Engine failure

[frcabot]

Just got a call from mechanic. Apparently pretty catastrophic loss of number 3 cylinder. Mechanic said it looked like the cylinder had "swallowed" a valve, whatever that means, and that it was "beat up inside."

The engine was 2100 SMOH but had mid-life top and bottom overhauls. And the annual inspection in August noted no engine issues and compression on the cylinder was 75. So I'm not sure how I got from a healthy engine to a disintegrating cylinder in a couple months and only 20 or so hours of flight time, but here we are. 

I'm wondering whether it makes more sense to just do an overhaul from a reputable shop (given the TSOH) or an individual cylinder replacement. Thoughts? What are my options for good, reasonably priced overhaul shops? Obviously the plane is not going anywhere...

Edit: Nope, apparently did not have top and bottom overhauls. Had a bottom "repair" ~430 hours ago after previous owned prop-striked it, and not sure what work was done on the top about ~1000 hours ago but it doesn't sound like it was a full overhaul (apparently the valves, for example, were not replaced).

[jetdriven]

What's the history on this cylinder and what's he history on the others? Which shop did the work, how many hours since OH, first run cylinders or not? New valves? I'd be inclined to simply swap out #3 unless they are from some crappy shop like Gibson then I'd change them all. 

[cnoe]

Glad you made it down safely. And sorry about your passengers' experience.

I wonder if a peek at the exhaust valves might have detected this beforehand. I try to get a look at mine occasionally with my handy-dandy USB Dental Camera from Ebay (lots of discussion about these on MS).

Here's what my #1 looked like last time I had the plugs out. Symmetrical burned pizza appearance = good.

 

[frcabot]

On 11/9/2015, 9:05:07, jetdriven said:

What's the history on this cylinder and what's he history on the others? Which shop did the work, how many hours since OH, first run cylinders or not? New valves? I'd be inclined to simply swap out #3 unless they are from some crappy shop like Gibson then I'd change them all. 

To be honest I'm not totally sure. The engine has never had a major overhaul, that I know. The engine has just about 2100 hours on it now, plus or minus 1. I think the bottom overhaul repair was about 450 hours ago and the top "overhaul" (?) was about 1000 hours ago.  No idea if the valves were new but I'd imagine they're be replaced as part of the top overhaul (Edit: apparently valves were not replaced).  I didn't own the plane when the overhauls were done so I don't know exactly what was done as part of that process. I'd have to check the log entries and they're in the plane.

[Yetti]

If the cam is OK then I would go with a new number 3 cylinder. You can get a lycoming  Cylinder from Plane power for about $2K.   flush all the oil related items if there was contamination which there probably is.  our engines are known for not getting enough oil to lubricate the valves. It cokes up, they stick, the engine eats them.  This is a good read.  http://egaa.home.mindspring.com/engine1.htm

They need to check all the other cylinders exhaust valves wobble test and possibly ream them.

[M20F]

If you sucked in a valve and the cylinder is beat up odds are you can't overhaul it and will need a new one.  The other issue is finding the valve itself has the mechanic been able to locate it?  Given you have a J I don't think you would have the 7/8 valves but if you do I would definitely recommend getting them all replaced with 1/2 valves.  I sucked one valve (7/8) in mine and intended to replace all three cylinders the following annual.  I made it five more months and sucked in another one and decided at that point to do the case and replace the other three (now all with 1/2 inch). 

A compression check is just going to tell you that you don't have a problem, not necessarily the cylinder doesn't  have an impending issue.  Likewise even inspecting with a borescope isn't isn't always going to tell you about the valve guides (too loose or too sticky) see Lycoming SB388C. 

[frcabot]

56 minutes ago, M20F said:

If you sucked in a valve and the cylinder is beat up odds are you can't overhaul it and will need a new one.  The other issue is finding the valve itself has the mechanic been able to locate it?  Given you have a J I don't think you would have the 7/8 valves but if you do I would definitely recommend getting them all replaced with 1/2 valves.  I sucked one valve (7/8) in mine and intended to replace all three cylinders the following annual.  I made it five more months and sucked in another one and decided at that point to do the case and replace the other three (now all with 1/2 inch). 

