Two-Stroke Oils: All the Same?

[Backstage]

Not to add 'fuel to the fire', but what is wrong with Stihl HP ULtra? Have been running it for years 1:50 or a bit richer, mainly in my 2 026's. Seems to burn quite cleanly...
If I'm not mistaken, it's also the oil they use in their 'Motomix' 2-stroke alkylate fuel.

Take a look down your spark plug or take off the muffler. It leaves a lot of carbon.

I’m willing to grant the possibility that if you’re using it at high temps constantly, like for a chainsaw mill or high volume logging, it would burn a bit cleaner. Even for that though, it’s not what it should be.

 

[Backstage]

Come on guys. Let's here it from the 100 to 1 crowd....

I’ll bite!

Trying Amsoil saber at that ratio this year. Obviously no results to report yet, but there’s more than a few folks who are running this way.

The saw manufacturer specifies an oil ratio based on a combination of the EPA requirements and what they have to assume is the worst oil saws are likely to see, and assuming people are going to run lean (ie: not fulling pouring the bottle out, so, say, 60:1).

Decades past, saw makers needed to specify running richer ratios because the oil sucked, less data was available on what would ruin a saw or how to build a saw, and tolerances were less exact.

So all that boils down to: follow the directions on the BOTTLE, not on the SAW.
Stihl/Husky/Echo etc CAN’T put 100:1 on their saw because they know everyone is not going to be using amsoil or similar products. Similarly, Stihl/Husky oil says 50:1 because you CAN’T run 100:1 with that product without ruining your saw.

 

[bwalker]

Take a look down your spark plug or take off the muffler. It leaves a lot of carbon.

I’m willing to grant the possibility that if you’re using it at high temps constantly, like for a chainsaw mill or high volume logging, it would burn a bit cleaner. Even for that though, it’s not what it should be.

Actually high temps would make it worst in all likelihood.

 

[bwalker]

Any oil that's actually Jaso FC or FD certified is going to work very well in your equipment. If it's not actually certified you are rolling the dice/guessing.

Echo Red Armor is very good oil.

 

[Backstage]

Actually high temps would make it worst in all likelihood.

I would have assumed that not running cool and limited idle time would burn cleaner?

 

[bwalker]

I’ll bite!

Trying Amsoil saber at that ratio this year. Obviously no results to report yet, but there’s more than a few folks who are running this way.

The saw manufacturer specifies an oil ratio based on a combination of the EPA requirements and what they have to assume is the worst oil saws are likely to see, and assuming people are going to run lean (ie: not fulling pouring the bottle out, so, say, 60:1).

Decades past, saw makers needed to specify running richer ratios because the oil sucked, less data was available on what would ruin a saw or how to build a saw, and tolerances were less exact.

So all that boils down to: follow the directions on the BOTTLE, not on the SAW.
Stihl/Husky/Echo etc CAN’T put 100:1 on their saw because they know everyone is not going to be using amsoil or similar products. Similarly, Stihl/Husky oil says 50:1 because you CAN’T run 100:1 with that product without ruining your saw.

What is the advantage to using less oil in a marginally lubricated motor?
The EPA has no requirements on mix ratios. They set exhaust emmissions. Two stroke oil contributes minimally to exhaust emmissions.
Oil ratios are set by the manufacturers not based on optimal engine life, but on things like spark plug life with poor tuning, visible smoke with poor tuning etc.

 

[SimonHS]

I’ll bite!

Trying Amsoil saber at that ratio this year. Obviously no results to report yet, but there’s more than a few folks who are running this way.

The saw manufacturer specifies an oil ratio based on a combination of the EPA requirements and what they have to assume is the worst oil saws are likely to see, and assuming people are going to run lean (ie: not fulling pouring the bottle out, so, say, 60:1).

Decades past, saw makers needed to specify running richer ratios because the oil sucked, less data was available on what would ruin a saw or how to build a saw, and tolerances were less exact.

So all that boils down to: follow the directions on the BOTTLE, not on the SAW.
Stihl/Husky/Echo etc CAN’T put 100:1 on their saw because they know everyone is not going to be using amsoil or similar products. Similarly, Stihl/Husky oil says 50:1 because you CAN’T run 100:1 with that product without ruining your saw.

It will be interesting to see how you get on. Please give us a report now and again. What saws are you running it in?

 

[bwalker]

I would have assumed that not running cool and limited idle time would burn cleaner?

The problem with ultra and all ashless dispersent type oils is the dispersent only functions up to about 300 degrees. After that its completely useless. As such running the engine hotter only makes things worse. Running cool/rich typically dirty the exhaust port and muffler, but the piston remains clean.
Conversely low ash, Jaso FC/FD oils use mettalic based detergents that function well above 300 degrees.
Ashless oils can be identified easily by smelling them. The ashless dispersent is a nitrogen based amine and they stink.

