF
    * 5 BIG MIXTURE PULL
    * 6 FINDING PEAK EGT
    * 7 SETTING MIXTURE USING THE RED BOX TABLE
    * 8 HIGH POWER LOP MAG CHECK
    * 9 DESCENT
    * 10 APPROACH
    * 11 CHECK LISTS

[edit] TAXI

After start, and after the engine has warmed up for 2-3 minutes, lean the engine until a rise in RPM is noted. You know you’re in the right place if any further leaning results in roughness. Maintain this setting for taxi and runup (yes, runup), going to takeoff rich setting as you’re taking the runway. For taxi, you should be leaned “brutally” enough so that any attempt to set full throttle will result in the engine stumbling. (No, this will not hurt your engine – only your ego!)
[edit] TAKEOFF

The MFD should be on the EMAX page for takeoff. Use FULL RICH or set fuel flow according to the POH table for the pressure altitude. After application of full power, watch for all 6 EGT’s to rise in concert, and “sweep” the EMAX’s engine “gauges” to ensure all are in the green. During takeoff, note fuel flow. At sea level, you should be getting at least 28 GPH (for the SR22). If not, get your shop to adjust your fuel flow to obtain at least 28 GPH. If they balk, get another mechanic.
[edit] CLIMB

Just after takeoff, press the Normalize button the eMax page. You are capturing the takeoff EGT, which you will maintain by gradually leaning during the climb to altitude. I do this at 500’, and then switch to the MFD Map page, where I have the engine monitoring block displayed.

During climb, watch the display of normalized EGT. As you climb, the numbers will display increasing negative values (-10, -20, etc.). What you want to do is to maintain “0”. If you see negative numbers, you will lean the mixture. (I think: “minus means pull the red knob back, plus means push the red knob forward.”) Note that a bug in the MFD software exists such that any time you are at a normalized zero the engine data block will display dashes ---- for all three parameters! So until this bug is fixed you are actually trying to maintain “dashes” instead of zero.This bug was fixed in version 2 of the MFD software.

If you are given a step-climb intermediate level-off, pitch to level off and note your fuel flow. Then do a “Big mixture pull” (see below) and just leave it in that safe state until you get your clearance to resume climb. Then enrichen the mixture back to the fuel flow you had noted, and refine it to again maintain that normalized “0” EGT as you climb.
[edit] LEVEL OFF

When reaching your final cruise altitude, level off and leave everything alone until the airspeed stabilizes. This seems to take a good 2-3 minutes in the Cirrus. Then position the power lever / RPM as follows:
2000’     2500 RPM (Max MP at 2500)
4000’     2600 RPM
6000’ or above     2700 RPM

The IO-550 is perfectly happy running at 2700 RPM all day long. This is where a good noisecanceling headset pays off! For running LOP, you generally want to be WOT: Wide Open Throttle (or as wide open as the above RPM guide will place you).

BIG MIXTURE PULL

The so-called “Big Mixture Pull” is a means of setting the mixture control to “park” your engine in a safe place. This will place your engine well lean of peak by moving rapidly “through the mountain” of peak temperatures and pressures to a safe place on the lean side. To perform the Big Mixture Pull, pull back on the mixture control smoothly and fairly rapidly until you feel the airplane decelerate. Stop! You’re there. The pull should take about 5 seconds or so. Do NOT enrichen a little when you feel the deceleration. At altitudes below 10,000 this usually results in a fuel flow of about 13-14 GPH. Less if you’re higher. Any time you want to park your engine in a known safe place, such as before finding peak EGT or for level-offs during climb or decent, just perform a Big Mixture Pull.

FINDING PEAK EGT

Since you’ve just done a Big Mixture Pull after leveling off, you’re done with maintaining takeoff EGTs for your climb, so switch back to the MFD’s engine page and press the Absolute button. Give the engine a minute or two until the EGT’s stabilize. Now we’ll use the eMax’s “Lean Find” capability to find peak EGT, but we’re doing it from the lean side of peak rather than the rich side. This is better for two reasons. First, the power curves are steeper on the lean side of peak, so you’ll be spending less time in the “red box,” and second you are looking for the first cylinder to peak rather than the last, also resulting in less time spent in the red box. Press the “Lean Find” button and begin slowly enriching the mixture. Watch for the first cylinder to peak (it will turn blue on the screen). (When I say “first cylinder, I do not mean cylinder #1 – I mean whichever cylinder reaches peak first! You’ll likely find it will be the same one every time.) When that first cylinder peaks, immediately press the Normalize button to “zero” that cylinder at its peak EGT. Then pull the mixture back lean again to a “safe” place well lean of peak, or, once you’ve gotten familiar with the “red box,” you can usually lean pretty close to what will be your final setting.

