Dry Stack is where it's at ... Conversion Thoughts?

Gian Milan · Feb 2, 2012

mrwright said: ↑

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?
Click to expand...

Is 240 isuzu the engine of Jeep CJ?

FAST FRED · Feb 9, 2012

Exhaust gases are routed 7' up from the deck courtesy of the piping.

A cap will be required to keep rain water out of the exhaust , most just hang a pail over the top of the exhaust pipe.

We cut an opening in the bottom of a tiny beer keg , attached a handle and tie cord.
The boat is in hurricane happy Florida.

The tie chord also prevents the cover from being blown off (overboard) on the days the engine is started with the cap in place. OOOPS!. but no problem.

FF

Gian Milan · Feb 5, 2012

FAST FRED said: ↑

Exhaust gases are routed 7' up from the deck courtesy of the piping.

A cap will be required to keep rain water out of the exhaust , most just hang a pail over the top of the exhaust pipe. OOOPS!.

We cut an opening in the bottom of a tiny beer keg , attached a handle and tie cord.
The boat is in hurricane happy Florida.

The tie chord also prevents the cover from being blown off (overboard) on the days the engine is started with the cap in place. OOOPS!. but no problem.

FF
Click to expand...

in this case the 70% of the heat goes out with the sea water.
cooled oil sump and exhaust manifold and muffler.
being all double bottom, the heat of the exhaust manifold and not more than 35°.
The heat of the head, instead, can not and should not be changed.
nothing would prevent to use a small exhaust fan for air exchange, even if the aspiration of the engine already does something.

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Dry Stack is where it's at ... Conversion Thoughts?

Gian Milan Previous Member

FAST FRED Senior Member

Gian Milan Previous Member

1974 Chris Craft aft deck dry rot

creating a dry riser from NPT pipe