7.0L EFI or 7.3L PSD for jet drive boat

Alright I know I am opening a can of worms here but what the hell can I lose. I will have to explain a little about my situation first.
-First off I live in the arctic so summer time temps on the water are extremely cold in the range of -5 to +5 give or take, water temp has to be above -4 seeing how salt water freezes at that temp. If it is above that temp it won't be by much.
-My available boat choices are a 22' or a 24' Lake Winnipeg Fishing boat. I can't elaborate on them too much right at the moment due to them being buried in rock hard snow. I do know they are thick FRP and have a rounded bilge hull with a fairly flat bottom. Transom dead rise ? (maybe average the boats are setup for outboards). Weight of the hull ? I will be making a phone call to the manufacturer to find out more of the particulars.
-I have at my disposal a 19?? 7.0L EFI and a 2003 7.3L Powerstroke.
-Either motor that will be used will have dry exhaust (the added heat is a big benefit).
-I really want to go jet drive due to our 30 whatever foot tidal fluctuation. Rocks have a tendency of jumping out and biting outdrives and outboards. Ask me I know our dump here is full of haha liquid cooled lower units.
-Now for my question if you had the choice and it was free for the taking would you go 7.0L gas or the Power stroke for a jet boat.
-I don't even know if these hulls are a viable choice for the use of a jet. And the choice of appropriately sized jet would be a whole other can that would have to be opened. Just asking any opinions will not be disregarded Oh one other thing to consider the shipping on a jet drive will be substantially cheaper than an out board or even all pieces of an out drive. Everything here is flown in. Also economy isn't a major concern, its a boat for Christ sakes, not a Ford focus. I'm not going to complain about it the two types of fuel are almost the same price here.

 

I'd go for the Powerstroke hands down, provided the boat can take the extra weight. Have installed three of those in workboats, one was coupled to a Rolls/FF 240 jet. The rpm range of the diesel suits the requirements for a jet better than the gas engine.

 

I have been doing some searching for suitable jet pumps. And the Hamilton Hj241 seems a really good match to the diesel. The only thing I don't like is not being able to find any prices of said pumps. I was also looking at the American turbine pumps I like how they aren't afraid to show some prices. But I am not sure if any of their products will suit my needs. I guess I am going to need some more info on the boat first. weight is probably going to be in the 5-7000lb range there are a couple of the boats here in town that are being pushed pretty good with a single 90hp outboard, up on plane and cruising pretty good. Nothing too fast but very usable. I would go that route but I want different and a diesel.....

 

Never mind my last comment about the 90hp motor I was just looking at a 24' with a 60hp 2-stroke OB on it. That tells me the hulls push through the water fairly easily I want to get some measurements of that boat tomorrow and I will post them here. LOA, LWL, BEAM, BEAM at water line(the hull has a nice water line stain on it) and transom dead rise. Now these measurements will reflect the weight only a sixty hanging off the back and I think they are in the 225-250lb range. there is a lot of freeboard on these boats, so I think the 1000lb motor and what ever a complete jet assembly weighs shouldn't be an issue. I want to try reaching the manufacturer tomorrow and hopefully they can give me the weight of the hull and the displacement. Now if I have to, can a jet drive be driven via a drive shaft if I have to move the motor farther forward to balance the boat. These boats are an open boat so there is nothing in my way.

 

I Just emailed American turbine for more information on their jets and Lake Winnipeg Boat Works for specs on their boat hull. Hopefully I hear back from them soon.

 

atkmboyd, Read these postings!!!!! backmo, on this panel was very helpful to me. AT are mixed flow pumps NOT axial. I asked AT some questions and for some performance data and they ignored me after that. backmo gave me info about what too ask them. Be careful. I do not like to be ignored if I'm going to spend 3, 000 bucks +++. backme is a Hydrodynomics expert.
http://www.boatdesign.net/forums/jet-drives/max-engine-rpms-jet-drive-47831.html

 

Well I just got an email back from American Turbine and they said that they do not have a pump that is well suited to the low end power that a 7.3L diesel makes. Oh well guess I'll keep searching for a suitable pump. From what I have been reading the HJ241 is the best match. Now a question about engine upgrade and pump compatibility can you make more and more hp and torque (you know how easy it is to do now a days with a diesel) and still be able to match an impeller to the upgraded hp and torque. Or do you have to stick with a motor's hp and torque and pump arrangement, I know there are different impellers for sale but are these for tuning a set , set of variables of a known power output, or can theses be used to upgrade a pump when extra hp and torque are applied to it. I don't know if any of my questions make any sense I am still learning so please bare with me. I am still trying to figure out the difference between a mixed and axial flow pump. From what I am understanding an axial flow is better suited to the low rpm torque of a diesel engine. The thought of being able to get full thrust from a jet at or around a 7.3L torque peek makes me giddy with excitement but is an 800 or so rpm power band usable in a jet. Meaning idling at 7or 8 hundred rpm and full thrust max boat speed at 1600 rpm is that doable with such a short rev range it seems like the boat would be like a high strung 2 stroke either on or off light switch kind of reaction. Sorry for being long winded. Thanks...

 

Oh also does any one know a price range that the hamiltons run in. I don't want to jump the gun here I still have to figure out if my hull is compatible for a jet. It was easy to see on American Turbine website the prices are there to see but I am always hesitant when a manufacturer does not show their prices, usually that means it is out of my price range.

 

I would call Hamilton and discuss the 241 as their specs suggest a high rpm diesel engine, Volvo, Steyr, Yanmar etc. We have installed the mixed flow Berkley, American Turbine and found that they work well but cannot digest foreign items such as weeds or rocks in the intake without causing cavitation and loss of thrust. I would not use them for salt water use. They are so sensitive to such a small bit of debris, such as a 1 inch round by 2 inch stick, that most boat manufacturers offer Easy Clean Grates to enable a person to clean the grate from inside the boat.


