So, I don't get this angst about not working a Diesel engine. Truck drivers often sit in truck stops 12 to 48 hours idling their engines just to have AC. In my own trucking company our engines almost always reached 1 million miles, sometimes more. And think of the cases when the same drivers idle their trucks in the winter for heat.
This is a bit of quibbling. In much of America this is still done. It was done much more a few years go. I know. I owned a trucking company. Still, no harm to engines. I think my observation stands.In almost all of America, this isn't done anymore, FYI.
But yes, "under loading" is way overplayed and worried about.
That works out to 0.6 HP per CID.
The reason truckers get away w idleing for hours is because they drag 30 tp 40 tons of truck all over the place including countless hills, stops and mountian passes. Peddle to the metal very very often as in 100% load. So different than boats any comparisson is mostly meaningless.
If I have correctly followed all the nuances from this discussion, I need only kick it up to 2200-2300 for X period of time for every Y hours operated at hull speed. If this is correct, what are X and Y, according to Cummings? Thanks, Gordon
This is a bit of quibbling. In much of America this is still done. It was done much more a few years go. I know. I owned a trucking company. Still, no harm to engines. I think my observation stands.
Suggest you get the correct answer from Tony Athen's who is located at boatdiesel.com
Why wouldn't you suggest he get the correct answer from the engine manufacturer?
I don't know Tony Athens at all but I'd follow an engine manufacturer before a web guru anytime. Tony has nothing to loose ... the manufacturer has.
I have no axe to grind in this discussion since I start out knowing nothing. Eric suggested looking at what the manufacturer suggests. So....
The boat that I have an offer on, and am having surveyed next week has a Cummins QSB5.9-380 HO engine (QSB 5.9L 380 hp High Output). According to the Cummins performance curves the max rated RPM is 3000 which produces 375 bhp. Cummins says that their HO engines are rated for pleasure boat use only and not intended for any commercial application that operate 500 hrs per year or less. The HO engines are intended for variable load applications where full power is limited to 1 hour out of every 8 hours of operation. Furthermore reduced power (ie not full power) must be at or below 300rpm less than max rated rpm.
So what does that mean for this engine? As I read it, it means that Cummins says the engine was designed to be run at rpms between 2700 and 3000 no more than 12.5% of the time. At 2700 rpm this engine will produce 260 hp or just under 70% of its rated horsepower.
So, what does this tell me (someone who knows nothing)? It tells me that in this case the engine manufacture says that I shouldn't run the engine at anything more than 70% load for more than 12.5% of its operational time. They also say that the rest of the time, it should be operated at below 70% load. In essence, Cummins is warning me that engine life is risked if operated at too high a load, but they don't have any warning about operating at too low a load.
Now, maybe I am missing some information from Cummins, but that is what it says on their spec sheets for that particular engine.
Care to share? I am a member but missed if there was a mod to protect the #6 cylinder.I just forked over the $25 a few days ago just to read the hidden posts concerning the #6 mod to help with cooling.
"They drilled and tapped the block."
Thats it, $25 my ......
LOL
I have no axe to grind in this discussion since I start out knowing nothing. Eric suggested looking at what the manufacturer suggests. So....
The boat that I have an offer on, and am having surveyed next week has a Cummins QSB5.9-380 HO engine (QSB 5.9L 380 hp High Output). According to the Cummins performance curves the max rated RPM is 3000 which produces 375 bhp. Cummins says that their HO engines are rated for pleasure boat use only and not intended for any commercial application that operate 500 hrs per year or less. The HO engines are intended for variable load applications where full power is limited to 1 hour out of every 8 hours of operation. Furthermore reduced power (ie not full power) must be at or below 300rpm less than max rated rpm.
So what does that mean for this engine? As I read it, it means that Cummins says the engine was designed to be run at rpms between 2700 and 3000 no more than 12.5% of the time. At 2700 rpm this engine will produce 260 hp or just under 70% of its rated horsepower.
So, what does this tell me (someone who knows nothing)? It tells me that in this case the engine manufacture says that I shouldn't run the engine at anything more than 70% load for more than 12.5% of its operational time. They also say that the rest of the time, it should be operated at below 70% load. In essence, Cummins is warning me that engine life is risked if operated at too high a load, but they don't have any warning about operating at too low a load.
Now, maybe I am missing some information from Cummins, but that is what it says on their spec sheets for that particular engine.
Eric, you may want to acquaint yourself with Tony Athens and the boatdiesel website. That site is well recognized as the go to Cummins Q and A site for marine diesels (other brands as well). Gordon J's question on Cummins 330s is right up boatdiesel's alley.
The company Tony works for is Seaboard Marine. Look them up. As best I understand they are the largest Cummins Marine dealer in the US if not the world. I'm sure I'll get corrected on this if I misspoke.
...I live about five miles from Seaboard Marine and have met Tony Athens. He is a fine gentleman very knowledgeable. He has a series of articles on their website that are worth reading...