Engine scare

[carusoam]

Where did you put the math..?  

1) you got the plane with six quarts in it..?

2) every time you checked the oil and it was a quart low, you put a new quart back into it..?

3) last time you checked the oil, it was at six quarts..?

4) doing a modified mass balance, we can keep an eye on where all the quarts went....

     starting level + oil added - oil burnt - oil leaked/vented = oil left in the sump

5) knowing that oil is neither created or destroyed in the engine, it either gets leaked, burnt or vented overboard...

6) it came with 6 quarts in it.

7) you kept it full with 6 quarts still in it.

8) your box of 12 quarts of oil only has two left in it.

9) did you ever fill the sump over the six quart line?  Did you have to clean the belly after that?  Filling to the seven quart line often blows a quart out the vent in an hour.  Making it look like it is going through oil at a high rate while making a mess.

10) 10 quarts have been introduced and left the engine in 80 hours.  Or one quart every eight hours... (closer to normal)

Tell us some details about the pre-flight mag checks, like how you did them and what you saw happen...

Best regards,

-a-

[gsxrpilot]

2 hours ago, greg51 said:

OK, you talked me into it. I will get engine monitor, however I am sure it would tell me the same thing my old gauges did. "things are getting hot time to land"

Well maybe if you don't know how to use an engine monitor any more than your "A&P" does.  I'm not an A&P or any other type of mechanic. But I know how to read an engine monitor.  

1. If I've got a fouled plug, I know which one out of 12, that is fouled.
2. If you've got two bad plugs, one on the right mag and one on the left mag, your mag check won't tell you anything, my engine monitor will tell me exactly which two are bad.
3. Induction leak leading to an overly lean cylinder, the engine monitor will tell me which cylinder is leaking.
4. A valve guide wearing resulting in a wobbly valve? This will eventually lead to a stuck or failed valve and cylinder damage. The engine monitor will tell me this is happening long before it becomes a problem allowing me to get it fixed before I lose a cylinder like you did.
5. Slipped timing on a mag, broken ring, stuck valve, cracked exhaust manifold (which is deadly serious because of inflight fire) and many other issues are not only diagnosed, but can be pinpointed in flight to the specific cylinder and specific problem, all by the engine monitor.

All of this can be done with even the cheapest engine monitor as long as it has a CHT probe and EGT probe for each cylinder. And then of course, you have to know how to use it.  In my experience, most A&P's don't, but then they're not flying behind it hour after hour.

You can pay for the engine monitor just by being able to tell your mechanic what the problem is and what to fix, rather than just saying, "it's running rough" or worse.

If you're going to own and fly an airplane, it just makes sense to know a bit about it and have good information. It's not your mechanic or his family in the plane when it all goes south. You owe it to yourself and your family to be educated.

[Oldguy]

Like most others I have read here, I encourage you to get an engine monitor, and even in you do not have a Savvy paid account, they allow you to upload your data into their system to review. I have been doing that for almost 4 years now and I can tell you with certainty when my vernatherm started going bad, how my oil temperature dropped when I changed oil brands, what the CHT change is between running ROP and LOP and many other things. None of which I knew or understood until I started reading some of the information on the Savvy website and the monthly newsletters. No, like Anthony and many others, I am not a mechanic, but just a private pilot with an interest in keeping my plane in the air safely.

Congratulations on having a good outcome on an in-flight learning experience. You showed quick thinking and good judgement.

[Oldguy]

3 hours ago, carusoam said:

Where did you put the math..?  

1) you got the plane with six quarts in it..?

2) every time you checked the oil and it was a quart low, you put a new quart back into it..?

3) last time you checked the oil, it was at six quarts..?

4) doing a modified mass balance, we can keep an eye on where all the quarts went....

     starting level + oil added - oil burnt - oil leaked/vented = oil left in the sump

5) knowing that oil is neither created or destroyed in the engine, it either gets leaked, burnt or vented overboard...

6) it came with 6 quarts in it.

7) you kept it full with 6 quarts still in it.

8) your box of 12 quarts of oil only has two left in it.

9) did you ever fill the sump over the six quart line?  Did you have to clean the belly after that?  Filling to the seven quart line often blows a quart out the vent in an hour.  Making it look like it is going through oil at a high rate while making a mess.

10) 10 quarts have been introduced and left the engine in 80 hours.  Or one quart every eight hours... (closer to normal)

Tell us some details about the pre-flight mag checks, like how you did them and what you saw happen...

