Oil mix concentrations

[AIM]

I've always wondered why different 2 strokes require different concentrations. Some are 16-1 some are 100-1 and everything in between. It seems like they would all be the same.

The only explanation I could think of is that different rated rpm's might require different protection but that is just a guess.

Anyone know the REAL reason for the difference?

 

[Bigdgb]

oh an oil thred?opcorn:

next please

 

[AIM]

oh an oil thred?opcorn:

next please

Well I'll take it that you don't have a clue why there are different concentrations.

 

[kevin j]

you will soon see why 'oil thread' is the inside joke.


two reasons:
1. application
engine loads and design, types of bearings, materials, rpm. Our observed trials engines run 80:1 routinely, some go 100:1 but not me. While there is enough lube in the crankcase surfaces for a long WOT hillclimb, that ratio would not work long term in a road racer or MX for instance.


2. oil quality
Manuals from old equipment might have said a half pint of SAE 30 engine oil, or something like that because that was the only source of oil available. Now, much better engine machining, and incredible advances in oil chemistry.



Don't over think it, or get so extreme with syringe measuring, etc that some do.
No ethanol fuel, 50:1 more or less, Amsoil sythetic Sabre 100:1 label, works for me in all small equipment.

Anything more complicated than that, Gary will have to chime in

 

[Bigdgb]

Well I'll take it that you don't have a clue why there are different concentrations.

sure sure sure, now just put oil mix in the search bar and you will get 50,000 different conentrations just to help you mix it up a bit

 

[AIM]

Yes I have read many of the oil threads and I do understand the "another oil thread" saying.

This isn't about which oil is best, I know what oils I like. This is just about why diff manufacturers of diff items want diff mix ratios. Seems to me that a bearing is a bearing. A piston is a piston. Why would the 2 stroke rototiller that I have says 32-1 and yet my yamaha golf cart says 100-1. They are both identically designed. (well not identical but you know what I mean)
So we have 2, single cylinder 2-strokes. Both air cooled. Yet both need a vastly diff ratio.

And here is another thing.
A friend of mine has an old 2 stroke mini bike that says right on the tank cap 16-1. He has ran the same spark plug in this bike for as long as he can remember. I'll bet my golf cart would foul out a plug in a day if I ran 16-1. This just confuses me as well..

 

[mikefunaro]

Yes I have read many of the oil threads and I do understand the "another oil thread" saying.

This isn't about which oil is best, I know what oils I like. This is just about why diff manufacturers of diff items want diff mix ratios. Seems to me that a bearing is a bearing. A piston is a piston. Why would the 2 stroke rototiller that I have says 32-1 and yet my yamaha golf cart says 100-1. They are both identically designed. (well not identical but you know what I mean)
So we have 2, single cylinder 2-strokes. Both air cooled. Yet both need a vastly diff ratio.

And here is another thing.
A friend of mine has an old 2 stroke mini bike that says right on the tank cap 16-1. He has ran the same spark plug in this bike for as long as he can remember. I'll bet my golf cart would foul out a plug in a day if I ran 16-1. This just confuses me as well..

A lot of it has to do with the quality of oil that was intended to be used with the machine and how old it is. You wont find stuff from the 70s and 80s that recommended 50:1 mix because the oil at that time wasn't sufficiently advanced to support that lean of a ratio.

 

[rupedoggy]

A lot of it has to do with the quality of oil that was intended to be used with the machine and how old it is. You wont find stuff from the 70s and 80s that recommended 50:1 mix because the oil at that time wasn't sufficiently advanced to support that lean of a ratio.

Maybe the EPA wasn't sticking their nose into it, in the 70s.

 

[o8f150]

i just run everything at 45:1,, as long as you are using a good oil you are fine

 

[BigMoneyGrip]

I think the ratio is more to do with the oil rather than the application. But, that's just the way I think. I've never had an oil related failure and I've been around 2-strokes for over 30 years. The technology in oil has increased ten fold over the last 15 years. Pretty much anything synthetic is gonna do just fine.

 

[AIM]

I just roasted my golf cart a few weeks ago. That is what got me thinking about this.

