O-200 Sudden Roughness in Flight

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buzzard86

Pre-takeoff checklist
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Jim R
So I made my first precautionary landing tonight.

Was cruising along at 2500' and out of nowhere got a really violent engine shake. I happened to be overflying an airport so I dove for the numbers and got it on the ground. Continued to shake on the ground (the plane and me) and I noticed that I couldn't pull the throttle back below 1000.

Nothing remarkable under the cowl and I am pretty sure that I still had good oil pressure. Parked it in front of the maintenance hangar and am waiting for angry wife to come fetch me.

Could this be a stuck valve or does it sound like something more sinister?

Jim
 
buzzard86 said:
So I made my first precautionary landing tonight.

Was cruising along at 2500' and out of nowhere got a really violent engine shake. I happened to be overflying an airport so I dove for the numbers and got it on the ground. Continued to shake on the ground (the plane and me) and I noticed that I couldn't pull the throttle back below 1000.

Nothing remarkable under the cowl and I am pretty sure that I still had good oil pressure. Parked it in front of the maintenance hangar and am waiting for angry wife to come fetch me.

Could this be a stuck valve or does it sound like something more sinister?

Jim
Click to expand...

Did you try switching mags? Running on Left only, then right only?
 
Very violent shaking sounds like a stuck valve - BTDT :eek:
 
vintage cessna said:
Did you try switching mags? Running on Left only, then right only?
Click to expand...

No I didn't. I was right over an airport and had it on the ground in
about 2 minutes. Not knowing what was wrong a fearing that i could potentially do more damage by running it, I just shut it down.

Are you thinking that I could have eaten a mag? And does the inability to pull the throttle below 1000 hint at anything?
 
buzzard86 said:
No I didn't. I was right over an airport and had it on the ground in
about 2 minutes. Not knowing what was wrong a fearing that i could potentially do more damage by running it, I just shut it down.

Are you thinking that I could have eaten a mag? And does the inability to pull the throttle below 1000 hint at anything?
Click to expand...

That is one possibility. Tach may not be reliable with so much vibration.
 
I had something similar happen on my Mooney. I knew something was wrong at cruise and when I pulled the throttle to descend it was as if I had lost a prop tip. I later found that one of the plugs that fill a hole where the fuel injectors or primer nozzle goes had fallen out. You might look on the cylinders where the primer tubing goes in for missing plugs. I think tubing for priming only goes to one cylinder the others get plugs. It could be broken primer tubing sucking too much air for too little fuel making the cylinder to rich to ignite. This will make it vibrate badly when closing the throttle.
 
buzzard86 said:
No I didn't. I was right over an airport and had it on the ground in about 2 minutes. Not knowing what was wrong a fearing that i could potentially do more damage by running it, I just shut it down.
Click to expand...
You did everything right. You're uninjured, the plane is undamaged. There's no better outcome. If you'd been a long way from the airport with crappy ground below, THEN is a good time to experiment.

Whether it's the valve, the mag, or a sweat sock stuck in the fuel line, with an airport right below you would have wanted to land fast anyway. Rule #1: Fly the Airplane. You did that.

Ron Wanttaja
 
Sleepingsquirrel said:
I had something similar happen on my Mooney. I knew something was wrong at cruise and when I pulled the throttle to descend it was as if I had lost a prop tip. I later found that one of the plugs that fill a hole where the fuel injectors or primer nozzle goes had fallen out. You might look on the cylinders where the primer tubing goes in for missing plugs. I think tubing for priming only goes to one cylinder the others get plugs. It could be broken primer tubing sucking too much air for too little fuel making the cylinder to rich to ignite. This will make it vibrate badly when closing the throttle.
Click to expand...

The 0-200-A only has 1 primer point that's the intake spider. there are no ports on the cylinder, there is a place for one, but must drill and thread it in the field for special applications.
This could be as simple as a fouled plug. or a bad as a carbon track on the distributor block or even a bad plug wire.
 
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Flavius Renatus said:
Could it have been carb ice?

That would explain the throttle not being able to be retarded.

Just a guess

Flav
Click to expand...

Interesting that you suggested that, as someone else also mentioned it to me tonight as a possible cause. I have had carb ice on numerous occasions in my C150/O-200, but all of those were dramatic but smooth reductions in power that was immediately corrected by applying carb heat. My symptoms today were an instant and violent shaking and, on hinsight, I did apply carb heat on the downwind without improvement.

I do intend to pull the historical temp/dew point to see where I was in term of icing conditions.

-Jim
 
Tom-D said:
This could be as simple as a fouled plug. or a bad as a carbon track on the distributor block or even a bad plug wire.
Click to expand...

It's going to be a long couple of days waiting for the mechanic to take a look and provide a diagnosis. Is there anything that I could make worse at this point by running the engine on the ground? I'd like to return to the airport tomorrow to ground run the engine to check the mags and see if runs any differently after sitting. However, I don't want to chance doing additional damage.