Best regards,

-a-

I'm just hoping that in that 80 hours there was an oil change....

[bradp]

Engine monitor.   I've had it pay for itself over and over again.   It's that important.  

[Guest]

From your engine "Overhaul" log entry and the installation log entry and your comments about the old gauges, I'd venture a guess that the engine gauges were not calibrated as required in Lycoming SI 1427C?  

Therefore the engine "Overhaul" was never really legally completed.

Clarence

1. Calibrate the cylinder head temperature gage, oil temperature gage, oil pressure gage, manifold pressure gage, and tachometer before the ground operational test. 

[Guitarmaster]

I just installed an EDM-900 and I can't believe I flew around without one for two years.  It already found a bad plug.

[takair]

3 hours ago, gsxrpilot said:

guide wearing resulting in a wobbly valve? This will eventually lead to a stuck or failed valve and cylinder damage. The engine monitor will tell me this is happening long before it becomes a problem allowing me to get it fixed before I lose a cylinder like you did.

Paul

Curious about the symptoms I might see for the wobbly valve.  A couple of annuals ago I had low compression on #3, and it was the exhaust valve due to wobble.  I did not notice anything different before or after on the analyzer.....key word being "notice".  Any tips on this would be appreciated.

I have  found fouled plugs and in the best save for me...blown gasket leading to loss of torque on an exhaust manifold which dropped in flight.  Only a slight change in sound, but the temperature fluctuation raised a flag.  Even an old used monitor is a good investment....but keep in mind the thermocouples can rapidly make a cheap used unit expensive.

[mccdeuce]

Something that also strikes me:   Broker said they flew it every few weeks...  30 hours in 3 years is a) not enough for any engine b) definitely not enough for a fresh overhauled engine.  

I am a believer that the engine break in starts in the first hour - and is 80% complete.  10 hours and you have a 90% solution and 40-50 hours for a 100%.   So for 3 years to only have 10 hours a year its just not enough.  But all is well and you landed safely.

So as you progress into fixing this issue and gaining an engine monitor - learn to use the monitor on deck first, because this may not be the last cylinder that needs help.  Hopefully it is. 

[kpaul]

19 hours ago, greg51 said:

oil usage was low. about a quart every 6 hrs

Screen was checked every oil change

I use a quart every 15 hours

[gsxrpilot]

13 hours ago, takair said:

Paul

Curious about the symptoms I might see for the wobbly valve.  A couple of annuals ago I had low compression on #3, and it was the exhaust valve due to wobble.  I did not notice anything different before or after on the analyzer.....key word being "notice".  Any tips on this would be appreciated.

I have  found fouled plugs and in the best save for me...blown gasket leading to loss of torque on an exhaust manifold which dropped in flight.  Only a slight change in sound, but the temperature fluctuation raised a flag.  Even an old used monitor is a good investment....but keep in mind the thermocouples can rapidly make a cheap used unit expensive.

Diagnosing a wobbly valve can be difficult in flight but will be very apparent if you are downloading the data from your engine monitor and looking at the resulting graph. Savvy's free online tool makes this very easy.  Looking at the downloaded data, you'll notice a single EGT will be tracing a jagged line instead of a smooth line.  This will get worse over subsequent flights. As the condition becomes advanced, you'll likely notice in flight, that one of the EGT's is trending higher than the others. With a JPI in "Normalized" mode it's easy to see this.  Also in flight, if your highest EGT cylinder is fluctuating rapidly, while others are steady, this will be an indication that you should probably download the data and plot the graph.

What's happening is on some strokes, the valve will seat correctly while on other strokes it will be out of position and therefore leaking just a little. When it leaks, the EGT is higher than when it seats properly. As this is happening many times per second, it's hard to notice it in flight, but downloading the data and plotting it will reveal the "fuzzy" line of the problem EGT where all the other EGT lines are smooth.

[DXB]

35 minutes ago, gsxrpilot said:

Diagnosing a wobbly valve can be difficult in flight but will be very apparent if you are downloading the data from your engine monitor and looking at the resulting graph. Savvy's free online tool makes this very easy.  Looking at the downloaded data, you'll notice a single EGT will be tracing a jagged line instead of a smooth line.  This will get worse over subsequent flights. As the condition becomes advanced, you'll likely notice in flight, that one of the EGT's is trending higher than the others. With a JPI in "Normalized" mode it's easy to see this.  Also in flight, if your highest EGT cylinder is fluctuating rapidly, while others are steady, this will be an indication that you should probably download the data and plot the graph.

