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paragonbuilder

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Sure you are not confusing octane with cetane?

https://en.wikipedia.org/wiki/Octane_rating

29260bb4908d86a371d2d5bd6522b985.jpg


In gasoline, it performs the way you describe. But just because oil has a lower octane rating, doesn’t mean it lowers the mix octane rating. I believe that is an assumption on your part. Chemistry does not always do what we think it will.
 

paragonbuilder

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The reason octane rating is not important in a diesel engine is that they have direct fuel injection, therefore the fuel ignites when injected rather than when it reaches too high of a temp. Only the air is compressed, before the fuel is injected.

Ever ran gasoline in a diesel?
 

MustangMike

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Ever ran gasoline in a diesel?

I would not, it does not have the right properties for that. (Wrong centane rating)

I used to believe that addl oil in the gas increased octane rating, but other pointed out to me that oil has a lower octane rating that gas, and they were correct.

I'm not saying you are wrong, but what is your source that the mix is higher octane even though the oil is lower octane?
 

MustangMike

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https://en.wikipedia.org/wiki/Cetane_number

So basically octane refers to the temp at which a fuel will ignite, and cetane refers to the speed it burns after it is ignited.

Hi octane gas has a higher flash point, but faster combustion.

Hi cetane oil has a lower flash point, but slower combustion.

Are we on the same page?
 

paragonbuilder

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I would not, it does not have the right properties for that. (Wrong centane rating)

I used to believe that addl oil in the gas increased octane rating, but other pointed out to me that oil has a lower octane rating that gas, and they were correct.

I'm not saying you are wrong, but what is your source that the mix is higher octane even though the oil is lower octane?

I’m just saying that I don’t believe adding oil makes the mix more volatile, which would correspond with a lower octane rating. I don’t know enough about the science to say definitively. But I don’t think your assumption that it lowers is substantiated.
Not trying to argue Mike. It just seems many may get the wrong idea.
 

NYH1

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I don't know much about 2 strokes and less about diesels. As far as their inner workings go.

I know more about car engines and how combustion chamber and piston design, quench area efficiency (you guys call it squish), cylinder head material as well as camshaft duration and overlap along with higher compression (dynamic comp. is more critical then static comp.) can effect detonation.

Maybe I'll figure the 2 strokes out someday!

NYH1.
 

Bigmac

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I know more about car engines and how combustion chamber and piston design, quench area efficiency (you guys call it squish), cylinder head material as well as camshaft duration and overlap along with higher compression (dynamic comp. is more critical then static comp.) can effect detonation.

Maybe I'll figure the 2 strokes out someday!

NYH1.[/QUOTE]
If you have a good working understanding of a four stroke, you can pick up on two stroke stuff, saw are different than many other two strokes, piston port motors for the most part and simple. Super fun an rewarding to work on!
 

Bigmac

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To overgeneralize in relation to a four stroke, port timing is like the camshaft of a four stroke with duration number you can understand, on saws guys use numbers from top dead center(on motorcycles and sleds, mainly reed valved motors the use full port opening numbers for duration) and much like dynamic compression, actual calculated compression is volume traped from when the exhaust port closes compared to final volume at top dead center, is saws most people talk in psi, not compression ratios. And quench area is like the squish band of a two stroke, but squish is actually piston to head clearance, squish band is the and quench is the same it is the design of the parallel part of the combustion area, hope that helps
 

CrystalRiver1

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I thought about going to pick up about 30-35 honey locust logs of assorted sizes, yet they went from being free to $50 plus about $20 in gas round trip!:eek:
That kinda sorta "queered me" on the deal so to speak:buitre:...least I thought about it though.:couch:
 
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Czed

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I push mowed grass in the near dark until 9pm
Trying to beat the heat
And a gully washer on the way
If that counts
Still didn't get to weedeat lol
 

Dub11

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I push mowed grass in the near dark until 9pm
Trying to beat the heat
And a gully washer on the way
If that counts
Still didn't get to weedeat lol

You dont have a rider?
 

Bigmac

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19360A6B-F92C-430A-86C4-6C16D7835C38.jpeg I am working on a banshee for a friend, head mill, v-force 4, timing advance and retune, he wants it ported and a 4mill, but this will be a nice bump until then! Had 35 thousands cut off
 

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