Fuel/Oil mix

[ontario026]

Correct me if I am wrong please. The fuel/oil mix for my 026 is 40:1 ??? Up to now I have always measured for 40:1 plus then "tossed in a little extra for good measure" Probably resulting in I'd guess around the 35:1 ballpark.... Is this a good practice? Or should I stick as close to 40:1 if possible????

Thanks guys
Matty

 

[Blowdown1]

so why the 40:1

Why does everyone that extolls the virtues of synthetic, especially the Mobil 1 MX2T (or whatever its called) run it at 40:1?

It seems that if the performance is superior you could run at the manufacturer's reccommended 50:1 and not run the risk of buildup/ash from the extra oil.

OK, this is not a troll. But honestly, for those of you running syn, would you run dino at a higher ratio?

 

[Stumper]

Matty, Tossing in extra "for good measure" isn't really a good practice since it can become inconsistent and be affecting the way the saw runs (honestly though -unless you are realy sloppy in the measuring you'd probably never notice). Stihl recommends 50/1, Most of us use 32/1 carefully measured. You could probably run 40/1 with no problems but I'd switch to 32/1 MEASURED.

 

[Stumper]

Blowdown, Becase most of us worry more about inadequate lubrication than we do about carbon buidup. The Mobil MX2T is great because it tends to be super clean. Yes it could be run at 50/1 but is 50/1 recommended because it is best for the saw or because it reduces particulate emissions? Most of us(who run 32/1 or 40/1) suspect the second reason.

 

[Lewis Brander]

Fuel/Oil Mix:

Hello to all. In my older saws I've ran 20/1 using Mobil 1, MX2T Oil and find that it gets blowen mostly out the exhaust and can be pretty messey. With the improvements in the oils today I now use a 32/1 mix in my older saws and they run just fine on it, from what I can tell. Any saw that runs a 50/1 mix will probably run on that mix just fine as long as you stay away from over reving the saw out of the cut, BUT for myself I'd run a 40/1 mix for added piece of mind. I also measure the gas and the oil exactly. I don't rely on the gas pump being calibrated correctly or someone else doing my mixing. Also, you should only mix up what you plan to use for the day, so that each day your have a fresh gas/oil mix for the saw. Be sure to shake up the gas/oil mix each time you fill the saw. I also use "Fuel Stabill" in all my gas for small engines, winter and summer. JMO. Take care. Lewis.

 

[begleytree]

Didn't someone here do a test a while back? Showed higher head temps with the lower (32 and 40:1) mix ratios? I'd want to keep the engine temps lower myself, heat kills.
Justin, I see a very noticeable difference in how my saws run at 32:1, (very poorly, with lots of smoke) I run (always have, regardless the tests) castrol super 2 stroke, mixed 50:1 with prem unleaded with no problems, and little to no smoke. My saws start easier on 50:1 (to me) and rev better (again, to me, no tach, tune by ear)
I suspect 50:1 is recommended by manufacturer because the saw runs as designed, the intelli carb was supposed to be for emissions, not mix ratios. Seeing as I'm an end user, as opposed to a new product engineer, I'll follow their recommendations. Same as I purchase saws, chipers, buckets, rope, ect because they build them better than I could, and have extensive product testing, support, ect.
What's the sense in purchasing equipment based upon dealer support, if you don't follow the manufacturers/dealers advice?
-Ralph

 

[Stumper]

Ralph, What can I say? I usually follow directions well-but not about mix ratios. Mine don't smoke at 32/1. Perhaps that is because my carbs are adjusted using that mix ratio?. I never have bought a saw based upon dealer support. I started out without a decent saw mechanic in the area I was living-did things for myself. Then moved to where I had a saw mechanic that isn't brand specific-he'll happily work on anything. Since I have lots of saws now if one goes down it is no biggie waiting on a parts order. Different (2) strokes for different folks.

 

[begleytree]

I usually follow directions well.

me too

You ever use Klotz in your saws? I ran 5 gal about a month ago, mix 50:1, really no difference, except I love the smell!
-Ralph

 

[Stumper]

I have never used Klotz products (don't even know if they are available in this area). Were you running their 2 cycle oil or their special racing fuel? My Firewood guy is a Stihl fan-everthing from 044s to 088s and he runs Stihl oil. He always comments about the smell of my saws-How it reminds him of his motorcycle racing days. -A nice reason for using Synthetic I suppose.

 

[begleytree]

oops, yeah, their 2 stroke mix oil, mostly used here in dirtbikes and 2 stroke 4 wheelers.
Kinda miss the smell, might have to switch over, use it full time.
I'll send you a qt if you can't get it locally
-Ralph

 

[Fish]

Ralph,
go back and do a search of the threads by a member named "Dagger". He worked
in the industry and his team did tests proving lower temps with the recommended
50-1 ratios. Of course it did little to sway this hard headed bunch, but I believed
him anyway.

