tripower222

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A little information on oil mix for two stroke engines. As I navigate around on this site I see a lot of opinions on oil mix ratios and how many are stuck in their ways at 32:1.

Let me explain why the higher mix ratios like 100:1, that make everyone so uncomfortable are ok in the correct engines.

First the 100:1 oils are ususlly little heavier viscosity. For example if you have a 40 weight oil mix at 40:1 and a 80 weight oil at 80:1 the lubrication viscosity in your fuel mix wont be much different. In fact if you take 1.28 ounces of 80 weight oil and add 1.28 ounces of fuel to it would look a lot like a 40 weight oil and if I gave it to you and said here mix this at 40 or 50 to 1 you wouldn’t have a problem with it, if you didn’t know what I did

Second, some oils claim you can use these higher mix ratios in any engine (not true) the high mix ratios should only be used in the higher quality engines that are 100 % roller and or ball bearing engines (both sides of the crankshaft and both ends of the piston rod). It doesn’t take near the amount of oil to make this type of bearing happy compared to a plain or bushing type bearing.

Third, your probably saying now after that last paragraph yea ok that makes sense but what about the cylinder walls. Consider this, most four stroke engines really don’t have a oil system that lubricates the cylinder walls they rely on the oil mist in the engine. When the 4-stroke engines piston is on its way up in the cylinder it is traveling up cylinder walls that have been squeegeed clean by 1 sometimes 2 piston rings when the piston was on the way down. The washed down by a fuel air mixture rushing in with NO oil in it. Essentially half the time it has almost no oil. The two stroke gets the oily fuel mixture on the walls up and down and sticking to the walls and a lower coefficient of friction is where these new synthetics shine. Also a little more theory, true synthetics don’t burn. This has a couple advantages over petroleum. One if it didn’t burn where did it go? What didn’t go out the exhaust is still in the cylinder lubricating. And two when it didn’t burn it didn’t turn into carboned up gunk in your engine.

Fourth, if you where an engine manufacture who stood behind your product for two or three years would you recommend an inferior lubricant for your product, probably not. Its as simple as this, they know their product and what it needs and they know the lubrication and lack of carbon build up is good for them.

Fifth, if you just cant do it, ok, but most people just cant do it because they have seen 32:1 for many many years and they know “lubrication is good” not realizing technology is passing them by. With advances in technology we use less energy to light a room, less fuel to go a mile, why not less oil to lubricate.

jedijody

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Rubbish!

driesbabe

[sm=confused.gif]

apalsson

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Is that snake oil?

mrbigg

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No, that's the stuff that carbons up the engine.

apalsson

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Great thread, by the way !

Rcpilot

My Feedback: (78)

DA 100
Amsoil
100:1
many gallons

jedijody

My Feedback: (1)

And what looks likethe beginnings of stuck rings on the exhaust side of the piston. Carbon on the side of the piston, above and below the ring and stuck to the top of the ring, all in the vicinity of the exhaust port which is typical of this oil and mix ratio. If we could see the exhaust port there would most likely be accumulations of hardcarbon there as well.

closetguy

My Feedback: (13)

i have two da50's,first one i used da's recommended ashless oil for break in @ 32:1 for 4 gals. and then amsoil there after @ 100:1.after two quarts of amsoil the piston had enough wear at the wrist pin to give a noticeable rod noise.
the second da had nothing but pennzoil @ 32:1, and i have more time on this engine than i did the first,with no rod noise yet.also both engines ran cooler with the pennzoil @ 32:1.
maybe it's just me, but i really think the engines get a little more noticeable power with the 32:1.
i don't usally respond to oil post, but it's four am and i couldn't sleep[&o]

dogshome

Of the many 'oil' threads on the net - I don't think I've actually seen one that says "this oil XYZ is really bad and don't use it". Apart from the snake variety of course

Happy on B&Q low ash mineral trimmer oil at 40:1 thanks anyway Tripower222. Been happy for the last ?? years on all my motors. Comfortably numb

Tired Old Man

My Feedback: (1)

Sounds like tripower is another Amsoil dealer with only a couple of engines in the house and very limited hours on any of them. I'll agree that 32-1 in most cases is excessive but I've learned that beyond 50-1 and you're begging to have issues come visit not far down the line. That poor ring seal depicted in Rcpilot's post is only one of them.

JoeAirPort

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Third picture on top shows the exhaust port....a little blurry but you can see it.

tripower222

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Carbon build up can only come from crappy gas and or oil burn, less oil, less carbon build up. In the case of a these two strokes there is no possability of a worn engine allowing excessive crank case oil past the rings, the carbon build up must come from the fuel mix. I would say its hard to believe that two engines operated under the same contitions and fuel,would have a higher carbon buid upwith a higher mix ratio. But if you have actually experienced it thats hard to argue with. I just tried to lay out some facts, use the info how you wish you me even want to print it off on some soft paper and bring it to the restroom with you. HE HE I am new to the forum and have got a lot of good information here just tring to contribute with some facts.

