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G10 Sailboat Inboard ????
Topic Started: Apr 26 2014, 09:04 PM (747 Views)
sixtharmy


I'm blue-skying here.
Many sailboats have Universal Atomic 4 gasoline auxillary engines. These 4cyl carbureted 64 cu inch 30 hp engines were designed in the 1940's and went out of production about 30 years ago. As a result they are not particularly efficient and they are quite expensive ($2-4K) to rebuild. I know there are a number of issues in adapting any auto engine to marine use (brass freeze plugs, sparkless marine alternator and starter, back-fire arrestor, cooling and exhaust systems, etc.), but what I'm interested in knowing at this time is more general.
One of the big criticisms I've heard of auto engines in this type of application is that they're not built to handle heavy loads for long periods. The argument goes that typically car engines only see high loads during acceleration, then loaf along at a small percent of full load once they've reached a desired speed. It is further argued that marine engines (gas or diesel) are usually modified industrial engines incorporating heavy duty features (like 4-bolt main bearing caps) that make them better able to handle extended loads. However, I wonder if this criticism is applicable to the G10. The Atomic 4 at full throttle (30 hp) only operates at 3500 rpm and more typically cruises at 2,500-3,000 rpm. On the G10 these rpm ranges are around the engine's peak tourque speeds where presumably it can best handle heavy loads. In aero applications Raven Redrives operate at as much as 5,700 rpm and I would think that spinning a prop on a flying plane (even at lower cruising rpms) must involve a pretty high continuous load. Pilots seem to find the G10 reliable (you can't pull over on a cloud), and I think all of us would agree that the G10 is a tough little beast. What do you think (especially you fliers)? Do you think that the G10 could stand up to a marine conversion. Let the games begin.
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punkozuna
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Why not one these? 32HP, air cooled (no salt water conversion needed), continuous output. Brand new. $2200. Kohler has models up to 38hp. Briggs and Stratton also has large v-twin engines of similar displacement and (I assume) similar power.

http://www.jackssmallengines.com/Parts-List.aspx?mfrname=KOHLER&catname=Engines&subcatname=Horizontal-Engines&filter=264%3a999cc
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perfesser
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Elite Member - Former Metro owner

I may be showing my nautical ignorance here, but isn't diesel the preferred fuel for auxiliaries due to the lower risk of explosive vapors? I know that's what my sister has in her 41' sailboat.
Edited by perfesser, Apr 26 2014, 11:38 PM.
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punkozuna
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Actually, diesel vapors are more explosive inside the fuel tank. Gasoline vapors in a gas tank are too rich to ignite. Leaks outside the tank, the situation reverses. Gasoline ignites more easily than diesel.
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sixtharmy


punkozuna - Air cooled engines aren't generally used as auxillaries in sailboats. Heat builds-up quickly in the small enclosed engine space deep in the hull, and long runs of wave vulnerable large bore ventillation ducting is best avoided. Heat build-up is enough of a problem that inboard engine exhaust manifolds and exhaust lines must be water jacketed to avoid overheating. The ~$2K I quoted for rebulding an Atomic 4 would pretty much only cover parts and a little machining all labor would be mine. With my labor I can rebuild a G10 for ~$500 leaving ~$1,500 to cover necessary marine parts, exhaust, transmission adapter plate, etc. I just don't know if a G10 will tolerate being used to power a boat.

perfesser - Yeah, diesels are preferred, because of fire hazard and because they're more fuel economical. However, gasoline motors were commonly used well into the 1980's, and an estimated 20,000 Atomic 4's (out of 40,000 produced) are still pushing sailboats around 30 years after they went out of production. Parts for diesel marine auxillary motors are even more expensive than Atomic 4 parts. (Some people believe that the Swedes fund their pension programs off the profits from Volvo Penta parts.) However, the biggest problem I've seen with small marine engines (gas or diesel) is that rebuildable engines are hard to come by.
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perfesser
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sixtharmy
Apr 28 2014, 10:48 AM
Parts for diesel marine auxillary motors are even more expensive than Atomic 4 parts. (Some people believe that the Swedes fund their pension programs off the profits from Volvo Penta parts.)
Seems to me my sister did mention something about that ...
Edited by perfesser, Apr 28 2014, 11:59 AM.
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PTA2PTB
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I'm totally awesome! I swear.

