SDR 98ZZZX2044

Service difficulty report · Spring Seat · Cessna 172K

Difficulty date
May 15, 1998
Submitted
March 26, 2000
Operation
General aviation
Aircraft
N46511
Make and model
Cessna 172K
Aircraft serial
17257315
Engine
Lyc O360A1A
Part
Spring Seat
Part number
65441
Condition
Failed
Location
Nr 4 Cyl Intake
Part time
273 hours
Stage of operation
IN
Nature of condition
O
Precautionary procedure
K

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

ENGINE SUCTION SCREEN REMOVED DURING ANNUAL INSP AND SEVERAL LARGE PIECES OF FERROUS METAL WERE FOUND. RECORDS INDICATED THE ENG HAD NEW CYLINDERS INSTALLED DURING OVERHAUL 272.7 HOURS PREVIOUSLY. THE PIECES OF METAL WERE FROM THE LOWER INTAKE VALVE SPRING SEAT P/N 65441. ALL 4 ROCKER COVERS REMOVED AND LARGE PIECES OF A BROKEN SPRING SEAT WERE FOUND IN NR 4 CYL ROCKER COVER. AFTER REMOVAL OF VALVE SPRING, FOUND 2 LOWER VALVE SPRING SEATS HAD BEEN INSTALLED ON THE INTAKE VALVE SPRING DURING BUILD-UP OF CYL ASSY. THE OIL SUMP REMOVED, CLEANED, FLUSHED, AND GEAR TRAIN INSPECTED. NO DAMAGE FOUND. SUMP REINSTALLED AND A NEW VALVE SPRING SEAT, BOTH SPRINGS AND VALVE KEEPERS REPLACED. GROUND RUN WAS NORMAL.

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