What's happening is on some strokes, the valve will seat correctly while on other strokes it will be out of position and therefore leaking just a little. When it leaks, the EGT is higher than when it seats properly. As this is happening many times per second, it's hard to notice it in flight, but downloading the data and plotting it will reveal the "fuzzy" line of the problem EGT where all the other EGT lines are smooth.

Very well explained- this is basically my understanding too. I suspect this type of EGT trace is very specific to this problem, but I wonder how sensitive it is. In other words what percent of exhaust valves undergo catastrophic failure without ever giving this type of warning.

[greg51]

Well whoever diagnosed wobbly valve, you win the prize. Just spoke to mechanic and engine shop said it was a bent valve. So they are going to hone cylinder and put in new valves. They are scoping other cylinders to check for damage and quoting me an engine monitor. Thanks to all who shamed me into getting one, tough love. I am all about safety first.

This is my first piston aircraft. ATP with 8000 hrs 7500 in turbine A/C so learning as I go. this website is awesome and I thank all of you for your tips.

[MB65E]

Glad you found the fix!!

For reference if it helps-In 80 hours I'd be on my 3rd or 4th oil change.

i would re-run mineral oil for at least 30 hours until you see clean plugs. 

-Matt

 

[greg51]

This will be my fourth oil change in 80 hrs. I have mechanics do the changes and I add when needed. I was stretching the last oil change due to annual scheduled

[ArtVandelay]

Did they say how the valve got bent?

[DXB]

and intake or exhaust - and can anyone explain how this relates to a runaway CHT?

[flyboy0681]

Go easy on the guy because I have a story to tell..

I picked my daughter up from college (Florida State) four weeks ago and was within forty miles of my home base when I noticed the oil pressure gauge was dancing around, left to right, right to left. At first I thought an existing problem of a poor ground was rearing its ugly head again because that's exactly what the gauges did when the grounding problem occurred, except this time it was isolated only to oil pressure. In the right seat was my a buddy who flies 767's for American and is also an A&P. We were scratching our heads while looking at all other functions on the JPI 700. Everything was running smoothly, CHT's were right where they should have been and the oil temp was within the normal range. By now we were halfway between home and an airport that we left behind miles ago, KPHK. 

After we landed and pushed her back into the hangar I checked the dip stick to find about two quarts remaining. When we left Tallahassee two hours prior, I checked on the ramp and there was a sold six quarts. I looked at the belly, no oil. Landing gear well, totally dry.

Under the circumstances, Lycoming highly recommends a tear down when oil pressure drops below 55psi. The next day our resident A&P removed the engine and we sent it out. A stuck exhaust valve was found, meaning all of the oil burnt off. The cascading damage meant only one thing: a complete overhaul, including cylinders. We should be back in the air the last week of this month. Just for good measure, we are adding an oil pressure probe to the JPI. The engine was at 1,250 hours SMO when this happened.

Looking back, there was probably a warning sign, we added oil about every four to five hours.

This scenario has been playing over and over in my head for the past month, I go to sleep with it and wake up with it and it haunts me throughout the day. The scenario that runs through my head the most is that nothing pointed to any problem. The engine was running very smoothly and temps were normal. The one thing we are all taught during our primary training is that if the engine is critically low on oil, check the oil temp because it will surely rise. The truth is, it depends on the engine. According to the data uploaded to Savvy from the JPI, the oil temperature actually came down, most probably because the probe is high up on the crankcase and oil wasn't reaching it.

I'm thankful for two things. The first being that it didn't seize as we were approaching home because it's a very densely populated area. The second is that I'm grateful that it didn't happen to my partner when he was flying over open water on his way to the Bahamas, a trip he does twice a month.

 

 

 

 

[carusoam]

Greg,

expect to be on a steep learning curve in your spare time for a year.

I appreciate that you have great flying experience.  We are going to appreciate your input on a few things in the future.

Unfortunately, that doesn't neccesarily translate directly into great reciprocating engine care and maintenance skills.

A couple of theoretical questions...

Would you like to keep this from happening again?

Or better phrased,  how are you going to keep this from randomly happening again?