Also, the plane is sitting away from home at the shop of a mechanic whom I do not know. Any pointers for a situation like this?

Jim
 
buzzard86 said:
...Are you thinking that I could have eaten a mag? And does the inability to pull the throttle below 1000 hint at anything?
Click to expand...

Well once when I was much younger and not nearly as wise as I am now I flew a 150 from Winslow Arizona to Albuquerque New Mexico on one mag because I failed to get it switched back to BOTH when I did my runup so no, losing a mag will not normally cause violent shaking. In fact there's a good chance you might not even notice it.

As far as not being able to get less than 1000 rpm well, you did say you were on the ground within two minutes...
 
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Silvaire said:
Well once when I was much younger and not nearly as wise as I am now I flew a 150 from Winslow Arizona to Albuquerque New Mexico on one mag because I failed to get it switched back to BOTH when I did my runup so no, losing a mag will not normally cause violent shaking. In fact there's a good chance you might not even notice it.

As far as not being able to get less than 1000 rpm well, you did say you were on the ground within two minutes...[/QUOTE

If one mag is malfunctioning and causing a mis fire and severe vibration , then switching to the single good mag would alleviate the shaking.
Click to expand...
 
buzzard86 said:
So I made my first precautionary landing tonight.

Was cruising along at 2500' and out of nowhere got a really violent engine shake.
Jim
Click to expand...

Had a similar thing happen to me in my student pilot days, flying solo for check ride prep. I was about to rehearse the simulated engine out drill, when the engine suddenly and violently started to shake.

At the time I also just landed. Turned out to be the left magneto timing. It was firing early (like it is supposed to for starting the engine.)

I now have all my students actually switch the mags to both mag position in the engine out drill. Why?
0) it never hurts
1) in some cases (like mine) that fixes the problem.
2) you will know afterwards whether your mags are at fault (and you simply lost your redundancy), or whether you are dealing with a bigger problem.
3) when you park in front of the shop, you can just tell your mechanic what needs to be done. No need for him to fire up the engine trying to reproduce the problems.
 
buzzard86 said:
So I made my first precautionary landing tonight.

Was cruising along at 2500' and out of nowhere got a really violent engine shake. I happened to be overflying an airport so I dove for the numbers and got it on the ground. Continued to shake on the ground (the plane and me) and I noticed that I couldn't pull the throttle back below 1000.

Nothing remarkable under the cowl and I am pretty sure that I still had good oil pressure. Parked it in front of the maintenance hangar and am waiting for angry wife to come fetch me.

Could this be a stuck valve or does it sound like something more sinister?

Jim
Click to expand...

Is it just me or is angry wife come to fetch me....seem like a bigger issue than the engine???
 
sballmer said:
It was firing early (like it is supposed to for starting the engine.)
Click to expand...
What??

Timing is retarded for start. That means that the spark does not occur until after normal run timing.

the 0-200 is timed at 28 degrees before top dead center for normal running, it is retarded by the impulse coupling to 0 degrees BTDC for start.
 
See if both mags are securely fastened. If one is not, its timing is screwed up. I had one loosen in flight and cause similar symptoms. Rotate the prop by hand and you could determine if its a stuck valve.
 
Sleepingsquirrel said:
.... It could be broken primer tubing sucking too much air for too little fuel making the cylinder to rich to ignite. This will make it vibrate badly when closing the throttle.
Click to expand...

Sorry, tou have that backwards. Too much air, too little fuel is a lean mixture, not a rich mixture.
 
Is this engine fuel injected or carbureted? If carbed, check that the primer is locked in. If it slipped out of its 'in and locked' position it could create all of your symptoms.
 
TEFLONSEAN said:
Is it just me or is angry wife come to fetch me....seem like a bigger issue than the engine???
Click to expand...

Ha. Wife is actually awesome and totally supports my flying addiction. We have company this weekend and I was supposed to be running errands instead of flying last night.

I got busted.
 
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Skip Miller said:
Is this engine fuel injected or carbureted? If carbed, check that the primer is locked in. If it slipped out of its 'in and locked' position it could create all of your symptoms.
Click to expand...

The 0-200-A, has but 1 priming nozzle, the primer line runs directly to the intake spider. and gives fuel to all cylinders.
 
Witmo said:
Rotate the prop by hand and you could determine if its a stuck valve.
Click to expand...

Went back to the airport this afternoon and pulled the prop through several rotations. I could definitely feel a difference between the cylinders. The first two cylinders definitely gave me quite a bit of resistance; the third cylinder practically no resistance; and the fourth gave resistance but not as much as the first and second.

I don't know what cylinder it is, but that third one appears to be the culprit if I understand correctly.

Jim
 
buzzard86 said:
Went back to the airport this afternoon and pulled the prop through several rotations. I could definitely feel a difference between the cylinders. The first two cylinders definitely gave me quite a bit of resistance; the third cylinder practically no resistance; and the fourth gave resistance but not as much as the first and second.

I don't know what cylinder it is, but that third one appears to be the culprit if I understand correctly.

