Service difficulty report · Rod Bolt

Difficulty date
September 3, 2002
Submitted
September 3, 2002
Operation
General aviation
Engine
Cont IO520D
Part
Rod Bolt
Part number
654068
Condition
Stretched
Location
Engine
Stage of operation
IN
How discovered
V
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

AT INSTALLATION OF THE NEW CONNECTING ROD BOLT AND NUT IT WAS NOTED THAT PROPER TORQUE WAS NOT ACHIEVED WITH THE SAME AMOUNT OF TURNS AS THE OTHER ROD BOLTS AND NUTS. A VISUAL INSPECTION SHOWED THAT MORE THREADS WERE SHOWING PAST THE NUT THAN OTHER BOLTS ON THE SAME CRANKSHAFT. THE BOLT MEASURED .054 INCH LONGER THAT THE ADJACENT BOLT ON THE CONNECTING ROD. UPON DISASSEMBLY A VISUAL INSPECTION SHOWED THE THREADS TO BE DEFORMED, THE SHANK NEAR THE HEAD EXHIBITED SIGNS OF STRETCHING AND THE BEARING FACE OF THE HEAD SHOWED SOME GALLING. IT IS POSSIBLE THE BOLT WAS SOFT AND NOT PROPERLY HEAT TREATED.