# Which Oil Ratio is Best: 40:1 or 50:1?



## max2cam (Oct 15, 2003)

Just wondering how many of you think dropping back to 40:1 instead of the usually recommended 50:1 does more harm than good or vice versa?

In other words, is the possible benefit of added lubrication using 40:1 outweighed by greater carbon build-up and fouling of spark plugs? 

Is the 50:1 ratio due more to EPA demands and to heck with your saw's life? Or are oils so good today that using 40:1 is asking for trouble with no gain?

I know there must be lots of opinions on this, but what are the facts?

(PS: I just mixed a gallon of 93 gas at 40:1 and am debating the issue....)


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## eyolf (Oct 15, 2003)

Here's what I think, FWIW.

Don't matter on average homeowner equipment. If you burn up the saw/blower/trimmer/whatever chances are it will be because of bad gas/water in the gas, carb trouble, leaking seals/gaskets, or lack of maintenance.

Maybe a pro would use the unit long enough to notice a slow degradation in power because of increased wear due to limited lube, or the pro might find that eventually the heavier mix built up more carbon.

The rest of us will get tired of the old unit long before trouble comes. My old McCulloch trimmer gave up the ghost due to a failed coil this summer. I've used it for 11 years, getting it used from an old tightwad that used outboard oil in everything...snomobile, chainsaw, boat motor, etc. and never ever mixed any new gas until the old was gone.

If the coil wasn't impossible to find, I would have kept using it...compression was still good, cylinder and rings looked fine, crud build-up not too bad on tearing it apart just to look.


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## Crofter (Oct 15, 2003)

Wouldn't carbon buildup be more a result of too rich a fuel to air ratio than too rich an oil to gas mix. I'd say more 2 strokes fail from no oil in the gas or running too lean a mixture either thru adjustment error or air leaks.
I still remember 16 and 20 to one mixes so a 50:1 makes me a bit nervous. 40:1 in all my 2 strkes = Tranquility!
Frank


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## Bills Oak (Oct 15, 2003)

*Which Oil Ratio is Best: 40:1 or 50:1*

I've already made a few guys mad so just one comment--Go 40:1 & don't worry about it--just use a brand name oil & 93 Octane!--Been working for me for years.......


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## Qatanlison (Oct 15, 2003)

I've been using alcylate-based ASPEN-gas for two years. It's an environment friendly gas which comes in a mixture of 2% or 50:1 if you like. It's a 95 octane and very clean; Cleaner sparkplug, airfilter and the exhaust is really pleasant; You don't get dizzy or nausious when working in snow or among dense vegetation that tend to keep the fumes for you to breathe... I think Husqvarna is supposed to carry it in their stores in the US.
Try it out, I've never looked back...

No, I'm not a salesman for ASPEN.

/Ola


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## Bills Oak (Oct 15, 2003)

*Which Oil Ratio*

Qatanlison, sounds interesting....any idea of price?--I'm willing to try anything once!--Marriage more than that but I'm hopefully smarter now!


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## z4lunch (Oct 15, 2003)

*50:1 oil... Please...*

Steve here...
Had to jump in here. Couldn't bear to see you guys go down this road again. I pulled this pic from an old oil issue post from last year some time. This is a pic of my dad's 025, with one tank of gas through it... You guessed it 50:1 Stihl oil. 
I run Maxima K2 Synthetic at 32:1 in all my two strokes. Even the LawnBoy. If you think it may smoke, look up the thread on the Baraboo saw race and check out the video of my 088KD, at 12000, in the wood... 
my two cents...again Steven


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## Fish (Oct 15, 2003)

For those of you that remember, Dagger was right! Correct!
ETC!.
You girls are just too pig-headed to ever agree!


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## Jacob J. (Oct 15, 2003)

32:1 with a quality oil is a universal mix. You can even run your Lombard Lightning or your Mall 2D or your Titan "Hornet" on it. I run Klotz Super 2 racing synthetic oil and Klotz Premium synthetic castor blended together.


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## stihltech (Oct 15, 2003)

*oil*

Funny, I have pulled no pistons out that looked like that from Stihl oil. Like I said, the failures are not from the lack of lube with properly mixed oil.


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## stihltech (Oct 15, 2003)

*025*

Was piston material on the cylinder? Which side of the piston was scored? Were the bearing cages intact? Any air leaks? New or used?


