Another Discussion on Diesels

[auguste]

Went out to supper with a buddy who has a Master's in Vehicle Engineering (?) from a small American school called MIT

He is much more knowledgeable about diesels than I am and he helped me decide on diesel over gas, for my application.

He says that the "big old diesels" like the 6 and 8v series and the 555 etc. are using 30 year old specs and that their life spans (with reasonable maintenance) can be graphed based upon hp per cubic inch, hours of operation, and total rpms at each 'rpm range'

He then went on to say that the new generation diesels are much smaller and lighter and turn higher rpms because they employ higher quality materials, have tighter manufacturing specifications etc.

He believes that comparing old and new generation diesels is like comparing 1960s V8s with today's smaller size higher hp engines

He says that preliminary results show that with equal attention to maintenance, the new engines should last as long as the older generation engines.

Fuel consumption and emmisions*are much*lower with the new engines, producing savings that should offset higher repair costs.

Just thought you might be interested in his views.

CHEERS

[jtburf]

Thank you .....

I know smaller and newer tech work's well untill you try to squeeze to much out of a small package ..

I.E 300 hp outboards!!!

John

[auguste]

jtburf - 8/28/2004 1:57 PM Thank you ..... I know smaller and newer tech work's well untill you try to squeeze to much out of a small package .. I.E 300 hp outboards!!! John

I agree . . . sometimes we try to do too much with too little engine . . .

[Mist-Rest]

FYI, Two of our new trucks (with a 3rd coming if the town OK's it) have 500 HP Detroits in them coming from 12 litre blocks. One of the techs and I were talking and he stated if that engine were put in an over the road application, it would not last 500K miles. You have to admire the way they burn fuel and make HP with the electronic controls. To bad you need a lap top to figure out what's wrong when they stop running right. Time will tell just how good the wiring and components will be with the salt. I was talking with the captain of a charter we were on and he told me that he was having a hard time as to if he was going to keep his tried and true 3408 Cat in his old boat or building a new one and having to buy the electronic diesel.

[reefhunter2]

I'm a firm believer in naturally aspirated engines and those with mechanical pumps vs turbos and electronics. The older engines will still be around fifty years from now, while the newer turbo whatever will be dead and buried.

[theoldwizard]

There certainly is not much changes happening in "over the road" (tractor trailer) or "off road" ('dozers, etc) diesel technology. The EPA tightened up emmission standard on heavy trucks a few years ago, but everyone in this field is following the "old school"; lots of cast iron and replacable liners. But these engines are designed to go a million of miles (at 25 mph, a million miles is 400,000 hours ) or more.

Lighter weight diesels are sweeping Europe (especially England), because of their fuel economy and lower taxes. These probably won't last as long, but who puts that many miles on a passenger car or light truck anyway ? This class of engines is also pioneering the lastest in tecnology (electronic controls amd common rail injection). I expect you will see more diesels in cars in the US once the low sulphur diesel starts showing up at the pumps in 2006.

If I were shopping for a marine diesel, I would definitely give Yanmar a very long look.

Hawknest, you might be surprised to know that most of the "over the road" trucks have turbos. They have been there for many years. I don't know about marine applications.

[stringer]

FYI, Go to this website and read the "diesels vs gas engines article" Part 1 and 2, by David Pascoe. http://www.yachtsurvey.com/engines.htm
He is very conservative (good or bad?), but is a very experienced surveyor and has some really good points of view on the subject. A good read for someone trying to decide between gas and diesels.

[auguste]

Naurally aspirated diesels, in my opinion, are going the way of the dinosars . . . whether or not you like dinosaurs . . . just visited 3 sites selling commercial*trucks . . . 21 of 26 trucks were not naturally aspirated . . . I have been window shopping the big battlewagons 45 to 60 ft long and not a single one is pushing naturally aspirated

Did you know that most naturally aspirated diesels are noisier than their turbo charged orn super charged brothers?

Did you know that naturally aspirated diesels burn more fuel to produce each hp . . . in the long run naturally aspirated engines are more expensive . . . even when taking into consideration maintenance costs

Pascoe is often quoted by those who are trying to justify gas versus diesel engines . . . however, in my opinion, his analysis is seriously flawed and favours gas engines . . . but that is just my observation

[4000]

Pascoe's opinion is just a matter of economics. It's pretty simple.

Anyhow, no one will argue that if you're getting a small 20 something boat, you get gas. A hefty 40 something boat needs diesel for its TORQUE.

[auguste]

4000 - 8/29/2004 2:20 AM Pascoe's opinion is just a matter of economics. It's pretty simple. Anyhow, no one will argue that if you're getting a small 20 something boat, you get gas. A hefty 40 something boat needs diesel for its TORQUE.

I still think that Pascoe's*analysis is flawed but your general statement holds water

I mostly agree with your statement "Anyhow, no one will argue that if you're getting a small 20 something boat, you get gas. A hefty 40 something boat needs diesel for its TORQUE" except I would add fuel economy and longer engine life as additional reasons for diesels in larger boats . . . IMHO

[reefhunter2]

theoldwizard - 8/28/2004 5:15 PM

There certainly is not much changes happening in "over the road" (tractor trailer) or "off road" ('dozers, etc) diesel technology. The EPA tightened up emmission standard on heavy trucks a few years ago, but everyone in this field is following the "old school"; lots of cast iron and replacable liners. But these engines are designed to go a million of miles (at 25 mph, a million miles is 400,000 hours ) or more.

Lighter weight diesels are sweeping Europe (especially England), because of their fuel economy and lower taxes. These probably won't last as long, but who puts that many miles on a passenger car or light truck anyway ? This class of engines is also pioneering the lastest in tecnology (electronic controls amd common rail injection). I expect you will see more diesels in cars in the US once the low sulphur diesel starts showing up at the pumps in 2006.

If I were shopping for a marine diesel, I would definitely give Yanmar a very long look.

Hawknest, you might be surprised to know that most of the "over the road" trucks have turbos. They have been there for many years. I don't know about marine applications.

Yep, I've been driving otr's for more than forty years and I've seen more than my fair share of turbo failures. The last time it was me hauling logs down from Columbia Falls when she went bye-bye. I coasted to a stop and $3200 later was back on the road with a new one. I love my old na's, better than my dogs.

The new lighter weight diesels that are coming for the suv's, won't last as long as the bodies. They're built to last only a couple hundred thousand miles, which is twice as long as the current gas engines. They're all throw-aways in my opinion. The automotive engineers don't want anything to last so long as it can't be replaced. You won't be seeing much of the 40-50 mpg engines like you did in the 80's. More like 20-30 mpg. Daimler's new engines which are replacing the older Cummins, Cats and Detroit's in Freightliners aren't built as well. Over in Europe most trucks are multifueled. They run on diesel and propane. Diesel out on the autobahn and LP in town. Up in Canada, most official vehicles are multifueled with gas/lp. Now LP doesn't quite have the same power, but it's far less on the emissions scale.

The oil company that supplies me with fuels just sent me a note last week that essentially says if I use their fuels come 2006, when ULSD goes into effect, my engines are additionally warranteed by them for 10,000 hrs. When those new rules go into effect, anyone using other than ULSD on a new engine, just kisses their truck engine warranty goodbye!