Another idle contemplation -the 300 six "marinized" for watersport

pmuller9

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sdiesel":1cnap29e said:
is that the same hydro as earlier, one you sent me some years ago, the miss dairy?
and how did you pre heat the coolant?
do you have figures on the dry weight of that engine?
i recall the fuel management on that engine was tops with no surging or slosh on pretty rough waters
Yes it is the same Hydro that I sent you a while back, The Miss Merion Bluegrass.
https://www.missmerionbluegrass.com/

We regulated the coolant temp with 1/4" to 1/2" jets in the water line coming from the rudder pickup.
The water first split to the gearbox and oil cooler then to the engine and out the back of the sponsons.
The gear box and engine oil heat exchanger offered a little preheat.
Water pressure peaks around 25 psi.
We once made the mistake of restricting the water with jets at the exit point. The pressure peaked at over 100 psi and ballooned the engine oil heat exchanger.

Never weighed the engine but I suspect it was near 800 lbs.
Kirk built a special heavy duty engine stand just for that engine.

The 26 gallon fuel tank is filled with wiffle balls and the fuel pickup is in an open top box with one way flappers in the sides so fuel can go to the pickup but not out of the box away from the pickup.

As far as lakes in WA state we ran Spanaway lake, Black lake, lake Chelan, lake Coeur d'Alene and several places along the Columbia river.
Other APBA events in WA are help in Silver lake, Angel lake and lake Lawrence.
 

sdiesel

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So in a marine application short of full on racing, the incoming coolant temp should be as close to operating temp as possible? Like 195 or so?

In a pleasure craft / tow boat that will see a ton of idling and low pre plane time,a closed system with heat exchanger or some valving to allowed cool water in and hot out might work. I've been told by persons affiliated, that much of the short life reputation the 351 has in marine application is due to inadequate cooling and excessive idling.
Not sure on this though
A " hood scoop" would aid induction mightily

Yes to the water pump driven by the snout pulley thx fer verification.
That engine looks very heavy....
 

guhfluh

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sdiesel":1n9szt64 said:
So in a marine application short of full on racing, the incoming coolant temp should be as close to operating temp as possible? Like 195 or so?

In a pleasure craft / tow boat that will see a ton of idling and low pre plane time,a closed system with heat exchanger or some valving to allowed cool water in and hot out might work. I've been told by persons affiliated, that much of the short life reputation the 351 has in marine application is due to inadequate cooling and excessive idling.
Not sure on this though
A " hood scoop" would aid induction mightily

Yes to the water pump driven by the snout pulley thx fer verification.
That engine looks very heavy....
I don't understand the problem? Marine engines use a thermostat in the cooling system just the same as all others. Heat exchangers take the place of radiators. Raw water is unrestricted and constantly circulated. Antifreeze/coolant flow is regulated by temp. Unless you're wanting to just go with a fresh/raw water only system, then heat exchangers are foregone but thermostats are still utilized and everything rusts away... :LOL:
 

sdiesel

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No, I'm trying to say with little success that the engine cannot use unheated lake water for cooling...

Actually asking
Can unheated water pulled up be used without preheating?
 

guhfluh

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On the marine engines I can remember working on, everything had the exhaust cooled last in the system. The engine coolers were the first to receive flow. On a freshwater only system, I'm not sure, as I've only seen a couple maybe. I see no difference than in a car with an oversized radiator and thermostat.
 

pmuller9

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Lazy JW":13i3qkzo said:
pmuller9":13i3qkzo said:
...

As far as lakes in WA state..., lake Coeur d'Alene ...

Ah, snuck over for a quick run in Idaho, eh? :cool: :nod:
Yep, you caught us.
Even though they put barges outside of the course the water was still rough enough to damage several flat bottom boats.
The flat bottom of our boat pushed up into the engine flywheel and cut a shallow groove in the wood.
Others in GP class cavitated the props and did engine damage.
It was an interesting weekend.
 

sdiesel

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If the 300 were put to use in this application I would start with carburetor , a quadrajet for sure, and some fancy ignition/ timing.
It would be a small step up to fitec, with a snorkel type
boat scoop isolating the carb from the engine.
Edis 6 with MS maybe and a long block with the magic numbers whatever they would be to give me huge torque down low.