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## z4lunch (Oct 16, 2003)

Steve here,
There appeared to no piston material on the cylinder. I mixed the fuel up myself. Warmed up the saw too. 
Anyway, when you pull the muffler off the saw the piston should be wet with oil, if it's not your not getting enough oil on the moving parts.
Steven

ps that pic is the intake side of the cylinder wall, not the piston. Sorry I didn't make that clear


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## max2cam (Oct 16, 2003)

> _Originally posted by Fish _
> *For those of you that remember, Dagger was right! Correct!
> ETC!.
> You girls are just too pig-headed to ever agree! *



For those of us who do NOT remember, what was Dagger right about? What did he say? Why was he correct?

Like pulling teeth....


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## max2cam (Oct 16, 2003)

From what I'm gathering here is that 40:1 won't do any harm and I might feel better. But that it's NOT a substitute for keeping your saw tuned right, no air leaks, etc. (I know about THAT because an impulse tube air leak "stuck" my 024. At least that taught me what an impulse tube is and what it does. It also scared me into using 40:1 -- whether I need it or not...)


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## Qatanlison (Oct 16, 2003)

Bills oak,

Here in sweden the synthetic gas is roughly twice the prize of ordinary gas, but I don't know about US. Check with a Husky dealer.

/Ola


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## shooter (Oct 16, 2003)

Max,

Today’s 50:1 mix oils are blended to be low smoke and to produce minimal exhaust port & muffler deposits. More oil does not in itself harm a 2 stroke; some bike racers feel that the additional oil improves the ring seal & gives them more power.

If you wish to be cautious and mix more oil with a 40:1 ratio, any effects that you see will be more of a long term issue. You can monitor this by periodically inspecting the plug & pulling the cover off the muffler.

Jacob J has some good advice for the older equipment. Probably for various reasons, 32:1 works better as an all purpose ratio.

Mike


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## Fish (Oct 16, 2003)

Max2cam, do a simple search and learn.....

I will hopefully meet with Dagger on 
Sat. at the Expo, so if you have any questions you want me to ask
him, let me know now, I will try to get him to log on there, as
well as others.

After reading all of the posts that he made, he makes good sense.


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## bwalker (Oct 16, 2003)

> Today’s 50:1 mix oils are blended to be low smoke and to produce minimal exhaust port & muffler deposits.


 Thats not really true as most oils on the market and all of the oem standard oils are blended to 70's era api tc specs and as such are not lowsmoke or deposit oils.


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## max2cam (Oct 17, 2003)

Here is a couple of Dagger's posts (who apparently worked in the industry as a young engineer) about oil-gas ratios that Fish must have been referring to. It appears that the truth about oil-gas ratios may be counter-intuitive in that a leaner mix actually cools better and extra added oil is not actually needed. 

From these discussions, it would appear that the oil that leaves the absolute least amount of piston and cylinder deposits would be the best (a synthetic like MX2T?) 



> (Dagger said Let me Mention a couple a things from an engine developers view...
> first..the wrongs...
> NO the 50:1 was not forced upon us by EPA regs!
> HEAT WAS THE CULPRIT..
> ...



And this:



> In the early 80's the market was heavily influenced by advertising warranty...most consumers seem to think that if you warranty a product longer than the other guys..it must be better.
> Actually it is a function of sales...not reliability
> so, the sales dept wants a long warranty period to enhance this image.
> This herein is where it all started. it was not the EPA...they had no jurisdiction on our market then, and we did not consider them fer a sec. That came several years later...after most had switched to 50 to 1 oil already.
> ...


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## bwalker (Oct 17, 2003)

Dagger was wrong on this and a few other issues. What takes more heat to evaporate it, oil or gas? Seeing that the boiling point of oil is much higher I am betting oil does, thus more oil in the mix leaches more heat out of the combustion chamber.


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## max2cam (Oct 17, 2003)

This other thread on actual measured heat data with different oil-fuel ratios is also very interesting....good empirical evidence. More to this oil ratio thing than meets the eye....so it appears....

http://arboristsite.com/showthread.php?s=&threadid=6222&highlight=dagger+oil


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## max2cam (Oct 17, 2003)

> _Originally posted by bwalker _
> *Dagger was wrong on this and a few other issues. What takes more heat to evaporate it, oil or gas? Seeing that the boiling point of oil is much higher I am betting oil does, thus more oil in the mix leaches more heat out of the combustion chamber. *



bwalker:

In reading that observed heat thread, I find what you said here thought provoking. Is the increased oil ratio getting the heat OUT of the piston and combustion chamber and thus out of the engine? This stuff is like alchemy or understanding the nature of hell-fire -- which it is!



> bwalker said: Also this may be out in left field...but what if the engine external temps are higher because the increased oil in between the cylinder piston interface allowed more heat to be leached out of the piston and into the cylinder causeing the higher temp readings."



