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wobo9a

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Ingested object - IO360

I'm writing to see if anyone has experience with damage done inside a cylinder by an ingested object.

Long story short, my Titan IO-360 sucked something into cylinder #1, spit it out the intake, sucked it into cylinder #3 and spit it out the exhaust.

There are only 15 hours on the engine. Looking at the #1 and #3 piston and cylinder heads with a borescope, there are small marks that are probably dents. I need a better borescope look to be sure, but there do not appear to be any sharp edges or peaks sticking out. The valves show no marks and compression is excellent. Cylinders 2 and 4 are flawless. Because I initially missed the diagnosis, I have since flown the airplane, and the engine performed normally.

I have heard of two engines that lived long and healthy lives after FOD damage and would like to think I'm dealing with only a cosmetic problem.

I don't expect anyone can (or should) give me a prognosis on my situation, but I'm interested in any experience others might have with engines that have been through this.

Thanks for any information you can provide,

David Woboril
 
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A little red flag....

...is up, until you find out what it was that the engine ate. If it was the alternate air hinge or whatever, that'll be a better clue. If it was a steel part....then I'd have to pull those two cylinders.

Best,
 
what sort of induction?

A friend had a similar thing happen, only he saw a missing screw on the induction air housing for a horizontal induction engine and had an "uh oh" moment. He borescoped the engine and found the screw inside one of the cylinders. If I recall correctly, his damage was mainly to the top of two pistons. He pulled those two cylinders. I don't recall if he only replaced the pistons and rings or if he redid the cylinders too.

I'm very inexperienced, but it seems to me if the FOD was hard enough to cause visible deformation marks on the inside of the cylinder...doesn't it seem likely that it was steel?

Good luck and I hope it's not that bad.

Jeremy
 
Look at it good, but I would never let that keep me from flying it. There was so much pitting in the (corrosion) in the bores of the O-360 that the cylinders were literally unrebuildable, and it was flown that way for 600 hours.

In my experience (which isn't so limited anymore) lycomings aren't real sensitive to this kind of thing if the valvetrain isn't compromised.
 
I had an o-320 that ate an exhaust valve on takeoff. I found bits of the broken valve in 2 or 3 cylinders. I was able to completely reassemble the broken valve with the pieces and I inspected the everything as best I could and called it good. I was never completely comfortable with that however.
 
apkp777 said:
I had an o-320 that ate an exhaust valve on takeoff. I found bits of the broken valve in 2 or 3 cylinders. I was able to completely reassemble the broken valve with the pieces and I inspected the everything as best I could and called it good. I was never completely comfortable with that however.
Click to expand...

But the question is what where the long term results of doing this and how many hours does the engine have since the ingestion, if you would be willing to share?

I ask because I helped Dave scope his engine but I don’t have any answers for him. In my opinion I would guess it’s fine to run, only the soft parts (top of piston and combustion chamber) are affected with a peppering of small dents, the valves and seats seem un affected and do not leak, But is a piston or head going to break because of one of these dents after running for some time. The dents are not very deep and there are no big ridges so I don’t think hot spots would be an issue. With that said, I, like Dave have no experience running one like this.
 
My 2 cents...

I've watched this thread with interest. To the best of my knowledge, there is no way to know how much damage there is without disassembly.

The borescope discovered dents. The question is, will the dents will materialize into a broken piston?

I believe the discovery process is known as a "penetrant inspection". Therein, they spray the aluminum part with green dye and they look under black light to see if there are any cracks. If no problems are found, you get documentation for your engine logbooks that demonstrates you used all reasonable & prudent efforts to identify any damage.

What it boils down to is the level of risk you're willing to accept and the risk you could pass onto others should you sell the airplane. Given that you shared this information on the internet has its own set of ramifications.

If you lived close by, I would happily volunteer to help you remove the jugs, have the pistons checked out, and reassemble. The cost of said project is infinitely cheaper than an in-flight emergency.
 
