Two-Stroke Oils: All the Same?

[KostasVolos]

Both ratios were tried within minutes of each other. I was running 40:1 Trufuel, somehow a can of 50:1 got snuck in. I dumped it in the saw, had to tune richer for the 50:1, and leaner again for the 40:1.

The oil burns. If it's not dripping out the muffler, then it's burning, and contributing to the fuel load.

Oil may not be getting to the combustion chamber as a vapor, but it is getting atomized, which will burn just fine. That's how diesel fuel injectors work, and the earliest ones even used compressed air. What kind of velocity is the oil pushed through the transfer ports at? Like driving a drop of oil through a straw with an air compressor.

If I'm not being mistaken :

1) Synthetic oils do not burn.
Yet engines seem to produce a bit
more power when the mix oil used is of the synthetic kind.

2) A Diesel engine has far different
arrangement and geometry than
a gasoline engine,exactly because the former is able to use any kind of oil as fuel ( never mind the possibly clogged filters ,pumps and injectors /becks ) .

3) Oil when combusted produces a low velocity gas expansion ,with
relatively "heavy" (high density) smoke as byproduct.Heavy smoke means more inertia.
( Why diesel engines do work with
lower revs per minute in comparison with a same cc /c inch gasoline engine ? Because of
lower "piston linear speed" ... )
The gas volume produced from oil is more than the one of the combustion of gasoline ,but it's velocity is low.
Different combination of bore vs stroke has to be used to work with
these conditions ( like in a Diesel engine ) .

Diesel engines run more efficiently than gasoline ones due to large volume of gas produced per mass unit of fuel.
Heat generated dissipates more
efficiently due to larger stroke.

But gasoline engines are more powerful because of the high velocity of gas produced inside the cylinder.Thus the larger bore and the shorter stroke (more revs per minute ) .

In a diesel powered chainsaw (!) ,the combustion of oil may contribute to the operation of the former.
Not so much in a gasoline powered chainsaw.
But rather on the contrary .

 

[Tomos770]

 

[Pioneer]

For what it's worth, some JASO ratings of 2-stroke oils. Scroll to the bottom of the page for the pdf.

https://www.mototribology.com/articles/jaso-explained-part-2-2-stroke
Just out of curiosity, I went into the garage where it is -20c right now to see if any of my oils will flow at that temperature. Most 4 stroke oils including 5-40 synthetic, no problem. 20-50 regular oil, poorly. Bar oil, not quite as bad as the 20-50. ATF, excellent. Opti 2, not bad, a bit slower than 5-40 synthetic. Castrol 2t, forget it! pretty much a gel.
Temperature may be the deciding factor in which oils you use if you have to cut in some really extreme cases.

 

[sean donato]

If I'm not being mistaken :

1) Synthetic oils do not burn.
Yet engines seem to produce a bit
more power when the mix oil used is of the synthetic kind.

2) A Diesel engine has far different
arrangement and geometry than
a gasoline engine,exactly because the former is able to use any kind of oil as fuel ( never mind the possibly clogged filters ,pumps and injectors /becks ) .

3) Oil when combusted produces a low velocity gas expansion ,with
relatively "heavy" (high density) smoke as byproduct.Heavy smoke means more inertia.
( Why diesel engines do work with
lower revs per minute in comparison with a same cc /c inch gasoline engine ? Because of
lower "piston linear speed" ... )
The gas volume produced from oil is more than the one of the combustion of gasoline ,but it's velocity is low.
Different combination of bore vs stroke has to be used to work with
these conditions ( like in a Diesel engine ) .

Diesel engines run more efficiently than gasoline ones due to large volume of gas produced per mass unit of fuel.
Heat generated dissipates more
efficiently due to larger stroke.

But gasoline engines are more powerful because of the high velocity of gas produced inside the cylinder.Thus the larger bore and the shorter stroke (more revs per minute ) .

In a diesel powered chainsaw (!) ,the combustion of oil may contribute to the operation of the former.
Not so much in a gasoline powered chainsaw.
But rather on the contrary .

No offense buddy, but you don't have a clue how an engine works, or the difference between a spark ignition engine and compression ignition engine.

 

[Highlander1959]

I've seen and read a lot of these 2-stroke oil "discussions" and they never disappoint. Personally, I've used Pennzoil synthetic marine oil in all my saws and other 2-stroke engines since it came out. I mix at 40:1 and I have yet to burn up a piston or cylinder. Maybe I don't push my equipment as hard as some do or maybe I've just been lucky but it is what it is. I even have four Poulan 3400's that were designed to be run on a 16:1 mix and they've been doing fine on the 40:1 Pennzoil. One evening, I had a guy at the local watering hole tell me that was was crazy to use anything but Lucas oil in my car, and that all the other oils would destroy my engine. That was 245,000 miles ago and it turns out he was working for Lucas. My advice? Take everything people tell you about oils with a grain of salt and use whatever works for you.

 

[ihookem]

For what it's worth, I run Saber at 66:1 in my paramotor, and have for YEARS. Single cylinder, 190cc 2-stroke, air cooled. All other equipment gets Saber at 100:1, even customer's equipment. Haven't had one yet come back with lubrication-related issues.

View attachment 1026061

NOW that tells me you trust your oil. As for me, I have a 32 yr. old Stihl and ran everything there is from the cheapest junk when I was poor, to Saber at 128/1 and never had a problem.. I settled on 50/1 Saber and called it good. I'm all but done trying to find good oil . It seems to all work fine.. I might go to some cheap stuff if it says FD. Saber is up to $17.50 qt. so it's getting high but it might be worth it. EDIT: When it comes to stroke oil threads, it is proof that we are worse than any woman on this earth... Final Answer,,, just use what has never failed you . It makes no sense to say one oil is junk , and the next guy says he used it for 10 yrs. and never had a problem.

 

[damifino]

NOW that tells me you trust your oil. As for me, I have a 32 yr. old Stihl and ran everything there is from the cheapest junk when I was poor, to Saber at 128/1 and never had a problem.. I settled on 50/1 Saber and called it good. I'm all but done trying to find good oil . It seems to all work fine.. I might go to some cheap stuff if it says FD. Saber is up to $17.50 qt. so it's getting high but it might be worth it. EDIT: When it comes to stroke oil threads, it is proof that we are worse than any woman on this earth... Final Answer,,, just use what has never failed you . It makes no sense to say one oil is junk , and the next guy says he used it for 10 yrs. and never had a problem.

Ahh.... but that's the esscence of an "oil thread" ....... breath it in.....

 

[Chevboy0167]

 

[jellyroll]

 

[dave ensign]

Olive Oil but only extra extra virgin.

 

[hotajax]

I've had great results with Echo Power Blend, think I'll try Red Armor next. I mix 40:1 for everything.

Yeah, both good. Red Armor, you need to offer up your first-born to pay for it.

 

[hotajax]

Olive Oil but only extra extra virgin.

On your tomatoes and fried onions

 

[Grouse Hunter]

I've had good results both with performance and cleanliness of piston, and ports with Red Line 2 cycle racing oil.

 

[bwalker]

I've had good results both with performance and cleanliness of piston, and ports with Red Line 2 cycle racing oil.

About the only oil besides marine oil that I would say absolutely do not run.
I ran alot of the stuff back in the day and the pistons and ports looked perfect. By looks alone one of the best oils I have seen. The problem is it also corroded the brass jets in my carb black and my crank was covered in rust.
Its really a racing oil ment for something torn down often and it's gross over kill in a saw.
Just run a FD certified oil.