Hi Everyone,
Have been reading a lot about “morning sickness” and sticky valves on Lycoming engines. Curious where you draw the line between a normal warm-up and what might be considered abnormal for a TIO-540-AJ1A.
In short, I’ve noticed that right after a (hangared) cold start and at 1000 RPM, the engine sounds like it’s not quite “firing on all cylinders.” When I increase to 1200 RPM (to begin leaning for ground ops) the engine smooths out and there’s nothing else abnormal from there. My only other observation is that one cylinder is slower than the other 5 to register a “bar” on the EGT gauge but this always resolves during the run-up when I flip to a single mag and that cylinder is pretty close to the others in cruise.
I always had assumed this throaty, “chug-chug” sequence was completely normal for the engine as it warms up. But it also occurred to me that a sticky valve might also be the culprit before it “shakes loose” at 1200 RPM and is fine the rest of the flight. Is there any good way to tell the difference?
Thanks for any experience you can share.
Have been reading a lot about “morning sickness” and sticky valves on Lycoming engines. Curious where you draw the line between a normal warm-up and what might be considered abnormal for a TIO-540-AJ1A.
In short, I’ve noticed that right after a (hangared) cold start and at 1000 RPM, the engine sounds like it’s not quite “firing on all cylinders.” When I increase to 1200 RPM (to begin leaning for ground ops) the engine smooths out and there’s nothing else abnormal from there. My only other observation is that one cylinder is slower than the other 5 to register a “bar” on the EGT gauge but this always resolves during the run-up when I flip to a single mag and that cylinder is pretty close to the others in cruise.
I always had assumed this throaty, “chug-chug” sequence was completely normal for the engine as it warms up. But it also occurred to me that a sticky valve might also be the culprit before it “shakes loose” at 1200 RPM and is fine the rest of the flight. Is there any good way to tell the difference?
Thanks for any experience you can share.