My 81 yamaha G1 cart was designed to run 100-1 ratio. Well being the guy I am I drilled out the governer so it would go a lot faster. Well it did indeed run a lot faster and did so for a couple years. Finally I seized her up. The guy I ordered my parts from told me that I should have upped my oil to 50-1 after I drilled out the governer. Just seemed to me that if 100-1 was fine before why is 50-1 better now?
That is why I suspected the "Manufacturers Intended RPM Range" to be the deciding factor on ratio.
But again I was just guessing.

 

[BigMoneyGrip]

I just roasted my golf cart a few weeks ago. That is what got me thinking about this.

My 81 yamaha G1 cart was designed to run 100-1 ratio. Well being the guy I am I drilled out the governer so it would go a lot faster. Well it did indeed run a lot faster and did so for a couple years. Finally I seized her up. The guy I ordered my parts from told me that I should have upped my oil to 50-1 after I drilled out the governer. Just seemed to me that if 100-1 was fine before why is 50-1 better now?
That is why I suspected the "Manufacturers Intended RPM Range" to be the deciding factor on ratio.
But again I was just guessing.

Another thing you'll have to look at is the jetting. Turning a lower RPM, you can get away with leaner jetting. Start twisting that baby up with the same jetting and you'll cook it.

I also think that the newer coatings (nikasil) and machining techniques play a part in the oil ratio needed.

 

[Ifishsum]

For a long time I wondered the same thing. My conclusions FWIW: An engine manufacturer will recommend a mix ratio based on the oil they choose to brand with their name or the brand they recommend at the time of production, and whatever testing they have done with it. Different cylinder materials, bore lining (or lack thereof), tolerances, and cooling efficiency of the designed application all affect their recommendation. Bearings are not necessarily the same either - some 2-cycle engines use bushings instead of ball or roller bearings. They specify an oil and a mix ratio that should keep you from coming back during the warranty period with a roasted engine. As soon as you use a different brand of oil or mix ratio, you're kind of on your own. The "correct" mix ratio at that point will depend on the quality and specifications of the oil used, the application and the engine design. A cheaper box-store or off-brand oil may not provide enough protection in a given engine even at the manufacturer's specified ratio- and high quality synthetic oil will usually offer better protection even at a thinner ratio than recommended. And then there's everything in between.

 

[T0RN4D0]

If you think "a bearing is a bearing", "oil is oil", "p&c is p&c", then you're going to be wondering for a long long time before you're going to get it.

 

[rmh3481]

Hi AIM,
Most of the two cycle engine oil changes have come from the EPA. They basically forced the makers into 50:1 warranty commitments because they knew of the advances in oil chemistry. What they dont tell you is that oil in a two stroke engine does more than just lubricate. It seals the piston rings and helps handle some of the heat. A little more oil can make a big difference in how an engine runs and how long it runs. When you stop and think about these ratio's, 50:1 converts to 2% oil by volume. 32:1 is 3% and 20:1 is 5% etc.

 

[one.man.band]

agree with aim. rpm's.

oil injection, cdi ignition (mid '70's if i remember right), better machining tolerances, lined cylinders etc. could be others.

EPA..... indirectly maybe. there was leaded gas available up here near me to about 1987. once the lead was out, (that was when gas was 99 cents or so), think most gas had MBT (or something letters starting with a M like that), that ingredient was supposed to lubricate and protect like the lead they took out did. the ingredient caused red fouled plugs in the long run and was eventually banned (thinks me) supposedly for killing fish and everything else for that matter. hopefully everyone knows about the danger of long term lead exposure these days. both of which are bad things in my book.

most folks, including me running 2S oils like castrol, valvoline or belray. most all 2S oils of 20 years old were composed of brightstock and napthnenic oils + sulfonates of sodium and calcium. WTH?

