Modern Vespa

... once and for all why TWC-3 oil is in any way bad to use in your two stroke Vespa?

I'm having trouble believing it is. In fact, I'll go out on a limb and say that I think it's a myth, and that it might actually provide better lubrication for these old two stokes than 99.9% of the oils out there.

Six months ago we took our scooter out of storage where it sat unridden for 17 years. From the day we first drained the fluids and put new oil in, we've run nothing but a TWC-3 2-stroke full synthetic, which I happened to have on hand. I read the specs and figured it would do the job. We've now put close to 2000 miles on the bike. Uphill, downhill, WOT (plenty of it), stop and go, hot weather, cold weather ... you name it. We've never used anything but the TWC-3. We've now been through several quarts.

We've had exactly NO issues. None. Zero. In fact, while we haven't had the engine apart yet, it starts, runs, and revs as well as, or better than, any two stroke I've ever had. Smooth, quiet ... literally no issues.

Maybe someone has had a different experience. But based on our experience, I'm calling the myth that TCW-3 is "bad" for your scooter busted.

Google is your friend.
Water cooled two strokes run cooler. Air cooled two strokes run hotter and prefer more resistent oils. Engineers will be more precise and this thread will get complicated...
Vespas are known for being tough and burning what you put in them. If you seek longevity and use "wrong oils" ride gently.
I hope you are right because I got a job lot of outboard oil dirt cheap when boaters world closed, and wish I could use it in my P200.

It's not a myth that TW-3 is formulated for a totally different kind of engine and service than a Vespa. That's science.

But you are free to think what you wish. As the saying goes, you live in a free country.

i always wanted to use castrol r but was told itll coagulate with me semi synth n proper fuck things up .... love the smell of that stuff

I understand outboards run cooler, etc. etc. I've looked at the specs. That's why I'm asking. What is the measurable difference in "resistance" - or any other characteristic - between a quality full synthetic TWC-3 oil and the non-detergent 30W Vespa says works fine? From the specs I've seen, and based on our experience with our scoot, I'm at a loss as to why a synthetic TWC-3 shouldn't perform just as well, if not better than a non-detergent 30W. BTW, we're not talking cheap stuff. The oil we're using runs about $12/qt. Thanks Aviator, no need for snark. It's an honest question. If the best you can do is say "it's science" you might as well say you don't know.

Snark is entirely necessary when someone is asking a question they've already got the answer to.

Whatever, people get snarky for a lot of reasons, no big deal. If anyone can provide any evidence that using a non-detergent 30W - or any other oil for that matter - has any measurable long or short term benefits over using a full synth TCW-3, I'd like to hear it.

Good luck on that.
Most people have better things to do with their time than quantify the demise of their scooter through varying the oils they put in. But there are plenty of people who've just thrown in whatever theyve had lying around the garage im sure.

I dont reckon aviator was being snarky, just kinda saying its your bike, fill it with what you like.
Vespa suggest that type of oil because theyve done the research and know it works for that application. Theres no conspiracy, its just they dont make outboards dude.

It may coke more if meant for lower temps, just a thought.

SoCal-

Oils are formulated to do certain jobs - far beyond just lubricating. 30W "works" and indeed was once specified - before better performing 2T formulations, with an additive pack specifically for the task, were readily available.

TCW-3 arose out of the very different operating conditions, lubrication and cleaning needs of water cooled, outboard engines:



Thus, TCW-3 is formulated with a different additive package to address these differing operating conditions and engine lube and cleaning needs:



The cooler operating temps of water cooled outboards makes detergents impractical, as they would leave more ash (ash, not carbon). Thus, more heavy oil and higher levels of other additives are used to compensate. However, in higher temp air cooled engines, heavy oils create exhaust port deposits and the lack of detergents increases ring varnish and sticking.

The question is not if TCW-3 is "bad" for your Vespa. Rather, is it optimal for your Vespa. The answer is that in the long run, API TC is the optimal lube for an air cooled scooter engine.

What what! That's dropping that orange, Aviator.

Marine 2-stroke oil is fine, especially so in these relatively stone age machines we all love so much

Early on I ran some marine stuff. ONCE. My motor didn't explode, or even seize. But after doing some reading, I never did it again. I figure, why trifle?