Crofter said this (below), which is how I feel too. Is just seems so RIGHT that more oil "should" be better....but....is it really????? But by God, if you're going to use more oil than 50:1, it should be the cleanest burning oil available (synthetic?).



> Crofter said: I still feel that more oil should make the saw run cooler - I wish these statistics would stop interfering with my intuition.


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## max2cam (Oct 17, 2003)

This is leaving me more wondering and puzzled than ever. I gotta get out of here. But, on the Observed Heat Thread, somebody noted this:



> This is why timbers readings are higher at 32:1 than 50:1 which is the manufacturers recommended mix. If timberwolf were to go to 24:1 and conduct the same tests his readings would again be higher than at 32:1



I guess then by this thinking, if we keep adding more oil to "pull more heat out of the engine" (my words more or less) we would gain great results until the saw melted into a puddle of plastic and alloy....

I might just stick to the mfg's specs after all....


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## Crofter (Oct 17, 2003)

> _Originally posted by bwalker _
> *Dagger was wrong on this and a few other issues. What takes more heat to evaporate it, oil or gas? Seeing that the boiling point of oil is much higher I am betting oil does, thus more oil in the mix leaches more heat out of the combustion chamber. *




What takes more heat to evaporate it, oil or gas? Seeing that the boiling point of oil is much higher I am betting oil does,

Ben; I see a potential problem in the logic of this. A material's boiling point is not relative to the amount of heat necessary to evaporate it. Heat, not temperature. Example; water with a boiling point of 212 deg. F. takes much more heat to evaporate it than mineral oil does, although the mineral oil has a much higher boiling point. Look up Specific heat and Latent Heat
I'm not so sure that more oil than sufficient will lower operating temperatures. I do know that running lean fuel to air mixtures will surely raise them though!

Frank


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## bwalker (Oct 17, 2003)

> A material's boiling point is not relative to the amount of heat necessary to evaporate it


Crofter, boiling point is not the term I should have used. I should have instead said end point. The various componets of gasoline generaly evaporate at around 200 degrees or less. The various components of mix oil evaporate at a much higher temp than this(double at least). Now the question remains-Which takes more energy(heat) to evaporate? Oil or Gas? I think you can test this fairly simply by pouring outt a small amount of gas and oil on a hot driveway and noticing which evaporates soonest. I promise I wont tell the EPA.


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## timberwolf (Oct 17, 2003)

I wonder though if the higher measured temps, may have been in part indicating better thermal transfer rather than just higher internal temp.

The temp was measured on the cooling fins with a lazer IR unit.

I tried to find data on the latent heat values for 2 stroke oil, but no luck, gas is about 145 btu/lb. 

But seing the mix oil is such a small % of the charge 0.5% change in the amount of mix oil would have next to zero impact on the total heat removed by evaporation even if it had a higher or lower latent heat value than gas.

I did note in the Stihl manual they recomend 50:1 with their product vs 40:1 with off the shelf 3rd party oil. Some reading on the matter seems to indicate that viscosity has a lot to do with the whole situation.

Manufactures of mix oils want to keep viscosity down to premote power, but must maintain suficient viscosity to make good compression seals and minimize blowby. In fact some mix oils are cut with volitile solvents to reduce viscosity and balance octane. But this reduces the actual amount of oil that is functionaly available to form a film between moving parts. 

All that said if the saw manufacture has no control over 3rd party oil they must build in a safety margine to thier recomendation just to accomodate variation in 3rd party oil products. So if your using the manufactures oil it has been tested to meet the demands of the saw at 50:1 as well as the EPA, but if your using some cheep oil that may be cut with a higher quantity of solvents, than your going to need more of that oil to create the same lubricating film. On the other hand higher quality synthetic stuff uses the properties of the esthers to help balance the octane and may preform as well or beter than the manufactures product.

Most certain EPA weighs into this also as one of the test criteria measures Hydrocarbons, it's a no brainer that if more oil goes into the mix more spits out the muffler. At least that has been a big push in the mariene industry driving mixes up to 100:1 and even 200:1.

TW


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## Crofter (Oct 17, 2003)

*How much oil is enough*

The question I would pose is more oil always better lubrication? What happenings would start to tell you that more oil was becoming harmfull. Taken the other way and diminish the amount of oil and what part of the saw would start to suffer - bearings, cylinder bore, or piston and rings. How little oil is too little. In both of these scenarios mixture would have to be adjusted perhaps by exhaust gas temperature to keep combustion temperature the same.
Too much oil in high speed bearings can create a condition where the roller elements start to slide temporarily instead of rotate. Granted this is probably at higher rpms than in a saw, but it does occur. I mention this just as an example of what seems intuitively right, being wrong in practise.