 

[WRW]

Hope Dagger doesn't mind:



"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..
JEEZ,... and air-cooled 2 stroke saw engine is NOT really aircooled..75 to 80 %of the cooling is effected by the fuel,,the remainder by air.
As we were struggling to get our RPMs up higher than the other guy..but still having to give a warranty as demanded by the sales dept, alot of things came in to consideration..
keep down the heat...a cooler engine last longer!
FACT: GAS cools BETTER than oil
FACT: GAS burns better and cleaner than oil (no , we didnt care about smoke)it was unburned deposits in the combustion chamber, ending up in the ring grooves and on the piston walls causing siezures...and oh man..we had alot a that in the early days
we found nika-sil helped keep the heat that was building up in the walls from transferring to the piston...which we could keep cool by the fuel on BOTH sides of better than we could keep the jug cool. (*** below)..( no , it wasnt to make the bore slicker!)

"FACT: the design CLEARANCE TOLERANCES and rpm level and side load factor dictate how much oil is needed..tighter tolerances...LESS OIL FILM THICKNESS..meaning less required in the ratio..we can caculate a volume requirement from this...
in other words % air/fuel (about 28 to one for highest cylinder pressure) X CFM's( that engine is just an air pump right?)
convert that to a volumetric measurement of your choice and we know how much fuel we have going thru the engine...now.in that much fuel, we put in the amount of oil need for lubrication..as dictated by above criteria..add a certain safety factor..(industry standard of 1.25 to 1.5 ) to help us get thru the warranty period whilst all them "EXPERTS" were fooling with the carb adjustments to make em run faster.
that is how manufacturers determine the recommended ratio
NOW..convince the public that MORE is NOT BETTER!
we have been trying to do that for years!
RULE..
a leaner oil mix ratio has better cooling properties than a heavier ratio. DUE to higher volatility (evaporative properities) of gas than oil.
unburned oil looks like varnish and gets "painted" on the piston skirt/sides..this in effect makes the piston "bigger" in the bore and decreases the thickness of the oil film.
This will lead to premature failure..

"Why would a manufacturer, who must guarantee his equipment, recommend anything other than the absoulte BEST ratio for it?
Why would a manufacturer spend countless dollars on service schools for their dealers trying to explain just why a higher ratio/MORE oil is bad?

"Some a you guys give me bad dreams!"

That's what he said.

 

[bwalker]

Dagger was wrong......

 

[Stumper]

Ben, I'm a 32/1 man but WHY was Dagger wrong?

We have hashed this before but it is still interesting and some of the new guys missed the fun. Long ago I started out with saws that "required" 16/1 mix. I soon adquired saws that called for 32/1. I reasoned from homespun logic that extra oil is better than not enough so I continued to run 16/1 in everything. Yes it smoked and it built carbon deposits in the exhaust port. I cleaned plugs and exhaust port occassionally and had no problems. New saws came out calling for 40/1. I met a saw mechanic who demonstrated a degree of competence. He told me that the difference isn't the tolerances in the engine but mostly the lubricating quality of the oils-"Run 40/1 in everything". I believed him but couldn't quite bring myself to put so little oil in the mix. I "compromised" at 32/1 -half of what I used to run but more than what the new saws called for. All my saws continued to run...and run and run and run. I noticed when I found this site that the highperformance saw mechanics seemed to favor 32/1. It works for me. Convince me that less is more and I'll change but CONVINCE me. I know that 32/1 works.

 

[Stumper]

P.S. If less oil is better why do all the manufacturers say to double the oil ratio if their oil isn't used? Yeah I know -they are worried about oil quality. If brand X has less "bright stock" then more oil will make up for it.........More oil makes up.....hmmm. Which is more serious? That terrible increase in heat fron doubling the oil content or that terrible increase in heat due to friction from inadequate oil? I think I know what the makers really think!

 

[Al Smith]

Hard headed?

Now who said that?Tsk,tsk!Bad dreams,no,way.50 to 1,good idea,in somebody else's saw.Mine do just okie -dokey on 32 to 1.

 

[glens]

I'd be inclined to agree with dagger on this.  I have absolutely no qualms about running at 40:1 with the MX2T since I know it works and works well.  Everything inside the engine is shiny and wet with oil, so why in the world would I want to throw more away?

Here's an AS search result to a couple of his posts (terms = gas cools oil, user = dagger, return individual posts; in case the link goes bad for some reason)

Glen

 

[bwalker]

Dagger's knowledge was circa the 70's.
I dont have the energy to go into depth right now, but consider this. Put gasoline into a teaspoon and heat it with a propane torch. Now do the same to mix oil. Which takes more BTU's to evaporate?

 

[bwalker]

BTW consider that the differance in oil content between 32 and 50:1 is only 1%.
Even if oil burned hotter, which it doesnt 1% would have hardly any effect and could easily be off set by things like decreased friction and better heat transfer.
Also consider that some of the highest stress air cooled applications like Yamaha KT 100 kart engines use a 16:1 and heat is very much a issue with these engines. If less oil did indeed lead to lest heat the Kart racers would be on the band wagon. many times in kart racing its not the person with the most power that wins. Its the person whos motor can SUSTAIN the most power for prolonged periods with becoming heat soaked.

 

[Crofter]

Ben If the oil doesnt evaporate, it absorbs no energy via change of state. Your analogy is flawed I think, but we have been here before too. A higher temperature to vaporise doesn't equate with a higher " latent heat". Also, Temperature and Heat are different things, but dont take my word, look it up!