[November 25, 2018]

So I was at my favorite watering hole on Friday night, Hightopps, and I got talking to a friend of a friend within our group. Turns out we both had our captains license OUPV/6-pack. The discussion then talked about if our TWIC (Transport Worker Identification Card - for some reason the USCG thinks captains should have it???) could get us through airport security in the same line as a pilots/flight attendants. I whipped out my pilots license and said "I have a better chance than you do". Immediately the conversation turned to aviation, and before too long, a flight was arranges for today.

I picked up Brian at KMTN, as he worked closeby. He was amazed at the ease of security in getting into this airport. I walked him out to the plane and gave him a quick synopsis of how it was built. For some reason he still hopped in and off we went towards CGE (Cambridge, MD) for some lunch. I let Brian do a majority of the flying and he immediately took to it. He was quick to relate everything aviation to everything nautical. He kept great heading and only struggled a little with altitude, as there aren't any instruments on his side of the panel.

We landed at CGE and met an Aircoupe pilot, Lee, who landed in front of us. Quick conversation struck up with him appreciating how slow he was in the pattern. We invited Lee to join us for lunch and the three of us talked airplanes for a solid hours.

Back off into the air and we went taking the "Long" way back to KMTN. We flew over all of the creeks Brian has explored via boat in his youth. Landing back at MTN, Brian's face was full of smiles and his mind had 1000 questions about aviation. Hopefully I've turned him to the dark side!

I made the quick hop back to KDMW and decided to top off the tanks. While hooking up the grounding cable, I noticed a lot of oil streaks out the left side of the cowl.

Holy smokes! That's a lot of oil on the belly!

And a healthy drip!!! WTF is going on??? Before I started my engine again to taxi to my hangar, I checked how much oil was in my sump. It seemed I lost somewhere between 0.5-1 QT. It's hard to say exactly how much with the engine still warm and a lot of the oil still suspended within it.

I was trying to figure out in my head where all of this oil, predominantly on the left side, was coming from. A blown out crank gasket would be leaking more towards the middle of the engine. The only thing I could think of is it had to be something specific to the #2 or #4 cylinder.

I removed the lower cowl and there was quite the mess of oil on it, concentrating around the #2 cylinder.

Ah-ha! The silicon gasket blew out of the #2 cylinder causing oil to blow out of it.

Upon closer inspection of the silicon gasket, it appeared to be in perfect condition. However, the rocker cover, was very warped with peaks at the 12 o'clock and 6 o'clock positions, which left larger gaps exactly where the failure happened. My hypothesis is the warped rocker covers caused excessive spacing where the cover wasn't applying pressure to the gasket, and over time the gasket slowly worked itself downward until fully dislodged.

I never considered this failure scenario with a silicon gasket. Would a cork gasket fail this way due to how thin it is? Or would oil just leak at a slow pace?

My immediate solution is to order new valve covers (Superior p/n SL61247, $21.60 each). Lesson learned - make sure your valve covers are not warped at annual!!!



Last Modified: June 24, 2024