Frank


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## timberwolf (Oct 17, 2003)

From what I found to read on the matter it sounded like less higher quality - higher viscosity oil was better for wear, but did not produce the highest level of preformance.

So it comes back to the question of do you want it to cut fast or for a long time.


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## Crofter (Oct 17, 2003)

> _Originally posted by bwalker _
> *Crofter, boiling point is not the term I should have used. I should have instead said end point. The various componets of gasoline generaly evaporate at around 200 degrees or less. The various components of mix oil evaporate at a much higher temp than this(double at least). Now the question remains-Which takes more energy(heat) to evaporate? Oil or Gas? I think you can test this fairly simply by pouring outt a small amount of gas and oil on a hot driveway and noticing which evaporates soonest. I promise I wont tell the EPA. *



Ben The analogy of proving which takes more heat to evaporate by putting the gasoline and the oil on the pavement does not prove which takes more BTUs to evaporate since the available temperature of the pavement is not sufficient to evaporate the oil at all while the gas will evaporate readily at room temp.
I dont dispute that oil takes a higher temperature to evaporate but I dont think that relates to its having a higher evaporative cooling effect. I think rather the opposite, but this is definitely armchair engineering on my part. I wouldnt be too quick to entirely dismiss everything Dagger said. I also realize that people such as K Dunn have found that in their modified saws that see service different than a normal saw, that higher oil levels are indicated. 

Frank


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## bwalker (Oct 17, 2003)

> But seing the mix oil is such a small % of the charge 0.5% change in the amount of mix oil would have next to zero impact on the total heat removed by evaporation even if it had a higher or lower latent heat value than gas.


Very true.





> Some reading on the matter seems to indicate that viscosity has a lot to do with the whole situation.


Not really as most pre-mix only(ie aircooled) oils have about the same functional viscosity. Besides viscosity can vary with how much bright stock is used and the amount of diluent needed to cut it. High vis oils would require the most diluent.



> Too much oil in high speed bearings can create a condition where the roller elements start to slide temporarily instead of rotate


 I dont think this is a issue as there are many applications that use ball bearings that are immersed in oil. The ring area could create more drag with more oil. This might be offset with the increased compression that more oil provides for.



> Ben The analogy of proving which takes more heat to evaporate by putting the gasoline and the oil on the pavement does not prove which takes more BTUs


 Crfoter, think about what you just said. Oil takes more btus to evaporate IE higher temp.



> but I dont think that relates to its having a higher evaporative cooling effect. I


 The heat to evaporate the oil has to come from somewhere and in the case of a engine it is the combustion chamber. Off course this coul be offset by the oil haveing more btus. Of course the amount of oil we are talking about when comparing a 32:1 to a 50:1 is very little.


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## 066 stihl (Oct 17, 2003)

Ben

How could more oil create more drag? Have you ever tested the oil ratio? I have in my racing saws and with a tach. They are faster with more oil.

066 stihl


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## bwalker (Oct 17, 2003)

> How could more oil create more drag? Have you ever tested the oil ratio? I have in my racing saws and with a tach. They are faster with more oil.


 IN a basic sense the rings would be plowing through more oil. Sort of like the differance between plowing a 4" of snow and 12" of snow. Also like I mentioned I believ this would be offset by the increased compression that mor eoil lends itself to.


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## Crofter (Oct 17, 2003)

Ben I am not proposing 50;1 as opposed to 40:1 . I personally mix synthetic 40:1 I think though that you are confusing heat with temperature. One is measured in BTU's and the other in Degrees F. etc. Rather like current and voltage in electrical terms.

Also the evaporative cooling effect of a material at a given temperature is a product of how easy something is to vaporize and the factor of its latent heat per unit of weight.

Frank


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## Jacob J. (Oct 17, 2003)

I've been burning 32:1 and 40:1 mixes using half synthetic and half castor oil. The great thing about running castor oil is I don't have to pack a lunch into the unit, I just eat castor fumes all day.


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## Sylvatica (Oct 17, 2003)

I have been running Motul 800 Offroad 2T at 40:1 in premium gas with excellent part longevity and saw performance. 

It is probably the wrong oil at the wrong ratio, but it's the best I've used yet, and luckily have not experienced the dreaded ester+water corrosion.

Also found that Zama carb'ed equipment would not tolerate anything at 32:1. They wouldn't perform well under most circumstances anyway. Will never buy another.

I have never fully figured the cost-benefit basis of this expensive oil for the long term, but at the end of every hot summer, the saws are just newer inside than they used to be with other oils.