The 2T, crankcase aspirated engine (2T CA) is the height of simplicity. If you include the wrist pin, it has 4 moving parts. No camshaft, no valves, no timing chain, no pushrods, no rocker arms, no oil pump. In return for this simplicity is one drawback, the lubricant aspirated into the crankcase to lube those moving parts also has to pass through the combustion chamber. Note that the area above the piston does not need to be lubricated. 4T and wet sump 2T engines do not lube above the piston. Lube above the piston is a "necessary evil" of the 2T CA engine.

Way back when, motor oil was used to lubricate the 2T CA. Wasn't the best approach, as motor oil was not formulated to deal with combustion temps. But it worked.

The oil chemists came up with 2T oil. Some of the unnecessary additives of motor oil were dropped, such as foaming reducers and acid neutralizers, as neither was a factor in a dry sump 2T CA. Two less combustion byproducts to deal with. New additives were introduced to better clean the hotter air cooled cylinder walls, etc and to clean away combustion byproducts unique to such oils. These new oils were also "better" than motor oil for older 2T CA engines for the reasons stated above.

However, the marine 2T engine industry found that these newly formulated oils still did not do an optimal job for the unique operating conditions of outboard engines. First, outboards are water cooled and thus run much cooler than air cooled engines in other applications. Second, it is common for an outboard to run very extended periods at low RPM (trolling) and long periods at fixed throttle settings at much higher RPM (cruising). They did not see the regular and routine throttle changes common in other applications.

Thus, the marine industry turned to the oil chemists for a new and different formulation, and that became TCW-3. It was never an "advance" over API TC, but a different oil for a different application.

HOWEVER, in North America, the largest consumer of 2T oils are outboard engines, and thus, TCW-3 became the most common oil on the shelf, resulting in it being lower priced than API TC. No big deal, as the major users of API TC were small gasoline powered tools (chain saws, leaf blowers, etc), and they generally bought in small containers. So not enough individual big users of API TC to raise a bitch about it becoming more expensive than TCW-3. 2T PTW operators were an even less significant consumer of API TC, either because many thought motor oil was good enough for them, or racers who used specialized oils.

"Myth" entered the game when Bombardier, manufacturer of SeaDoo watercraft, specified only API TC "low ash" (not no ash) as meeting their warranty requirements on specific SeaDoo Rotax engines. And, for a while, the US FTC allowed them to limit it to their own brand, as "low ash" had not been generally adopted as a standard in the oil industry. Now, a large number of 2T watercraft owners were tossing around theories that Bombardier specified the more expensive API TC to line their own pockets, as API TC is more expensive than TCW-3 and the Bombardier brand even more so. Bombardier issued a host of tech bulletins explaining exactly why those Rotax engines did not do well on TCW-3, but that did not stop the conspiracy theorists.

When it comes to Vespas, "myth" also enters the game because Piaggio once specified motor oil for pre-mix. If one does a little research, one finds that there were no readily available alternatives. Motor oil was selected because, whatever its shortcomings, it was the only oil in town. There was nothing else to specify. When 2T oil became a readily available product, Piaggio changed their spec to 2T oil because it was a better overall product than engine oil, not because of any basic "redesign" of the engine.

So, from a technical standpoint, yes, all three oils "work". However, API-TC does a better job of it in air cooled non-marine engines, as it is formulated particularly for that application. How much better is difficult to quantify, but the very fact that many deposit forming additives of motor oil are not in API-TC, and other additives are included that do a better job of cleaning a high temp air cooled combustion chamber, piston and rings should tell you why it's better.

And API TCW-3 does a better job in water cooled outboard engines than API-TC or motor oil for the same additive mix versus operating condition differences.

Aviator, thank you for that write up. I know it is not the first time you have done this, so I also want to thank you for your patience.

It's probably the last we will hear from that guy, since he didn't get the answer he wanted.

Yes thanks Aviator. But I think you're missing the point. No one doubts that all three oils "work" (and just to be clear the three oils we're talking about are: 1. non-detergent 30W, 2. API-TC, and 3. full synthetic TWC-3). The question isn't whether they work, the question is where is the data supporting the claim that API-TC does a "better" job in air cooled non-marine engines? In fact, forget data for the time being. Where's even some verifiable anecdotal evidence? Has any Vespa engine failed because it ran full synthetic TCW-3? Merely repeating over and over that API-TC oils are "specially formulated" with "additives" that address this or that doesn't demonstrate anything. Marketing claims aren't science.

