On September 13, 2014, about 2130 eastern daylight time, a Bellanca 17-30A, N6648V, operated by a private individual, was substantially damaged during a forced landing into trees, following a total loss of engine power during approach near Monroe, Georgia. The private pilot and passenger were seriously injured. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Night visual meteorological conditions prevailed for the flight that departed Dallas Bay Sky Park (1A0), Chattanooga, Tennessee, about 1940. No flight plan was filed for the planned flight to Greene County Airport (3J7), Greensboro, Georgia. The pilot reported that prior to the accident flight, he completed a preflight inspection of the airplane, which included adding 100 low-lead aviation gasoline to the left and right wing fuel tanks. He had anticipated fog at his destination airport and planned for a potential diversion to several alternate airports. He subsequently diverted to Monroe-Walton County Airport (D73), Monroe, Georgia. About 3 miles from D73, the pilot heard a "bang" as the engine began to run rough and catch fire. He then pulled the mixture lever back and moved the fuel selector to off. He also dove the airplane until the fire was out. The pilot set up for a forced landing and attempted to glide to D73, but the airplane impacted trees about 1 mile from the airport. The four-seat, low-wing, retractable-gear airplane, serial number 30301, was manufactured in 1970. It was powered by Continental Motors IO-520, 300-horsepower engine with a compression ratio of 8.5 to 1. The engine was equipped with a McCauley three-blade, constant-speed propeller. According to the aircraft logbooks, the airplane's most recent annual inspection was completed on September 21, 2013. At that time, the airplane had accumulated 2,969 total hours of operation. The engine had accumulated 1,798 hours since it was remanufactured in 1974. The airplane had flown about 68 hours from the time of the most recent annual inspection, until the accident. The pilot purchased the airplane on November 20, 2013. The engine was equipped with an F&M Enterprises Inc. (model C6LC) oil filter adapter. The oil filter adapter was not original equipment, but could be installed on the engine under Federal Aviation Administration (FAA) Supplemental Type Certificate (STC) number DE09356SC; however, review of the engine logbook did not reveal any record of the oil filter adapter installation. Further review of FAA airworthiness records for the accident airplane did not reveal any record of the installation being filed with the FAA. Review of the oil filter adapter manufacturer's installation instructions revealed that one fiber gasket and one copper crush gasket were to be used in the installation. Initial examination of the engine revealed a hole near the top front of the case. The wreckage was recovered to a salvage facility for further examination by a representative from the engine manufacturer, under the supervision of an FAA inspector. The examination revealed that the Nos. 4 and 5 connecting rods had separated and exhibited heat damage due to a lack of lubrication. Further examination revealed that the oil filter adapter was loose and had been installed using two copper crush gaskets, rather than one copper crush gasket and one fiber gasket per the installation instructions. Additionally, automobile gasoline was recovered from the fuel tanks, which was not approved for that model engine. Examination of the Nos. 1 and 2 cylinders revealed little to no combustion deposits, consistent with higher operating temperatures of automobile gasoline in that engine.