On July 27, 1993, about 1131 central daylight time, a Champion 402; N9981Y, operated by Stephen E. Unger, sustained substantial damage during a forced landing in a field 1.5 miles west of Valparaiso, Indiana. The airline transport pilot and one passenger were uninjured. The flight was operating under 14 CFR Part 91 in visual meteorological conditions with no flight plan on file. The flight originated form Valparaiso, Indiana. Immediately following takeoff from runway 27 at Valparaiso, the right engine lost power. The pilot determined a return to the airport was not possible, and made a forced landing in a large field to the northwest of the airport. The aircraft's right wing was damaged. Further investigation found the exhaust stack assembly, Champion part number 4-1218, cracked and separated at the weld. The P-Leads were melted by the hot gases, shorting out the magnetos.