 

[Backstage]

It will be interesting to see how you get on. Please give us a report now and again. What saws are you running it in?

Give me a few years. Nothing worse than “unboxing reviews”.

However, I’ll probably take some muffler/cylinder temperatures with Stihl ultra vs the amsoil during cutting this year.

 

[bwalker]

Give me a few years. Nothing worse than “unboxing reviews”.

However, I’ll probably take some muffler/cylinder temperatures with Stihl ultra vs the amsoil during cutting this year.

There are so many variables that effect muffler temp readings that's it's really not of much value.

 

[Backstage]

What is the advantage to using less oil in a marginally lubricated motor?
The EPA has no requirements on mix ratios. They set exhaust emmissions. Two stroke oil contributes minimally to exhaust emmissions.
Oil ratios are set by the manufacturers not based on optimal engine life, but on things like spark plug life with poor tuning, visible smoke with poor tuning etc.

I don’t claim to be an expert here, just what I’ve seen of other people‘s findings and claims. So feel free to join that group and correct me where I’m off course.

More fuel in the engine vs less oil without sacrificing lubrication? That means cleaner burning, less carbon, less gunk, longer engine life, etc. Also, the oil is burning hotter and slower than the gas. Hotter cylinder, less available power.

Some guys are interested in saving $1/gallon because they can use half the oil, but that’s not my interest at the volume I’m operating at.

In all honesty, I’ll most likely do some testing with the IR thermometer and noodling around for a few tankfuls at the 100:1, then jump back to the amsoil alternate 80:1 recommendation, do some more noodling and testing, etc.

 

[Backstage]

There are so many variables that effect muffler temp readings that's it's really not of much value.

Agreed, it’s a single data point, not a conclusive, comprehensive test. The comprehensive test will be pulling the cylinder after several years.

I’ve seen the videos where they fail to adjust for tuning whatsoever and introduce that as a variable, so I’ll be playing with this on an autotune saw.

 

[bwalker]

I don’t claim to be an expert here, just what I’ve seen of other people‘s findings and claims. So feel free to join that group and correct me where I’m off course.

More fuel in the engine vs less oil without sacrificing lubrication? That means cleaner burning, less carbon, less gunk, longer engine life, etc. Also, the oil is burning hotter and slower than the gas. Hotter cylinder, less available power.

Some guys are interested in saving $1/gallon because they can use half the oil, but that’s not my interest at the volume I’m operating at.

In all honesty, I’ll most likely do some testing with the IR thermometer and noodling around for a few tankfuls at the 100:1, then jump back to the amsoil alternate 80:1 recommendation, do some more noodling and testing, etc.

The amount of fuel passing through the engine does not change with mix ratio assuming your tuned properly. The oil in a two stroke is deposited in the crankcase when the liquid fuel flashes to vapor. The oil then migrates up into the combustion chamber where it coats the surface of the piston ETC as it's still a liquid. When the spark plug fires the fuel in vapor form begins to combust. The heat from this combustion then flashes the oil to vapor where it is then burnt. It may burn slightly hotter than gasoline as it has more BTU's based on its density. But these imcreased BTU's also contribute to moving the piston. Combustion characteristics of good oil doesn't inhibit combustion.
Carbon,gunk etc, comes from the oil type and tuning, not the ratio. Engines tuned well running at something like 20:1 with the proper oil are very clean internally IME. Why wouldn't they be? You are passing more detergents through the engine. Further more much of the deposits formed in a two stroke come from the terrible quality gasoline we have in the US and Canada.

 

[bwalker]

One thing to consider with 100:1 oils. They leave less residual oil to protect your motor from corrosion. They are also typicly ester based oils which have lousy corrosion protection properties to begin with. On top of that less residual oil leads to more wear at startup when Hou have alot of liquid fuel wiping oil off the engines internal surfaces.

 

[sean donato]

The amount of fuel passing through the engine does not change with mix ratio assuming your tuned properly. The oil in a two stroke is deposited in the crankcase when the liquid fuel flashes to vapor. The oil then migrates up into the combustion chamber where it coats the surface of the piston ETC as it's still a liquid. When the spark plug fires the fuel in vapor form begins to combust. The heat from this combustion then flashes the oil to vapor where it is then burnt. It may burn slightly hotter than gasoline as it has more BTU's based on its density. But these imcreased BTU's also contribute to moving the piston. Combustion characteristics of good oil doesn't inhibit combustion.
Carbon,gunk etc, comes from the oil type and tuning, not the ratio. Engines tuned well running at something like 20:1 with the proper oil are very clean internally IME. Why wouldn't they be? You are passing more detergents through the engine. Further more much of the deposits formed in a two stroke come from the terrible quality gasoline we have in the US and Canada.

