Controversial oil question

[oilresearchaccount]

According to the article Low Ashe type 2 cycle oils use metallic additives. It also says:

Most, if not all, high performance 2-stroke oils are manufactured using API group III and IV and occasionally group V base oils.

Assuming a 4 cycle engine oil is also based on a group 3-4 base oil, would there be any differences in the base oil whatsoever compared to 2 cycle oil? Or the 2 cycle oil just has a different additive package? If there is a difference, what differences are they?

 

[SuperSalad]

Yes, low-ash oils may use some metallic additives. Ash-free oils will use zero or very near zero metallic additives. Either way, they use significantly less metallic additives than 4-cycle oils to reduce ash and deposits.

I've said several times now that the base oils used are different. There are only 5 groups of base oils to choose from, so you will inevitably find similarities in groups. However, there is a lot of variation within base oil groups (especially V). Just saying two base oils are in the same group (be it V, IV, III, or I) doesn't mean they are the same base oil. Bright stock and mineral spirits are both group I oils. They don't exactly have much in common with one another.

If you have a specific question, ask it and I'd be happy to answer it if I can. I feel like I've already answered what the differences are several times in this thread.

 

[oilresearchaccount]

I just want as many details as I can get, if you feel the question is redundant you can say you've explained it already and leave it at that. I mostly want to know the differences between the base oils. What really is the difference between, say, a group 3 base oil used in a 4 cycle engine compared to a group 3 base oil used in a 2 cycle engine? Why can the two not be interchanged?

Maybe @MolaKule would like to answer this if I am being redundant and you have already explained to me, I just came here to learn.

Thanks for the helpful replies.

 

[wpod]

Why are the additives needed in the 4 stroke oil and not in the 2 stroke oil.

 

[oilresearchaccount]

4 stroke oil is in a sump and reused for longer, 2 cycle oils are used shortly and expelled from the engine, if 2 cycles didn't need to burn oil they would have more additives too.

 

[Tom NJ]

It's been many years since I worked with 2-stroke formulations, but in my day the base oil mix contained solvent to facilitate rapid miscibility with gasoline, and a heavy base oil such as PIB, bright stock, or POE for stay-behind lubrication of the pistons. Not sure of the current technology.

 

[oilresearchaccount]

Thanks for sharing, that's really interesting. Ive been trying to find more information about the differences between 2 cycle and 4 cycle base oils but cant find much information. I do know that a 4 cycle oils additive package is not designed to burn and creates deposits and ash if burnt though. Aside from that, cant find much information on why a 4 cycle oil would fail to lubricate a 2 cycle engine. I guess it really comes down to the base oils.

 

[SuperSalad]

Looking over the different performance specifications and testing protocols for the two types might give you some of the insight you are looking for. Rather than the formula components, it tells you the kind of characteristics each product needs to have in order to pass testing requirements and prove performance levels in each application.

One ingredient in one product might be used in another for an entirely different purpose. For instance, @Tom NJ mentioned PIB being used. PIB is used it a lot of product types to modify viscosity and adhesive properties. In 2-strokes specifically though, it is a particularly good anti-scuffing agent so is often used for that purpose because that performance requirement is particularly important to 2-stroke applications.

 

[oilresearchaccount]

That could be really helpful. I'll do some research on that, thanks for the suggestion.

 

[kschachn]

Looking over the different performance specifications and testing protocols for the two types might give you some of the insight you are looking for. Rather than the formula components, it tells you the kind of characteristics each product needs to have in order to pass testing requirements and prove performance levels in each application.

One ingredient in one product might be used in another for an entirely different purpose. For instance, @Tom NJ mentioned PIB being used. PIB is used it a lot of product types to modify viscosity and adhesive properties. In 2-strokes specifically though, it is a particularly good anti-scuffing agent so is often used for that purpose because that performance requirement is particularly important to 2-stroke applications.

An excellent explanation as to why what amounts to self-certification of anything is dangerous especially when you really don't know what you're doing.

 

[dwendt44]

Don't know when 2 cycle oil was developed but way back in the
early 60's, we used plain old 30 weight auto oil mixed with
gas for ring-ding motorcycles.

My 2¢

 

[oilresearchaccount]

I found this: https://www.infineuminsight.com/media/1822/11-small-engine-lubrication-na.pdf

Explains a little more on the differences between 2 and 4 cycle oils. From what it says 2 cycle oil's additive package is not what it depends on to help with lubricity, but rather PIB and the base stock, but 4 cycle oils rely on the base stock and antiwear additives, is this correct?

 

[Surestick]

If I had to guess it would probably be fine to use 4T oil in a 2T but the tradeoffs would be more plug fouling, more carbon build-up, and more smoke.

I don't have an issue with smoke but the other two would quickly get annoying.
I wouldn't want to use it in anything with a power-valve due to carbon build-up.
I'd say do it if you absolutely need to use your 2T equipment right away and have run out of 2T oil but probably not worth it to do all the time.

