Quote:
Originally posted by fahrgewehr
Mike,
I realize diesel engines are used in trucks, buses etc...This is to keep fuel consumption down, and im sure having the low end torque makes the diesel a much better choice in a dump truck. This however, does not convince me that diesel engines last longer. You say they are built more robustly, but as I mentioned before, diesels have double the compression ratio, so they NEED to be built to withstand their own inherant stresses.
As for operating costs, the days of diesel simplicity are over. EGR valves, trap oxidizors, turbos, glow plugs, vaccume pumps...there is plenty to go wrong with a diesel. And that is just for the 80's diesels. A 211 diesel car will have everything controlled electronically, just like its gas powered cousins. The new generation diesels are not simple engines.
So as far as I can tell, the only advantage to the diesel is the MPG. And the smell.
Please don't get me wrong, I like diesel engines (see my car list), I just find this an interesting debate. Mike
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Glow plugs need to be replaced FAR less often than spark plugs, and even if they do go bad, once the engine is strarted, they have no effect on how it runs...the same is NOT true of spark plugs. Vacuum pumps last AT LEAST as long as the electric fuel pumps on gas engines--and are fairly easy to rebuild or replace when the time comes. Trap oxidizers were a bad idea...that's why MB recalled them and removed them for free. Turbo problems on diesels, particularly Mercedes diesels, are almost unheard of. Diesel fuel itself is basically a lightweight oil, so it has much better lubricating properties than gasoline. Also, as someone pointed out above, diesels are shut off by cutting off the fuel supply, so you have less fuel draining past the rings...but the fuel that does get past them lubricates better than gas would. Diesels tend to generate less heat than gas engines.
I don't mean to turn this into a debate over which is better...It's apples and oranges...But the numbers don't lie. With very few exceptions, diesel engines of all kinds, ESPECIALLY Mercedes (except the notorious 350), far outlast comparable gas engines. Diesel engines are used in trucks for the fuel mileage and torque like you say, but they are ALSO used for ease of maintenance, lower operating costs, and longevity! Believe me, if they were more expensive and shorter-lived than gassers, trucking companies, farmers, commercial construction contractors, and the military would switch to something else QUICKLY!
Ask any truck driver, ask any bus driver, ask any farmer, ask any marine mechanic, ask any military mechanic, ask any heavy-equipment operator, do a search on the internet, pick up an automotive magazine, ask any Mercedes mechanic, ask ANY mechanic....they will all tell you that, love 'em or hate 'em...they last longer.
Mike