Diesel IOs?

[ted655]

Are there diesel engines that can bolt to existing outdrives when the original gas engine wears out?<br />OR...<br />Are there rebuilt diesel complete IOs that can be installed?<br />Thanks

 

[Bondo]

Re: Diesel IOs?

Both Mercruiser,+ Volvo have been building Diesel I/Os for Years..........

 

[tommays]

Re: Diesel IOs?

The price is kinda of SHOCKING makes the normal prices seem like a bargin <br /><br /><br />tommays

 

[ted655]

Re: Diesel IOs?

How shocking?<br />Who boughr rgem? We are looking at buying a used houseboat and it seems they ALL have gas IOs.<br /> Where do I look for diesel? Was there a type of boat that used the diesel IOs more than another?<br />Not finding anything "used" in my Google searchs. I'm probably not asking the right question.<br /> Thanks.

 

[tommays]

Re: Diesel IOs?

Well on a New 25 ft Searay the diesel is a 21000 dollar option and thats not a real big diesel<br /><br />tommays

 

[Gary H NC]

Re: Diesel IOs?

With the price of diesel being so much more than gas,why want one? I guess it would last forever if serviced properly..

 

[jlinder]

Re: Diesel IOs?

$21,000 ??? Does anyone know why it is that much? <br /><br />Why would a diesel cost so much extra?

 

[ted655]

Re: Diesel IOs?

Aside from not blowing the boat up, not worrying about electrical mishaps, I guess the longer life is attractive. Reliability is a bg plus. Fuels can't be compared equally. There is more heat (power) in diesel, so mileage per gal. is greater. Torque is greater and the power band is flatter.<br />That being said, oil is more and water seperation more important. I wonder if maintaince might not be a bit higher. THEN, there is that 21K initial cost above gas. Ouch!<br />Why the xtra cost, well we pay more for less here. Sugar free cookies, salt free crackers, fat free chips and spark free engines. Its the American way.

 

[Bondo]

Re: Diesel IOs?

I met a fella from Clayton that refitted an Old Town Atlantis hull, just like mine,...<br />With a 4cyl. Volvo Diesel,+ the Duo-prop drive,... All New, 2 years ago,+ the Motor Alone was Over $13,000.00..........<br />He claimed the the price of Fuel down the the Caribbean Islands was Worth the Difference......<br /><br />I'd Love to drop in a 7.3 Navistar/Merc. V8 Diesel into Mine,.......<br />But,.... As you're finding,..... Used Parts are Very Hard to Find,..... And I'm Toooo Cheap to Buy New........

 

[lilmandavis]

Re: Diesel IOs?

no need to find used parts for diesel!.. a diesel properly serviced. will outlast a gas engine 5 or more times... id love to have a diesel.. instead, im feeding a 460. and getting used parts... lol. i wish i would of just made my ol lady real mad at first. cause she would be real happy now. cause we would be on the boat instead of fixin it....lets see...21k? im at 15k now. i wonder how much more than 21k ill be spending...........and looking forward to something else happening !!!!! but im stuck with gas for now.. good thing i got the thing for free

 

[ted655]

Re: Diesel IOs?

In case you win the lottery.<br /> http://www.cmdmarine.com/recreationalsterndrives.html

 

[whywhyzed]

Re: Diesel IOs?

I suppose with a diesel transplant, it's just a case of finding water cooled manifolds, some sort of bellhousing, and the right ratio gears?<br />Or are the Merc and Volvo drives built differently? (more than just diesel ratios)<br /><br />All the electrical spark protection not an issue....?

 

[ted655]

Re: Diesel IOs?

My concern would be the higher torque and lower unit damage. Kinda like when Jr. drops in that bigger V8 and trannys, drive shafts and rearends start mysteriously failing.

 

[Bondo]

Re: Diesel IOs?

no need to find used parts for diesel!..

What I'm talking about is,.....<br />I've already Got 2 Engines,.....<br />I Don't have a set of Water Cooled Manifolds,.. Or a Water Cooled Turbo,... Or Any of the Other Marine Parts,....Flex plate, bellhousing, Motor Mounts, Etc...<br /><br />IF I Did,..... I'd be Building a 7.3l Diesel,... Instead of a SBC.......<br /><br />Nor do I have the Bravo Drive to make it Work.........

 

[lilmandavis]

Re: Diesel IOs?

what did those navistars come in bondo? what ratio do they need. there are several bone yards down here with all kinds of hurricane damaged boats. im looking to find this stuff. didnt don say that the bravo will bolt up to the transom that a cobra was on?? in that other diesel discusssion i started a while back?

 

[Bondo]

Re: Diesel IOs?

Ayuh,.... The Mercruisers,.. The Later OMCs,+ Most of the Later Volvos All use the Same, or Nearly the Same Key-Hole Cut-out in the Transom.....<br /><br />Mercruiser used the 7.3 Power-Stroke,+ the 7.3l IDI motors in front of Bravo drives......<br />I'm not at all sure What ratio is Needed,...... I know the motors run to 3750rpms....<br />If I could find a Blown, or Frozen complete Motor,...... I'll just Wing It for the Drive, for now......<br /><br />I'm Not sure if anybody else used them or not......

