# SDR CA971110003

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 30, 1997
- Submitted: March 26, 2000
- Operation: General aviation
- Make and model: Cessna 421C
- Registry model: [Cessna 421C](https://openairdocs.org/model/cessna-421c) (OpenAirDocs)
- Engine: Cont GTSIO520L
- System (JASC): [8520 · Reciprocating Engine Power Section](https://openairdocs.org/jasc/8520)
- Part: Crankcase
- Condition: Cracked
- Location: Nr 1 Cyl Bore
- Stage of operation: CR
- Nature of condition: E, K
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CA971110003

## Discrepancy

(CAN) PILOT REPORTED NR 1 ENGINE WAS RUNNING ROUGH.  MAINTENANCE FOUND OIL LEAKS AND EVIDENCE OF COMBUSTION DETONATION AT NR 1 CYLINDER.  FURTHER INSPECTION FOUND NR 36 STUD WAS PULLED OUT OF THE CRANKCASE THREADS.  THE NR 1 CYLINDER BORE IN THE CRANKCASE WAS FOUND CRACKED FROM NR 35 STUD THREADS UP INTO THE CYLINER BORE.  THE ENGINE WAS REMOVED FOR REPAIR AND A FACTORY REMANUFACTURED ENGINE WAS INSTALLED.

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