You say it's "difficult to quantify how much better" of a job API-TC does in a Vespa engine. If you can't even quantify if is doing any better job, it might as well be fiction.

As for "deposit forming additives" let's be clear what you are referring to. If you are talking about ashless additives, true there was some concern back in the 1990's that ashless formulations in TWC-3 were leading to sticky power valves in Sea-Doo's high-output, high-rpm Rotax marine engines. As a result, Bombadier (maker of Sea-Doo) started requiring API-TC, which contains "low ash" detergents. It was an issue specific to the Rotax. And it had nothing to do with build up on pistons, rings, or deposits in the combustion chamber. No other manufacturer specified API-TC because no other manufacturer used the Rotax engine.

Last I checked we don't have a Rotax in our '76 Super. As far as I know, there isn't a field test, a study, a report, or anything else done under scientifically controlled conditions - heck, there aren't even any rumors - showing that API-TC actually does a better job cleaning the combustion chamber, rings and pistons in a Vespa engine than the full synthetic TWC-3 we've been using.

At some point we'll rebuild the engine and who knows what we'll find. In the meantime, our plugs aren't fouling, there's no build up in the exhaust port, no soft seizes, no symptoms of piston sticking. All seems fine.

The bottom line is that the synthetic TWC-3 we're using meets or exceeds every performance spec of the ND 30W Vespa recommended back in 1976 when the scooter was first sold. The TWC-3 we've been using is doing the job, and doing it well. If you think API-TC works better because Sea-Doo specifies it for its Rotax machines, like you say, you're free to use it. Nice Beastie Boys pull.

ive seen this movie before, it has a really boring ending

I laughed so much a little wee came out!

+1

I think you guys actually agree with each other.

Rob

I mentioned the Rotax embroglio, not because their engines are in any way similar to Vespa, but how the battle royal and myths about TCW-3 began. An issue pertaining to one manufacturer's actions pertaining to a particular line of engines broadened out across the whole 2T world. Most likely because the average self appointed "expert" really has no idea about what lubricant standards really are intended to do.

The difference in performance between API TC and NMMA TCW-3 in an air cooled 2T engine has not been "quantified" simply because the two standards are tested at different operating conditions in two different types of engines. Sort of like the reason diesel or jet fuel does not have an octane rating. API TC requires testing in a 50cc and 350cc air cooled 2T for (1) anti-scuff characteristics, (2) piston ring sticking and engine cleanliness, and (3) pre-ignition. If an NMMA TCW-3 oil passed this test, it could be rated API TC/ TCW-3. Simple fact is that few, if any (NMMA) TCW-3 oils have been labeled to have passed API-TC standards. That's a simple "pass/fail" test. It either performs within the limits or it doesn't. Of course, the lack of labeling could simply be because they never tested the oil to TCW-3 standards, but there is no way of knowing for a particular oil. What is known is that several TCW-3 oils have been tested to API TC standards and have failed.

The same goes for 30W ND. It does not pass one or more of the anti-scuff, ring sticking, engine and/or pre-ignition cleanliness standards of API TC.

API TC is not a destructive test. It's a normal operating limits test. You run the engine through the test profile with a given lubricant. If the scuffing, ring sticking and deposits and pre-ignition are at or below the maximum level of the standard, the oil passes. If any of those limits are exceeded (doesn't matter by how much) the oil is not API TC. Nor did API ever attempt to say at what point scuff, ring sticking, deposits or pre-ignition are "damaging". Rather, a level was identified consistent with proper engine performance and long life.

Now, if you set 30W motor oil as your performance standard, then that's a different story. Both API TC and NMMA TCW-3 do a "better" job in any type of 2T engine.

As I said, all three "work". The issue is which standard is "optimal" or at least tested in a manner directly relevant to providing an industry accepted level of protection. Besides the science and chemistry not supporting TCW-3 being optimal for an air cooled 2T, a rating of TCW-3 is not based on testing in an air cooled engine, nor to operating conditions of the typical air cooled engine. Kinda like applying Rotax to Vespa, to use your words above.