 

[bigbrownbuku]

Re: Diesel IOs?

Originally posted by tommays:<br /> The price is kinda of SHOCKING makes the normal prices seem like a bargin <br /><br /><br />tommays

cummins/mercruiser are in the process of releasing to the market drive/diesel packages that rival gas.<br /><br />visit a cummins mercruiser dealer and at least ask about it.

 

[tommays]

Re: Diesel IOs?

You can get the new 120 HP cummins/mercruiser in a Trophy 2052 Walkaround its only 8000 more than the base motor and 2000 more than a 220HP FWC 4.3 MPI motor<br /><br />I am scared to think what a 220Hp diesel would cost<br /><br /><br />I think you way off on engine life,in my useage like sking and barefooting non-stop on a 1975 correct craft the orginal motor lasted until 2003 and it was not totaly dead it was just time to repower<br /><br />And we have plenty of motors that have lasted that long in the ski club<br /><br />IF you DONT allow water in a gas engine they last a REALLY long time its gonna be pretty hard to go 5 times 28 years <br /><br /><br />And most of these NEW diesels are HIGH SPEED and LIGHT WEIGHT and spinning over 4000 RPM <br /><br />Thats really not a good plan for a really long life compared to and old heavy diesel that probley never turned over 2200 RPM which is why it lasted forever <br /><br />And at this point qualifed marine diesel techs are few and far between<br /><br /><br />tommays

 

[QC]

Re: Diesel IOs?

tommays is correct on pleasure craft gasoline engine life. However, I would say that newer high-speed diesels will still outlive a spark ignited engine of any vintage.<br /><br />Although ted is correct that diesel fuel contains more energy (BTUs) per unit volume, the major contributor to better diesel efficiency is the lack of an air intake throttle. The higher peak torque output of a diesel engine is well known, but in a marine application, especially on a displacement hull like a Houseboat, the higher torque will not get you anything. Some advantage in a planing hull, but pretty minimal unless the boat is underpowered to begin with. Prop load curves are almost perfectly linear and do not get near the peak torque values associated with better lug-ability in a wheeled vehicle. Without hills and/or higher gears to get the engine into a lug condition, peak torque just simply doesn't come into play. However, with that said, I would be somewhat concerned about the drive unit as you would either need a bigger wheel to transfer the lower RPM power or a higher numeric drive ratio. The combination of higher torque output against a higher gear ratio or a higher pitched prop or both could potentially lead to shorter drive life. This would be especially true if this setup exceeded design torque input at cruise speed.<br /><br />I also believe that there is no case where a diesel engine will get a financial return on the additional investment in a pleasure craft application unless you factor in higher resale value. Let's assume that a 200 bhp gasoline engine is used for 100 hours per year at 6 gallons per hour at cruise. Let's be especially conservative and use $3 per gallon for both fuels. Let's also assume that we get 33% better fuel efficiency over those 100 hours for the diesel (6 gal. per hr x 100 hours = 600 gallons of gasoline). With 33% better fuel efficiency we will only use 400 gallons of diesel for a savings of $600 per year (200 gal. saved x $3/gal.). It would take over 16 years to get a return in this example if the cost was a conservative $10K ($10K / $600 = 16.7 years).<br /><br />I think proper maintenance costs will actually be higher unless you extrapolate this out to overhaul which if maintained properly does not come into play for either example except maybe for your grandkids <br /><br />I love diesels. I have lived with them every working day for almost 30 years. I would want one in a large boat as well. But it is an emotional decision, not an economic one. Without the safety discussion, theoretically, you would be light-years ahead by putting that cash into the stock market plus you still have the $10K, so that negates by a bunch the resale benefit . . .<br /><br />Edit: All of this goes out the window if you are Bondo and do it McGyver style

 

[rodbolt]

Re: Diesel IOs?

most boat fires I see here are diesel.<br /> most are cased by not keeping the engine cleaned of waste fuel and oil taht accumulate then the water pump or exhaust elbow fails and the manifolds get hot and poof.<br /> that being said, saltwater cooled is salt water cooled here, only difference is you think that merc 260 riser is a honker buy one for a cat or a kad42 volvo.<br /> let that same riser fail and dump water into a cyl and you will see how fast a diesel can self destruct.<br /> usually catastrophically.<br /> diesel does not like water in the cylinders.<br /> at idle a diesel has a lot of speed up/slow down on the crankshaft due to its compression and idle characteristics.<br /> most clutch dog drive dont like it, Volvo developed a special Nedox cone for it.<br /> If I was running an offshore boat over 30 ft with inboards diesel would be the only way to fly. in a small boat they are a waste of time.<br /> diesel fuel systems typically require more maint than gas, but ethanol may bring them about even.<br /> if you have never fought algae in the diesel tank, especially after long storage and a biocide treatment you dont know what fun is.<br /> my uncle ran a six cyl Izuzu for years in his crab boat, parts were very very expensive.<br /> and turbo's require special treatment in a small boat, took two turbo failures for me to convince him to install a cold start accumulator setup for pressurizing the turbo bearings before starting.<br /> first turbo failure was about 1600, second was almost 3800.<br />second one fed metal into the intake manifold while running at 1800.<br /> while diesel is nice and has applications, I dont see any in the small boat world.