Now i am not saying a small diesel can't pull anything.

You could have a 1 liter 2 cyl engine move 100,000 lbs if you wanted, and the engine could also last a long time.
The problem is when you crank the power in an engine to move the load faster.

The reasoning behind it is "fairly" solid, power per cubic inch.

The 3 liter engine you speak of, is it 400 HP? or more like 200 ?
Small diesels move big loads all the time, but that is because the vehicle is usually slower than for EG, a super duty.

Truck / towing engines are also a little different than a car engine, as they are made to run at a much higher work load. That is why you can have a car with high HP diesel that is small displacement.
There are many small diesels that can tow quite a lot, but they are also lower power, but not compared to their displacement size.

If we hypothetically replaced the 6.7L diesel engine in an f350, with a 3 liter diesel, then tuned it to 400 HP, then towed the biggest camper trailer we legally could, and loaded the truck down to the maximum weight, do you think the 3.0 liter could survive a single trip around the country? How about several years of use? It's not a car, it doesn't get occasional WOT with 90% of the driving under 50 % throttle, it would be 60-80% steady output I'd roughly guess.
I know theres small diesels that would pull this load all day, but at reduced speed.
Can you find a 3 liter diesel, with similar power ratings to a 6.7 powerstoke, that is made for heavy duty truck use?

 

I can't wait to see this 400 hp 3 liter workhorse engine.

For some reason, no fruition of such has occurred yet.

 

You are right that theoretically big, engine with low power ratio should last longer, especially in heavy applications, but there is much more to it than a displacement.
Try to do some research on RV market. There are 24-30 foot motorhomes powered by 8 or 10 cylinders US made engines and the same size motorhomes powered by small 5-cylinders German made engines. Guess which one last longer?

 

The engines you keep bringing up have been small displacement engines.
Some of them have been low output heavy duty engines, and others have been high output light duty engines.
You have been trying to prove to me that diesel technology is far superior on the other side of the pond, but so far any differences talked about are near trivial.

If they are so advanced and ahead of us, I want to see a diesel that can put down 400 HP with emission equipment, tow what these ford F350's - F550's do, and be the same or less displacement.
A 5 cylinder german engine might possibly last a long time in an RV, but does it put out 300 + hp like the ford v10 thats in lots of those?

I think there are a lot of smaller diesels from europe, because of the fuel costs. I also think they have some really cool stuff going on as far as power etc. What I havn't seen yet, is a diesel engine that would compare with for example, fords 6.7 diesel.

 

US build engines need lot of HP just to carry its own weight.
I am not too familiar with the 300HP Mercedes engines used for last few years in US towing industry, but looks like this is what you are looking for?



2007 FREIGHTLINER BUSINESS CLASS M2 106 Medium Duty Trucks - Expeditor / Hot Shot Trucks For Sale At TruckPaper.com

 

Yeah and what does than engine weigh in at, around 1300 lbs ?

How come it doesn't weigh 330 lbs? Cause it would last a week if you put a high performance 330 HP car diesel motor in it.

 

My 7.3l is about 1100 lb

I doubt the OM 906LA engine is heavier than that. Can't find the engine weight, but the Mercedes Atego seems to be in exact chassis class with Superduty weighting 9000 lb. My F450 is 10,000 lb with the bed.
http://www.northside.co.uk/documents...x2_tractor.pdf
Than the Mercedes tractor is rated for 57,000lb GCVW. Something way above any Superduty dreams.

 

I don't know, I saw one a while back in a water truck, and it looked like a heavy sucker, like most big truck engines.

 

The OM906LA weighs in at 1200 pounds. 1800 Pounds with accessories and transmission - with a maximum output of ~300HP.

How about the F-650/750? GCWR of up to 60,000 pounds. You can get them with the 6.8L V10, or a 6.7 Cummins ISB

You can also get the same truck labeled as an International with the 6.4 PowerStroke/MaxxForce 7.

 

Where'd ya find that one? Of course I'm not doubting you, but I'd love to read up more on some of those European diesels that are so vastly superior than our own.

 

Project Engine MB OM906LA / Allison 6spd Auto- Tranny & Hydro Pto. - Page 2 - Benzworld.org - Mercedes-Benz Discussion Forum

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Thats what I was leaning towards... basically it's just another truck engine.