SETTING MIXTURE USING THE RED BOX TABLE

The “Red Box” table depicts the “edges” of the red box, based on the amount of power you are producing. The “Red Box” defines a region where higher internal cylinder pressures, and the resulting higher cylinder head temperatures, may result in decreased engine life. The limits of the red box are defined in terms of degrees rich or lean of peak EGT, and the “width” of the red box changes depending on how much power you are producing (NOT altitude). So to set your mixture so as to respect the red box limits, you first need to know, at any point, how much power you are producing. You can then look at the table, find the row for that percentage of power, and make sure you are at or outside of the limits shown for that amount of power. For example, if I’m developing 70% power, I can look at the table and see that for that power setting I need to be 125 degrees rich of peak or richer, or I can be 25 degrees lean of peak or leaner. It shows me that at 70% power the area between 125 ROP and 25 LOP is to be avoided – that’s the red box at 70% power.

http://www.copapedia.org/images/e/ee/N521jl-lopredfin-image001.jpgImage:N521jl-lopredfin-image001.jpg

So the red box is “wider” at high power settings, and smaller or nonexistent at lower power settings. As a matter of fact, a look at the red box table will show you that at 60% power or less, there is no red box, so you can put the mixture control anywhere! (More on that momentarily.) Here’s another way to look at it. Same information. Maybe we’ll call this the “red fin!”

http://www.copapedia.org/images/0/05/N521jl-lopredfin-image002.jpg
NOTE: For a “red fin” graph suitable for use with the IO-360 engine in the SR20, see SR20LOPRedFin.

So now that you know how to get the EGT limits from the table, you need one piece of information to set your mixture control: “How much power am I developing?” Lean of peak, the answer is surprisingly easy, because when lean of peak, power is directly proportional to fuel flow. It turns out that you can simply multiply your fuel flow in GPH by 15 to obtain horsepower.

Dividing your horsepower by 310 (for the SR22) yields percent power. To make this easy, the red box table does this for you. Find your fuel flow in the third column and look over to the first column to find your percent power (interpolating if necessary). So the table tells me that if I am lean of peak and my fuel flow is 13.5 GPH I am developing 65% power.

You can use the “red fin” graph’s horizontal axis for this purpose as well. Note that the eMax display of percent power may be way off when LOP! IGNORE IT! Use the red box table (or that factor of 15 and a whiz wheel), not the eMax display, when LOP. So how do you use all this knowledge to set your mixture in flight? Easy. Here’s an example. Assume you’ve leveled off, done the big mixture pull, found peak EGT and normalized there, and have leaned again back to the safe region.

You will use the normalized reading from the first cylinder that peaked for this procedure. Ignore the others. Let’s call this cylinder the “key cylinder.” Look at your fuel flow and find where it is in the table. So let’s say your fuel flow is 13.5 GPH.

You can quickly see from the table that you’re developing 65% power. Now look on your eMax page and see where your normalized key cylinder is relative to peak EGT. Let’s say it is showing -40. The red box table says you must be at 0 degrees LOP or leaner at 65% power (in other words, ANY setting at or leaner than peak EGT is OK). Well, you are! You are out of the red box on the lean side by 40 degrees (-40 is less than 0). So if you want to develop more power but still stay out of the red box, you can.

So you can enrichen the mixture, let’s say to 14.5 GPH. A glance at the table says you’re now developing 70% power. Say you look at your normalized key cylinder and see it now shows –25. You look at the table and you see you’re done. Your -25 degree LOP setting is right at the red box limit for 70% power.

If that key cylinder showed -30 at 70% power, you could even be a bit richer if you wanted to max out your LOP power. But if you went to, say, 15.6 GPH and the key cylinder showed, say, -10, ouch! You’re inside the red box, because at 15.6 GPH = 75% power you must be at -40 degrees LOP or leaner and you’re not!

