Dry Stack Conversion - Trojan 3100 Seabreeze

mrwright · Post by **mrwright** » Tue Jan 17, 2012 11:21 am

A while back, I posted a threat about whether to keep my little diesel engine or repower with a gas 350 on my 31' Trojan. After a lot of research, I've decided to keep the diesel. So, here's what's next:

DRY STACK CONVERSION!

The Isuzu C240 Diesel engine I have is currently set up for a keel cooler (engine, trans) and raw water cooling in the manifold only. In fact, the water enters the manifold right at the outbound end of it and essentially just cools the tip of the manifold before water and exhaust gases mix and go overboard.

The Setup
Since I have to install a keel cooler anyway, it would be easy to add a little extra capacity to keep the engine cool without raw water exhaust. Then, thru-hulls for water would be closed up. The current manifold is wrapped to keep heat to a minimum and I may be able to use it. Exhaust would be routed up through the floor in a 3 or 4" pipe with a truck muffler. That would be enclosed in 8" stove piping and boxed in. The stove piping would be vended so there should be plenty of engine room ventilation.

The Rationale
The entire setup for this dry exhaust never enters the cabin due to my boat's design - noise and heat should be at a minimum.
Exhaust gases are routed 7' up from the deck courtesy of the piping.
This setup in the end should be easier to maintain and last longer.
Less thru-hulls at the end of the conversion - always a good thing
Still able to keep my keel cooler and cabin heater + hot water setup.
It's different and therefore cool.
If I ever needed to repower, I could use a truck engine with minimal marinization.

So what do you think? Anything you would add?

prowlersfish · Post by **prowlersfish** » Tue Jan 17, 2012 1:11 pm

I have thought of a nice way to put this but I can't . It sounds like a easy way to screw up a nice boat , It going to be noisy no mater what type/ size muffler you use and, you going to have a lot of fumes , If you making a work boat out of it fine , but a pleasure boat ? I can even think of a way you could make it look good . IMO a real bad idea .

Sorry but wet exhust is what belongs on that boat.

summer storm · Post by **summer storm** » Tue Jan 17, 2012 2:44 pm

I agree with Paul on this one. The image of the Orca from the movie Jaws comes to mind, and that was no yacht. Besides, I think the space the stack and heat shield will take up will be a bit much.

rossjo · Post by **rossjo** » Tue Jan 17, 2012 4:13 pm

Since you asked ...

It will be noisy. And safety becomes an issue. You should check USCG regs on non-cooled exhaust piping below decks ...

It may not be insurable.

Last (bit not least) - it will be worth much less on the used market if/when you decide to sell it.

Up to you - but I'd marinize it.

It can't cost that much, as there a ton of sailboats out there with your Isuzu engine, so you should be able to find the right stuff somewhere at a bargain.