Piston Problems

During oil and filter change, chips and large metal pieces were found. During an annual inspection, the engine oil quick drain valve was blocked with debris. About a dozen pieces of what appeared to be piston ring pieces were removed. While performing a condition inspection, a crack was found on #6 intake. After takeoff, the crew noted engine vibration and lack of power. Inspection revealed excessive oil in the engine area and on the aircraft belly. After a precautionary landing due to power loss, a compression check showed zero on cylinder A4.

Editorial Staff

Wednesday, January 20, 2016 at 12:00 AM ET

Verified

Key Takeaways:

The article describes multiple instances of piston and piston ring failures, including broken skirts, seized rings, and stuck rings, across various aircraft engine models.
These failures are often detected by metallic debris in the oil system, or manifest through symptoms like engine vibration, loss of power, and low compression.
Piston and ring issues can lead to severe secondary damage to critical engine components such as cylinders, camshafts, crankshafts, and connecting rods.

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Continental IO-470-C
Broken Piston Skirt

During oil and filter change, chips and large metal pieces were found. Investigation revealed the #2 cylinder’s piston skirt had broken off, including a piston ring, causing severe damage to the cylinder, camshaft, crankshaft, crankcase and connecting rods.

Part Total Time: 205.0 hours

Continental IO-470-N
Broken Piston Skirts

During an annual inspection, the engine oil quick drain valve was blocked with debris. About a dozen pieces of what appeared to be piston ring pieces were removed. The oil filter displayed no visible contamination and an oil sample came back normal. Compression tests results were normal for all six cylinders and the engine produced normal, smooth and acceptable power. The engine was disassembled: three piston skirts were broken, the bottom scraper ring from each broken piston was found in the oil sump.

Part Total Time: 1099.0 hours

Continental TSIO-550-BB
Broken Oil Ring

While performing a condition inspection, a crack was found on #6 intake. The piston was found to have a large part of its skirt missing, plus a broken oil control ring and cracks near the piston pin area. Metal was found in the oil filter.

Part Total Time: 550.0 hours

Lycoming O-235-L2C
Seized Piston Rings

After takeoff, the crew noted engine vibration and lack of power. Inspection revealed excessive oil in the engine area and on the aircraft belly. Less than three quarts of oil remained. Further inspection revealed a #1 cylinder spark plug had been damaged and was oil fouled. That cylinder had no compression. Removal revealed seized rings and severe piston erosion. Metal particles were noted throughout the cylinder and engine.

Part Total Time: 42.0 hours

Packard V-1650-7 Merlin
Stuck Piston Rings

After a precautionary landing due to power loss, a compression check showed zero on cylinder A4. The cylinder was found to have excessive carbon build-up, with the top ring stuck and excessive side play clearance. Two other pistons from this engine were in similar condition. The piston is not controlling the amount of oil reaching the top of the piston and carbon build up in the top ring groove results. The excessive carbon causes the ring to stick and the ring ends to flutter. A new-design piston is recommended for this application.

Part Total Time: 140.0 hours