Engine exhaust run on Diesel Carvers

I'm a little concerned that the exhaust run from my Cummins Diesel powered 355 ACMY maybe a little flat. After posting pics on boatdiesel.com it got some comments.

Has anyone operating a Carver Aft Cabin boat heard of any issues with water backing up into the engine due to a too flat exhaust run??

Thanks, Tim

There is no riser at the turbo. It's a flat elbow out of the turbo and then to the back of the boat.

The water line is a foot or more below the turbo but as the photo shows the immediate section past the turbo has very little slope down.
The boat is a '98 and to my knowledge has had no issues with water flowing back into the engine. But of course I may have just been lucky though I would think if this was a problem, Carver would have had a bunch of issues with this.
There is very little room above the turbo because of the floor boards.

The picture shows the port engine which does not have the original exhaust elbow. The PO had the work done. The stbd engine has the original exhaust elbow, all metal, not like the black one shown in the picture. I called the company that I believe made the elbow shown in the picture and they said the elbow is stainless steel covered with a black composite thermal covering. I suspect who ever did the work copied the original elbow and replaced it with whats in the picture. This is OK and probably better than the original but still retained the very little slope away from the turbo.

My other concern is the stbd engine which has the original elbow. The place that made the port elbow highly suggested I replace the stbd one due to its age, 14 yo.

I've got some research to do.

Thanks guys for all your comments. I finally got down to the boat last weekend and took a good look at the exhaust systems on both engines. The picture I posted does not show the slope very well. Reading Bill106 comments I measured the vertical distance from the flange where the exhaust elbow connects to the turbo and where the exhaust tube connects to the muffler. It is a constant slope with a run of 40" and a vertical drop of 5.5" The exhaust is out the side of the boat very near the transom.

The starboard side (not pictures) has pretty much the same slope. Gravity will move water well away from the turbo on both engines.

With this in mind I am not concerned with the design of the exhaust system but rather the integrity of the starboard side mixing elbow. It will not be a simple matter to check because the flange bolts (4) that connect the elbow to the turbo cannot be removed. I had a mechanic heat them and it did no good. So I'm going to have them cut off to remove the elbow and then the holes drilled out, hopefully without doing damage to the holes in the turbo where the exhaust elbow connects to. If they are damaged I guess they will have to be re-tapped.

I will probably not reuse the existing elbow since I'm going to so much trouble to remove it and it is 14 years old.

Tim

The exhaust elbow on the port engine was replaced as RB480 mentioned and is pictured at the beginning of this thread. I don't know why or under what circumstances or how long ago it was replaced. The PO turned hostile and is no help.

After doing some research it appears the exhaust system on my 355 ACMY is properly designed and installed. Due to the slope away from the turbo any failure due to corrosion in the exhaust elbow should allow water to drain toward the muffler and not into the engine.

The starboard exhaust elbow is 14 years old and is working fine but given it's age I want to be proactive and deal with it now before a potential failure. We're planning an Abacos cruise next year and I want the peace of mind that all is well.

Anybody know of a exhaust specialist in the Tampa Bay area?

Thanks Bill. The starboard side is original so no drawings on file. I talked to Marine Exhaust about the port side (pictured at beginning) and they have no record on file because the PO probably had a mechanic do the work and the work order would be under his name. But since the boat was located in the Punta Gorda area, I suspect they did the work. I'll call DeAngelo too.

Know anyone in the Tampa area that would install it?

I'll look close to see if there is some id on the elbow. Good idea.

3 of the 4 bolts will have to be cut out and then drilled out of the turbo. If done carefully hopefully the turbo won't have to be re-tapped. Already had a mechanic spend nearly an hour heating the bolts to no avail. The retapping is the part I'm not comfortable with.

follow up

Thanks guys for all your help.
I had an exhaust specialist look at the starboard exhaust system. He dug right in and removed the old riser. It was pretty much shot and he showed me where it was leaking. Actually I had seen the leak, but thought it was coolant, not raw water. A green stalagmite had formed on the bottom of the riser flange which I thought was coolant leaking from the heat exchanger.
He was able to remove the 3 bolts without cutting them by using a product called thru flow. It works like PB Blaster but better. It took about an hour of working with them, but he did get them out.
The new riser should be ready by the end of the week. It is a duplicate of the port riser that is made by Marine Exhaust System in Stuart FL. Not cheap, but should out last the boat.