Trumpyscooter is spot on: People often base their evaluation of whether an oil "works" or not on their evaluation of their engine in isolation from established lab tests and standards. That's fine. But if your engine doesn't fail or end up too crappy for your view, that does not in any way refute lab standards and analysis, nor make the standards a "myth".

In the long run, it's what makes you happy that matters. API and NMMA on the other hand, simply establish and enforce standards, and are not in the business of being happy - just accurate.

Your OP asked if TCW-3 "was in any way bad". Based on standards, there is no way to tell. The standards for TCW-3 do not address an air cooled, non-marine application. The standards for API TC do. Standards are "pass/fail", not "bad, good, better, best". All that can be said is that TCW-3 is not subjected to a "pass/fail" standard for our type of application. Feel free to decide whether that is "good" or "bad" in your view. I simply offer that based on the chemistry and standards, it is not "optimal".

Aviator, you are assuming that oil formulated for a specific set of conditions will be "optimal" for other conditions, which is just not true.

I won't beat this horse any more, but the API-TC spec was developed to address conditions Rotax and racing motorcycles and snowmobiles operate under; namely, high-rpm, high-output 2-stroke engines operating under severe load conditions. If that sounds like your Vespa, go for it. Also, virtually all API-TC oils have "low ash" additives because Bombadier determined that ashless formulas were causing the power valves to stick in some of its Rotax engines, a quirk of the Rotax design. Again, does your Vespa have power valves?

Are there drawbacks to using API-TC certified oil? Probably not. Is it demonstrably better for our 1976 Super than what we're using? I'm not convinced.

API certification is a little more complicated than you make it out to be. There's a bit more to it than submitting your product for a simple pass/fail test. API tests are a huge expense. The market for 2T non-marine oil is small and for a lot of boutique oil manufacturers it's hard to justify cost. Then there's the question of which certification to get - JASO, API, ISO? And at the end of the day, even if one or two certifications is financially justifiable, there's the risk the oil may be pigeon-holed or "typecast" as good for that particular application, but not others, even though that might not be the case.

Bottom line is no certification makes a particular oil "optimal" for every scooter. Optimal is up to you. You need to look at the base stock, viscosity, flash point, pour point, how you ride, what you ride, how old is the bike, is it autolube or pre-mix, how often you tear it apart, whether smoke & spooge are issues... Generally, you get what you pay for, but not always. No oil does it all.

Everyone asleep yet?

Hell no! I love sticking around to see Al win these ones!

Ha, V your engine probably is so clean you don't even need oil! You run the snot out of it to, you don't lug it, you keep it tuned, and you don't or operate it too lean or at low power percentages, all of which anybody who rides motorcycles will tell you are more likely to result in scuffing, sticking and carbon build up than using a non API-TC oil. I don't think you would have had any different results with most name brand oils...

can we fast forward the ads to the good bit please?

Well, after reading your enlightening words, I can now save a bunch of money. My neighbor has several litres of SAE 80W GL-5 gear oil that he can't use. It's approximately the same viscosity as 30W motor oil (which Piaggio once specified for both premix and gear box), contains no detergents, and nowhere is it published that it could harm my PX 150. Surely I can use it as 2T oil. (OK, that could be seen as snark)

You left out that TCW-3 was developed by the National Marine Manufacturers' Association specifically for water cooled (significantly lower combustion chamber surface temps than air cooled) 2 T engines that operate for extended periods, under load, at either constant low power settings (e.g. trolling) or constant high power settings (e.g. cruising). Does that describe my Vespa?

Neither Standards Agency promotes their Standard as suitable for the other's purposes. My experience in mishap investigation, fleet maintenance and fuel/oil lab operations led me to accept that the manufacturers and standards agencies know what they are doing. Operating with and to published standards rarely, if ever, resulted in reduced life or component failure. Operating in disregard of, or outside published standards was regularly and routinely proven to be the underlying or a contributing cause of reduced life or failure.

Of course I did not describe the entire oil formulation and certification process. Didn't want to put Vader to sleep. I simply identified three major performance criteria where API TC test specs (doing the testing in an air cooled engine under conditions alien to normal marine operations) failed to ensure that the oil performed satisfactorily in water cooled marine applications. Similarly, the resultant NMMA TCW-3 test specs do not ensure an oil performs satisfactorily in an air cooled vehicle engine. As I noted above, if an oil passed the three tests I mentioned for water cooled marine AND air cooled vehicle and small gasoline engine equipment, it would be no big deal to rate it "API TC/TCW-3" or a newly created "multi-purpose" rating. Sure would make production and packaging easier for oil companies. Hasn't happened.

