3000 express exhaust

[ropes]

I have a 1999 3000 express powered by twin Steyr 256 diesels. I had a problem in the summer with a quick stop to avoid a log. There must have been some water intrusion through the exhaust as when I powered up a cam follower broke and there was a horrible noise. It ended up being a cheap fix that I was able to do myself. I am not 100% sure but it makes sense that the quick stop allowed water up through the exhaust and into cylinder #1? Anyways I want to prevent this from happening again. Can I simply put an inline exhaust valve at the terminal end where the exhaust hits the outside at water level? I was thinking of a stainless valve vs a rubber flapper valve. Any ideas?

[MarkT]

Hi Chris. Are you sure it is the number 1 cylinder? That is usually the cylinder closest to the front of the engine. Was it the front or rear cylinder? I would be interested in seeing a picture of the exhaust system to compare to mine ( Cummins 4BTA-250) to see if there is something different between the two. Compared to some sport fisherman exhaust systems we are missing any type of surge tube to handle just what you had happen. What did you have in mind as a valve?

[ropes]

It was the front cylinder which is the furthest from the exhaust but I am no mechanic so not sure. I am just willing to take things apart to learn about them. Usually I can get them back together without too many spare parts. I was thinking of something like the mmd 4 inch inline ss check valve $55 each. You can see them on the Marine Parts Source website. My only concern would be if they failed then the exhaust water would build up in the line and flood the system. Not sure if that could happen or not. My problem is where we boat there is a lot of wood in the water and quite often we are slowing quickly to avoid logs. I would feel more comfortable with the exhaust valves.

[MarkT]

Couple of things Chris. I don't think that if it was in fact water I doubt it would get to #1 cylinder passing by 5 others. Valves open and close so quickly that water would go in the nearest to the source. Instead I think it would have gone into the turbo and damaged that. I looked at the valve you are talking about and the first thing I noticed is that it is only a 4 inch valve. I have 5 or 6 inch exhaust and I bet you would also. Diesels are not happy with back pressure and you may get more than allowed with that valve. And if it failed you would get water and exhaust back pressure and might have some serious damage. I have at times thought about running the exhaust out the back for other reasons and that might be the way to go with rubber flappers on the end. The exhaust piping itself does not give us much room for change. Check out this link:
http://www.yachtworld.com/core/listing/ ... noOfPic=15
Picture 15 shows the port engine. If you look at the exhaust you can see the exhaust pipe that actually goes forward about 6 inches from the y connection. This is a surge tube and when the boat is backing down hard or stopped quick the water rushes into the tube instead of up the pipe into the turbo.