 

[oilresearchaccount]

I havent seen any evidence to prove it wont lubricate, nor have I seen any engine be damaged from running it even for years. There are differences in the oils but I have a lot more to learn. From what ive read 2 cycle oils additive package has a lot less metallic anti wear additives compared to 4 cycle oils to reduce ash formation, and uses PIB to improve lubrication along with a good quality base oil. 4 cycle oil is harder to burn and maybe could continue to lubricate in a 2 cycle engine even in very high temperatures where other oils would burn off, but would run dirty. As for formulation and PIB in 2 cycle oils vs the composition of 4 cycle oils, I am not sure.

It would be helpful to know how PIB effect the oils film strength and properties.

 

[BigCahuna]

This guy actually tried itand states in a pinch or emergency it will work, per these tests.,, https://video.search.yahoo.com/yhs/...8b50d84d0a701bae66a36dc4c3f4b24b&action=click

 

[ragtoplvr]

About 50 years ago when I started mowing yards in the summers, I got my first brick lawnboy.

A brown c engine. It said mix SAE 30 SA or SB oil at 16 to one. So that is probably where it come from. The we had went to SE by then. Every other week I needed to drop the muffler and clean exhaust ports. Rings stuck at about 300. I was mowing about 20 hours a week.

After the first summer I got some of that fancy 2T oil and ran all summer with only 1 port cleaning at 24 to one. I had a quietflight too, great for early summer mowing. Then I got a green brick, much more power. Paid the unheard of price of 100 dollars with tax. Used lawnboy oil at 32 to one. It put me thru college probably close to 2500 hour on it. 2 sets of wheels, one set of rings and a piston and one slightly used carb from a run without oil mower. Not one single other part, not even points, I just filed them once. My sister inherited it, she managed to bend the crank and break the ears off the crankcase. She has a talent. Now I have my 82 F engine. Probably 4 electronic ignitions. It is still going with one overhaul, 2 sets of wheels (needs another set of the front wheels) and several primer bulbs. I hope it lasts until I have to go electric.

Rod

 

[Astro_Guy]

I have owned and operated many pieces of 2-cycle equipment over the past 35 years. The list includes at least four chain saws, one Lawn-Boy mower, three weed whackers, two leaf blowers and a snow blower. Never once did I experience an oil related failure. Is it possible that you are over thinking this?

 

[blingo]

What you have is two trick questions instead of a research going ;-) The flash points (much like Noack evaporation rates) can be so different from very different contents of the mentioned solvents used or not used in products. Racing oils sometimes do without, but may no longer work for separate lube supply, may even require you to actively premix in canisters and tend to no longer be -> JASO FC or FD, ISO L-EGC or EGD oils.
The answers regarding the PIB could somewhat vary because of a certain range of PIB grades used. Two or three grades might actually end up in a product, as sometimes lighter ones would be added instead of solvents without doing much for actual lubrication and the heavier ones as such should be chosen or blended correctly, they say.
Products are tailored for racing or street use, snow mobiles, outboards, garden tools, scooters etc. With a desire for 4t-oils for unknown reasons you could at least go for diesel oils acceptable in old Detroit Diesel two strokes.

 

[Srt20]

I havent seen any evidence to prove it wont lubricate, nor have I seen any engine be damaged from running it even for years. There are differences in the oils but I have a lot more to learn. From what ive read 2 cycle oils additive package has a lot less metallic anti wear additives compared to 4 cycle oils to reduce ash formation, and uses PIB to improve lubrication along with a good quality base oil. 4 cycle oil is harder to burn and maybe could continue to lubricate in a 2 cycle engine even in very high temperatures where other oils would burn off, but would run dirty. As for formulation and PIB in 2 cycle oils vs the composition of 4 cycle oils, I am not sure.

It would be helpful to know how PIB effect the oils film strength and properties.

I think one of the things you maybe missing is the fact that most of a 2 stroke engines cooling comes from the fuel. Therefore the oil does not burn off before combustion. And does not need to continue to lubricate after a 2T oil would burn off.
With the additives in 4 cycle oils, as mentioned you "could" suffer engine issues/damage from build up on the piston crown, exhaust ports, etc. This could lead to all sorts of issues.

But IMO 4 cycle oil will, for a period of time anyway, lubricate a 2 stroke engine just fine. I have run full tanks of fuel and 4 stroke oil mix in 2 stroke engines without any issues. Though I wouldn't do it long term, and the fact that I am able to buy 2T oil as cheap or cheaper than 4 stroke oil.

I am less knowledgable about oil and its additives and properties than probably most on here. But I do know what kind of things happen inside engines and high hp 2 stroke engines is a huge hobby of mine and my close friends.

But thanks for the VOA of the 2T oils. I had never seen one before. Reaffirms my belief that most 2T oils are very similar, and high priced 2T oil is just that, high priced.

 

[Pablo]

This part is incorrect:

Looking at the additive package of a 2 cycle engine oil, it seems all it has is some calcium, and the rest of the additive package is slim to none.

A simple $25 VOA does not tell you much at all about 2T oils. By their nature they are NOT high in elemental additives, in particular metallic and semi-metallic additives. For obvious reasons, even the 2T oils that are not super low ash - don't have a lot of elemental additives as mentioned above. Point is, yes the other additives do make a big difference, and you don't see them in a VOA..........so there is a difference and it's not just price.