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## Crofter (Oct 17, 2003)

> _Originally posted by 066 stihl _
> *
> 
> Have you ever tested the oil ratio? I have in my racing saws and with a tach. They are faster with more oil.
> ...


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## 066 stihl (Oct 17, 2003)

Hi Frank

Yes, on readjusting on the carb setting. They are faster with no load rpm's and in the cut with a stopwatch. In my racing saws on gas I run klotz oil at 25:1. Turning high rpm's and with no big end rod bearing problems.

066 stihl


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## bwalker (Oct 17, 2003)

> I have been running Motul 800 Offroad 2T at 40:1 in premium gas with excellent part longevity and saw performance.


 Motul 800 is a greta oil. If you are having problems running 32:1 with zama carbs it needs to be adjusted properly.


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## max2cam (Oct 18, 2003)

> _Originally posted by TreeCo _
> *
> 
> More oil should equal better lube but if it raises the temperature of the engine it may not be a benefit.
> ...



That's what I'm thinking too. So then why use more oil than what is needed?

This all came up for me when I stuck the piston in my old 024. I thought at first I had forgotten to shake the oil/gas mixture, but came to find that I had an impulse tube ripped in like 5 places. That saw never would idle right. So the stuck piston was probably a lean air-gas mix and not lack of oil. But still, afterwards in my paranoid state, I though more oil would save me next time. 

But maybe not....


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## max2cam (Oct 18, 2003)

> _Originally posted by timberwolf _
> *I wonder though if the higher measured temps, may have been in part indicating better thermal transfer rather than just higher internal temp.
> 
> The temp was measured on the cooling fins with a lazer IR unit.
> ...



I thought about that angle too. You would need internal probes measuring the temps of the piston crown and piston skirt and cylinder wall to really know.

But since heat migrates from a hotter to a cooler area, wouldn't the internal temps have to equal or exceed the temp measured on the outsite? In other words, wouldn't the insides of that engine need to reach a higher temp to get the fins that hot too?

I "think" those small increases in oil just made those engines run hotter....period!

The same type of oil ratio heat tests would be interesting using regular Stihl or Husky oil vs. a full synthetic like MX2T. Would the full synthetic also raise temps like that with more oil?

I want to know more too.....


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## bwalker (Oct 18, 2003)

The tes in question was by no means valid. I suspect the reason for the temp increase was jetting real;ted. When the thread in question was orignaly started I asked a contact I have at Phillips 66 what he though oabout the subject. Hi basic response was that it depends on the oil. stoichemetric ratio, and a few other things. he said most quality oils do not increase temps when used at a 32:! ratio.


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## glens (Oct 24, 2003)

Ben, I think the flaw in your thinking re: "oil is capable of removing more heat from engine parts than is gasoline" has to do with the time factor.&nbsp; Given the time to get the work done, your conclusion is probably valid.&nbsp; I mean, there's no doubt a drum of oil would suck gobs of heat out of a piston immersed in it.&nbsp; I believe you'd find in a 2-stroke-cycle engine running at ~10k the fuel component of the mix is the most responsible for heat removal because, though it's slower, it's got a hell of a hole-shot.

Equate the more-oil mix to a 'vette and the more-fuel mix to a CR500R.&nbsp; In a 16 mile drag race I'd go with the cage as no doubt would you; but I think if you'd join me in pondering the outcome of a 1/16 mile race, you'd probably opt for the other machine along with me.

The relevant factor to this discussion would be the length of the drag race, and I'm thinking in a high-revving chainsaw it would be more like a shorter race than a longer one.&nbsp; Or in other words, there's not the contact time necessary for the oil to outcool the more-refined(?) oil a.k.a. "gasoline".

Your industry friend didn't happen to say that most quality oils at 1/32 <i>decrease</i> temps (as compared to 1/50), did he?&nbsp; A statement like that would be something to chew on.

Here's a thought:&nbsp; suppose, to substantiate your theory that the heat increases were driven by improper carb settings, you could repeat TW's test but instead record the tach readings no-load after each test mix is certainly solely in use.&nbsp; Maybe the best would be to set the carbs to a common no-load speed and then check the temps -- that should better isolate the effect of the ratio on heat.

Glen


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## bwalker (Oct 24, 2003)

> 10k the fuel component of the mix is the most responsible for heat removal because,


 Without a doubt , but only because there is more fuel than oil. Keep in mind a good oil is designed to vaporise in the combustion chamber so it can be combusted. In order to do this it takes heat. All this is really a joke anyway as no one outside of the *** industry would come up with such lame reasons not to use more oil. Do yuo think shifter Kart guys would run 16:1 if it made there engines run hotter?




