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#31
posted to rec.boats,rec.boats.cruising
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mixing gas and oil questions
Wilber and all,
The stoichiometric A/F ratio for gasoline and diesel is almost the same by mass. 14.7: vs. 14.5:1. However, the auto ignition temperature for diesel is lower than gasoline and lube oil auto ignition temperature is lower than diesel, hence the potential risk of detonation. Also, the released heat by combustion in BTU/gram is almost the same across all hydrocarbon fuels. Look, I'm getting a bit tired of repeating myself on this subject. I thought I would just slip this oil thing into the group because it isn't common knowledge. Guess what....it isn't common knowledge. For all you doubters look it up yourself, Wiki is your friend. Steve "Wilbur Hubbard" wrote in message anews.com... "Ron" wrote in message news  On Mon, 25 Oct 2010 14:23:46 -0400, I am Tosk wrote: In article 29b625b4-9ffe-4736-b512-dff137d6aa81 , says... haven't figured out what it was, but I shipped it: 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. Yeah, I gathered he isn't a internal combustion engineer so what's your point? I worked on cars for a long time and really never thought about ping as it relates to two stroke fuel/oil mix, I just mix it right  andwith the octane we run, ping is not really an issue.. As to why the high mixture and why it would cause ping, I have some ideas, but really, I don't think it's all that important as long as I have a measuring cup... That being said in my lawn equipment and boats I run regular fuel with Spectro32:1 which is designed to run at that mixture in most two stroke engines.. It's universal. No it isn't! Water cooled outboards run at much lower temps than air cooled lawn equipment. The requirements for the oil are quite different. And 32:1 will cause an engine that is designed for 50:1 to run lean. Not good! It's apparent you don't understand what the ration you used means. 32:1 means 32 parts gasoline to one part oil 50:1 means 50 parts gasoline to one part oil Therefore, you are wrong to say 32:1 will burn leaner than 50:1. Fifty to one burns leaner by virtue of the fact that there is more gasoline to burn and less oil. A richer oil/gasoline ratio (more oil to gas as in 32:1) will cause a two-stroke engine to run richer - not leaner. Oil also burns (most of it) but oil burns less easily and more slowly (under the compression ratios present in gasoline engines) because it's less combustible than gasoline. It takes a high compression, diesel engine to burn oil efficiently. It ain't gonna happen efficiently in a gasoline engine because of the low compression ratios Wilbur Hubbard |
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#33
posted to rec.boats,rec.boats.cruising
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mixing gas and oil questions
"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. Just different names for different NSPs. The Wilbur account seems to be temporarily on the blink today. -- Gregory Hall aka Wilbur Hubbard |
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#34
posted to rec.boats.cruising
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mixing gas and oil questions
Rick Morel wrote:
On Mon, 25 Oct 2010 22:30:42 -0400, Wayne.B wrote: On Mon, 25 Oct 2010 18:48:23 -0500, Rick Morel wrote: Not water cooled, but a real world example. About 20 years ago I built and flew a gyrocopter.... Interesting! Do you happen to know Ken Brock? He was one of the gyrocopter pioneers and flew one across country for the publicity. He and I appeared together on a television show called "To Tell The Truth" back in the early 70s. I was one of his "imposters" and Ken of course was the real thing. No, but I did meet him. A great guy. About all the gyrocopters used his horizontal stabilizer and control system. Rick I thought he flew a Bensen. But it turned out his mods were sufficient to make it a new design. copy: The Ken Brock story as it relates to sport gyroplanes begins around 1970 with a Bensen gyrocopter he had built and subsequently modified. These modifications led directly to a design that Igor Bensen told Brock was a new design and could no longer be considered a Bensen Gyrocopter. The popularity and innovations of Brock’s design lead to the formation of Ken Brock Manufacturing with the intent to market and sell Ken Brock gyroplanes. Brock was one of the first to use the term gyroplane, a term the FAA would later use to define the aircraft type in general. Ken Brock gyroplanes would carry model designations of KB; other models include the KB2 and KB3. The design, as mentioned before, was based off the Bensen Gyro-Copter and from this basic design Ken created an aircraft that would be easier to handle, and fly. While it was not much of a real stabilizer the KB gyroplanes were among the first to add it. Initially installed as a rock guard to protect the propeller on Bensen and other designs. Ken's gyroplanes were among one of the first to start the debate and research of the addition of horizontal stabilzers and would lead to future gyroplane designs incorporating such devices. Brock and Brock Manufacturing would always make safety a top priority with any gyroplane it designed and through the history of the company many changes and modifications would follow the design such as in better rotor designs and manufacturing processes to build them. -- Richard Lamb email me: web site: www.home.earthlink.net/~cavelamb |
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#35
posted to rec.boats,rec.boats.cruising
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mixing gas and oil questions
"Ron" wrote in message
... On Tue, 26 Oct 2010 14:27:26 -0400, I am Tosk wrote: In article , says... "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. http://en.wikipedia.org/wiki/Jo%C3%ABl_Robert Your daughter sounds good. I wish you all well. Thanks, she's livin' the dream... Wilbur/Gregory/Neal is dreaming as well. Dreaming that you're a PUTZ? Oh wait a minute. That's no dream; that's reality. lol -- Gregory Hall |
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#36
posted to rec.boats,rec.boats.building,rec.boats.cruising
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mixing gas and oil questions
Interesting that my comments should have had the group ranting and raving.
