Have you cleaned tank, bleed lines, and exhausted all hope. If its running run it, a diesel engine that size is going to probably run $5k+. If you really truly destroyed yours beyond a professional rebuilt do an extensive Google search of your engine model, very good chance its used in towed air compressor, light tower, pump, or industrial generator. If it is, a used unit might be found at your semi local/regional equipment auction for a couple grand.