> could repeat TW's test but instead record the tach readings no-load after each test mix is certainly


Tach readings are a really crude way to measure heat. To do it right you would need a piston with a heat sensor in the crown like SWI sells.
BTW I have seen a cr500 based motard bike spank a zx-7 up to just over a 100 mph. So I think I could spank the vette in at least a 1/8 mile.


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## max2cam (Oct 24, 2003)

I started this thread, but after reading all the posts (some of which are beyond me), I'm left unclear and unsure whether increasing the gas to oil ratio from 50:1 to 40:1 is a good thing or a bad thing (or maybe it doesn't matter?) 

The only thing that I'm somewhat clear about is that using old fashioned dino 2-stroke oil at a higher (more) oil ratio might be a bad thing because dino-oil leaves more deposits on the piston and in the combustion chamber.

I'm tempted to start a poll thread not what you guys think about the best gas-oil ratio, but what ratio you run in everyday use. But I hesitate to start such a thread because the oil topic seems to have been beaten to death many times. 

But if you'd like to just state here what gas-oil ratio you routinely use in your chainsaw I'd appreciate hearing that...


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## bwalker (Oct 24, 2003)

> The only thing that I'm somewhat clear about is that using old fashioned dino 2-stroke oil at a higher (more) oil ratio might be a bad thing because dino-oil leaves more deposits on the piston and in the combustion chamber.


 Max, I bet you would find the oposite to be true. More oil= more detergent and dispersent additives. 40:1 with stihl mix wouldnt be a problem, but mx2t is cheaper and much better quality wise. FWIW I run 32:1 in everything I own that requires mixed fuel.


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## django (Oct 24, 2003)

Mercy! I've been running Echo oil for YEARS at 50-1 in EVERYTHING
from my lawn Boy mower to my old saws to my newer Dolmar saws. No problems. None. It ain't broke, I ain't fixing it. The dynamics of all that is taking place inside the engine while it is running at 12000 RPM is something that I can only speculate about. Also, how "clean" is the air it is sucking in/spitting out? Far more critical to me than 40 or 50 to 1. However, manufacturer's like Stihl, Echo, et al, do the homework. Have the engineers, and most of all, the experience to claim they know best. Acedemic discussions are fine. This stuff is interesting. Mix your oil what the Manf. says to mix it at, or play around with it. SEE what works.


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## stihltech (Oct 24, 2003)

*mix*

OK, explain this one.
I have a customer who has brought in an 026 pro twice now. He runs 32 to 1 pennzoil. The saw will not run correctly. I have dumped out his fuel, put in 50 to 1 Stihl mix, and the saw runs perfect. Fixed jet carb. I have done nothing else to the saw.


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## geofore (Oct 24, 2003)

*mix up*

Moisture in his mix, what do you want to bet he's got water in his mix and doesn't know it. If you want to see if he's over on the oil mix, dump 1/3 of the fuel he uses and add gas to get close to 50 to 1 and see if the saw goes any better.


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## Stumper (Oct 24, 2003)

Strange, I used to run Pennzoil mix(32 or 40/1) years ago-nary a problem.


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## rahtreelimbs (Oct 24, 2003)

*Re: mix up*



> _Originally posted by geofore _
> *Moisture in his mix, what do you want to bet he's got water in his mix and doesn't know it. If you want to see if he's over on the oil mix, dump 1/3 of the fuel he uses and add gas to get close to 50 to 1 and see if the saw goes any better. *




Maybe you have moisture on your brain!!!!


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## bwalker (Oct 24, 2003)

Something is obviously wrong with the mans fuel Stihltech and the fixed jet carb is a pos.


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## stihltech (Oct 25, 2003)

*mix*

OK. But what is wrong if it runs fine on my mix.


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## bwalker (Oct 25, 2003)

Maybe he mixed the oil with kerosene.Who knows. It also coule be a issue that can not be resolved because of the fixed jet. You saw runs corectly with stihl mix I saw I have never seen a 026 run correctly with a fixed jet regardless of mix. They just run better sometimes, but they are allways a comprimise in performance.


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## glens (Oct 25, 2003)

> _Originally posted by bwalker _
> *Tach readings are a really crude way to measure heat.*


I'd think it would be nearly impossible to draw a correlation that way.&nbsp; What I'd had in mind was simply to see if the no-load speed had changed (hence jetting had changed) with the fuel-mix change.


> *BTW I have seen a cr500 based motard bike spank a zx-7 up to just over a 100 mph. So I think I could spank the vette in at least a 1/8 mile. *


I'd given a moment's thought to a good distance figure which could be inverted and considered 1/8 mile to be too long a distance since the 'vette might get a pretty good head of steam by then.&nbsp; I'd figure up to 100 or so too.

