GA pilot reported executing a forced landing in a field after the engine failed in flight.

Narrative:

[The] run up and magneto check was good and the engine produced full RPM on takeoff. While enroute the engine started to vibrate slightly; oil pressure was normal and temps were normal. As a precaution I changed my course to deviate around any populated areas and flew over open ground in the event of an engine total failure and forced landing. [A short time later] there was a loud bang and the engine quit. I was at 1200 feet AGL and set up a glide for landing in an open field. I landed the aircraft gear up as the field is a rice field and fairly rough. I touched down at almost stall speed and slid approximately 330 feet. I secured the cockpit and left the aircraft. Upon inspection I found a cylinder had blown off the case and embedded itself in the cowl and the piston was found in the lower cowl. I am not a mechanic; but it looks like the rod broke on #4 cylinder which hit the cylinder skirt breaking off pieces and eventually blew the cylinder from the case.

Original NASA ASRS Text

Title: GA pilot reported executing a forced landing in a field after the engine failed in flight.

Narrative: [The] run up and magneto check was good and the engine produced full RPM on takeoff. While enroute the engine started to vibrate slightly; oil pressure was normal and temps were normal. As a precaution I changed my course to deviate around any populated areas and flew over open ground in the event of an engine total failure and forced landing. [A short time later] there was a loud bang and the engine quit. I was at 1200 feet AGL and set up a glide for landing in an open field. I landed the aircraft gear up as the field is a rice field and fairly rough. I touched down at almost stall speed and slid approximately 330 feet. I secured the cockpit and left the aircraft. Upon inspection I found a cylinder had blown off the case and embedded itself in the cowl and the piston was found in the lower cowl. I am not a mechanic; but it looks like the rod broke on #4 cylinder which hit the cylinder skirt breaking off pieces and eventually blew the cylinder from the case.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1564456
Time
Date	201807
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft Low Wing 1 Eng Retractable Gear
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	None
Component
Aircraft Component	Engine
Person 1
Function	Single Pilot
Qualification	Flight Crew Private Flight Crew Instrument
Experience	Flight Crew Last 90 Days 16 Flight Crew Total 1912 Flight Crew Type 175
Events
Anomaly	Aircraft Equipment Problem Critical Ground Event / Encounter Other / Unknown