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Default mixing gas and oil questions

"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 and
with 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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Default 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 and
with 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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