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-   -   Lost a cylinder on take-off (https://vansairforce.net/community/showthread.php?t=94516)

DakotaHawk 12-26-2012 07:29 AM

Lost a cylinder on take-off
 
I'd like some help on troubleshooting...

Christmas Eve - I was taking a wanna-be pilot up for a second flight in my RV. She's starting ground school next week. After a normal engine run-up, we taxied onto the Rwy 34 and smoothly applied power. The IO-360 was purring along, we rolled down the runway, and lifted off. Everything was still running smooth.

At about 350' agl, the engine suddenly started running rough. My #2EGT immediately started climbing, all other EGT stayed normal. I didn't notice any change to CHT, but I was paying attention to other things at the time. I used my airspeed to zoom to about 650' agl, pulled power back to about 1700 rpm, and held airspeed (which had bled off in the zoom) at about 80 mph. I made a shallow left pattern turn to downwind, and then realized that I had the pattern to myself and Rwy 11 directly under my wing.

I chopped the power, dropped in full flaps, and slipped down to land on Rwy 11. I landed on the last 1/3 of the runway since I had made my decision to land when I was over the numbers and I had 650' to lose.



After landing, I did a quick runup, and the engine ran just fine. Back to the hangar - still running fine.

Back at the hangar, I pulled the cowl and did a compression test. Compression was good and I didn't hear any intake or exhaust leak-by. The exhaust stack coming from the #2 cylinder was sooty, the other stack was clean. Pulling the plugs from #2 cylinder - dark brown color.

So... What's next?

LettersFromFlyoverCountry 12-26-2012 07:30 AM

#2 injector check?

DanBaier 12-26-2012 07:34 AM

Assuming fuel injection. Using 100LL? Mags or EI? Any recent maintenance? Do you have an engine analyzer with recorded history?

Dan

DakotaHawk 12-26-2012 07:49 AM

Quote:

Originally Posted by DanBaier (Post 728317)
Assuming fuel injection. Using 100LL? Mags or EI? Any recent maintenance? Do you have an engine analyzer with recorded history?

Dan

I've got the Dynon D100 EMS - I'm going to take the laptop to the hangar this afternoon to see if I can download data. (I've never done this before, so I don't know if I have it set up to record data)

The engine is an IO-360, running straight mogas (except for cross country) for the past 500 hours. One mag, one LightSpeed Ign. Plugs are in good condition with correct gaps.

Quote:

#2 injector check?
What's an injector check?

frazitl 12-26-2012 08:03 AM

my wag is
 
a sticking exhaust valve on #2. I would do a wobble test and make sure my push rods on #2were still straight...

Great job getting her down. How did your passenger react?

WAM120RV 12-26-2012 08:03 AM

Cool head
 
Hey,

Well done keeping a cool head and making the best of a bad situation!!!

Walt 12-26-2012 08:04 AM

A little rough and high EGT may also indicate you are losing ignition to one plug. First thing I would do is check wires, connections etc. and replace plugs on offending cylinder.

Greg Arehart 12-26-2012 08:27 AM

Glad you're safe. I think the default on the Dynon is to record data (I don't remember the interval but somewhere between 1 & 5 seconds probably), so you should be ok.

Cheers,
Greg

billgill 12-26-2012 08:48 AM

Seen this before
 
Scott.

In fact, seen it twice on a friends IO-390. After pulling plugs on the problem cylinder, a chunk of carbon was found bridging the gap.

BeeGee

Kahuna 12-26-2012 08:49 AM

A cylinder miss & rising egt should be no cause for alarm or need for a cool head. Pulling power, pushing the nose over and dropping flaps and heading back to the runway really kept you from determining what the problem was. There was more sleuthing to do.
There are a number of items that could be the cause as others have mentioned.

Perhaps its the way you wrote the issue, but I got far more concerned about the reaction than I did the problem while reading. Even a completely out cylinder, while feels terrible, is no cause for 'I have to get down now'. Let it stumble, climb and access.

A nice pattern while troubleshooting would help pinpoint the problem. You could simply have a fouled plug, bad plug, intake leak, ign wire, plugged injector, or a number of other items. Some of these are difficult to troubleshoot on the ground.


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