A general exhaust question

[Adirondack]

Hello all,
I'm new to the forum. When I found it yesterday I couldn't leave. I just had to keep reading. You guys know your stuff.

I have been boating my whole life, and owned the same boat for 30 (yes I said thirty) years. A 1971 Browning bowrider with a 140 four banger. I have repowered it once, and had the sterndrive off numerous times for regular service. Waterpump, bellows, cables and such. Never had a gear case apart on her, or had to replace a joint. It's a pre-Alpha drive. That being said after 30 years sitting in fresh water eight months a year the drive is basicly disintigrating so I purchased another boat to rebuild, and "old brownie" is seeing her last year of service for me. Gonna miss her. Raised all my kids on that boat. Sorry for running on, but now to my question.

I'm a truck mechanic, and used to be a hot rod guy. I have always done any work on my boat right by the book, with all the right parts. I have always wondered why the big affection for running the engine coolant out the exhaust? It just always seemed to me like there would have to be an easier way, that would avoid the necessity for the big heavy (and expensive) manifolds. I'm sure some of you guys are getting a chuckle right now, but hey, I'm a car guy. I'm betting there's a quick simple answer that will make me say "DOH!"

Love your forum. After reading some of the threads on rebuilds i want to go finde myself a v-drive and turn into a kid again. Thanks.

 

[EddiePetty]

Re: A general exhaust question

........... I have always wondered why the big affection for running the engine coolant out the exhaust? ..........It just always seemed to me like there would have to be an easier way, that would avoid the necessity for the big heavy (and expensive) manifolds.

....the coolant out the exhaust is a cooling measure for the hot exhaust gases.
Remember, inboards and I/O's are usually trapped in an enclosure and thus no way to adequately expell exhaust heat. Plus, should the exhaust be 'dry', the danger of fire would be greatly increased (plus it's against USCG regs).

Even the thru hull exhaust are water cooled and usually with mufflers.

 

[Eric 3.7LX Alpha 1]

Re: A general exhaust question

Hello all,
I'm new to the forum. When I found it yesterday I couldn't leave. I just had to keep reading. You guys know your stuff.
.

Welcome aboard, HA your wife is gonna hate this site! It's like a drug. There ARE a lot of wise salts on here and all the different fourms you can go in. I personally like this one, electrical and resto.

Good luck with the new boat.

 

[Adirondack]

Re: A general exhaust question

....the coolant out the exhaust is a cooling measure for the hot exhaust gases.
Remember, inboards and I/O's are usually trapped in an enclosure and thus no way to adequately expell exhaust heat. Plus, should the exhaust be 'dry', the danger of fire would be greatly increased (plus it's against USCG regs).

Even the thru hull exhaust are water cooled and usually with mufflers.

Thanks. I wasn't aware that it was a regulation. I know everything cools the exhaust. I just couldn't figure out why even the performance boats had it. LOL rules are rules. But I can see how engine compartment temp could be an issue. I knew it was an easy answer.

 

[Adirondack]

Re: A general exhaust question

Welcome aboard, HA your wife is gonna hate this site! It's like a drug. There ARE a lot of wise salts on here and all the different fourms you can go in. I personally like this one, electrical and resto.

Good luck with the new boat.

Thanks Eric, I'm going to need it. I picked up an 87 Sunbird 195. A newer version of the boat I was running all these years. The difference is it has an Alpha I drive that's in good shape. Due to neglect the 3.0 block is cracked. I figured it would be a piece of cake until I actually tried to find a block for it. Can't find them. I tore the engine down, and it made me sick. It's brand new inside. The biggest waste I have ever seen. Letting a brand new block freeze. Now I'm wrestling with whether I want to try and stitch the block, or wait until I pull the old boat out for the season and canibalize it. Spending 3 grand to repower an 87 boat with new just doesn't seem smart to me when I have all the tools and skills to do my own rebuild.

 

[Bondo]

Re: A general exhaust question

Now I'm wrestling with whether I want to try and stitch the block, or wait until I pull the old boat out for the season and canibalize it.

Ayuh,.... Use your old motor in the new boat,...
Stitchin' a 3.0 usually isn't sucessful as the blocks are to light a casting...
Depending Exactly where it's cracked of course...

 

[Adirondack]

Re: A general exhaust question

Ayuh,.... Use your old motor in the new boat,...
Stitchin' a 3.0 usually isn't sucessful as the blocks are to light a casting...
Depending Exactly where it's cracked of course...

That's why I've been wrestling with it. It's a 9 inch crack that runs about 3/4 inch below the deck. No water getting in the oil, and the motor ran good except for the water running out the side. What I'm thinking is to do the stitch, then check the deck for runout. If it's still within planable specs I'd give it a shot. This motor is so new inside the only cost is going to be having it decked, and a set of gaskets. LOL time I got. It's another two months before I would even consider taking my old boat out of service to do the swap. BTW the boat is going to go. The motor you won't pry away from me for any money.

 

[Bondo]

Re: A general exhaust question

No water getting in the oil, and the motor ran good except for the water running out the side.

Ayuh,... Stitchin' it is gonna blow the deck outa shape,...
Clean it up, sand it,+ Epoxy it closed....

 

[Adirondack]

Re: A general exhaust question

Ayuh,... Stitchin' it is gonna blow the deck outa shape,...
Clean it up, sand it,+ Epoxy it closed....

Wise words. Gotta love that JB Weld.

 

[Doernuth]

Re: A general exhaust question

Since you have experience with engines get a block out of a car at a junkyard and do a requild with the marine parts from the cracked block.

 

[Adirondack]

Re: A general exhaust question

Since you have experience with engines get a block out of a car at a junkyard and do a requild with the marine parts from the cracked block.

If you can find one I'll buy it. They haven't been in automotive production since the late 60's.

 

[frank246]

Re: A general exhaust question

If you can find one I'll buy it. They haven't been in automotive production since the late 60's.

Even worse...the 3.0 Never-ever have been in automitive production.

 

[Adirondack]

Re: A general exhaust question

Even worse...the 3.0 Never-ever have been in automitive production.

I believe that block was actually a 153 ci. in the chevy II as opposed to the 181 ci. / 3.0 in todays marine application. I think Mercruiser did use the 153 ci. in early models as a 120 hp.