Tired Old Man

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Taking the oldest engine you have, how many hours have you logged against it in actual documented run tests? How many hours total have all your documented run tests accumulated? What data points have you personally used to establish your findings? What kind of engines were used, and how were they used? What was the average period of time per engine test run?

I have facts developed over the course of hundreds of engines and thousands of hours that clearly show that 100-1 ratios are for those that believe in advertising over reality. There are also facts noting that two similar engines running the same fuels and oils, but loaded differently, have different oil performance results over the same period of time. One thing is certain, you are dead wrong when you state that less oil equates to less carbon build up. Up to a point, just the opposite is true.

I'm not trying to beat you up at all but some have been through this under lab and field tests for many years now. You cannot equate anything four stroke with two stroke where oil performance is concerned. Unless you have access and use of CO meters and controlled test environments you cannot arrive at conclusive results from a 10 to 15 minute flight of a lighty loaded r/c aircraft. Even numerous flights would not provide conclusive results since the engine NEVER fully heat soaks during those flights. I can dig up visual comparisons of 100-1 versus 50-1 mixes used in the same engines over the same period of time under the same and similar conditions. Those also would cover numerous oils. The results are startling. The leaner oil mixes are the most damaging by an order of magnitude and generate vastly more hard carbon development and acretion. Some well advertised oils are considerable lower in performance and capability than many oils thought to be inferior because they either cost less or were not listed in an engine manufacturer's manual. Depending on the engines used in testing, age and condition of the engine, and the manner of ring design, it is easily possible for oil to be blown past the rings from the case.

BTW, oil mist is the primary type of lubrication received by wrist pin and bottom end bearings in R/C use two strokes. They don't like to be immersed in oil.

jedijody

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With all due respect Tripower222,there were no facts in your post, just personal theory and speculation. There are a few of us that work on these exact engines in model airframe applications for a living, not motorcycles, lawn mowers, scooters, automobiles, or locomotives. Next to none of them would recommend oil ratios with less oil than a 50:1 mix would provide, I have piles of prematurely worn outfacts to back it up. Of the model aircraft engines I service,when it comes tonon warranty andun-crashed engines sentin that "don't work", there are2 oilsthat are most commonly used in them and the #1 oil used in failed engines I see is mixed at 100:1.

tripower222

My Feedback: (5)

Im sure you know more, and have done more testing than the engineers and teems of engineersat Fuji, Amsiol, Evinrude Johnson, Mercury Marine, Desert Aircraft, Yamaha to name a few.

oil + combustion = carbon
oil times 2 + combustion = more carbon

If the engines are failing prematurely mybee their not designed to run on the high mix ratios or maybee you missed that part of the post.

w8ye

My Feedback: (16)

Tripower, No one has told you that you cannot run your own engines with Amsoil at 100:1

These other guys do not wish to run their engines at this level and there is nothing you can do to make them run their engines with 100:1 oil

SO LET IT REST!

flatspinjim

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Tripower welcome to the threads. Being new I'm sure you don't know Jody and T.O.M but they both have TONS of experience with these engines. It's what they do for a living.

rc bugman

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Tripower,

Here is an oil test I ran a few years ago. Most on the forum know of it. Since I am a public scientist (as opposed to a private company employee), I am free to share the information. TOM has a greater depth of results but he cannot share the data due to contractual restraints. Perhaps this will be of interest.

I also work the stuffing out of engines on airplanes towing very draggy loads at full power for long periods of time. Anything less than 40:1 shows excessive wear and heat on the engine.

http://www.geistware.com/rcmodeling/...test/index.htm

Like was stated earlier, run your engines at any ratio you like. Others have seen the light after they have prematurely worn out engines.

Hope you find this interesting

Elson

Tired Old Man

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I can truthfully state that I most certainly DO put more hours on engines than their manufacturers do. Many times more.

I've found that oil test results published in advertising to be quite misleading, and that actual lab and performance testing by independants involved in commercial flight applications to be far more accurate and valuable.

Here's a couple of 100-1 picture for you. I have to get back to another storage device to provide some 50-1 comparisons obtained at the same hourly cycle.

tripower222

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rc bugman good link, as for old mans reply that is pretty hard evidence to dispute.

Mokken

My Feedback: (63)

All of you, I mean all of you should listen very carefully to what Tire Old Man has to say, he's not making any of this up.

I ran all my engines for years, mostly DA, on the belief that Amsoil at a 100:1 was the way to go. Just take one apart after running gallons and gallons through it and you will see the same thing as posted in those pictures above. No one is making any of this up. The fact that Amsoil is stated to run at a 100:1 means nothing for us flying our planes in the manner we do. I have since switched to Redline at 50:1 and will after a few more gallons take apart my DA-100 to see exactly what Tired Old Man and many others have claimed, the motor will look like new inside.

