# SDR 2020FA0000007

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 15, 2019
- Submitted: January 8, 2020
- Operation: General aviation
- Aircraft: [N1218S](https://openairdocs.org/aircraft/N1218S), registered now
- Make and model: Cessna 172S
- Registry model: [Cessna 172S](https://openairdocs.org/model/cessna-172s) (OpenAirDocs)
- Aircraft serial: 172S11161
- Engine: Lyc IO360L2A
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Exhaust Valve
- Condition: Sticking
- Location: Engine
- Stage of operation: NR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2020FA0000007

## Discrepancy

ENGINE S/N L3049651E EXPERIENCED A STICKING EXHAUST VALVE AT 582.4 HOURS TOTAL TIME WHILE IN FLIGHT.  THE PILOT MADE A SUCCESSFUL PARTIAL-POWER LANDING.  CYLINDER NR 3 EXHAUST VALVE STUCK IN FLIGHT, THE VALVE HIT THE PISTON AND THE PUSH ROD WAS BENT.  THAT CYLINDER WAS REPLACED WITH A NEW ONE.  WHEN REAMING THE REMAINING EXHAUST VALVE GUIDES, ALSO FOUND CYLINDER NR 4 STICKING.  THIS WAS REAMED OUT AS WERE THE OTHER 2 EXHAUST VALVE GUIDES.  LYCOMING SB388C WAS PERFORMED ALL GUIDES WERE REAMED TO WITHIN BALANCE.  THE ENGINE INCORPORATES NI-RESIST VALVE GUIDES AND THE TIME TO FAILURE IS CONSIDERED BY THIS AGENCY TO BE PREMATURE.

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