Light Loading of Diesels -- How Harmful?

[a64pilot]

Originally Posted by Wotname

Your .02 makes a lot of intuitive good sense

Yes it does, restricting airflow on the exhaust is just as if not worse that one the suck side,
Use a blocked exhaust elbow as the example.


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[GrahamHO]

Originally Posted by Dockhead

Yes, I've noticed some differences in smoking, using different fuels. I bought a load of sweet, high cetane diesel fuel in Russia (I had it brought up by truck from St. Petersburg!) last year. It was diesel fuel, but different -- sweet smelling, and lighter and clearer in color, almost white. Running on this fuel, my engine smoked much less than it does with other fuel. Also ran noticeably smoother. This surprised me.

But other boats also running our heavy UK fuel, don't smoke like mine does, so I don't think this is the main problem.

Are you sure that St Petersburg diesel wasn't vodka? Did you taste it? Different, clear in color---sweet smelling....you can buy vodka by the truck load there....so I'm told. Sounds a good way to get it past Customs.

[Dockhead]

Originally Posted by poiu

The lower end of that curve is missing, which would show a steep rise in output as the turbo boost comes on. The turbo clearly is working well at 2000 rpm and the engine should be burning efficiently and cleanly. Assuming the turbo is working well down to 1800 or maybe less then I don't think you are operating it too slowly. Assuming also your prop is correctly matched. That said, I can't imagine long periods of very slow operation are too harmful. Your engine is probably similar - my engine is used widely in agricultural/construction equipment and buses for example and they routinely spend many hours at idle.

Peak efficiency and cleanest, leanest, hottest burning should be somewhere approaching the max torque of 2600rpm.

Concerning the prop -- it's a variable pitch Brunton Autoprop, which should be especially good for getting a load on under any circumstances. Not a Hundested, but the next best thing.

[Cadence]

Originally Posted by GrahamHO

Are you sure that St Petersburg diesel wasn't vodka? Did you taste it? Different, clear in color---sweet smelling....you can buy vodka by the truck load there....so I'm told. Sounds a good way to get it past Customs.

Customs will crack the valve on the scuba tanks to see what comes out.