My Wooden Airplane
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8/14/2016 - 8/27/2016

Cylinder Heads

Earlier, I had removed my cylinder heads and brought them to a local machine shop because I wasn't getting any compression in cylinder #1. They told me that the heads were warped, but they could fix them, and it should only take a couple of weeks. Well, after waiting for more than two months, it turns out the machine shop had done absolutely nothing with them! When I called for another status update, they told me they had fired the original technician that had been working on them, and would have to essentially start all over again, since they had no idea how far he had actually gotten. I told them not to bother, that I'd pick them up and fix them myself, and pay them for the work already performed. But when I got there, it turns out the technician had been lying all along, giving me false status updates (one of the reasons why he was fired, apparently). The heads had just sat on the shelf, untouched, the whole time!

So, my friend Roger offered to help me with them. We determined that one head did seem a little warped. Although it took several attempts, we finally managed to get them squared up again by removing the high spots with a milling machine. I was concerened that we might have removed too much material, so I used a burette to measure the volume of each of the chambers. Although I can't believe it, we didn't actually reduce the volume appreciably, and all six chambers were within 1.6 CCs of each other.

Once the heads were straightened, I decided to fix the valve seats. It turns out that the valves in cylinders 1 and 3 weren't seating properly! Fortunately, these Neway cutters made the job pretty simple. After a final lapping of all 12 valves, I was ready to reassemble the engine.

Total Time: 33.0 hrs.