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Thread: My Kilo Motor

  1. #91
    Sam Cullis Mark75H's Avatar
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    Thank you for that research, Tim.

    I hope everyone has taken note of the relatively narrow BTU range of the fuels and oils (other than the alcohols). They all fall within 20% of each other. Now factor in the narrow dilution range of 6% to 2% we use for lube oil ... any difference in fuel energy from oil is negligible, and if there is a difference, it is likely that oil adds energy to the combustion process.


    A question that was asked earlier was relevant: does oil affect the octane rating of gas in a negative way?

    The answer is most likely yes ... with a "but ..."

    The but is ... we aren't putting that much into the mix.

    If lube oil was real crap had an octane rating of 60, mixed with 89 octane gas at 25:1 the end result mixture would be 86 octane. Before you freak out about this ... you've been running your motor this way since it was new ... 86 finished octane is all it needed. At 50:1 the octane performance would be degraded to 88.5.

    These degrades are already accounted for by the manufacturers in their gas recommendations.

    Now for a ringer in the game ... synthetics

    Most synthetics have additives to significantly suppress flammability, that's why you see often see liquid synthetic oil dripping out the stack or stinger of a motor running synthetic. This is not the majority of the oil that was mixed with the gas or alcohol ... just a small amount of it. Any oil that was sticking to the edges of the combustion chamber ... especially in a "squish band" or dammed area may not have exceeded the ignition point with the flammability suppression additive (of about 1,000 degrees) ... and when the motor is not running wide open, combustion temperature can be much lower than normal (for a race motor). So, even though most of the oil was consumed with the gas, some dripped out as unburned liquid. Mineral oil and castor oil have an ignition point some where below 200 degrees if I am not mistaken; where unsuppressed synthetic is around 300 degrees.

    Enter a third player ... there is a product on the market that claims to be both lubricant and octane booster. It is a synthetic based oil. Guess what it does not have ... oh, my ... this product does not have the high temp ignition suppressant.

    My theory about this product is that by accident this manufacturer discovered that the flammability suppressant decreases octane and the base synthetic increases octane. Simply leaving out the additive that suppresses ignition from the 300 degree range to the 1,000 degree range, lube oil became octane increaser. I think they sell it for about $130 a gallon, but say you can use it in addition to your regular oil at your regular ratio something like 60:1 or 50:1 to gas and get decent octane improvement.

    I would really like to see some of this junk tested to see if it really provides results or if it is simply a case of it being used by guys who think their motors need a lot higher octane than they actually do (and it is doing little or nothing).
    Since 1925, about 150 different racing outboards have been made.


  2. #92
    Team Member 850cc racer's Avatar
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    im liking all this info in here.

    i ran the motor today... it sounds so crisp. amazing how good the mod50 exhaust makes them sound... i will be giving her a run up on wednesday night to see final numbers.. she hasnt had WOT yet.

    so far she has done everything i want..

  3. #93
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    Great post Sam

    I wonder what the octane or cetane rating of outboard oil is?
    Would a diesel run on it and would that be a dyno test to see what the TCW oil does?

    Cheers
    Powerabout

    PS we were always taught by Merc and OMC, the longer you leave the oil mixed with the fuel the lower the octane ratings goes as well?

  4. #94
    Sam Cullis Mark75H's Avatar
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    Quote Originally Posted by Powerabout View Post
    PS we were always taught by Merc and OMC, the longer you leave the oil mixed with the fuel the lower the octane ratings goes as well?

    I've never heard that. I wouldn't have a theory about it, other than the regular "old gas" situation where some of the better higher octane components WERE some highly volatile ingredients like butane. If the gas was really dependent on the butane and you let it evaporate ... the longer you left it, the lower the octane would be. Some components would also oxidize while in the mixture (at the surface where exposed to oxygen in the air).

    Since new cars are for the most part fuel injected, vapor pressure for gasoline is lower than it was in the past and less butane is used. Unfortunately, since more cars have fully closed tank vent systems, more of the junk that oxidizes when exposed to air can be tolerated by cars ... gas companies put it in because its OK to use in new cars ... the primary market.

    A Diesel will run on any flammable liquid you can properly get thru the injectors. Some early versions used coal dust mixed with water ... just because they could use an otherwise waste product. Some of those things had injection systems larger than the rest of the engine; not practical in a vehicle, but great to replace a steam engine or mill wheel.
    Since 1925, about 150 different racing outboards have been made.


  5. #95
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    Could be Sam, I'm talking service school info of 20 years ago in Oz.
    We went unleaded in 87 by the way, evaporative emissions regs came in, in the mid 70's
    (ADR 27a was the regulation, strange the things you remember from your younger days?)

    Looks like boats need that reg now with ethanol exposed to the air
    Isn't the US doing that next year?

  6. #96
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    Was that benzene or butane Sam?

  7. #97
    Sam Cullis Mark75H's Avatar
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    Benzene is the foundation of the aromatic family of chemicals and has not been an ingredient in gasoline since about 1950. It is both directly highly toxic and highly carcinogenic. It is not especially volatile, it boils at 176, butane boils at 31.
    Since 1925, about 150 different racing outboards have been made.


  8. #98
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    Shell
    Admitted that there is a small amount of Benzene in their fuel in Singapore
    when describing their fuel that they blend for the Ferrari F1 team and how similar it is to V Power sold at the pump.
    ( F1 fuel cannot contain any additives that are not in EU pump gas, so there must be benzene in EU gas?
    2009 F1 spec allows 1% by weight)
    The tree huggers had a go at them and they said the level is so small its not dangerous?

    http://argent.fia.com/web/fia-public.nsf/130A104E1769D120C1257617002D4CAE/$FILE/Stable%20Technical%20Regulations%20-%2024th%20July%20-%20CLEAN.pdf

  9. #99
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    Lean, most likely ain't goin to make the back to back, flat out runs. never did a run a kilo but as i understand it, you gots to flat out, full steam when you cross the startin line. then you got 15mins to turn it around and do it again. lean most likely ain't goin to make it

    Part one of "Secrets of the OMC Mod 50" : http://www.boatracingfacts.com/forums/showthread.php?t=2052

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    I have been following this thread with much interest, and am surprised a the concern and interest in oil mix. From 1968 until the fall of 1973 I worked snowmobile engine lab at OMC and ran many dyno tests there. At that time two cylce oil was rate at TWC-II. All dyno runs, unless indicated otherwise, where run at 16:1. We did run make some runs at 24:1, 32:1 and 50:1 oil mixes and noted no change in power. We did noticed however, a rise in temperatures as the oil was leaned out. Not a big jump but 20 to 25 degrees from 16:1 to 50:1. I then went to Mercury in the fall of 1973 and left there in late summer of 1974 (got divorced). I worked in Advance Research and worked on Snow Twister snowmobile engines and C-6 outboards. We ran all dyno checks on Aviation gas and 18:1 oil mixes. I run all my modified outboards at 24:1and my stockers at 32:1 mixes. I hope this helps.

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