None of us wants to believe that these things just fail at random. Only Hirths do that (?).
Bernard, would you care to share some history of this engine? Do you use pure synthetic oil? Has the engine sat unused for awhile at any time, with or without fogging? Might the bearings have rusted?
Hi Doug,
Believe me, I am THE most interested in what happened. I bought the engine new three years ago and installed it, and have flown consistently since then. June will be three years that it has been flying and I have 260 some hours on the engine. It has only seen Pennzoil air cooled oil, and since I've never let it sit long, its never been fogged. Even when weather might have been bad for a stretch, its been started and run.
When we dismantled the engine, we looked for anything that might have caused the bearing to fail. That's the point I have been trying to make about the conidtion of the cylinders, head, and pistons. The tech, a 20 yr guy, thought everything looked normal, and I didn't see anything to suggest otherwise. The one rod bearing was the only thing that looked bad (the top ring was thrown due to this and the top of the piston had minor damage from this). The tech was surprised that we didn't find more damage and his assessment is that my engine seized very quickly, and therefore didn't cause more damage. This was not so much of a piston seizing as the bearing causing the rod to seize. The seized bearings look cooked but no visible sign of issues with any other bearings.
I know we'd all like something to hang this on, but the conclusion of my Rotax certified tech, and Lockwood, is that it just failed. Lets face it, there is a TBO because these things do wear, even under the best of circomstances. If I were at 360 hours, I don't think anyone would question the failure and would chalk it up to being over TBO. TBO's are of course based on data compiled by the manufacturer, but all engines have examples of units not making TBO. I was close. I did find in my searches others who experienced rod bearing failures with about the same hours as mine. That does give me some pause.
Anyway, the engine is being rebuilt, and frankly, I'm looking forward to getting it back so I can fly.
Bernard