I purchased a S/D 8kcab one year ago with only 200 hours on it.(1999 manu). Now the camshaft has failed possibly due to underuse we are facing an $15 thousand rebuild. Had I done a borescope inspection on purchase this corrosion problem would have shown up and I could have either renegotiated or pulled out. Please be more careful than I was.
Climb inside that engine..........!!!!!!!!!!
- Thread starter aifreeman
- Start date
Sorry to hear this. You know we made the airplane to be flown, not parked!! 
This is exactly why Lycoming has a 12 year TBO as well.
The poor cam shaft at the top of the engine doesn't get to be coated in oil for as long as the lower parts. But then, the top of the case is the oil sump when inverted...
Additionally for 8KCAB's (and post 1974 7KCAB) you should make sure they get a little inverted time every now and then. Its like 4WD on a truck, you need to push the parts around and get the system lubed up once in a while. Too much level time and residue collects on the ball check value instead of flowing through and catching on the screan.
This is exactly why Lycoming has a 12 year TBO as well.
The poor cam shaft at the top of the engine doesn't get to be coated in oil for as long as the lower parts. But then, the top of the case is the oil sump when inverted...
Additionally for 8KCAB's (and post 1974 7KCAB) you should make sure they get a little inverted time every now and then. Its like 4WD on a truck, you need to push the parts around and get the system lubed up once in a while. Too much level time and residue collects on the ball check value instead of flowing through and catching on the screan.