 

Fortunately, we collectively, have even more specific short body Mooney experience to share.  You probably want it.  Get ready to take on some more useful advice.  It often comes delivered without any pretty wrapping.  That takes more writing skill than some of us have.

 

there are some pretty smart people here...

1) There are some pro aviators here that have tremendous airframe and mechanical skills, too...

2) If that isn't enough, there are medical doctors that fly Short body Mooneys as well.

 

As a pro flyer there are a few things you want to have in your Short body Mooney.  The only logic for not having them is you ran out of cash for something more important like the house, the kids, the wife.....

 

Three Things my M20C didn't get... house and kids were expensive...

 

1) Engine monitor.  I got a stuck valve in my first 10 hours of flight.  There was no MS around to ask what happened...

- looks like you got a stuck valve.  As did I.

- it is noticeable by it's bent shaft. So was mine.

- there is only one way to bend that shaft. Get it stuck in the open position.  This generates a huge bending force.

- there is now a matching dent on the top of the piston.  Look for yours.  An equal and opposite force was supplied by the aluminum piston.  The steel valve compresses the aluminum piston.

 

2) Fuel Flow / totalizer instrumentation.  Your Fuel level gauges are crap on their best days.  A pro running out of fuel would look really bad in the NTSB report.  As a human, you are equally probable of having this happen as a non pro.  Your extra experience will help you fly it to the ground safely.

 

3) I forgot one, New Seatbelts with shoulder straps.  When the plane was built, these didn't exist.  

 

4) follow up maintenance.  There is a procedure to keep this from happening again.  Do a search on the 'rope trick'.  This is a method of cleaning the valve guide.  

 

5) Since the four cylinders are like four independent motors, sort of...  what happens to one can likely happen to the other three.

 

6) Since you described the results of one stuck valve.  You may have some symptoms of others.  Look up the term 'morning sickness'.   This is the result of valves sticking during the start-up phase until things get warmer...

7) tell us about your PPI.  The pre purchase inspection.  Were you aware they existed..?

 

When looking for help, try to give the details the best you can.  Having modern instruments is the only way to safely transport family around.  Kind of like buying a car with airbags for your daily driver.  

If family joins you all the time, the Short body Mooney is in for some maintenance and instrumentation.  Our planes were built back in the day, but we live in modern times. Stuff changes over time...

We are here to help, don't be shy...

my appologies, I'm one of the guys that is less skilled at writing...

Best regards,

-a-

[greg51]

carusoam,

Thanks, I am learning a lot here thanks to all off you (feeling like a rookie) 

The engine shop says the piston was not damaged. I am not convinced the valve was the cause. more  the result of overheat. I have fuel injectors and have asked them to check these also. I really need to be sure of the cause before I fly it again

[carusoam]

Most likely a result of over heat with a combination of cooked or coked oil...

There are a couple of known causes of the extra heat...

1) Poor cooling of the cylinders on the climb... based on 'proper' attitude.

2) Poor baffling of the engine.  They degrade terribly and seal poorly over time.

3) Poor data for the PIC to follow because the POH with the most data for your plane wasn't written until 1976 or so.  If you don't have a real POH for your plane, get the latest version to go with the one that matches your model year.  One is for legality the other is for important information...

4) Without instrumentation, as mentioned, it is challenging to fly an E LOP.

5) The fuel injected E is a great plane with fabulous efficiency skills.  Unfortunately, without the engine monitor and fuel flow data it is impossible to know what your GAMI spread is.

6) GAMI spread test is what we use to know how well our FIs are actually working.  

7) There is an alternative to this.  It is called the glass jar test.  In the mechanic's hangar, he takes the fuel injectors out and puts them over four identical jars.  Times the flow of fuel into the jars.  Measures each one.  If there is a blockage, he will know which one it is.

8) FIs are often cleaned with a product called Hoppe's #9.  A gun barrel cleaning solution...

9) yes, fuel injectors do get clogged with things that can't be strained out by the usual filters and strainers. Another topic... something about rubber hose interior liners in the engine's fuel system after the filters...

10) a JPI (or other) will give you a hint of a semi clogged fuel injector.

 

Re-read your thread again, top to bottom, there is a lot to absorb while reading this only once.... you wouldn't want to miss something accidently.  Human brains aren't really strong as we would like.  

Best regards,

-a-

[bradp]

Greg while the cylinder is off borescope the cam.  It's very easy and given that the plane was sitting so long having not flown, it may be a good idea.

