With an irrigation engine, the jug fins and oil cooler fins are a prime concern. When they put them in combines, the additional dust and chaff they were exposed to would eat away at the fans and sharpen the fan blades to the point that they would no longer move enough air to keep the engine properly cooled. When I talked to an experienced parts supplier about a new fan, he seemed puzzled because he had never sold one. AC dealers sold a lot of them though and there were about three different grades a guy could buy, depending on how much money you wanted to spend and how long you intended to run the machine. As I remember, the hardened version was around $800 at the time, for just the fan.
The thing that makes a Deutz so fuel efficient is they can run a lot hotter than a liquid cooled engine. Liquid cooled engines are limited in the temp they can run by the boiling point of the liquid coolant. That temp puts an upper limit on how hot the engine can run. There is nothing to say that an engine can't run even hotter without damage. Because the Deutz is directly air-cooled, the running temp can be determined by things other then the boiling point of the coolant and it will be hotter. The hotter an engine runs, the less heat is wasted by heating parts that have been cooled too much because we don't want boiling coolant. We also do away with problems caused by cavitation erosion on the cylinder liners of a liquid cooled engine.

Hasn't it become problematic to get an air cooled engine to meet the ridiculous emissions requirements?

Show me the discounts....I'll take 'em. 

I'm not fond of working on Cats. 

Is it a coincedence how the slope of the DD and the MBE seem to always be inverse?

I never really understood the emissions situation.  I was told that Duetz was pushed away from the air cooled engine by emission requirments, but previously I was also told that Duetz virtually owned the underground mining market because they were the only diesels which could meet the stringent emissions requirements. 

I never thought those two statements regarding the same engine made sense.  

I do know our Duetz tractor runs pretty clean compared to similar age Deeres, but it is no where near as clean as the new Perkins of similar size.   Even the newer small NH and Deere turbo engines don't seem nearly as clean as the late '90s Perkins 100- series engines.   This is my unscientific observation...basically based on how long you can have one running in the closed shop comfortably.  I think the Fastrac or telehanders could run for an hour and still be fine, compared to the 4010 or 4000 Deere that have you heading for the door a minute.   The TS110s or 6415 Deere will have your eyes burning in ten minutes or so.  I think the old D8006 is about comparable to them.

According to Deutz, the max permissable oil temp for an Air-Diesel  is 257°F. Max permissable temps for the cylinder fins is 338°F. To keep water from boiling at that temp you will need a minimum of 115 PSI. Good luck with designing a radiator and plumbing system to handle that and you'll need an extra measure of luck to deal with a superheated steam explosion that will occur when a hose or radiator bursts. Of course, you will need even higher pressures to keep the hot spots along the cylinder liners from boiling and really causing a cavitation wreck.
While high operating temps are great for efficiency, you can imagine the amount of NOx the high temps in a Deutz would cause. With the advent of exhaust after-treatment solutions like SCR, we may indeed start to see some air-diesels begin to appear in trucks again, like was common in Europe in the past.

A diesel without EGR always runs lean or with a surplus of oxygen. If you build a very hot fire during the combustion process, all the carbon in fuel gets converted to CO₂. We are still left with unused oxygen and some of that combines with the nearly inert N that is in the air the engine inhales and we have NOx as part of the exhaust gasses. If the fire isn't hot enough to literally burn some of the N, NOx isn't as big a problem.
As for the water jacket temps compared to the finned jugs, you have just stumbled on why higher cooling jacket temps makes an engine more efficient. If you cool the cylinder sleeve to 200° and only cool the finned jug to 300°, then when you light the fire in the cylinder, more of the heat and expanding gasses are used to reheat the cylinder to the point where it begins to make energy than will be used in a cylinder that is already 100°+ hotter than the liquid cooled version. Air-Diesel wins here.

A diesel engine with a non-pressurized cooling system and a 150° thermostat?
The same engine with a non pressurized cooling system and a 180° thermostat?
The same engine with a pressurized cooling system and a 190° thermostat?
The same engine with your pressurized system and a 250° thermostat?
My money goes on the engine that can run the hottest without burning down . . .

Don't really even need a water pump if you are going to raw water cool it off a pump set. 

What is the advantage of a heat exchanger and a hot thermostat compared to just running a hot thermostat with raw water?  Other then water quality problems, I don't see any advantage to the added complexity.  Can't the operating temperature be maintained by controlling how much flows through the thermostats?

If your pump stops pumping water, do you really want it running?    Don't you have a murphy switch on that?

Yeah, I get the water quality problems. 

I priced stuff for a friend the other day, I seriously doubt you can rebuild any other 100-200 hp engine for the same cost as you can a Duetz 912 or 913, unless it was a 2 stroke DD.  About $200 per hole gets you complete pistons, jugs, and  heads.    I don't  think the bottom end of a Duetz wears out.  Lol...the block and crank on a 913 are about the size of most 10L

No offense intended, but you do realize that you are comparing to about the least efficient diesel engine you could find.

I kinda like DD engines....but without a turbo the one thing they weren't was fuel efficient. 

you should add naturally aspirated to that. 

92TA engines hold their own against their contemporaries pretty darn well, especially with DDEC.  Go look up fuel curves for an 8V92TA and a Bog Cam or Big Cam III if you don't believe me.

I may be outdated, but I thought the most efficient was a big  2 stroke Sulzer from Switzerland.  I remember it being in all the diesel publications when it came out. 

Have 2 914's new last year.

No problems yet. One thing's for sure......outside temp doesn't bother them......been 103 here all last week. I've got it loaded too.

A question for the experts: Is the temp gauge for oil or air?............(factory gauge panel)

Thanks, John

Mine must be oil then, only goes to 300*.

Thanks, John

BF6L913 is 6.128 litres.
You're right, it's not even close to 374 CID. My calculator says it's ONLY! 373.9535 CID ;-)

"....my 9190 DA 584 cubic inch BF6l913,..."

I stated that I did not think that the BF6L913 was nearly that large of displacement, and I think it is not the engine used in a 9190."   I still believe this to be correct.