To add to this thought. I'm big into 1/5 scale rc. 2 stroke powered to be more exact. 25 to 1 is considered a standard ratio. The engines are a good bit more high performance then our saws, however even at the higher mix ratios its rare to see an engine in good tune carbon up internally with a decent oil. Does seem there is a lot of oil that migrates out into the pipe though. The pure castor guys complain a lot about Carbon build up.
I'm lazy and run the same 40 to 1 mix in my rc engines that I run in my saws. Thought i had pictures of my little g320 zen when I tore it down for port work. At the time it had a little over 20 gallons through it, and looked like new internally.

 

[Backstage]

The amount of fuel passing through the engine does not change with mix ratio assuming your tuned properly.

Agreed, mostly. Your tune will NEED to go slightly richer for a 10:1 (ad absurdum example) because you’re introducing less burnable fuel into the engine per stroke.

Carbon,gunk etc, comes from the oil type and tuning, not the ratio. Engines tuned well running at something like 20:1 with the proper oil are very clean internally IME. Why wouldn't they be? You are passing more detergents through the engine. Further more much of the deposits formed in a two stroke come from the terrible quality gasoline we have in the US and Canada.

Correct assuming good tuning and quality oil, and completely agreed. Until you hit the spark arrestor. Cooled, partially partially burned oil hitting a metal mesh surface creates predictable results. I know, just clean your #$%& spark arrestor once in awhile, no problem.

That slower burn of the oil should also have some effect on the timing itself. Faster burn…equals an advance? Having trouble visualizing the run right now, but I think that’s right. Probably a small change either way.

Also agreed on the terrible quality fuel as well. I’ve even seen problems from the canned premix stuff.

From the results people are having with the saber oil, it’s actually doing as good if not better job leaving a coating than the traditional mix oils. Another thing to monitor in actual use. I’ll be pulling muffler and checking the saw cold.

 

[sean donato]

I've been told the addition of the oil lessens the octane rating of the gas, but I have no way to confirm this and have no idea if it's just an old wife's tale.

 

[bwalker]

To add to this thought. I'm big into 1/5 scale rc. 2 stroke powered to be more exact. 25 to 1 is considered a standard ratio. The engines are a good bit more high performance then our saws, however even at the higher mix ratios its rare to see an engine in good tune carbon up internally with a decent oil. Does seem there is a lot of oil that migrates out into the pipe though. The pure castor guys complain a lot about Carbon build up.
I'm lazy and run the same 40 to 1 mix in my rc engines that I run in my saws. Thought i had pictures of my little g320 zen when I tore it down for port work. At the time it had a little over 20 gallons through it, and looked like new internally.

Sean, you are running those on alky though, right?

 

[bwalker]

Agreed, mostly. Your tune will NEED to go slightly richer for a 10:1 (ad absurdum example) because you’re introducing less burnable fuel into the engine per stroke.


Correct assuming good tuning and quality oil, and completely agreed. Until you hit the spark arrestor. Cooled, partially partially burned oil hitting a metal mesh surface creates predictable results. I know, just clean your #$%& spark arrestor once in awhile, no problem.

That slower burn of the oil should also have some effect on the timing itself. Faster burn…equals an advance? Having trouble visualizing the run right now, but I think that’s right. Probably a small change either way.

Also agreed on the terrible quality fuel as well. I’ve even seen problems from the canned premix stuff.

From the results people are having with the saber oil, it’s actually doing as good if not better job leaving a coating than the traditional mix oils. Another thing to monitor in actual use. I’ll be pulling muffler and checking the saw cold.

I've never, ever had to clean a spark arrestor screen running 32:1. If you do it's a tuning issue or a oil quality issue.
You are assuming oil burns slower. It may or may not. A good oil does not effect the combustion process at all at all.
Residual is mostly a product of how much oil is in your mix. I say mostly because Red Armor oil for some reason unknown to me really coats the engine internals even at 50:1. Indont have an answer as to why.
I did run some Saber at 50:1 years back and didn't notice any more residual than I would expect for the ratio.

 

[bwalker]

I've been told the addition of the oil lessens the octane rating of the gas, but I have no way to confirm this and have no idea if it's just an old wife's tale.

It may or may not. Honda HP2 uses Cumene as a diluent so it likely boosts octane.
Regardless, Octane is of no consequence to a chainsaw as they have pathetically low compression ratios.