At higher altitudes, your engine will not be able to develop more than 60% power. So where do you set your mixture at high altitudes? The answer will depend on the mission being flown. If range isn’t an issue and you want to “go fast,” a setting of 50 degrees RICH of peak will always result in the most power and thus the highest airspeed. Peak EGT is going to give you almost the same airspeed but will save a little fuel. For “go far” (economy & range) I use another MFD page – the trip page. Switch to the MFD trip page, and, assuming your destination airport is the final fix, look at the “fuel remaining” value for your destination. If the fuel remaining at destination is less than your comfort level for the conditions, lean the mixture until the fuel remaining value suits you.

(Leaning to idle cutoff to get truly spectacular remaining fuel is not recommended, however!). For IFR reserves, put your alternate airport and the course to it in your flight plan and use the trip page as described to ensure adequate fuel.

HIGH POWER LOP MAG CHECK

The very best way to test your ignition system is to perform a high-power lean of peak magneto check. The typical ground mag check is next to worthless in terms of really testing your ignition system and plugs. Sure, it will tell you if a plug is completely fouled or not firing, and that’s what it is for. But to really test your system, perform a high-power LOP mag check in cruising flight. First, switch to the eMax engine monitoring page. Press the Normalize button to zero all EGT’s. Then switch to one mag and observe the EGT for each cylinder. Let 20-30 seconds go by. Don’t rush it – you’re not hurting your engine at all. All EGT’s should rise, and by similar amounts (which will be quite a bit more than they will during a ground mag check). If a cylinder’s EGT doesn’t rise, or rises somewhat less than the others or exhibits erratic indications, you’ve found a problem (likely a bad or marginal plug) and you’ll know exactly where the problem is. Perform the same test on the other mag.

DESCENT

If you’re running LOP and you’re ready to descend, you can leave the mixture control right where it has been in cruise for the descent. As you descend, the mixture will gradually become leaner, and you’ll gradually become increasingly lean of peak and you’ll be developing less power. In smooth air, it works out just about right to keep you out of the yellow arc at a 500-700 FPM descent. So for typical descents, do nothing with the red knob! If you’re descending from higher altitudes (>= 10,000’), you may find that you need to enrichen a bit as you get to lower altitudes so as to keep the engine running smoothly. If I get a level-off during descent, I’ll either leave the mixture where it is or simply do a variation on a Big Mixture Pull to “park” the engine in a safe place during the level-off.

APPROACH

In the approach phase, I’m still leaned, and I leave the mixture right where it is as I reduce to my approach maneuvering speeds (I use 19” MAP). With all this said, it must be noted that this is merely an overview of the “how” of LOP operations. A good understating of the “why” is really required to get the best performance out of your airplane and, especially, to understand how educated interpretation of the eMax engine monitor can save your engine, and possibly your hide. I strongly urge you to attend the Advanced Pilot Seminar course. It will be the best two days you’ll ever spend with regard to understanding and operating your engine.

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Re: Conti TSIO 520-R Cylinder problems

I just read your post. I have had a T210 for 15 years - two of them actually. The first one I owned had the JPI multi probe engine analyzer, my present one has only a single port EGT and single CHT. I was quite interested in your problem and the reply you received. I attended the AOPA convention in October and attended the presentation from Cessna Pilots Association (John Frank I think was his name) on engine performance. He strongly suggested LOP operation. I thought about this a long time and spoke to several mechanics. Bottom line if you do not have a balanced induction system and a multiport EGT don't even think of it. I don't so I gave up the idea. I just keep my CHT well below 400. I try not to get above 375. In addition, I keep the EGT below 1500. I know what continental says about EGT and TIT, but when I had the Multi port JPI system I went through cylinders and an engine! Now I get good cylinder/engine life and I probably only burn less than an extra gallon/hour - cheaper than cylinders!

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Re: Conti TSIO 520-R Cylinder problems

I have a C210T and have only flown 10 hrs on new OH engine. I have an EDM 700 on board and I am using the standard injectors. My #5 Cylinder is running way to hot 410 - 430 at full rich to Top of green on the mixture , RPM at 2500 and boost at 30 inches. Cowl flops full open.
This has to happen for the first 25 hrs. What oil cooler mods are there to get # 5 & 3 CHT temps down ???   

I noticed that the oil cooler is infront of the #5 Cylinder and the baffle behind the oil cooler covers 1/2 the cylinder.

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Re: Conti TSIO 520-R Cylinder problems

What rpm and manifold pressure are you using for cruise say around 7500 to 10000 feet asl?  I recently purchase a 1982 210N and don't know the best route to go for fuel economy, cyl life etc.  It has the standard CHT and EGT guages.  What do you recomend I install for guages?