(sulphur BTW does not particularly like nikasil).

newer 2S oils also contain some zddp. (zinc/phosphorous). which are bad for cat converters, but good for anti-wear.

most everything smoked 20 years ago. if it didn't, it got you worried.

these days with the carbs smaller stock jet openings, cats in newer saws, unleaded fuel, smaller stock jet openings, and the like, could likely are the reasons.

most synth 2S oils are a waste of money for anyone who burns less than 5 gallons through one saw in a year anyway IMO, (unless they run higher rpms, or continually cut with dull chains, or run ludicrously light oil ratios). the average folks need mineral oil which fights corrosion better, which is more important when the saw is pulled out only a seasonal basis. (to me anyway).

today's carbs seem to be jetted leaner (as folks say on here anyway), if you want to run the fatter oil ratios, hope folks adjust accordingly, because they are not set up that way stock. much easier to run whatever ratio manufacturer recommends.

-OMB

 

[CTYank]

Hi AIM,
Most of the two cycle engine oil changes have come from the EPA. They basically forced the makers into 50:1 warranty commitments because they knew of the advances in oil chemistry. What they dont tell you is that oil in a two stroke engine does more than just lubricate. It seals the piston rings and helps handle some of the heat. A little more oil can make a big difference in how an engine runs and how long it runs. When you stop and think about these ratio's, 50:1 converts to 2% oil by volume. 32:1 is 3% and 20:1 is 5% etc.

Is this speculation/conspiracy theory, or can you cite some admissible evidence to support your claim? How then does the PP5020AV (like I have) have 40:1 molded into plastic?

Of course, oil refiners would never strive to improve their products. Why bother? :msp_tongue:

You might look into how different oils affect deposit buildup in piston ring-grooves. The sort of stuff that reduces the ability of the rings to move radially and seal against the bore.

"Handles heat"? Meaning? Expand heated gas to output work?

 

[tsarna]

once the lead was out, (that was when gas was 99 cents or so), think most gas had MBT (or something letters starting with a M like that)

MTBE

Methyl tert-butyl ether - Wikipedia, the free encyclopedia

 

[Andyshine77]

agree with aim. rpm's.

oil injection, cdi ignition (mid '70's if i remember right), better machining tolerances, lined cylinders etc. could be others.

EPA..... indirectly maybe. there was leaded gas available up here near me to about 1987. once the lead was out, (that was when gas was 99 cents or so), think most gas had MBT (or something letters starting with a M like that), that ingredient was supposed to lubricate and protect like the lead they took out did. the ingredient caused red fouled plugs in the long run and was eventually banned (thinks me) supposedly for killing fish and everything else for that matter. hopefully everyone knows about the danger of long term lead exposure these days. both of which are bad things in my book.

most folks, including me running 2S oils like castrol, valvoline or belray. most all 2S oils of 20 years old were composed of brightstock and napthnenic oils + sulfonates of sodium and calcium. WTH?

(sulphur BTW does not particularly like nikasil).

newer 2S oils also contain some zddp. (zinc/phosphorous). which are bad for cat converters, but good for anti-wear. most everything smoked 20 years ago. if it didn't, it got you worried.

these days with the carbs smaller stock jet openings, cats in newer saws, unleaded fuel, smaller stock jet openings, and the like, could likely are the reasons.

most synth 2S oils are a waste of money for anyone who burns less than 5 gallons through one saw in a year anyway IMO, (unless they run higher rpms, or continually cut with dull chains, or run ludicrously light oil ratios). the average folks need mineral oil which fights corrosion better, which is more important when the saw is pulled out only a seasonal basis. (to me anyway).

today's carbs seem to be jetted leaner (as folks say on here anyway), if you want to run the fatter oil ratios, hope folks adjust accordingly, because they are not set up that way stock. much easier to run whatever ratio manufacturer recommends.

-OMB

Oil thread here we go. No! 2 Cycle oils do not contain zddp, as Zinc does not burn off and will leave ash everywhere, polymers are use to eliminate ash as much as possible. Calcium is another anti wear additive use in normal engine oil, not 2 cycle oils as it would also leave deposits.

As long as you jet properly 32:1 or 40:1 will work fine in just about every non injected 2 cycle engine. 50:1 is too lean IMHO and is the cause of most premature bottom end failures IMHO.

 

[AIM]

From what I have read here there is no ONE answer.
Diff manufacturers arrive at their mix ratios due to.

Expected load
Intended RPM
Component quality
Build tolerances
Quality of oil that they are testing with
EPA compliance
And likely a couple more factors

Would you all say that this is a good answer to my question???