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Been avoiding posting about this, but then the question came up in another thread, so I decided to vent with the full story. It may be therapeutic.
And, it is a long story, now extending to probably three months of AOG torture. A maintenance nightmare in "slow-motion". I'm climbing the walls.
Aircraft was grounded 1st August.
To make a long story, shorter, back in July noted indications on the engine analyzer tracing suggesting a future #4 exhaust valve failure. We had recently borescoped, but with an abundance of caution borescoped again. The tracing was actually featured on the Savvy site.
Borescope now suggested a possible crack in the exhaust valve seat, rare but possible, and would be compatible with the findings. Pulled the cylinder, no crack, but there was some wobble, and irregularity to the valve edge, but the color was completely symmetric and normal color. Inspected the cam portion that we could see, all looked fine. Hmm'd and Haw'd, the oil usage was up, maybe the rings, and if one valve wobbles perhaps the rest do. Certainly the #4 exhaust valve is highly suspect now. Wanted to run the engine longer, so elected to do a top overhaul.
Two weeks waiting for the new cylinders. On installing them, inspecting the rest of the cam, there was clear evidence of one cam lobe failure, the double one at the back, together with its two followers. Should have been caught earlier, but you hate to pull more than one cylinder at a time, etc. The rest of engine was pristine, no corrosion, not surprising as the plane is flown a lot and often. No matter, snookered. I guess, a victim of the Lyc overhead cam.
Happily the engine shop would credit the cylinder purchase towards an overhaul. That said, I was planning a new factory engine when the time came, to get the two magneto mod (this O-540 has the 3000D magneto) which would allow an easy electronic ignition mod, and roller tappets. No can do that now.
Then it continued ...
Once the case was cracked, evidence of the center bearing starting to scuff, need a case overhaul. Not expensive, but that is four weeks.
Oh, the prop was sent off for inspection, it failed. New three blader ordered, about the same price as a full overhaul of the two blader.
Case overhaul took five weeks (no surprise), engine got back to the shop last week, it will likely be done next week. Then my guy has to install it, another week. So maybe back in the air, end of October.
I'm busy writing checks, and not flying now for 2-1/2 months, right through prime flying weather, had to cancel a number of trips. Engine will be ready right for when the icy clouds of the Great Lakes region descend. Oh, and to make it even worse my IFR cert expires 1st Nov - in Canada we have to do a full PTS and oral every two years.
Ya, I'm bummed.
Well, with the panel overhaul, interior redo, and now the slightly premature engine overhaul, there is not much more to fix, it is a "brand new" plane. Good thing, as I may be tapped out now.
* Orest
And, it is a long story, now extending to probably three months of AOG torture. A maintenance nightmare in "slow-motion". I'm climbing the walls.
Aircraft was grounded 1st August.
To make a long story, shorter, back in July noted indications on the engine analyzer tracing suggesting a future #4 exhaust valve failure. We had recently borescoped, but with an abundance of caution borescoped again. The tracing was actually featured on the Savvy site.
Borescope now suggested a possible crack in the exhaust valve seat, rare but possible, and would be compatible with the findings. Pulled the cylinder, no crack, but there was some wobble, and irregularity to the valve edge, but the color was completely symmetric and normal color. Inspected the cam portion that we could see, all looked fine. Hmm'd and Haw'd, the oil usage was up, maybe the rings, and if one valve wobbles perhaps the rest do. Certainly the #4 exhaust valve is highly suspect now. Wanted to run the engine longer, so elected to do a top overhaul.
Two weeks waiting for the new cylinders. On installing them, inspecting the rest of the cam, there was clear evidence of one cam lobe failure, the double one at the back, together with its two followers. Should have been caught earlier, but you hate to pull more than one cylinder at a time, etc. The rest of engine was pristine, no corrosion, not surprising as the plane is flown a lot and often. No matter, snookered. I guess, a victim of the Lyc overhead cam.
Happily the engine shop would credit the cylinder purchase towards an overhaul. That said, I was planning a new factory engine when the time came, to get the two magneto mod (this O-540 has the 3000D magneto) which would allow an easy electronic ignition mod, and roller tappets. No can do that now.
Then it continued ...
Once the case was cracked, evidence of the center bearing starting to scuff, need a case overhaul. Not expensive, but that is four weeks.
Oh, the prop was sent off for inspection, it failed. New three blader ordered, about the same price as a full overhaul of the two blader.
Case overhaul took five weeks (no surprise), engine got back to the shop last week, it will likely be done next week. Then my guy has to install it, another week. So maybe back in the air, end of October.
I'm busy writing checks, and not flying now for 2-1/2 months, right through prime flying weather, had to cancel a number of trips. Engine will be ready right for when the icy clouds of the Great Lakes region descend. Oh, and to make it even worse my IFR cert expires 1st Nov - in Canada we have to do a full PTS and oral every two years.
Ya, I'm bummed.
Well, with the panel overhaul, interior redo, and now the slightly premature engine overhaul, there is not much more to fix, it is a "brand new" plane. Good thing, as I may be tapped out now.
* Orest
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