Nice, however, to see WH/GH ack their duality, finally, after all the "he's my roommate" and the like denials. Meanwhile, inquiring minds still want to know... Why do outboard manufacturers insist that you run double the oil during breakin, and under severe operating conditions, if it's likely to blow out the pistons as liquid aluminum? Never mind whether or not a certified mechanic can be trusted or whether or not I selectively read. At least one poster has verified doubling the oil during breakin so it stands to reason that it MIGHT be possible that the manual actually says the same about severe operating conditions... L8R Skip, chasing his starting issues, still, report to follow -- Morgan 461 #2 SV Flying Pig KI4MPC See our galleries at www.justpickone.org/skip/gallery! Follow us at http://groups.google.com/group/flyingpiglog and/or http://groups.yahoo.com/group/TheFlyingPigLog "Believe me, my young friend, there is *nothing*-absolutely nothing-half so much worth doing as simply messing, messing-about-in-boats; messing about in boats-or *with* boats. In or out of 'em, it doesn't matter. Nothing seems really to matter, that's the charm of it. Whether you get away, or whether you don't; whether you arrive at your destination or whether you reach somewhere else, or whether you never get anywhere at all, you're always busy, and you never do anything in particular; and when you've done it there's always something else to do, and you can do it if you like, but you'd much better not." |
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#37
posted to rec.boats,rec.boats.building,rec.boats.cruising
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mixing gas and oil questions
On Tue, 26 Oct 2010 16:54:44 -0400, "Flying Pig"
wrote: Never mind whether or not a certified mechanic can be trusted or whether or not I selectively read. At least one poster has verified doubling the oil during breakin so it stands to reason that it MIGHT be possible that the manual actually says the same about severe operating conditions... I don't think so. That's when you're likely to experience pre-ignition/detonation due to the lowered self ignition temperature of the fuel mix. |
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#38
posted to rec.boats,rec.boats.cruising
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mixing gas and oil questions
On Tue, 26 Oct 2010 17:09:13 -0400, Harry®
wrote: Are you guys here just to disturb the serenity of rec.boats? They are refugees from "alt.sailing.asa" who escaped through a wormhole in the fabric of the space-time continuum. Hopefully someone will beam them back up. |
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#39
posted to rec.boats,rec.boats.building,rec.boats.cruising
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mixing gas and oil questions
"Wayne.B" wrote in message
... On Tue, 26 Oct 2010 16:54:44 -0400, "Flying Pig" wrote: Never mind whether or not a certified mechanic can be trusted or whether or not I selectively read. At least one poster has verified doubling the oil during breakin so it stands to reason that it MIGHT be possible that the manual actually says the same about severe operating conditions... I don't think so. That's when you're likely to experience pre-ignition/detonation due to the lowered self ignition temperature of the fuel mix. Duh! Increasing the oil to fuel ratio does not lower the self-ignition temperature. It raises it. We are not talking diesel engines here. We are talking two-stroke gasoline engines with their relatively low compression ratios. Try running a two-stroke (two-cycle) engine on pure two-stroke oil and they won't self ignite to combustion EVER! Even a spark plug won't make the thing fire. Try running them on half and half gas and oil and they might just barely run given a source of ignition like a spark plug before it fouls with oil in about a minute but they won't self-ignite EVER. Try running them on nothing but gasoline and they will have a much higher likelihood of self-ignition (aka detonation, knock or ping) for about a minute before the piston seizes to the cylinder wall. I hate like hell to say it but SKIPPY IS CORRECT. Increasing the oil to fuel ratio will not damage the engine from detonation, etc. Wilbur Hubbard |
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#40
posted to rec.boats,rec.boats.building,rec.boats.cruising
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mixing gas and oil questions
"YukonBound" wrote in message ... "MMC" wrote in message g.com... "YukonBound" wrote in message ... ted@theted. wrote in message ... i have a jetski and a boat with an evinrude 115 hp outboard. can they both use the same gas/oil mix? someone told me it should be a pint to six gallons but i would rather mix a pint with 5 gallons because it's easier and to be on the safe side if that's ok. is a pint to 5 gallons ok for both the jetski and the evinrude? thanks! ted I follow the manual recommendations. i also dropped into the Vespa scooter store and bought the little plastic measuring device. It's great for a 50:1 mix. Saves guess work when out on the high seas. You take a Vespa out on the high seas Don? Why not... strap a couple of pontoons on the side and engage the marine drive.............................. Haha! Probably gets great milage. |
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