From the NTSB report:
"The wreckage was recovered from the river the following day and was transported to the West 30th Street Heliport, New York, New York. An initial examination of the wreckage revealed that the airframe was generally intact. The engine remained attached to the airframe. A cursory examination of the engine revealed that the number 18 cylinder on the Pratt and Whitney R-2800 radial engine was damaged, consistent with an in-flight occurrence. Oil was present on the exterior of the engine."