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mixing gas and oil questions
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#3
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mixing gas and oil questions
"MMC" wrote in message
ng.com... " Sir Gregory Hall, Esq." wrote in message ... "Ron" wrote in message ... On Tue, 26 Oct 2010 13:20:30 -0400, " Sir Gregory Hall, Esq." wrote: "I am Tosk" wrote in message ... In article , says... Wilbur, You have it almost correct, but what actually happens is that in the hottest point in the combustion chamber, the fuel/oil mix diesels starting a flame front, but before that flame propagates across the piston surface, the spark sets off another flame front. When the two fronts collide there is a very high temperature explosion that causes the aluminum to actually melt. This can be heard as a knock, but it is very difficult to hear in an outboard engine. At low throttle, this can be tolerated for a few seconds, but at high throttle, it is almost instantaneously terminal, as much of the head and piston blows out the exhaust port as molten aluminum. The entire point of this thread is to point out that lube oil will lower the auto ignition point of the fuel charge. Catastrophic damage, on the other hand is a product of chamber temperature, fuel/air ratio, as well as the fuel mix tolerance to auto ignition. If the engine is of the low performance variety, fuel/oil mix tolerance will be greater, but in a high performance configuration much more attention must be given to the fuel mix. Historically, the migration from the recommendation of 25:1 to 50:1 occurred with the change from plain bearings to roller/needle bearings. Oil injectors allow even more reduction, because lubrication can be assured at low throttle settings where lube starvation always occurs with premix fuel. This lube starvation was the primary driver for fat fuel/oil mixes. Steve "Wilbur Hubbard" wrote in message anews.com... "Bob" wrote in message ... WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING Interesting. The Outboard Shop, the local evinrude/johnson dealer, gave me the exact opposite recommendation....... Fact: people forget 50% of what they hear immediatly. In other words SKip you probablly heard, "bla bla bla recomend bla bla evenrude bla..." Further, my manuals for both engines show ........ Gaaaaa you have to comprehend also my selective reader. I grant you that quadrupling the oil may have some deletorious effects, but my common sense tells me........ should not be a problem. Hey sikp have you been using your BrontoThesaurus again ? Please dont use such big words as deletorius. They sont have a Salubrious effects on my comprehension. Also, I've never seen oil being more subject to explosion/flash than gasoline. How does adding oil to fuel make it more volatile? L8R Skip :: Your comment and question shows a basic lack of fuel and combustion :: concept understanding. Will those here more knowledgable please :: inlighten SKip. Im off to watch the 30 foot 17 second swells hit the :: jetty. I think Mr. Grundlach may be correct for once. Adding more oil to a given amount of gasoline actually acts as an anti-knock ingredient. It lowers the rate of speed at which the flame front propagates from source of ignition (spark plug) to cylinder/piston surfaces. It increases the duration of the burn and thus lowers the temperature of the burn. Add too much oil and the motor will run as if the choke were on. I don't know of any cases where piston damage from heat will result. The worst that will happen is the works (piston rings piston crown) might become gummed up, the exhaust port will become carboned up and exhaust gass passage restricted and exhaust port opening retarded because the piston will have to travel down several millimeters more before it reaches the exhaust port opening. I have seen exhaust ports so carboned shut that one could barely poke a finger through it. The engine would not rev up and it performed like the choke was on all the time. Too much oil is, indeed, a bad idea but not for the reasons you listed. Wilbur Hubbard (worked as a two-stroke mechanic for seven years and as a technical advisor for a Japanese motorcycle company for seven years) What motorcycle company? This year my daughter is on an '09 RMZ 250 that was Tony Lorousso's Nationals bike last year... Bettencourts, Pro Circuit, Factory Connection... Lowered with a Pro Circuit link, PC Pipe, and a couple of extra toys  Last year she took third place for the season in the womens 125/250 class, working her ass off on a KX100 all season. If you still have friends over there, we could sure use some help racing next season Got a lot of room on the side of the "white trailer"!-- Rowdy Mouse Racing - Pain is temporary, Glory is forever! Yes, it was U.S. Suzuki Motor Corp. I think they've renamed it since. I used to race motocross myself on the old TM 125 and TM 400 and then on a Maico 400. Held AMA national number 42 at one time. But, this was years and years ago back when Hans Maisch, Heikki Mikkola and the great Joel Robert were in their prime and I've lost contact with any and all.They're probably all retired by now anyway. Bwhahahahaha! Priceless! What's priceles? Everybody with half a brain knows that Wilbur and Greg are one and the same. And Anonymous, Anne Omine, Lady Pilot, etc, etc, etc. As you said, everybody knows. Anonymous, Anne Onime, George Orwell etc., are stock remailer nyms. Anybody can post anonymously and receive one of those nyms. Lady Pilot is not Wilbur Hubbard or Gregory Hall. She's another alt.net subscriber. Wilbur Hubbard |
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