For us, more oil is better. The main purpose of the oil it to lubricate the engine, not keep it running cool, that's what the air running across the motor does while your flying it. The fact that we don't punish our R/C engines and heat them to hell and back also is the reason you will see a clean engine when running at a higher oil content, and a good oil for that matter. The reason you see carbon build up with 100:1 ratios is because of the heat and the oil crystallizing instead of exiting the motor like it should.

Rcpilot

My Feedback: (78)

You nailed it.

Those rings were stuck tighter than a frogs arse. BOTH of them. Thats why the engine was disassembled - it was very low on power. The cylinder looked clean, but there was noticeable carbon in the exhaust port. I did not measure it. Would not say it was bad or good. It had carbon in the exhaust port. There was heavy HARD carbon on both pistons, inside the ring grooves, and on the rings. Light carbon on the pistons, past the rings on the exhaust side of the cylinder - blow by because the rings had stuck.



Yup!

People drinking the Kool Aid. They think if it don't cost $25 a quart it's junk oil. Many don't even put 2+2 together when the engine manufacturer is also the "exclusive" dealer of the oil they just happen to recommend in the engine manual. Or if they DO know it they choose to plant their head in the sand and ignore plain facts that stare them directly in the face.

So, engine manufacturer XX sells AND recommends brand 246Q oil for their engines - and people don't make the connection?

T.O.M. alone has many thousands more hours of 2-stroke gas engine operations then even the professionals in our hobby. I won't name names - but all the top guys in our hobby - we all know who they are..... they don't have 1% of the time on these engines that TOM has. I can just about promise you that. Thank him for taking the time to share his knowledge with you. It was free and it was GOOD advice.

And the same for BugMan. The man uses these engines for long hours and under grueling load conditions to drag big nets around the sky and collect airborne insects. You know how much drag a NET is? I'd pay attention to his tests and his wisdom.

The guys who are still stuck on lean mixes will probably never change. But it's their engine and they can do as they please.

I run what many would consider cheap oil. I run it at 40:1. It costs me $27 per GALLON so I can make 40 gallons of fuel with it. I've never observed any engine damage from an oil related problem. Granted, I don't have many seasons flying gas engines. Only 5 or 6 yrs total exposure to these types of engines.

99.9% of my engine problems result from brains, thumbs and hard dirt or concrete....... YES, in that exact order. I don't think it's possible for a guy like me to actually wear one out using a reasonable mix of ANY cheap black label Wal-Mart 2-stroke oil. I break 'em..........

crazyjoseph

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Compared to some of you motor heads I dont know ****. But common sense tells me that the last sentence in your post says it all. What I would like to know from you amsoil users is what is it you like about this oil. Is it name recognition? Do you think you get more power with less oil? Do you like the fact that there is less residue in your plane? With all the threads I have read on oil the one thing I cant figure out is why the hell would anyone want to run an engine with so little oil. What do you think the benefit is? I could be wrong but my gut tells me the original poster doesn't know crap from Crisco about oil and engines. Newbies will read a post like that and think amsoil at 100 to 1 is the way to go. And thats a shame. But thats just my opinion.

Tired Old Man

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For our R/C uses, the Wal Mart brand at 32-1 has proven to be a better oil than a few of the "exalted" lean ratio brands, and a few others. I've got a DA 150 opened up in the shop at the moment that has been running Redline at 50-1 like all of my personal engines. If my camera at the house still works I'll shoot a couple of piston/cylinder pics. The top of the pistons have a little bit of flame front carbon, the exhaust ports have a thin coat of soft carbon, while the combustion dome has zero carbon. The rings are free and the piston skirts have no evidence of blow by or oil anti wear additives cooking out of the oil. When the anti wear additives cook out of the oil and glaze the cylinder and piston you just had an oil failure and engine failure is imminent, usually due to a stuck ring but wrist pin bearings also enter into the failure chain.

Full synthetics do not combust so some carbon is to be expected with any of them over time. Those running less than 40-1 should anticipate the need to clean the exhaust ports every hundred hours of running time or so, although many, many engines go much longer than that without any need for internal care. I'm referring to the better synthetics here and won't recommend any oil that's suggested to be run at 100-1. Redline states that it can be run at that ratio but I heartily suggest you do not. Oils not only lubricate, they also clean and cool. Without enough oil they cannot assit in cooling or carry away combustion and wear debris, causing scoring of the piston skirts and carbon accretion at the top and back of the ring. Meaning a later stuck ring at the exhaust port side of a cylinder. I've seen this literally hundreds of times and know that it's not a "one off" or occasional situation. Both pistons that were associated with the pics also had severely stuck rings. Oil also sets the quality of the ring seal. Not enough and a loss of compression occurs, lowering engine output and creating an unstable idle while making engine tuning more difficult to accomplish.

So those that have a burning desire to run certain oils at lean ratios can most certainly do so. It's their engine and they can do what they like with them. However, my advice is not to go that route. A few pennies more for a little extra oil or a little periodic clean up work is all it takes to avoid early engine repairs or replacements. There are many great oils out there and all that's required to get the best performance out of them is to use enough of it.