Another favorite fantasy of mine is a power glide ...but that is purely fantasy autos have had limited success in marine applications... But this is my fantasy boat, what the heck!!?
The plastic would be a gekko 20gts, cause they are cheaply made and light and sexy as hell in the water.great lines
 

pmuller9

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sdiesel":qquwuk0x said:
Edis 6 with MS maybe and a long block with the magic numbers whatever they would be to give me huge torque down low.
I would think that you would want huge torque from 2000 to 5000 rpm and operate mostly at 4000 rpm for long high speed runs?

Boat props are usually geared high than the engine rpm.
 

sixtseventwo4d

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sdiesel":30mq0rl0 said:
No, I'm trying to say with little success that the engine cannot use unheated lake water for cooling...

Actually asking
Can unheated water pulled up be used without preheating?

It would negatively effect engine longevity, engine heat transfers better to warm water.
 

sdiesel

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4000 or less sounds right.
Boats today may ,or should have gps.
A good boat drivers in my youth on lake shasta was the difference .
He was priceless.
All day he had to make pass after pass sometimes 40 times or more a day. Using 2 airguide speedos and calculating by eye the average difference between readings to get precisely 26 mph or 28 or whatever the
Pass called for. And he had to do it perfectly every time, calculating the many different body weights of competitors, skiing style, windage, water conditions, even temperature.
He had to know his boat.
This was compounded ly more difficult if the boat was twin rigged or triples cause he had to manipulate two hand throttles. tracking , pitch and yaw, as well as cavitation ( trim) could cause a competitor points. And the boat driver would hear about it.

With the inboard this was made easier because weight of boat, single screw and the response of an auto v8 was a bit more tractable that two high strung 2-stroke outboards.

But obviously a high torque low rpm engine with long stroke would do well at this. I remember 30 or 32 being top speed in competition.
So nothing fast just grunt. And do it all day long.
I never understood the boating worlds fascination with the v8
The six , properly built would hunker down , draw a breath of air and pull like an elephant, I believe.
 

pmuller9

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sdiesel":fqgdu4pf said:
But obviously a high torque low rpm engine with long stroke would do well at this. I remember 30 or 32 being top speed in competition.
So let's look at the 300 six.

A naturally aspirated 300 six can muster up between 325 and 350 ft lbs of torque at sea level.
The rpm at which that occurs depends on the engine configuration.

If you are looking at making those numbers at 3500 rpm the head will need the usual big valve and port work modifications along with a cam profile to match.
So lets say you want to push the 300 six to 300 ft lbs at 3500 rpm. That is equal to 200 hp
If that is enough power to get the job done then then you are good

If you need more then that at a low rpm it is time for a turbocharger.

Two great things about using a turbo.
The torque at any any given rpm is no longer fixed and can be varied to match boat drag.
The engine becomes more fuel efficient.
 

JackFish

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Mercury and OMC used straight six engines a lot for their inboard/outboard drives.

Our 21' Starcraft was usually cruised between 3000 and 3500rpm, and would max out just over 4000.
165hp Chevy engine in that one.
 

sdiesel

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I did have some trouble locating torque spec for the 351 marine app. Seems most boat owners or shoppers are mesmerized by HP numbers thus tq numbers fade from view.
The 351 was a 240- 310 hp engine and forums report a run rpm of 4800. I'm going to guess that v8 delivers 265 - 300 tq...

Thus assuming that diddly research holds across many different boats , we can assume that a well built 300 can out pull a V8 and do so more efficiently at a lower rpm.
With less weight, heat, fuel consumption.
To add a turbo would be delicious. Unsure if the USCG would allow, but I sure would.
Thus and finally I am going to surmise that an inline is a worthy competitor for a tow boat offering advantages a V8 cannot, and no drawbacks.