Old pilots and bold pilots

Gotta agree with Barry on this one------Just too much unknown, and potential for future problems/disaster.

Dents in the top of the piston tell a story----but not all of it.

Future cracking is a possibility, stuck rings are a good possibility, and who knows what the inside of the combustion chamber looks like???

Did the FOD get caught between the piston and a; valve? meaty part of the head? plug? valve seat area?

As Stein would say, "my $.02"
 
The dents are normally peened into the head and top of the piston. Depending on their severity and depth they may be able to be run or not. If there is the possibility of an edge from one of the dents to cause a hot spot, pre-ignition and or detonation may not be far away. If you are talking about a few dings that are smooth on the edges, that will fill in with combustion deposits in very short order then you will likely be OK but anything more then that or with sharp edges should be addressed.
Look at the spark plugs real close, a lot of times they have damage to the center insulator and also to the electrodes that is easy to miss.
Also look for dings or burn marks in the valve face or seat.
Be certain, the contaminate isn't lurking in the intake system or another cylinder. I would take everything apart all the way back to the air filter and bore scope all the cylinders to make sure it isn't still present, awaiting a chance to wreak havoc again.
Good Luck,
Mahlon

?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
Van's FAB

I know of one nasty scratch caused by a pop-rivet "leftover" from the FAB.
Remove all the leftover innards from pop-rivets in the airbox.
 
Thanks you guys! I think a removal and inspection is in the works, hopefully no replacement is needed, these are ECI cylinders:eek:
 
When my o-320 (Cherokee) ate the exhaust valve, I scoped all the cylinders. I found no damage (except the failed one). As I said, I was able to reconstruct the failed valve with the parts. Basically 3 parts I believe were all that it broke in to. I knew that I had all the pieces so that gave me some piece of mind. I pulled the valve covers and inspected all the valves, guides and seats as best I could. Did a compression test (normal) and then followed up by high power static run and some solo flight testing. I am sure that I didn't damage the other cylinders, but I did lose some sleep over it. I ran the plane for another 2-300 hours before I sold it. The current owner hasn't had any trouble. The engine had 1300 SMOH hours on it when this happened and I think it had 1650 or so when I sold it.

At the time of the failure, I was running my first tank of 100LL even though for most of the planes life it had run on MOGAS. I don't know if that had anything to do with it or not, just curious coincidence.

I was pretty P.O.d about the quality of the Lycoming valve train. Exhaust valve failure in that engine model was not a rare occurrence. That same engine had one a few years before I bought it. One reason why I chose a Lyclone rather than a factory Lyc.

There is no specific Service Instruction or other guidance for FOD inspection. Neither is there any compulsion to overhaul the whole engine because of it. However, imagine flying over some inhospitable terrain, at night. Let that be your guide in decision making. I was in the process of restoring that plane when I was furloughed from UAL and was forced to sell it. Had I kept it, the engine would have been torn down before TBO.
 
Thanks for giving my situation some thought -

I appreciate the experience and perspective you have contributed.

Russ and I will pull the affected cylinders this weekend and lay eyes and hands on the damage. With your input and some offline information, I'm confident I can make a good decision about how to proceed. I've learned that one possiblity is that some smoothing will give me a perfectly safe engine, but I'm also determined not to live with any uncertainty.

Dave
 
Let you know the out come. We pulled the two affected cylinders and found only superficial damage to the head and top of the piston. As per a well known engine builder we could and did buff off the few sharp edges and the engine is back together and has 10 or so hours and is running like new.

We also found what caused the damage, well we did not find the piece but we found the piece missing and how it got ingested. It ingested the factory head off a 1/8? truss head solid rivet. It was ingested through the open alternate air on the bottom of the vertical induction fuel injection air box; this should probably have some sort of screen to keep the big stuff out!
 
Good for you Russ and Dave!!

We may never meet but we'll all sleep a little bit better knowing that you will be safe.

Thanks.
 
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