If TCW-3 was suitable for air cooled 2T engines, it would have replaced TC or supplemented (ever seen GL-4/GL-5?), just as has been the case with all kinds of oil specs. Apparently, the industry holds that the two specs are different enough to be basically mutually exclusive.

Prior to the general availability of designated 2T oils, Piaggio, as well as most 2T engine manufacturers specified motor oil as the appropriate lube. When API T series spec was established and compliant oils became available, Piaggio and most manufacturers changed their spec to API T series. When the Marine Manufacturers realized that API T series did not do the job optimally for their particular application, they developed TCW-3 for their particular application. API T series remained the standard for air cooled 2T, non-marine, and selected marine engines. TCW-3 has been around for quite some time. Piaggio (as well as other 2T engine manufacturers) have not adopted TCW-3 as a primary, additional nor alternate spec for their engines.

However, as I said before, you are free to use what you want. My point is that neither the "science" nor industry published standards specify the use of TCW-3 in engines such our Vespas. I have been responding in that regard, not anecdotal experiences. The industry does not publish the "harm" using gear oil rather than API TC might cause either.

I made my living working with published standards, some of which I assisted in developing. Served me and thousands of machines and people very well. I also investigated mishaps and equipment failures resulting from folks refusing to follow published standards. You could say that my professional experience prejudiced me. YMMV.

Thanks Aviator, we're starting to go around in circles. Yes, I realize I am free to use what I want. Yes, it's a free country. No, I'm not suggesting you put gear oil, with all the anti-foaming and other additives that go with, in your gas (you probably wouldn't be the first to try it though).

The simple fact is for the past six months we've been using an ashless, full synthetic, high performance oil, that isn't API-TC certified, and it's doing a great job. The oil purports to be recommended "for use in both pre-mixed and oil injected gasoline 2-cycle engines in outboard motors, motorcycles, jet skis ..." We've now put more than 2000 miles on the engine and it purrs like a kitty. We've had no fouled plugs, no carbon build up, no signs of sticky rings, no weird noises, it just runs fine.

It's possible that the oil meets or exceeds the API-TC standard and the manufacturer just hasn't had it tested. I've contacted them and will let you know. It's also possible Vespa engines don't need the same low ash additive package that Rotax and other power valve racing engines need. It's also possible that our lowly Super is just a slug that doesn't demand much from oil.

But you seem convinced that the use of a TC-W3 lubricant will lead to a reduced life of our engine. Maybe I'm not clear exactly what you mean. Reduced by how much? What is the "normal life" of a Vespa engine? You have experience in mishap investigation, a background in fuel/oil lab operations. You've been riding for many years and you moderate a Vespa forum. When would you expect to see some premature component failure or unusual engine wear? 3000 miles? 5000 miles? 10.000 miles? And what do you expect is going to wear? As I said, we'll tear the engine apart eventually and take a good look at it. I'm interested in what you think we're going to find. Not sure what your point is here. Are you saying the optimal oil is what the manufacturer recommends? That may be true, but again, back in 1976, Piaggio recommended non-detergent 30W for our scooter. I think we both agree that today there are better choices. The API-TC spec has been out since 1993. Has Piaggio has ever specified API-TC rated oil for any of its 2T engines? I could be wrong, but I don't think it has. In fact, I'm not sure any PTW manufacturer besides Bombadier specifies API-TC oil for its air-cooled 2T engines.

You keep referring to the generally cooler combustion temps of engines that specify TC-W3 oil. I don't think it's a factor. The oil we're using is a full synth and its flash temperatures and viscosities are nearly identical to API-TC rated oils.

http://www.discovery.com/video-topics/cars-bikes/motorcycle-guide-videos/greatest-bike-ever.htm

If used fryer oil works in a Honda Cub's crankcase, why not as an injector oil in a Vespa? It hasn't been measured as harmful . . .

The PX 150 manual has specified "API TC" or "API TC++" oil for at least 10 years. My wife's 2002 Malaguti 2T manual specifies "API TC". The Vespa ET2 2T specifies API TC++. And so on.

