Tuesday, July 03, 2007

I knew I had a weak cylinder. I could tell every time I pulled the engine through, hot or cold. One of them had almost no compression. I wanted to change it, but was waiting for a good time to do it. Now, with the Waco Fly-In done and Oshkosh 3 weeks away, seemed like a good time.

I went and flew the airplane for 30 minutes and pulled up in front of Glenn's hangar. The spark plugs are pretty easy to get to on the right side of the engine, so in about 30 minutes I had the cowling off, the plugs removed and Glenn standing by with the tester.

The cylinders tested fine until the 5th one, #2. It showed an unbelievably low 20 pounds. We went around the horn and tested it again. This time it showed 40 pounds. Better, but still pretty bad. The most we could get it up to was 58 pounds. The really bad thing was we couldn't hear a leak, but the air had to be going somewhere. We're hoping it's not a piston.

"Start Wrenching," was all Glenn said. I have 3 cylinders that are fresh from overhaul, ready to go. We decided to replace the weakest three, send them in to be overhauled and use them to replace the others.

With Glenn having to go to California a week from Friday, you can guess what I'll be doing on the 4th-pulling cylinders. I have to work this Thursday, but I can order a new gasket set and pistons if needed from Fresno Air Parts and have them overnighted. We have no trips scheduled next week, so I'll have plenty of time to work on it provided it doesn't need anything other than gaskets.

Here I'm pulling the nuts off the studs that hold the exhaust stack in place. I also have a new exhaust stack to put on the plane, so I'm eager to hear what she sounds like with more power from the new cylinders and the bark from the new, different stacks.

Glenn is busy building up two new distributors for the Liberty on the Dh4. He finished one today, another tomorrow. He had brand new parts from a guy in Texas, but they proved to be poorly constructed. He took the 2 best of all the original parts he had and built up the distributors from there.


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