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Re: Conti TSIO 520-R Cylinder problems

Anton van Reenen Wrote:
-------------------------------------------------------

>
> I noticed that the oil cooler is infront of the #5
> Cylinder and the baffle behind the oil cooler
> covers 1/2 the cylinder.


My mechanic removed the baffle above the oil cooler and my #5 cylinder is 20-25 degrees cooler.

Ed

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Re: Conti TSIO 520-R Cylinder problems

Thanks  for that tip Ed

any one els  done  this  mod  ??

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Re: Conti TSIO 520-R Cylinder problems

I have the same situation with #5 (and #3) running hotter than my others.  My #1 is by far the coolest.  I too would like to investigate removing this baffle or shield.

Cheers,
John
Temple, Texas

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Re: Conti TSIO 520-R Cylinder problems

I drive a T210N with a TSIO-520R engine. I've had this aircraft since 1981. The engine sucks. I've have a cylinder die at 400 hours and some at the same time run to 1100 hours. (None got to TBO) I've tried changing only what's necessary, but will not this time either. All cylinders will get changed out.

I had Barrett fully rebuild the engine in 1996 @ 2600TT to 0 time and it now has 500 hours. They did beautiful work!

I do most of the ordinary work on the aircraft and am the only one flying it. I never rapidly cool the engine... -1degree manifold pressure per minute etc. After spending what one has to spend to own and operate an aircraft for 27 years, I watch everything I do during operation.

So... #5 & #6 show some ring blow by, & washboarding, but compression above 66/80. #1 & #2 are down to just 40+/80 with burnt valves and blow by and here we go again.

Any suggestion on cylinders for replacement? I plan to change them all. Brand... Condition...

Any key suggestions on operation. I've always used 50 ROP on leanest cylinder (#4). I've got Gamis, but didn't understand their setup... so stuck with Cessna's recommendations. Today, after an education on LOP I'll run the next engine LOP.

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Re: Conti TSIO 520-R Cylinder problems

I have owned a Cessna TU-206 for 25 years now and have had the same problems with the cylinders made by Continental. After 2 top over hauls I finally took the advice of a mechanic and bought Millemium cylinders. I now have a little over 600 hours on them and at last annual they were all over 75/80. I have my fingers crossed but so far there is no comparison. I have a 6 cylinder CHT and EGT so I can monitor them fairly close. All the clinders run between 350-375 with EGT 25 degrees below peak, much cooler than before, even in the hot summer I get to close the cowl flaps and can keep then well under 400.I only use 2 quarts of oil between my 50 hour oil changes.One thing I can say for sure is that it was worth a few extra bucks for these cylinders so that I wasn't looking at a tear down every other annual.I dont' work for Superior Air either just a converted believer.

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Re: Conti TSIO 520-R Cylinder problems

Thanks Jerry!

I hear that the key is to get the cylinders plated... Ni and Nicarbide to prevent corrosion.

Your 206 will be the same as my 210. There is simply no rational reason for the poor wear on TCM cylinders.

I see that RAM now sends their new cylinders to ECi for Nicarbide coatings.

So... for $10K I guess I just take another chance and get the hangar queen unstuck.

Thanks again Jerry.

Paul

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Re: Conti TSIO 520-R Cylinder problems

I own a T210N and it went in for its MPI with 480 hours on the engine. They have found that it has vale stems have been worn and overheating has occurred. We have Millenium cylinders (had) and we have found that even the conrod bearings have moved. The inlet and exit valves are badly worn and have to be replaced as well as the pistons, sleeves (rebored) and all the other moving parts. We have laway flown at 65-70% of power, below 400 and 50 rich of peak. I spoke to our AMO and they are finding it more and more that the valve guides do not last.

I am looking at putting in a JPI 800  to try and monitor the whole mess a bit better. What else can we do and do anyone have advice for us?

Thanks,

Eugene Watson
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Re: Conti TSIO 520-R Cylinder problems

Eugene Watson Wrote:
-------------------------------------------------------

<edited to include specifics>

I own a T210N and it went in for its MPI with 480 hours on the engine. They have found that it has vale stems have been worn and overheating has occurred. We have Millennium cylinders (had) and we have found that even the conrod bearings have moved. The inlet and exit valves are badly worn and have to be replaced as well as the pistons, sleeves (rebored) and all the other moving parts. We have always flown at 65-70% of power, below 400 and 50 rich of peak. I spoke to our AMO and they are finding it more and more that the valve guides do not last.