A compression check is just going to tell you that you don't have a problem, not necessarily the cylinder doesn't  have an impending issue.  Likewise even inspecting with a borescope isn't isn't always going to tell you about the valve guides (too loose or too sticky) see Lycoming SB388C. 

Sorry, to be clear the choices were simply replacing the cylinder (with a new one) or overhauling the whole engine.

[carusoam]

Are you ready for an OH?

Sounds like it is time to become really familiar with what you have.  To see if it is worth saving anything.  Or get on to the next steps of OH.

in other words, what are your priorities?  Fixing things as they come up, because there is no cash available.  Minimum cost is to replace the bad cylinder with a serviceable used one. (Been there, done that, family still thinks I could have done better...)

Ask your mechanic to show you your parts. What broke and why. Get familiar.  If you get familiar, you can decide better.

In my case, an exhaust valve stuck open on T/O. The piston came up and hit it. The valve's shaft bent making an emergency situation.  The minimum amount of work was replacing the whole cylinder assembly.

There are procedures  for cleaning the valve guides and checking their movement and how well they have been operating.

1) cleaning the guides is called the 'rope trick'.  Lots of coked carbon is typical of a sticking situation.

2) checking for looseness is called the 'wobble test'. Lots of wobble is indicating wear.

3) CNOE has done a nice job of showing the 'pizza image' of a good valve.

Get your old broken valve and see if it has a pizza image or something really different.  If the broken shaft is coated in a block of carbon it was probably sticking. Now check the other three cylinders for the same situations.

Cleaning and measuring all your valves is going to cost a few AMUs.  You may want to save the dough to apply it to your OH.

This is my experience from being a young aviator with an M20C.  Daycare costs used all my airplane money...

I Am only a PP, not a mechanic.  You don't need to be a mechanic or engineer to get these done. Talking to your mechanic will often help. Bring bagels and coffee, it may take some time...

Best regards,

-a-

[Tony Armour]

frcabot, Since I have been watching the results/hanger talk of the recent Cirrus landi...errr...crash.....errrr....save...

I'm curious, did you make an immediate turn toward the airport and mostly on my mind, did you start descending before you had the airport made or ?

No judgements here but what you did and the thought process behind it....I am very interested in. Did controllers give you instructions ?

If you are familiar with the Cirrus incident you will understand my questions. I hope I have learned from it.

Regarding what to do on your engine (based on auto experience, may mean nothing) Once you get shrapnel in one cylinder it can make it's way back thru the intake to other cylinders. I'm sure all will be checked out well before putting you back in the air. Anything I could do to make it safe to fly back to my home mechanic....I might do that. The cheapest reman cylinder I could find or a good used one to buy or borrow. Get it home and then make a decision.

Once again GREAT JOB !

[Loogie]

Here is another perspective on the Q whether to overhaul or just replace cylinder.  

You have to have confidence that whatever repair you choose will give you peace of mind and confidence that you have a safe engine. 

The engine is past TBO, regardless of any repairs done in the past, bottom or top, they still don't count as an overhaul.  You can rationalize it as such but that engine has reached TBO w/out an overhaul.  And now it failed...

Ask yourself this, what will it take for you to feel safe and your passengers safe.

This is just my opinion for what it's worth...I would not do anything short of an overhaul on that engine assuming it was a good candidate for it, if it's not then I would get a new or an overhauled engine.  

But that is just one opinion...other folks are more comfortable w different angles, I am not.  I am am victim of my background and experience, single engine is a different state of mind, specially when you don't have the chute or the ejection seat option

again just a thought, hope it helps.

 

vr

Loogie

[M20F]

2 hours ago, frcabot said:

Sorry, to be clear the choices were simply replacing the cylinder (with a new one) or overhauling the whole engine.

If you have 1/2" valves and the other cylinders look good (compression, borescope, not too loose/tight on the valves, etc.) I would personally just replace the cylinder with a new one.  There are some things to consider though.  If you found all the valve parts than life is grand.  If you can't find all the valve parts than it either went out the exhaust or it went somewhere in the case which is bad.  In my case having a Rayjay turbo was a positive in the valve was found quickly, bad in the sense that the turbo needed work.