How's come you didn't start talking about specific gravity and such in response to Stihltech's query?

Glen


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## Fish (Oct 25, 2003)

I only believe the "physicists" that can spell correctly, call me
old fashioned!


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## bwalker (Oct 25, 2003)

> OK. But what is wrong if it runs fine on my mix.


Its the carb that needs to be adjusted then. So in the case of the 260, ditch the overpriced pOS and get a 346 or put more money into the saw and invest in a adjustable carb.


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## arboles (Oct 25, 2003)

I've been mixing my fuel at 36:1 for years in my saws and bikes too. I've seen dyno tests that prove 50:1 makes more power. I've also read that more oil will actually lean out the fuel air mixture. Dont understand that one at all.


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## bwalker (Oct 25, 2003)

> I've seen dyno tests that prove 50:1 makes more power.


 Where are these test's? The SAE paper I have seen written on the subject by MAC in the seventies came to the conclusion that more oil made more power because of superior ring seal. There are no peer reviewed papers that suggest the opposite that I am aware of. I have searched for these types of papers many times and was able to find nothing. FWIW any hamfist,amsoil salesman with a dyno can come up with a test to validate their views, but peer reviewed reaserch papers are abit harder to dispute.


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## Crofter (Oct 25, 2003)

> _Originally posted by bwalker _
> *Where are these test's? The SAE paper I have seen written on the subject by MAC in the seventies came to the conclusion that more oil made more power because of superior ring seal. There are no peer reviewed papers that suggest the opposite that I am aware of. *



Ben that is pretty old research. The bit about more power because more oil probably helped compression seal leads me to think that the engines used to establish that more oil gives more power, were VERY loosely fitted. In such a setup a functionally very lean mixture can be run providing an excess of oil is present. The functionally lean mixture could be responsible for the high output. In other words the data may have been collected in a very special set of circumstances. In a normally fitted saw do you think more power can be produced with a 16:1 ratio rather than a 50:1
Frank


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## bwalker (Oct 25, 2003)

> In a normally fitted saw do you think more power can be produced with a 16:1 ratio rather than a 50:1


With out a doubt.


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## Crofter (Oct 25, 2003)

Ben: 

Why?

Frank


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## arboles (Oct 25, 2003)

The dyno test I read about was in the late 90's conducted on a Suzuki RM 250 with a liquid cooled two stroke with a power valve used to regulate exaust port timing. If memory serves me correctly, they ran the test using three different ratios and were able to produce the most power (fifty horses) using 50:1

Here's an article I found that you guy might find very intersting.

Psychologists know that when people are confronted by information that goes against their pre-existing ideas, the result is cognitive dissonance, a sort of "static" in the thinking process. It doesn't matter how smart a person is ... cognitive dissonance occurs in highly intelligent people !!

When someone receives information that is opposite to what they think, cognitive dissonance can discredit that information, so that the person won't seriously consider it. In fact, if a new idea drastically opposes one's previously held ideas, the threatening info won't enter their consciousness at all !!! The idea becomes simply 'unthinkable' that it could possibly be true, even with things that are totally obvious to an outside "impartial" observer.

Cognitive dissonance is a primitive, yet amazingly powerful self-preservation mechanism which can completely override the natural human desire for truth !!! It's also the main reason that it's so hard for some to re-think new ideas about how horsepower can be achieved.

Here's a real world example:

Many years ago an engine builder bought an engine from one of my customers at the end of the race season to find out why it was so fast. There it was: high velocity (smaller than stock) ports and there was no way I could hide the secret from my competition any longer. 

Needless to say, I wasn't too happy about it.

To my surprise... after seeing the inside secret to my customers success, seeing the race wins and seeing high speed of the bike, the engine builder refused to see that smaller ports worked, and refused to even try it. That's the incredible power of cognitive dissonance !!


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## Crofter (Oct 25, 2003)

*Cognitive Dissonance!*

Arboles: 
This is priceless. I have had bouts of this malady over the years, but never knew what to call it Sometimes I can feel it coming on and even so it is very hard to shake.

Frank


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## stihltech (Oct 25, 2003)

*026*

Fixed it. Combination of a bad coil and crank seal. Still have my mix in it, we will see what happens when his goes back in.
It runs great, EVEN with the fuxed jet carb. AMAZING!


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## django (Oct 25, 2003)

Cognitive Dissonance! 
Bull headed, pig headed, hard headed, obstinant, obstreperous,
stubborn, Don't confuse me with the facts, I have my mind made up. Generally followed upwith a hearty helping of crow. Been there, done that. 
It's all fun and games 'till someone loses an eye.