Jim
Click to expand...

It might have swallowed a valve, and some bits of metal may have travelled out the intake and into another intake, weakening that cylinder too.
 
Dan Thomas said:
It might have swallowed a valve, and some bits of metal may have travelled out the intake and into another intake, weakening that cylinder too.
Click to expand...

Too early to start speculating on worst case scenarios.
 
Dan Thomas said:
It might have swallowed a valve, and some bits of metal may have travelled out the intake and into another intake, weakening that cylinder too.
Click to expand...

That can not happen.
 
If you "swallow" a valve on an O-200 the engine is gonna quit - period.
 
Silvaire said:
If you "swallow" a valve on an O-200 the engine is gonna quit - period.
Click to expand...


Not true. Had a friend swallow a valve 2 years ago, whole head of the exhaust valve came off. She made it a few miles up the road to an airport and shut off the engine on the ground with mixture.


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Silvaire said:
I stand corrected then
Click to expand...

And we had one swallow a valve. They couldn't maintain altitude but did make it back to the airport..

Tom: We were told just the other day by the Continental rep that they do find trash from a grenaded cylinder inside the other cylinders. It travels through the intake system. A bad cylinder makes no vacuum but the vacuum generated by other cylinders will suck junk out of it and into themselves.
 
Awhile back, I was re-positioning a Grumman Cheetah for the owner and during preflight, found some water in the right fuel tank. Continued to sump right tank until I didn't see water. Also spent some time sumping left tank, but no water apparent. Started up, did an engine run-up, no problems. Took off, climbed to 2500, and all of a sudden, I get a violent shake, very rough-running engine, massive rpm drop. Tried switching mags, different power settings, etc. Nothing helped, so called ATC (inside Class C airspace), informed him of problem and he cleared me to land at airport directly below me. With engine at idle and still running, set up a glide, got it on the runway and taxied clear. Did an engine run-up and and got full power. I couldn't believe it! Could not duplicate problem I had while airborne. Turned out to be a massive amount of water making its way through the fuel system. Aircraft had bad, deteriorating gaskets around both fuel caps and airplane had been sitting outside and not flown for 3 or 4 weeks. It was the rainy season. I'm very lucky it didn't happen right after takeoff. Wouldn't be here probably.
 
The verdict is in on my engine. My #4 cylinder was "toast." Mechanic thinks I lost a ring which led to the failure. He is going to see if my cylinder is a candidate for OH.
 
buzzard86 said:
The verdict is in on my engine. My #4 cylinder was "toast." Mechanic thinks I lost a ring which led to the failure. He is going to see if my cylinder is a candidate for OH.
Click to expand...

Where is all the debris generated by that failure?
 
Dan Thomas said:
And we had one swallow a valve. They couldn't maintain altitude but did make it back to the airport..

Tom: We were told just the other day by the Continental rep that they do find trash from a grenaded cylinder inside the other cylinders. It travels through the intake system. A bad cylinder makes no vacuum but the vacuum generated by other cylinders will suck junk out of it and into themselves.
Click to expand...

I have seen and repaired hundreds of cylinder failures, yet to see debris go any where. I simply don't believe your TCM rep.
That debris will be required to drop all the way to the intake spider, and then be sucked all the way up the long intake tube of the other cylinder. IF ... IF it gets to the intake spider it will stand a 99.99% chance of dropping into the carburetor, and jamming the throttle valve.
 
buzzard86 said:
That's a good question. I haven't seen the extent of the damage.


Do you have advice in this regard? I have not been down this path before.

Jim
Click to expand...

If it has a serious metal generating failure, tear it down and see what it did to the crank/ cam / lifters. These cranks are about $4500.00 the cam kit is now well over 3500. you can't afford to not check.

The filter adaptors we see on the 0-200 are by-pass type, when the oil pressure across the filter exceeds a certain pressure it will dump unfiltered oil directly to the crank,lifters oil passages. With the 0-200 you can't see any of this until the cases are opened.
The forgiving graces of the 0-200 is that it has a kidney type sump with a pick up tube that does not go all the way to the bottom. Pull the plug and flush that tank really well see what comes out. any metal, and I'd tear it down.
 
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I made the assumption, that the 0-200 in question has a filter.
If it doesn't, it's an automatic tear down IMHO.
 
Tom-D said:
I made the assumption, that the 0-200 in question has a filter.
If it doesn't, it's an automatic tear down IMHO.
Click to expand...

It does have a filter.

The mechanic didn't mention anything about a tear down. He only said that the filter "did its job." I will be sure to inquire further. I have't used this shop before but the mechanic seems to be well regarded and was recommended to
me by several people when I first bought my plane so I think I am in good hands.
 
Im currently working this engine. C-145

I just stumbled upon this:
5b452b5aadeb898226a8bf6bde834094.jpg


Pulled the connecting rod off and found this in the bearing:
1d831e976e6484f7890519430a952580.jpg


Of course, it was in the mains too


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