The other thing to consider is to be counted as an overhaul you need to replace certain parts and one of those things is all the exhaust valves.  So if you do this cylinder and next year you decide to do the other three and split the case your choice is either redo a cylinder with 100hrs or call it a repair/return.  In my case I had a cylinder with less than 50hrs and don't have any plans to sell so the wording in the paperwork which impacts resale didn't matter to me, for all reality I have a firewall forward engine it just isn't written that way because 1 cylinder didn't get redone.

If somebody else flew the bulk of those 1000hrs you also don't know how those cylinders were treated.  Overhauling wide deck cylinders is a lot cheaper than buying a new one (and you might want to be sitting down when you get the price on a new cylinder/piston/rings), thus if you overhaul them all now (top it) you can probably do that for less than what 2 new cylinders would cost (the one you are buying now and the one you might have to buy if you snap another valve in the near future) assuming your cores are good.  I would really get a good set of eyes on the cylinders and if there is any suspicion top it.

Do a lot of research, ask a lot of questions, and remember everyone in aviation has crazy opinions (I gave you mine) so make your own decisions.  While expensive it is a nice feeling when you come out the other side with the knowledge you have a motor which only you will abuse and all things being equal get at least 10yrs of use out of before you have to spent a ton of $$ again. 

[carl]

question if your cable breaks on mixture it should go full rich, if the throttle, it should go to full.

 

or is that not true.

[Guest]

4 hours ago, frcabot said:

Sorry, to be clear the choices were simply replacing the cylinder (with a new one) or overhauling the whole engine.

The first thing to do is have your A&P remove only the effected cylinder and nothing else.  Have the cam and lifters inspected for damage.  If you are considering or are forced to the route of buying a factory engine they will not accept the core if it is disassembled, a cylinder pull for inspection is generally OK but a split case is not.  Once the exhaust system is removed have your guy carefully inspect the other 3 exhaust valves for pitting/erosion of the stems.

If the cam and lifters are good you could replace the cylinder assembly, there you have a few choices.  A new one on a past TBO engine does not make a pile of sense, a good overhauled one at lower cost does.  The choice is yours.

If the engine goes back in service you'll have to do a very thorough inspection of the intake and exhaust systems for metal junks from the dead cylinder.

Clarence

[cliffy]

Just a couple of thoughts:

Is there a hole in the piston? If so you may have to go overhaul

Were the rods checked for parallel and the rod ends rebushed at the bottom end time? If not you have rods that need to be looked at.

As mentioned make damn sure the cam and lifters are examined thoroughly.

You can do a ( I know heretic ) field overhaul of you own engine maybe cheaper than factory.

 

[Shadrach]

2 hours ago, Loogie said:

Here is another perspective on the Q whether to overhaul or just replace cylinder.  

You have to have confidence that whatever repair you choose will give you peace of mind and confidence that you have a safe engine. 

The engine is past TBO, regardless of any repairs done in the past, bottom or top, they still don't count as an overhaul.  You can rationalize it as such but that engine has reached TBO w/out an overhaul.  And now it failed...

Ask yourself this, what will it take for you to feel safe and your passengers safe.

This is just my opinion for what it's worth...I would not do anything short of an overhaul on that engine assuming it was a good candidate for it, if it's not then I would get a new or an overhauled engine.  

But that is just one opinion...other folks are more comfortable w different angles, I am not.  I am am victim of my background and experience, single engine is a different state of mind, specially when you don't have the chute or the ejection seat option

again just a thought, hope it helps.

 

vr

Loogie

Loog,

 I'm trying to follow your line of thinking. I agree that one must have confidence in their equipment. However, I don't follow why a cylinder set with recommended TBO of 2000hrs should be considered beyond TBO with only 1000hrs SOH? Similarly, why would you consider a bottom end with 400hrs SOH beyond TBO? If both were operating together on the same engine, why would you say it's time to OH or replac the engine when none of the components have spent anywhere near there lifetime in service. I understand that there are practical reasons to renew everything at the same time. I also understand that certain types of failures make a complete tear down prudent. However, from an operational standpoint, I don't see how having a top and bottom out of sinc matters if they are both within calendar time and time in service.