Reference this thread:

 

 

[greg51]

The oil temps never overheated, only CHT's 

I also just had the cowling mod put on for better cooling and small boost in speed

[takair]

5 hours ago, gsxrpilot said:

Diagnosing a wobbly valve can be difficult in flight but will be very apparent if you are downloading the data from your engine monitor and looking at the resulting graph. Savvy's free online tool makes this very easy.  Looking at the downloaded data, you'll notice a single EGT will be tracing a jagged line instead of a smooth line.  This will get worse over subsequent flights. As the condition becomes advanced, you'll likely notice in flight, that one of the EGT's is trending higher than the others. With a JPI in "Normalized" mode it's easy to see this.  Also in flight, if your highest EGT cylinder is fluctuating rapidly, while others are steady, this will be an indication that you should probably download the data and plot the graph.

What's happening is on some strokes, the valve will seat correctly while on other strokes it will be out of position and therefore leaking just a little. When it leaks, the EGT is higher than when it seats properly. As this is happening many times per second, it's hard to notice it in flight, but downloading the data and plotting it will reveal the "fuzzy" line of the problem EGT where all the other EGT lines are smooth.

Thanks...good input and it explains the difference.  I have an older EI analyzer without recording capability.  I do run it in normalized mode because the EGTs are quite spread otherwise.  CHTs are quite level no matter what.  I never really noticed the cylinder reading different, but I think you are right about looking at a longer string of data.  I think I also caught it early.  The valve actuall didn't look bad, so likely had just started leaking.

Im curious if you know the update rate on your recorded data.  I want to see my sample rate is every 6 seconds.  If I added the recording feature do you think that would catch this type of valve problem?  Seems the sample rate may be too slow...that said, the thermocouple saturation time is quite slow too.  Or do you see the leak/wobble over a longer period.  I suppose this is where the fast acting thermocouple can be beneficial.

[takair]

1 hour ago, flyboy0681 said:

Go easy on the guy because I have a story to tell..

I picked my daughter up from college (Florida State) four weeks ago and was within forty miles of my home base when I noticed the oil pressure gauge was dancing around, left to right, right to left. At first I thought an existing problem of a poor ground was rearing its ugly head again because that's exactly what the gauges did when the grounding problem occurred, except this time it was isolated only to oil pressure. In the right seat was my a buddy who flies 767's for American and is also an A&P. We were scratching our heads while looking at all other functions on the JPI 700. Everything was running smoothly, CHT's were right where they should have been and the oil temp was within the normal range. By now we were halfway between home and an airport that we left behind miles ago, KPHK. 

After we landed and pushed her back into the hangar I checked the dip stick to find about two quarts remaining. When we left Tallahassee two hours prior, I checked on the ramp and there was a sold six quarts. I looked at the belly, no oil. Landing gear well, totally dry.

Under the circumstances, Lycoming highly recommends a tear down when oil pressure drops below 55psi. The next day our resident A&P removed the engine and we sent it out. A stuck exhaust valve was found, meaning all of the oil burnt off. The cascading damage meant only one thing: a complete overhaul, including cylinders. We should be back in the air the last week of this month. Just for good measure, we are adding an oil pressure probe to the JPI. The engine was at 1,250 hours SMO when this happened.

Looking back, there was probably a warning sign, we added oil about every four to five hours.

This scenario has been playing over and over in my head for the past month, I go to sleep with it and wake up with it and it haunts me throughout the day. The scenario that runs through my head the most is that nothing pointed to any problem. The engine was running very smoothly and temps were normal. The one thing we are all taught during our primary training is that if the engine is critically low on oil, check the oil temp because it will surely rise. The truth is, it depends on the engine. According to the data uploaded to Savvy from the JPI, the oil temperature actually came down, most probably because the probe is high up on the crankcase and oil wasn't reaching it.

I'm thankful for two things. The first being that it didn't seize as we were approaching home because it's a very densely populated area. The second is that I'm grateful that it didn't happen to my partner when he was flying over open water on his way to the Bahamas, a trip he does twice a month.

 

 

 

 

Wow, that is some rapid degradation.  We always hope to see a longer failure trend than one flight.  Makes one think hard about not checking oil every flight... 

Im sure you would have mentioned it if you saw it, but I am surprised the EGT on the guilty cylinder didn't move.  That makes this one even more of an evil scenario.  Glad you guys landed with the two quarts...they at least got you down.