The enhanced fuel efficiency you refer to Is picked up through steady speed operation? Of a boat?
Realizing a turbo increases the efficiency of an engine, it has been my observation that most turbo engines actually consume more fuel.
Of course I cannot factor improper combination of parts , or poor tune or simply driver enthusiasm. All of them will cause poor fuel consumption numbers that I've heard about with turbos.

Sure would be a fun project if a lighter eight tow boat with a bad engine were available. I see no reason a six would be inferior and the obstacles to making it suitable for marine use could easily be overcome
.
 

pmuller9

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Looks pretty strict.
https://www.usawaterski.org/pages/divis ... Manual.pdf

The turbocharger takes some the exhaust energy that would have been wasted and returns that energy to the engine.
A naturally aspirated engine has to work against intake manifold vacuum to draw air fuel mixture into the cylinder which is seen as a pumping loss.
The turbocharger instead pressurizes the intake manifold which pumps the piston downward during the intake stroke like a mini power stroke.
The pumping losses are replaced with power derived from the exhaust system.

Unlike a road vehicle that can spend a lot of time cruising without boost, a boat will spend most of the time under boost to take advantage of the energy recoop.
Here the boat is being driven the same whether naturally aspirated or turbocharged so an efficiency comparison may be accurate.
When adding a turbo to land vehicle the driving habits usually change and the right foot gets heavy.
 

sdiesel

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I'm sold , turbo it is!!
And would look wildly cool if ever a glimpse of such a power unit were to be seen..

Above someone said that warm water transfers heat more efficiently- this I did not know.
So the captured warm water in a ski boat, would require some fancy engineering to make best use, including , I suppose a water-cooled turbo.

As for tow boat testing- yes very strict even back in my day.
There were three
Correct craft ( ski nautique)
MasterCraft
And
The mighty hydrodyne.
These were sanctioned boats with the "Dyne" being superior to the others for any number of reasons.( Unbiased opinion), but eventually losing out to the popularity of v8 power and cost.
Today's Dynes, are custom built boats one at a time , the company is long gone , but the design is perfect for the application
In the literature concerning the " Dyne" :
I like reading the spec.for maximum rated power.
It says " unlimited" that tickles me. And indeed there is some gossip about mounting 3 Merc 400's on a Dyne

We would try at 26 mph to make a twin rig boat to turn 180 degrees within its own length, a good driver could.
 

Firepower354

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There's a big-ole-log 300 marine manifold on the 'Bay for $1000. Egad

A Holset/Cummins marine water jacketed turbine housing should size up easy enough

I haven't been in the belly of one lately, but unless there's room to move the bellhousing flange rearward, the balancer is going to run in to the ski pole.

I think the 34mph at 4000rpm is close to what they do, but prop mods can alter the "gearing"

I don't see a chance of running a non-jacketed exhaust in the confines of a ski boat. Too much heat.

I may have skipped that day in thermodynamics, but I'm struggling with the warmer water cooling better. Now, TOO cold, which I think happens in some freshwater engines, leading to excessive wear, I'm onboard with.

The lower weight of engine, manifolds, risers, etc, should be a bunch, but on a 3500lb boat, it's not likely to matter
 

sdiesel

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To fit a turbo six would require some intelligent engineering.
The pylon could be moved easily enough , and not upset the placement balance.

I woul ask about cool water injection to exhaust to control temps a wrapped turbo, and the exhaust wrapped also

It would be invasive swap.
Stringer modification cuts the floor up to make room.
Not huge problem but is part of swap.

Many older boats I might consider for this swap need new stringers anyway.
New motor box
Yikes ! 3500 pound boat, that's a ton. Actually it's getting nigh onto 2 tons!!
I had no idea they were that heavy.
 
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