intersting theory on 2 stroke oils

Awk08

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found this on the net, just another good read.............

IF YOU DON'T WANT TO READ ALL OF THIS, AT LEAST READ THE LAST PARAGRAGH

Does a 2 Stroke Engine Really Require a Synthetic Oil?
Comparing the 4 Stroke Engine to the 2 Stroke Engine, Regarding Oil

NOTE: This article is not intended to be a full, detailed, explanation of synthetic and petroleum based oils, NOR, is it intended to be and "End All" to any discussion regarding these oils.
It IS purely an informative based article based on experiences from RK Tek.

Many ask why RK Tek Inc. does not recommend synthetic oils in 2 stroke engines?
First, a little history on why synthetic oils were introduced.

Synthetic oils were invented to help combat the break-down that a petroleum based oil experiences under a high heat application/environment (ie. Hot running automobile engines) In other words, under extreme heat, the petroleum based oil can break-down and cease to properly lubricate the engine's internal components. This, obviously, can result in catastrophic engine failure.
Synthetic oils can be chemically engineered to avoid break-down under extreme conditions. They can also be engineered to chemically bond to specific metals that are present inside certain engines. They also stay cleaner.
More detailed info on synthetic oil can be found at Synthetic oil - Wikipedia, the free encyclopedia.
OK, So, it sounds like this synthetic oil is the clear winner for high heat applications.
So, why does RK Tek not recommend it in the 2-Stroke Engine?
The flow and environment of oil in a 4-stroke engine is much different than a 2 stroke engine.
Let's break it down a little......
4-STROKE:
1) Oil is the main source of cooling. Its primary purpose is to flow onto, into, and around the piston, cylinder, crank components, cam components etc. etc. etc.. It keeps these internal components cool and lubricated and helps avoid excessive heat and friction.
2) Oil is continually re-circulated throughout the engine. The oil is not given much of a chance to cool down until the engine is turned off. The oil is always being heated whenever the engine is running.
3) Oil is constantly be subjected to "dirty" entities and will capture these entities and become more impure.
There are many more.. but we will stop here for now..

2-STROKE:
1) Oil is NOT the main medium for cooling the engine. The main cooling agent is the fuel.
2) Oil is held in suspension with the fuel. Meaning the fuel is the vehicle for the oil's travels.
3) Oil is NOT re-circulated. It is introduced into the engine, does its job and is ejected out of the engine. This process repeats over and over. This is why you have to add oil after every few rides. Simply put, the oil does not stick around, it is consumed.
4) Oil is NOT constantly subjected to the internal engine components. It is not super-heated.
OK, this touches on a few key differences between the 2 types of engines.
Let's now examine the functions of the oil.
4-STROKE:
1) Oil remains in the engine and is pumped to the engine's components. It is a batch system that relies on dedicated pathways and "Splash" techniques to reach the required components.
2) Oil is constantly heated whenever the engine is running
3) Oil is re-circulated and requires frequent purging (oil change) in order to keep it clean.
2-STROKE:
1) Oil falls out of suspension in order to perform most of its duties as a lubricating agent.
2) Oil is NOT re-circulated. It is a waste product. It gets in and gets out.
3) Oil temps are kept very low due to the constant presence of fuel.
4) Oil forms a light film on the cylinder wall to keep the piston and rings from seizing to the the bore. In fact, and this is a strong statement.. If the oil film never breaks-down/fails you can not have an engine seizure. you can still have engine failure, but not a seizure.
5) Oil lubricates the connecting rod, wrist pin, wrist pin bearing, and crank bearings. These bearings are also kept cool via FUEL constantly passing over them. Of course, the outer crank support bearings are not subjected to the fuel.

So, what does all this mean???
It means that the oil of a 2 stroke and 4 stroke engine are introduced to the engine very differently and they are subjected to much different environments.
It would stand to reason that these oils are engineered very differently and they are.
SUMMARY:
Synthetic Oils are engineered to withstand high heat without chemically breaking-down like their petroleum based counter-parts.
2 Stroke Oils are NOT subjected to the same level of heat of that of a 4 stroke oil.
Fuel, not oil, is the main cooling agent in a 2 stroke engine.
Oil, not fuel, is the main cooling agent of a 4 stroke engine.
Due to the method in which the oil is introduced, and the fact that it is not re-circulated, a synthetic based oil is not required to avoid oil break-down. The elements that mandate a non petroleum based oil are simply not present in a 2 stroke engine.

Here is a VERY good Oil article: The Late Great Oil Debate

SIDE NOTES:
1) BRP/ Ski Doo quit recommending synthetic oil to be used in their snowmobile engines in 2006.

