water in engine

I own a 40.7 with a 20:40 Volvo Penta engine, which in now in pieces due to water getting into the engine. How this happened has yet to be found, but it may have been from water coming back through the exhaust, so I'm told. The company working on this say that they have only seen this on this engine and on 40.7's. Has anyone else experienced or know of anyone who has had the same problem