An AA5B pilot experienced an engine failure inflight; after a rod bearing had a catastrophic failure. The Pilot declared an emergency with ATC; who was providing VFR flight following; and landed uneventuflly.

Narrative

VFR en-route assigned transponder code and traffic advisories from TRACON. All engine parameters normal - engine ran rough momentarily and seized. Windshield covered with engine oil -reduced forward visibility - executed a descending turn and ran emergency checklist. Advised ATC and declared emergency. I requested emergency equipment and ATC advised local Sheriff Department notified. [I] successfully completed a no-power landing. Initial check of engine showed the #2 piston rod/bearing appeared to have had a catastrophic failure resulting in extensive damage to the crankshaft; engine case and cam shaft - the engine could not be rotated by hand. #2 cylinder had been replaced approximately 36 hours before this incident as a result of a stuck exhaust valve that damaged the exhaust valve push rod and tube. The exhaust valve failure occurred on the ground shortly after start- up. Compression check on #2 cylinder performed approximately 8 hours after installation during a required Annual Inspection was 75/80. Further inspection is necessary to determine route cause of failure.