# SDR CA960619031

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 10, 1996
- Submitted: March 26, 2000
- Operation: General aviation
- Make and model: Mooney M20K
- Registry model: [Mooney M20K](https://openairdocs.org/model/mooney-m20k) (OpenAirDocs)
- Engine: Cont IO360G
- System (JASC): [8520 · Reciprocating Engine Power Section](https://openairdocs.org/jasc/8520)
- Part: Counterweight Pl
- Part number: 633976
- Condition: Broken
- Location: Crankshaft
- Part time: 875 hours
- Component: Cont
- Stage of operation: CR
- Nature of condition: E
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CA960619031

## Discrepancy

(CAN) THE ENGINE DEVELOPED A SLIGHT VIBRATION INFLIGHT. THE ENGINE OIL PRESSURE & VACUUM SUCTION DROPPED TO ZERO. THE STANDBY VACUUM RESTORED SUCTION. THE ENGINE OPERATING TEMPERATURE INCREASED BUT STAYED IN THE GREEN. THE MANIFOLD PRESSURE WAS NORMAL. POST FLIGHT INSPECTION REVEALED THAT A CRANKSHAFT COUNTERWEIGHT PIN RETAINER PLATE HAD FAILED ALLOWING THE PIN TO FALL INTO THE CRANKCASE, THE LOOSE PIN FRACTURED AN INTAKE VALVE PUSH ROD CREATING A REDUCTION IN OIL PRESSURE. THE VACUUM PUMP SHAFT SHEAR BUSHING ALSO FAILED. NO OBVIOUS CAUSE FOR THE RETAINER PLATE WAS DETERMINED.

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