crystal ball

[ozbee]

i always watch with interest the 2 v 4 stroke debate as i own all three di ,carby and four stroke, while di and four stroke are a step forward in reality and efficiency as they both deliver there fuel either after the port is closed or valve closed it is no great step in technology as both have been around in engine design for over 10 years in other industries so you can only wonder who's getting all the money as we are definitely being ripped off good thing they don't run the car industry. as for the winner personally i think all of the above will fail in larger 100 hp above bracket you only have to look at new modern diesel engines like nissan navara. they rev like a petrol with the torque of a diesel. i would just love to attach a couple of these in a outboard con fig. imagine power , torque and fuel economy all in one ;D, maybe have to run it on bio diesel but who cares if you smell like a fish and chip shop:D

[Noelm]

think the biggest problem with a diesel is weight, people whinge now about the weight of a 4 stroke, but Diesel does have lots of plus features, like safe fuel as far as fire goes, engine life, no ignition problems (electrical that is) almost completely water proof, what more would you want from a boat motor?? speed of course!!!

[PADDLES]

it'll be very interesting to see in the coming years how long these new generation high revving, often turbocharged, light weight automotive diesel engines last in terms of engine hours. increased horsepower, pressures and rpm all come at the expense of reliability. there's some awesome diesel power plants coming out of europe these days with power figures similar to petrol. hell, le mans was won by a diesel powered car.

[ozbee]

i would reckon engine hours would suffer in these light weight engines but even if it was halved be still a long way ahead of the present four strokes also if you added a variable pitch prop, that would be the ultimate outboard.

[peterbo3]

I have a new alloy boat on order from Fisher & did the numbers on a diesel with a Merc leg. A 220 HP turbo Steyr was going to cost $35000 plus the extra costs associated with building the hull to suit an inboard motor. The difference for the motor/leg alone over an outboard was $16000 plus.
$16000 is a huge cost upfront with not a great deal of benefit at the pump. Allowing for the greater cost of diesel with the better fuel consumption, it would still take at least 15 years to come out square compared to a 175 HP Suzi based on around 100 hours use per year. This is based on fuel use alone.............repairs & services are not in the equation. If you are doing 300 plus hours a year then the numbers will change but you really need to be running a pro boat to afford a diesel in a smaller (less than 8M) hull.

[gone_fishing]

only time will tell with the increasing technology of deisel motors it is a mater of time before the technlogy is filtered into the outboard industry just as 4 strokes i guess
but power to weight is a killer at this time

[Noelm]

hey peterbo, what you are saying is true, it will take forever to recoup your initial outlay, but economy is not the only Diesel plus! there is the safety factor of the fuel, the almost complete water proof engine, a Diesel would technically run under water if the intake and exhaust was above the water (and the things like the dipstick hole was plugged) and the complete lack of any electrically produced ignition system.

[Noelm]

I kind of thought maybe LPG might come into it somehow, and not too sure why there is not more LPG inboards now, the few limitations should be reasonably easy to overcome, then of course LPG price might just suddenly increase if it was in almost every car and boat.

[BM]

LPG is worth pursuing again I think. It is viable for sterndrive and outboard (particularly the DI and 4 strokes.

I really doubt if diesel outboards will ever come out in large hp's (ie: to suit smaller pleasure craft). They are around up to about 30hp but very heavy.

[PADDLES]

g'day bm, there's a new range of high speed diesel on the market here in oz now. i can't remember where i saw them or what brand they were, i think it was maybe in a boating mag somewhere. but they were marketed squarely as a straight replacement for mercruiser powerplants i'm pretty sure they fitted straight to the mercruiser leg as well. they were quoting pretty much a 2 or so day turnaround for retrofit.

[dnej]

The trouble with turbo,is the wear factor.They run dry,and fast,and are subject to wear.And when one blows,a big repair bill.
David

[BM]

Hi Paddles. Yep, have seen what you are referring to but I was talking outboards.

Cheers :)

[PADDLES]

no worries, i agree, can't see diesel outboards ever taking off but crazier things have happened :)

[BM]

It could work on big commercial boats, work barges that type of thing. Sonething big and heavy enough to cope with the weight of a 150hp diesel outboard or 2 or 3... :)