We then tried Kodiak axials, a copy of the Hamilton 3 stage 777 and found a big difference in hole shot (350 and 454) economy and the ability to handle debris.

The 3 stage became extinct with Hamiltons 212 which became our popular pump.
The 241 is bigger but you need to know if you can run sustained high rpm with your diesel.

I would not try to move the engine forward to "balance the boat" with a 7 foot chine width and 12 degree deadrise, and 80 gallons of fuel at the transom, we mated the engine to the pump with the short coupler. Of course we had hard chines, will be much better than round chines

A dry exhaust will be an issue if you put a cover over the engine. The bigger issue is the fact that the gas engine is not marinized by which I mean that the starter, alternator, air intake will not be spark arrested which can cause a problem in any boat.

You really need to get a commitment from any pump manufacturer about the thrust ability of trying to match the peak horsepower of your diesel at a low rpm

 

After doing a little more thinking about the project at hand I am starting to think that the 7.0L gasser might be a hole lot easier to make an affective jet boat out of. With it being a 429 f700 truck engine duty rating should be high enough and I believe it will be a nice boat motor after it has been marinized. All marinizing parts for the 429 are readily available. Good high flow wet or dry exhaust or water jacketed manifolds, carbs, starters and flash supressors as well. I also think a stand alone wiring harness will be much more available or even easier to make than the one for an 03 PSD. Plus there will probably be a lot more jet pump choices to choose from. Fuel consumption is going to be much steeper than the diesel though. Any thoughts on the matter I am still no convinced either way of which motor is going to be better. Oh the weight savings will be an added benefit to the gas engine as well. Keep your opinions coming guys I really appreciate them.

 

You will find that marinizing components are very expensive and sometimes it is just about as cheap to purchase a marinized engine if you shop hard. Try Kodiak Marine as they offer various engines to mate to a pump. You will save enough going to a 212 matched to say a 5.7L as compared to a 241required for the diesel to make this feasible. Go EFI, and mate a 212 to it and it will drive your boat well. Due to the possible freezing conditions, consider the freshwater cooled version so you do not have to worry about draining any water from the block in the winter time if you have antifreeze in it. Need heat, there is a take off and return port to hook up a hot water bus heater.
Let them know what pump that you are going to use and they can supply the factory coupler and mounting system and a set of 4 inch exhaust port. Perhaps they offer Hamilton now.
In the past with carbed 5.7 and carbed 7.4L we did not find any fuel consumption differences when we matched the impellers with the engines. With our 21 footers, we would get 3.7 miles per US gallon with both but the 454 would give us the same miles per hour at 2800 rpm while the 5.7 would need to turn about 3300 rpm. (30 mph)
The new EFI's are better than the old 5.7.

I am not sure how you would hook up the intake to the fibreglass, as we used welded in aluminum intake blocks for pump mounting.

The floor will have to be very stiff as you do not want the floor to flex, causing the pump and engine to lose concentricity with more loading put on the ujoint coupling

 

Something I have been thinking about is there are no trees here so sticks are not an issue. The rocks are van sized so there really isn't an issue there. Water is so cold not much vegetation. But the one thing is ice early spring there is quite a bit out there everything from building sized ice burgs to snow flake sized crystals. How well will a jet drive be at digesting ice. I guess if all else fails I'll just bring some tequila out and make margaritas for everyone.

 

For engine longevity- the 7.3 PSD should outlast the 7.0. I imagine in terms of hours at full power, it might last a LOT longer than the 7.0.

They are heavy- 920lb for the engine. The earlier models are quite loud in terms of combustion noise, but an 03 should be better. With fresh glow plugs, starting at 30 F is fine.

The earlier non intercooled models are lower power, but don't need water for an intercooler.

Diesel fuel is far less likely to explode in the bilge, and doesn't contain ethanol to rot injectors. The 7.3 has a ~15 quart oil sump. A good thing for a hard running engine.

 

I have owned both a 1988 7.3idi with the banks turbo kit on it. That motor is now rebuilt, tweaked and stuffed in my dads moose hunting school bus. I think it's the fastest bus around in his area. A 1998 PSD 7.3 and than the bad child 6.0 PSD. Once the head studs,egr delete, exhaust and intake was installed on that motor I would drive it anywhere with confidence. I love the PSD but I don't think I want to invest that much money into a jet to match the power curve. I am thinking it will actually be much cheaper, jet wise to go with the gas motor. Shipping a marinized motor here is not an option, the price of shipping would be deadly. So a DIY is the only option. I have been checking the part prices for it and it isn't that expensive at all 1000$ for a boat exhaust I paid that for a turbo back on my 04 SD with the 6.0. Starter and alternator, I would want a new one anyway the truck that has the 7.0L in it has been siting for 5 years now. I just bought the 22' boat with the sixty on it today. 2500$ was a steal with a running 60 motor, a parts motor and the hull with a fresh cabin built on it.

 

I took some measurements of the boat today seeing how the manufacturer does not want to get back to me with my requests. The 22' is 22' OAL, 21' at WL, 77" beam and the beam at water line is 70" I did not measure transom dead rise but it looks around 10* or so. There are three ribs on the bottom of the hull the middle one runs from the front to about six feet from the transom and then there is two outboard from that one starting at transom and running about 6-8' forward almost looks like the hull wants to be jet powered. I will get some pics tomorrow and tell me what you guys think as I said opinions are appreciated for or opposing that's how problems are solved.