# SDR 98ZZZX4056

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 1, 1998
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: N5HMSW
- Make and model: Cessna 210N
- Registry model: [Cessna 210N](https://openairdocs.org/model/cessna-210n) (OpenAirDocs)
- Aircraft serial: 21063789
- Engine: Cont IO520L
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Spring
- Part number: TCM631521
- Condition: Broken
- Location: Engine
- Part time: 983 hours
- Stage of operation: IN
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/98ZZZX4056

## Discrepancy

DURING ROUTINE MAINTENANCE, METAL FOUND IN OIL FILTER.  TRACED TO BROKEN INNER VALVE SPRING OF NR 5 CYLINDER.  BROKEN ENDS HAD STARTED TO EAT INTO CYLINDER HEAD.  SUBMITTER SUGGESTED CAUSE AS METALLURIGICAL FAILURE OF SPRING STEEL. VALVE SPRINGS ARE A MANDATORY REPLACEMENT ITEM AT OVERHAUL (OR RE-MANUFACTURE).  THEREFORE, THIS PART HAD ONLY ACHIEVED ABOUT HALF OF ITS RATED LIFE.  THE OUTER SPRING WAS INTACT.

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