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## arboles (Oct 25, 2003)

*Re: Cognitive Dissonance!*



> _Originally posted by Crofter _
> *Arboles:
> This is priceless. I have had bouts of this malady over the years, but never knew what to call it Sometimes I can feel it coming on and even so it is very hard to shake.
> 
> ...


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## glens (Oct 25, 2003)

I've fetched and looked through the article once quickly.&nbsp; I'll read it carefully when the danger of my sessionhash cookie expiring here has passed.&nbsp; The article looks like it contains the same type of viewpoint I currently hold.

As I recall, in the mid-eighties at any rate, it wasn't totally uncommon to clean the cylinders/pistons/rings with acetone just prior to (dry) assembly and the rings would be seated during the first few revolutions.&nbsp; That was with air-cooled 4-stroke bike engines used in road racing, and I have to say I never tried it myself.

Glen


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## glens (Oct 26, 2003)

> _Originally posted by arboles _
> *I've also read that more oil will actually lean out the fuel air mixture. Dont understand that one at all. *


Picture having four aces (representing gasoline parts) and a deuce (representing the oil part) in your left hand, and a stack of chips (representing the amount of air those five cards mix with) in your right.&nbsp; Things are looking and working good, no doubt, with that arrangement.&nbsp; Now take away one of those aces and substitute a five for it.&nbsp; No doubt you'll want to use a smaller stack of chips with <i>that</i> mix (too much chip per ace and you can burn out quickly).

Seriously, if you had 51 units of pre-mix, 1 of which was oil, getting metered with each intake stroke, and then changed it to 51 units containing 1.25 units of oil (from 50:1 to 40:1) you'd be short 0.25 units of fuel in your fuel/air mix, i.e. lean by about a half percent.&nbsp; Naturally, you'll want to increase the number of units admitted from 51 to 51.25 in order to restore the proper balance of fuel/air with your new oil payload.

Glen


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## bwalker (Oct 26, 2003)

> arboles


I didnt see alink to the 50:1 test and there is no way in hell a rm 250 ever made 50 hp.


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## bwalker (Oct 26, 2003)

> It runs great, EVEN with the fuxed jet carb. AMAZING!


 I am sure you think so.


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## vsteel (Oct 26, 2003)

Just a short note on why more oil in the mix makes the engine run leaner. think of it this way, if you have a funnel, can you get a quart of honey or gas poured through it faster? As you keep adding oil to the mix it goes from the flowability of the gas to the flowability of honey. It doesn't change that much, but its kind of the same idea. The funnel represents the jets in your carb.

As for me I use 32:1 synthetic in everything.


Just as a side note, more power is not always a better thing, I read an old dirt bike or dirt rider where they took a rm 250 and messed with differnt octane of gas. The really cheap low octane stuff was making the most power, right up to the time it put the hole in the piston. So while it could be possible that you can make more power from 50:1, that doesn't mean reliability will be anygood.


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## max2cam (Oct 27, 2003)

Arboles: 

The article on cognitive dissonance is great. I'd heard the term, but didn't know the meaning. I may have to incorporate cognitive dissonance it in my work on early Harley-Davidson, as many people find it impossible to believe that H-D didn't build or sell any bikes in 1903 and that it's all a myth.

http://www.atthecreation.com/ 



> _Originally posted by arboles _
> *
> 
> Here's an article I found that you guy might find very intersting.
> ...


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## bwalker (Oct 27, 2003)

*cogntive BS*

There is also something called real life fact and scientific knowledge. I'll take that any day over what seom psychologist comes up with. After all psychology really isnt even a science.


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## Fish (Oct 27, 2003)

I have my hip waders on, and still am having trouble wading
through all of this.

It is possible to get people to believe anything, just takes
some strategy.


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## stihltech (Oct 27, 2003)

*YES!*

My hero!


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## bwalker (Oct 27, 2003)

I learned something long ago. Never trust someones oppinion on a product that they sell or sell against.


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## Crofter (Oct 28, 2003)

*No Cognitive Dissonance Here!*

I thought I was wrong once but I was mistaken!

Frank


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## the GOAT (May 13, 2015)

bwalker said:


> *cogntive BS*
> 
> There is also something called real life fact and scientific knowledge. I'll take that any day over what seom psychologist comes up with. After all psychology really isnt even a science.


This has been going on a long time.


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## president (May 13, 2015)

timberwolf said:


> I wonder though if the higher measured temps, may have been in part indicating better thermal transfer rather than just higher internal temp.
> 
> The temp was measured on the cooling fins with a lazer IR unit.
> 
> ...


good point re heat transfer to cooling fins,never would have considered that


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