I am looking at putting in a JPI 800  to try and monitor the whole mess a bit better. What else can we do and do anyone have advice for us?

Eugene,

---

I hope you don't mind, but I am going to post the meat of our conversation for everyone else's collective benefit - with selected edits where necessary.

Part 1:

You got a couple problems, one of which you mentioned the solution for - a JPI. But it does not end there.

As you have discovered, the t210 runs hot, very hot infact. It is likely the most temperature sensative aircraft in the world at this point, perhaps with the exception of the cessna 400 series. You have a cowl, and baffling that likely is not hermatically sealed.

But let's drive the following home so there is no confusion - HEAT is your worst enemy. For all intents and purposes, 380 cht is the highest practical limit you want your engine to be for any continuous period. At 400, oil is no longer effective and you begin to suffer viscosity breakdown. Anotherwards, you get metal on metal contact, the pistons expand exponentally faster then the steel barrel of the cylinder, and you get an effect in the cylinder called an "out of round condition." this is akin to sticking a square peg in a round hole, since the piston now instead of gliding up and down the cylinder buffered by oil and the rings, now finds itself physically contacting the cylinder walls. This, in turn leads to a nasty process called Thermal Runaway. rub your hands together vigerously, they get hotter and hotter from friction. The same process is with your cylinders, it gets hotter until it stops rubbing. Continue operating like this for a few minutes leads to burnt pistons, trashed valves and pushes your cylinders closer to detonation margins.

But that is only part of the story - with 1 cht you have absolutely no clue how the other 5 cylinders have lived the previous 500 hours. Oil analysis would likely show elevated levels of nickel from the exhaust valves and valve guides, iron from the rings and rust, and chromium from the cylinder metallurgy itself, and maybe a bit of lead from piston blowby. If u have analysis, let me see it. If not, the best group in the world is Blackstone Labortories. Www.blackstonelabs.com  buy a 12 pack from them, I'll send u some of my reports so u know how the reports are. Anyway, if there was trouble brewing, you would've had advanced warning had this been done.

I hate to put it in this light, but the damage is in most cases because the way you were taught to run the engine. Now before you jump out of the window - here me out. 90% of pilots on the planet were taught incorrectly, unless you run into folks who drove big radials like the r3350 and r4360 for the military or the airlines. And what you will hear from those folks and the millions of hours on radials, is they did NOT operate rich of peak. This was an operational consideration to allow them to get extended longevity from their engines.

Let's do a test: which way of operating  your engine results in higher internal cylinder pressures and CHT; 50 ROP or 50 lean of peak? If you can answer this question correctly, I'll explain the rest of your engine problem and how you ended up where you are.

Alex
-----

Thanks, I started reading about the problem for the last few days. It seems that lean of peak is cooler, but how can that be?

Sent by Eugene Watson

------------

You are coming toward the ah-ha and holy shit moment in life simultaneously. First a little background information.

Lean of Peak Engine Operation with LOP Curves Explained


Lean of Peak Operation simply put, gives you a 20% reduction in fuel flow, with corresponding lower CHTs, EGTs for more simplistic engine operation. In a typical 4 hour cross country, the cost savings is between 12 and 20 gallons, allowing you an increased payload carrying capacity and lesser fuel loads.

This is a "concept" chart, intended to represent all internal combustion, spark-fired, fixed-timing, gasoline-powered engines. It is taken from the TCM chart in the back of the Installation and Operations Manual, generalized, and the ICP (Internal combustion pressure) curve has been added from actual test stand data. The Brake Specific Fuel Consumption (BSFC) curve has been inverted, so instead of the customary "pounds per horsepower," it shows "horsepower per pound." This way, the BSFC curve also peaks.

Imagine a ruler held vertically, and moved from left (rich) to right (lean), representing the leaning process (a "mixture sweep"). Each of the curves will touch the ruler and show what that parameter is doing at that point on the mixture curve.

http://i145.photobucket.com/albums/r207/wolfala/Engine%20Related/ICP.jpg

When you lean from FULL RICH on a properly set up engine, EGT, CHT, power output, horsepower per pound of fuel, and internal combustion temperatures and pressures ALL rise at first. At some point during that leaning process, FIRST the Horsepower peaks, THEN the CHT and internal pressures peak, THEN the EGT peaks, THEN the HP per gallon peaks, all at slightly different fuel flows.