 

[philiplane]

If the cylinders were "repaired" then valves may be re-used. If they were "overhauled" then it is required to replace the exhaust valves. 200 HP Lycomings are known to eat an exhaust valve from time to time. The head snaps off in part or in whole. When this happens parts of the valve head often go back into the intake and migrate to the next cylinder in firing order. 

This is where field repairs and overhauls often cost more down the road, because a lot of people don't know the requirements for overhaul. And some very old parts get re-used. 

If the cylinders were simply "repaired", then if the existing exhaust valves were unserviceable, a used valve from the shop's spares pile, with unknown hours, could be used to repair the cylinder and it's perfectly legal. Unwise, but legal. 

[Yetti]

Which is kind of like a factory re-manufactured. A bunch of used parts checked if they are within tolerance and put together.  But since it is the Lycoming they get got 0 time the engine.

[Shadrach]

In the late 90s my Father and Brother were making there way East from an aerial road trip when the engine swallowed a valve near Winner SD (uneventful landing). I was in my early 20s and it was the only time my old man had ever asked me for short term financial assistance.  He was at the end of a 3 week vacation when the cylinder failed. The MX on field found an overhauled unit. The ran it up everything seemed fine. On climb out they lost another cylinder. Appearently the MX on field did not throughly inspect the air box for debris. A piece from the recently replaced cylinder destroyed another jug. Replacing the second cylinder cost him 2 more days and I don't think his credit card was prepared for the cumulative  workout.. We overhauled 150 hrs later because the engine was 33yrs old. Opening it up, it was appearent the the bottom end would have easily made the next 250hrs to TBO.

[Shadrach]

5 minutes ago, Yetti said:

Which is kind of like a factory re-manufactured. A bunch of used parts checked if they are within tolerance and put together.  But since it is the Lycoming they get got 0 time the engine.

What better reason for one to puff out their chest and proudly proclaim their loose formation of parts to be "0 time"... What a crock!

[mcpilot]

Well done on the safe landing.  I am curious if you noticed any warning signs like "morning sickness"  Also, did you run LOP or ROP and how many degrees?

 

Best 

 

Mike

[Shadrach]

11 hours ago, frcabot said:

Mechanic is taking a look today hopefully so I'll let you know. By the way, the audio is posted on liveatc, the kbfl archive Nov 7 at 2330Z. Starts about 15:45 in (the initial radio calls were on 121.5 and I had a guard nazi yell “you're on guarddddd" to me, I replied “I knowwww," lulz).  http://archive-server.liveatc.net/kbfl/KBFL-Nov-07-2015-2330Z.mp3

Basically the conditions were ideal because this happened during the day, in good visibility, at high altitude (11k feet), within 25 miles of a large airport (KBFL), and I only lost partial engine power at first so had time to react before total engine failure. Had I been flying at night over unlit, mountainous terrain, this could have ended altogether differently.  

Just listened to this. Both you and the controller did an excellent job. He just removed obstacles and cleared you to do what you needed.

[Houman]

Man I hope I'm as calm and precise when in this situation... I have never had any serious emergency, only a door pop open on takeoff, and decided to come back to airport and fix it on the ground.

Great job...

[takair]

3 hours ago, carl said:

question if your cable breaks on mixture it should go full rich, if the throttle, it should go to full.

 

or is that not true.

No spring on the 360 engines.  Not sure about other models.

[chrisk]

Great job on the landing!  So very glad you are here to tell us about it.

[M20JFlyer]

FRC

GREAT JOB. LISTENING TO ATC you can be added to the cool and collected fan club

FRC: adding you to mooney great pilots list

YOUR POST UNEARTHED A BENDIX START SWITCH QUSTION

THE SWITCH BULLETIN IS in 1976 ...my airplane mfg in 1991. 

No mentin in my logs of this being complied  24 years and counting...any comments from the group