Ruh-Roh
Posted: Fri Jun 14, 2019 10:28 pm
Bad news today. Looks like I'm in for an extended down time and significant decrease in my liquid assets. Yesterday I flew my airplane and then changed the oil. I was also planning to install my ADS-B setup. Well, when I removed the suction screen, this is what I found:
1) Pull the engine and have my mechanic split the case, inspect, replace the set screw (and anything else he finds wrong). I trust him, and he gives a two year warranty on his engine work. This would be the cheapest option, although not necessarily the quickest.
2) Buy an exchange engine from Lycoming (either new, overhauled, or rebuilt). If they have an engine in stock, it could be shipped out, and meanwhile we could dismount the old engine and prep the airframe for the new one. Of course, unless I take the new option, I don't know what the overhauled or rebuilt engine has been through (prop strike, number of rebuilds, etc.).
3) Remove my engine and ship it to Lycoming to be overhauled or rebuilt. Longer downtime, plus twice the shipping cost (once to get the shipping crate here, once to get the engine back to Lycoming, again here for the new engine, and then the empty crate back).
So any guidance/advice would be appreciated. I also wanted to make the Group aware of this issue, and I would recommend doing the inspection SI if you ever have the prop off your aircraft.
Steve
My A&P/IA and I spent the next hour or so poring over the engine assembly and parts manuals. The only part like this in the engine is a 10/32 set screw which secures the propeller governor idler shaft. Without this set screw the shaft can move back and forth in the engine case, and apparently has led to a couple of engine failures. Lycoming put out an AD addressing this in 2015, but it only applied to aerobatic engines, not the IO-360-M1A:
There is a Service Bulletin which specifies an inspection procedure to determine if the set screw is loose:
and a new procedure to install the set screw to prevent loss:
So, I pulled the prop off today. Here are two photos of us doing the inspection:
You can see how the shaft is easily pulled forward using a magnet in the second photo. It should not move at all. We conferred with Lycoming Technical Support, and (of course) they said that the engine has to be split. So now, I have to decide how to approach the issue. My engine has about 725 hours, starts and runs great, has good compressions, and has had good oil analyses since new. On the other hand, it is 18 years old. My choices are:1) Pull the engine and have my mechanic split the case, inspect, replace the set screw (and anything else he finds wrong). I trust him, and he gives a two year warranty on his engine work. This would be the cheapest option, although not necessarily the quickest.
2) Buy an exchange engine from Lycoming (either new, overhauled, or rebuilt). If they have an engine in stock, it could be shipped out, and meanwhile we could dismount the old engine and prep the airframe for the new one. Of course, unless I take the new option, I don't know what the overhauled or rebuilt engine has been through (prop strike, number of rebuilds, etc.).
3) Remove my engine and ship it to Lycoming to be overhauled or rebuilt. Longer downtime, plus twice the shipping cost (once to get the shipping crate here, once to get the engine back to Lycoming, again here for the new engine, and then the empty crate back).
So any guidance/advice would be appreciated. I also wanted to make the Group aware of this issue, and I would recommend doing the inspection SI if you ever have the prop off your aircraft.
Steve