I just thought I would post this as I was going through some old pictures. This was our Mack E9-900HP engine that failed after 2500 hours. I really believe at one point in her life that she was over propped. I believe that only 13 were marinized of this engine and I know 3 weren't sold. This is just coming from the mechanics at Mack, who did the service work for American Marine Diesel.
I believe the one thing that really ended up hurting this engine was a poor design in regards to a coolant jumper between the exhaust manifold and engine block. It blew off the engine on more than one occasion and finally at one point cooked an exhaust manifold. When we went to order it, they said it was the last one, never makes you feel comfortable. This little jumper was silicone hose, really knarling looking thing, it was so short that a normal hose couldn't be used, almost like two 90 degree elbow's connected sort of 90 degree's out form each other. I think think that a custom pipe should have been put in here even if one side had a flex joint on it. Hindsight is always 20/20.
Engine ran really dirty but man did it have a push, boat had a true 24kt cruise. Ended up replacing her with a Cat 3406E - TWICE.
I miss the boat.