                              THE RED FIN



The "Red FIN" defines a region where higher internal cylinder pressures, and the resulting higher cylinder head temperatures, will result in decreased engine life and engine damage. The limits of the red box are defined in terms of degrees rich or lean of peak EGT, and the "width" of the red box changes depending on how much power you are producing (NOT altitude). So to set your mixture so as to respect the red box limits, you first need to know, at any point, how much power you are producing. You can then look at the table, find the row for that percentage of power, and make sure you are at or outside of the limits shown for that amount of power. For example, if I'm developing 70% power, I can look at the table and see that for that power setting I need to be 125 degrees rich of peak or richer, or I can be 25 degrees lean of peak or leaner. It shows me that at 70% power the area between 125 ROP and 25 LOP is to be avoided – that's the red box at 70% power.


http://i145.photobucket.com/albums/r207/wolfala/Engine%20Related/Redfin.jpg

So the red box is "wider" at high power settings, and smaller or nonexistent at lower power settings. As a matter of fact, a look at the red box table will show you that at 60% power or less, there is no red box, so you can put the mixture control anywhere!

So now that you know how to get the EGT limits from the table, you need one piece of information to set your mixture control: "How much power am I developing?" Lean of peak, the answer is surprisingly easy, because when lean of peak, power is directly proportional to fuel flow. It turns out that you can simply multiply your fuel flow in GPH by 15 to obtain horsepower. So for 8 GPH * 15 = 120 HP. Dividing your horsepower by 200 (for the SR20) yields percent power. 120 / 200 = 60%.
BIG MIXTURE PULL

The so-called “Big Mixture Pull” is a means of setting the mixture control to “park” your engine in a safe place. This will place your engine well lean of peak by moving rapidly “through the mountain” of peak temperatures and pressures to a safe place on the lean side. To perform the Big Mixture Pull, pull back on the mixture control smoothly and fairly rapidly until you feel the airplane decelerate. Stop! You’re there. The pull should take about 5 seconds or so. Do NOT enrichen a little when you feel the deceleration. Any time you want to park your engine in a known safe place, such as before finding peak EGT or for level-offs during climb or decent, just perform a Big Mixture Pull.


So to your question - HOW CAN IT BE COOLER. Lets look at that diagram with respect to PEAK EGT. Look at where the hottest CHT and highest INTERNAL CYLINDER PRESSURE (ICP) are located. You pretty much notice how they are ALL at their maximum precisely where you have been running your engine ROP? Time to get a beer, because this is the part that hurts. You can now infer that 50* ROP is pretty much the worst place you can ever run an engine from all power settings down to 65%. You can also infer that ROP has a much wider region of real-estate from which you will be doing damage to the engine unless you are running extremely rich mixtures (Well beyond the TCM spec SID-97-2; you would need to exceed those values by 10% at least to ensure you were out of the red-fin on the ROP side.

Now, something to really piss you off. TCM's operators manual instructs us to run 50* ROP or greater. So here you are, motoring along, and the entire time you are breaking something when you are working under the assumption that you are doing it according to the manufactures recommended best practices.

As to why your engine is damaged the way it was - there is a relatively simple explanation. Since you were operating in the middle of the red fin - at a setting where you by sound engineering principles had the engine working at its highest internal cylinder pressures, highest CHT, and generally all around worst possible conditions: everything got burned up. But heat (CHT) wise isn't the only worst enemy, but in your example ICP. When you have high ICP, you are putting a tremendous strain on the con-rods, bearings, pistons, rings, and the cylinders. I'd like you to ask your mechanic if ANY of the piston rings had any rigidity left in them (They should snap in place and hold their station.) I'd bet they were very very elastic.

Now cross over from peak to the Lean side of peak and look at the relationships between ICP, CHT, EGT and Brake Specific fuel consumption. Notice how the first 3 are lower, and your BSFC (efficiency) is through the roof (good). Suffice to say, this is the lesson here - lower ICP and CHT will prevent you or anyone from experiencing what you did. The only way you will do that is either by running rediculously rich, or running Lean of Peak. And the only safe way to run LOP is by having the proper equipment in place, being on a spectrographic oil analysis program - and lastly - being re-educated.

You need to go back to school - and the only school for LOP in the world aside from me is http://www.advancedpilot.com/store.html

You have George Braley (the guy who invented GAMI), John deaken, and Walter Atkinson. Its around $400 USD and can be taken online or flown out to in person, but considering the amount of money you are about to spend on a top-overhaul + internals, it pocket change.

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