*bump* :evillol

I'm still diggin' on this idea, I don't care what anyone says about why it's not a good idea, or why it "won't" work.
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poorman1


The Coast Guard law requires (for good reason) that that the starter, alternator,and distributor are equipped with Flame arrestors to make them explosion proof.

You can not have pressurized fuel lines to tank so that eliminates the fuel and return line. So you'd have to convert to a marine carb Or adapt a vapor separator type system off a I/B or I/O Or even an OB motor, I would install a xfi cam to get more torque at a lower rpm
You needn't worry about frost plugs just set it up for closed cooling with a heat exchanger
You'll have to rig up a belt driven sea water pump. Easily done where the A/C would go
Nothing above is all that difficult, But making the water cooled exhaust would be far beyond my abilities
Edited by poorman1, Dec 28 2017, 10:02 PM.
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sixtharmy


Yeah I pretty much gave up on the idea when I realized how difficult all the stuff outside the engine would be. As poorman1 said, you need to design and build a custom heat exchanger system with an extra pump, because you really shouldn't run raw seawater through an aluminum engine. Next, you need to modify the water lift exhaust, as well as a design and build a custom adapter plate to mate the engine to the marine transmission. In addition, the engine to hull mounting points would need to be modified. All in all too much trouble.
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PTA2PTB
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I'm totally awesome! I swear.

Yes, the problem of what to do for a custom exhaust mainifold/heat exchanger, has been my biggest impediment, too. It's a shame, as I think it would have been a good combination, taking advantage of the gas-sipping economy and light weight of a the 1.0l engine, that's rarely, if ever, been used in a boat.

Now if one had access to a foundry, and could use the exhaust manifold from a G10 for the inner portion of the mold, to cast their own heat exchanger manifold? :hmm

Maybe in a few years, as 3D printing gets more evolved, it will be possible to print one out of some kind sintered metal alloy?

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PTA2PTB
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I'm totally awesome! I swear.

sixtharmy
Dec 29 2017, 09:09 PM
Yeah I pretty much gave up on the idea when I realized how difficult all the stuff outside the engine would be. As poorman1 said, you need to design and build a custom heat exchanger system with an extra pump, because you really shouldn't run raw seawater through an aluminum engine. Next, you need to modify the water lift exhaust, as well as a design and build a custom adapter plate to mate the engine to the marine transmission. In addition, the engine to hull mounting points would need to be modified. All in all too much trouble.
Had I, ready and economical, access to one of these, off a 3 cyl Kubota, sure as I'm sittin' here, I would try and give it a go.

I can't imagine that the exhaust port ctc's would be that far different. Perhaps a 1/2" differential, at most; that could be easily corrected and connected to, with a, custom made, exhaust manifold connector manifold.
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sixtharmy


Yeah, I liked the idea and I also believe it would make a good boat engine, but I think the cost of the customization of the whole system would far exceed the cost of a newly rebuilt Atomic4 or a lightly used diesel. If I were to do the work it would be a purely shits and grins project. As it stands, it was most cost effective to hang a 90's era Yamaha 9.9 on the stern. I mean it is a sailboat. I only use the outboard to get in and out of the harbor, and if the wind's right I don't even use it for that,
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PTA2PTB
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I'm totally awesome! I swear.

For what little you need to run yours, fuel efficiency is not really a concern. As you may recall, from our Palooza campfire rap session, my (tentative) plans, would involve a thousand mile powerboat journey, down "the ditch". For me, obtaining the maximum possible FE, would be paramount.

What I don't understand, is why all IB marine engine offerings, be they gas or diesel, all appear to be constructed of, cast iron. These manufacturers do know that the craft must float, and that greater bouyancy of a craft, is a GOOD thing, don't they? Sometimes, I wonder. Why they can't come up with a lightweight, all aluminum, engine, completely escapes me. Thus my desire to repurpose a Metro engine.

The other option I've been researching, is going all electric. The cost of the Lithium batteries is the biggest drawback and impediment to that.
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