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Exhaust Valve Failure- Caught in time

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raymoeller

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I wanted to share with you all a very educational, and eye opening, experience I just went through with my hangar neighbor who has become a very good friend and a mentor over the last few years I've been building my Skybolt. He has both a clipped wing Cub and a Pitts S-1S, and has been flying all his life- He's in his 70's now. Don has been doing the conditional inspection on his cub over the last couple weeks, and as part of it asked me if I'd give him a hand performing the compression test. Of course, we had to take the airplane up for an hour and warm it up, shoot some touch and go's, and the obligatory slow-roll on the way home. The little O-320 purred along.. never missing a beat. However, once down and in the hangar, the first cylinder we tested gave us a reading in the area of 20/80 and we could hear the air escaping through the exhaust. All the rest came out in the area of 75/80. Cutting an even longer series of events that followed short, we finally got an inspection camera into the cylinder (just to verify the decision to yank the cylinder) and to our dismay could see right away what the issue was. This engine has a little less than 1000 hrs on it since its last major. Luckily, the decision had been made not to fly it again before figuring out what was causing the compression loss. The results could have been catastrophic.

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