new, lightweight diesels with small footprint

[Sortie]

from my reading of recent Soundings articles, there's a new generation of lightweight, quieter diesels with small footprints.

I'm not in any rush, but I'll eventually re-power my boat with a small diesel. The Yanmar 190 has been recommended by other Tripp 22 owners...any other powerplants come to mind?

p.s. why are Volvo diesels so dam' expensive?

[Mistress]

Because Sweden's taxes are so high.

The trade off on lightweight diesels is typically reduced longevity. Most marine diesels come in various horsepower configurations. The higher the horsepower the lower the expected lifespan. This is also expresed in the "intended use". A higher hp unit may get a pleasure rating while a lower hp (same block) will get a heavier duty rating (commercial, working, etc.). Everything is trade-off.

[fisherofmen]

I think the rule of them is 1 HP for each cubic inch displacement and this will give you long service life. One you exceed that, you are into the "high performance" diesels which compromise longevity. My old 190 yanmar was 210 cubic inches therefore on paper it should have a long service life. My new 300 yanmar is probably something like 250 cubic inches and therefore the service life would not be as long as my old 190. Who knows, the boat will be bought and sold 4 time before the engine wears out anyway. My 2 cents

Rick

[Mistress]

The "rule" I've heard for diesels is hp per pound. I don't remember the numbers though. HP per cubic inch, I've always attributed more to gassers. I think I'm safe with 1/4 hp per pound and 4/7's hp per inch. ;-)

[palmer1]

Sortie,
Just thought I might chime on your "Why are volvo diesels so expensive question." The Volvo Diesels are Fully electric and common rail. A much more expensive system. Cummins has a Common Rail system as well in there QSB series. Very expensive as well. They also have a compromise electric controlled Diesel that is not Common Rail. That is a little less expensive but still more than a Mechanical Diesel like the Yanmars. The bad news is that Diesels will all be expensive like the Volvos in less than year. In the 2007 model diesel engines in recreational power boats will be required to all meet much more stringent Environmental requirements. Volvo is a little a head of the curve right now so they look pretty expensive right now. Cummins has been working on the QSB series so they are ready for 07 and can work the kinks out prior to having to be 100% common rail and electric. The common rails are really nice but some of the manufacturers are working through the transition and have had some issues with their systems. I do not have alot of info on yanmars plans and have been meaning to talk to them about there plans. This is probably more of an explanation than you were looking for but this is another environmental protection that will affect boaters pocket books. Hopefully they can get the prices a little more affordable after all of the manufacturers are building more common rail stuff and the competition is a little better. I hope this helps.

[scoffshore]

I'm not sure about that one mistress.."The higher the horsepower the lower the expected lifespan" I wouldn't neccisarily say that that is true, if you were going to make a comparison like that you woluld have to speak about higher RPM's lowering the lifespan, not the HP. If that were true, most of the large ships you see running around wouldn't have engines that are over 20 years old and run pretty much everyday, except for routine maintenance. I have a 1969 Grand Banks that came over from the far east on it's own bottom, and still has the orginal engines in it, We have no problems with the engines themselves, but with the other parts of the system. Typically running a larger HP engine allows you to run at a lower RPM and still maintain the expected cruise, while sometimes even reducing the fuel consumption, believe it or not. the only downside, is the increased weight!

[Mistress]

Perhaps my comment was incomplete. When given the same block and more hp is expected out of it, the trade-off is forcasted lifespan. Look at any of the mfg's and see the different outputs and their use ratings. And yes...the highest outputs come at increased rpm and are strictly pleasure rated.

Going to a bigger block (displacement and weight) then you don't lose durability (and often gain). Is that Grand Banks running Lehmens? If so, they are massive motors for the somewhat minor output and are slow revving. 5000 hours is just broke in.