HERE'S THE IMPORTANT PART.................

2) Synthetic Oil can NOT be used to properly seat piston rings. This is a KNOWN fact to the manufacturers of synthetic oil. MOST have a non-synthetic "Break-In" oil that is used to properly break-in a new engine.
 
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did you read the part about the rings not seating properly during break-in
and the synth oil companies recommend and sale non synth "break-in oil"
 
Thanks for scourcing this great info Awk.

I was not aware that Sin oil was not suitable for break in, but I have always had strong doubts that it would lubricate too well for the rings to bed in quickly, hence my recomendations of running 2 tanks of gas through berore giving the bike full throttle.

I only use Sin oil for the transition from Semi Syn to Castor oil, because mineral oil should not be mixed with Castor.

I run a couple of tanks of pre mix Sin through in favour of flushing the engine.
 
Stihl now doubles your warranty if you buy a6 pack of their new synthetic oil at the time of purchase. They sell quite a few 2 strokes
 
Great info!! I am a newby and this is my first post. Been lurking for a while and have found alot of good info on this site. I had a couple questions and wanted to add some of my experience.

I am assuming this article is referring to synthetic oils used when mixing with fuel in a 2 stroke. I have only had my blaster for a year and a half and have only used Yamalube 2S in my injection res. And conventional 10w30 in the transmission. From my understanding, the crankshaft is sealed from transmission and is lubricated from the gas/oil mix, just like a 2 stroke chainsaw or weedwacker engine, correct? What effects will synthetic oils in the transmission have on the clutch? I was told that people who switched to synthetic oil had clutch slippage issues. Any truth to that? I have a friend with a high hp banshee (80+hp) that has run Mobile 1 in his trans since new and said he has had no problems, maybe cause the clutch was broke in with synthetic?

In automotive engines I have a ton of experience. Been drag racing for many years and have been building engines for myself and friends for quite a while and 100% agree with breaking in engines with conventional oils to seat rings. What I have found is that even current conventional oils dont have wear additives that were found in oils of years past. Newer break in oils have those additives and since just about all OEM engines these days have roller cams and with higher EPA regulations, those additives are not really needed. When working with older engines with flat tappet cams, it is very importaint to have those specific "break in" oils (learned that lesson the hard way unfortunatly). Roller cam engines I just use a good conventional oil (shell rotella is what I prefer). Some OEM engines that specify synthetic oils may use a synthetic for the inital fill but compensate for ring seating by using a different finish hone on the cylinder walls.

A good tech article I found from comp cams that explains the additive issues in more detail: http://www.compcams.com/Base/pdf/FlatTappetCamTechBulletin.pdf
 
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correct on the 2 stroke tranny/crankcase seperation

the driveline performance clutch i installed this year recommended
mobile 1 full synth, 5w-30, so thats what it drinks now

the oils with "friction modifiers" are the ones to avoid

and nice addition to this info, have your first rep points
 
Thanks AWK!

I have learned alot from this site and still have alot to learn. Mustangs are my specialty and I am new to quads, glad I could add something to the forum!
 
That gave me a headache! But interesting, If everyone would use Super M premix and belray in the tranny we wouldn't need these discussion! HAAA

Ole man looking out for us again!
 
Wish i would have read this a week ago!
Just done my heat cycles with lucas synthetic.
Still got over a half a tank of it at 32:1 in her.
NOW WHAT TO DO?
 
Wish i would have read this a week ago!
Just done my heat cycles with lucas synthetic.
Still got over a half a tank of it at 32:1 in her.
NOW WHAT TO DO?


heat cycles aren't enough to fully seat the rings, mainly just to "set" the gaskets then retorque the head/base bolts.
I'd switch to a regular oil (yamalube) for a few tankfuls for the rings, then back to full synth if you'd like
 
heat cycles aren't enough to fully seat the rings, mainly just to "set" the gaskets then retorque the head/base bolts.
I'd switch to a regular oil (yamalube) for a few tankfuls for the rings, then back to full synth if you'd like

Ok i get it
That was all they had in at napa other than some already mixed 50:1
When I get to town i will start running regular oil after reading this

THANKS
 
Ok so after reading all this what do you recomend for mix oil and what do you recomend for case oil Awk im fixing to break in an 88 blaster motor i rebuilt and didnt no these oil facts
 
Would yamalube 2r be a good oil to break in new top ends? I used it on several bikes to break in top ends and it worked great and all run strong to this day
 
Would yamalube 2r be a good oil to break in new top ends? I used it on several bikes to break in top ends and it worked great and all run strong to this day

yamalube 2r is good for break in and daily use in these engines