WebRuss
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- Jun 14, 2013
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Hello All
This thread will be dedicated to the overhaul of the engine in N803TW. I will post updates and pics as the repairs occur.
BACKGROUND
Original reason for bringing the plane to my local mechanic was that the engine was using a lot of oil (6 qts in 20 hours) and developed a new behavior of spraying oil out of the whistle hole in the breather tube. The assumption was that pressure was building up in the engine case due to weak piston rings allowing blow-by and thus pushing oil out of the breather.
So a compression test was conducted. The results were:
#4 - 70
#3 - 65
#2 - 63
#1 - ~45
Also #1 cylinder has a significant exhaust valve leak - could hear a lot of air coming out of the exhaust. So at this point #1 was removed in a plan to send it out to be redone.
With #1 cylinder removed, an inspection of the cam shaft and lifters revealed significant spalling on the faces of the lifters.
CORRECTION - The damage shown in the photo below is pitting on the face of the lifters as Phillip Lane pointed out that "Spalling is where ragged chunks are broken out from the corrosion pits"
Beginning the process of an engine overhaul.
This thread will be dedicated to the overhaul of the engine in N803TW. I will post updates and pics as the repairs occur.
BACKGROUND
- 803TW is a 1968 Cherokee D 180.
- 6506 TTAF
- Engine is Lycoming O-360-A4A
- 750 SMOH
- Engine was overhauled in 2000.
- I use Shell Aero 100 SAE 50 oil.
- I keep the oil level at 6 QTS as anything more is just wasted.
- Former owner flew it a little each week. Maybe a couple of hours.
- I bought the plane in June and I've put about 100 hours on it between getting re-certified and recreational activities.
- I practice lean-of-peak as much as possible and try to run at 2350 rpms when cruising.
Original reason for bringing the plane to my local mechanic was that the engine was using a lot of oil (6 qts in 20 hours) and developed a new behavior of spraying oil out of the whistle hole in the breather tube. The assumption was that pressure was building up in the engine case due to weak piston rings allowing blow-by and thus pushing oil out of the breather.
So a compression test was conducted. The results were:
#4 - 70
#3 - 65
#2 - 63
#1 - ~45
Also #1 cylinder has a significant exhaust valve leak - could hear a lot of air coming out of the exhaust. So at this point #1 was removed in a plan to send it out to be redone.
With #1 cylinder removed, an inspection of the cam shaft and lifters revealed significant spalling on the faces of the lifters.
CORRECTION - The damage shown in the photo below is pitting on the face of the lifters as Phillip Lane pointed out that "Spalling is where ragged chunks are broken out from the corrosion pits"
Beginning the process of an engine overhaul.
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