A Standards Agency Spec does not tell when and how non-spec oils will fail. They do, however, assure you that an oil to their spec will perform to a stated and consistent level, when following the engine manufacturer's instructions.

API-TC sets a limit on the physical wear, as I described above. TCW-3 sets similar physical wear limits, but for different engines using different operating parameters. Engine manufacturers accept and publish their oil spec based upon being able to have a defined performance expectation. That's what they are called "standards" and "specifications".

Engine manufacturers also use these oil specs to be able to enforce warranties. If you don't specify the oil, then you are responsible for whatever the owner puts into the machine. The more precise the spec (e.g. API or NMMA standards) the less arbitrary warranty enforcement becomes. "Any good 30W ND motor oil" is a very subjective statement. Who defines "good"? "API TC" is a set standard, and if "synthetic" is specified, even more precise (Ask Mercedes Benz).

I'm sure there are non spec oils which work just fine, but without tear down analysis, how does one know? The whole purpose behind standards and specs is to take the guess work out of it, and provide something that both the oil and the engine manufacturer will stand behind.

My PX 150 has well over 30K km on it and has not needed decoking. My mech has a bore scope for checking piston and cylinder condition, and we scope it every other spark plug change. Compression is right on the button. Been using AGIP API-TC++ Synthetic as specified in the manual. Wife's Malaguti has over 20K km and it's the same drill. In fact we decided to go with the bore scope due to the difficulty in accessing the Malaguti's engine, and then decided to just do the PX that way as well.

We are not talking in circles. We are talking about two different things.

One more piece of food for thought.

Let's look at the "Scuffing" standard. API TC states the maximum scuffing an oil can allow in the conduct of a test cycle. That does not predict the life of a specific engine. It is just a benchmark engine manufacturers can use in developing their engines and service schedules. It's a "given" that an API TC oil will allow X amount of scuffing or less in an air cooled engine tested at specified conditions. The oil standard adds certainty to the equation. It is a standard set by a independent professional entity. Thus, engine manufacturers and engine operators do not have to wade through competing claims by a variety of oil manufacturers. API TC is API TC and will always perform to API TC standards, or the oil manufacturer is liable for the damages. Easy peasy. Follow the instructions and get the expected results. And to keep it truly simple and predictable, the API standards are "pass/fail". The oil either meets every spec of the standard or is doesn't get the rating.

What we don't know about a given TCW-3 oil, is what aspect of the API TC standard it fails. Scuffing? Deposits? Ring Sticking? pH? In short, it is not to the industry standard for the Vespa application, but we don't know why. All you can do is run it in your engine and see what happens. With the specified oil, that uncertainty is not there.

Aviator, you have the patience of Job and wisdom of Solomon. I'm writing a letter to the Pope to nominate you for Sainthood.

Thanks. Patience, yes. The "wisdom" I have to attribute to my early mentors in aviation. They taught me to stick to the standards, and time, aided by a couple of embarrassing screw ups, proved them spot on. Also, with time, I was fortunate to learn more and more about why it is spot on.

I owe the late Mr J.J. Ryan, our 7th and 8th grade shop teacher, an apology for failing to mention him in the post above. He taught us to seek out and understand the real hows and whys of things mechanical, electrical, etc. His teaching of troubleshooting principles was equal to, if not a bit better, than what I received during the Aviation Maintenance Officer/Test Pilot Course many years later. At every class reunion, classmates would praise the value of what he taught us.

Yes thanks Aviator, appreciate the info. You clearly are a follow the standards kind of guy, which is commendable. But we're going to use our own judgment on this. We're dealing with a 40 year old, 5hp thumper that isn't high output by anyone's standards. Now that you mention it, it arguably does have more in common with a trolling and cruising outboard than a Rotax race bike. So API approvals or not, we're going to stick with the oil we're using for now because it's working perfectly.

We might do things differently if it were a new scooter, but it isn't. Consider it an experiment.

I contacted the oil manufacturer and asked about certifications or lack thereof (btw, it's a well known company, very respected in the racing community). I've used their oil for years and it's always performed great. The rep said frankly they hadn't even looked into getting any approvals for the 2T oil because it was such a small market for them. Given the current distribution they didn't think the cost was justified. He was confident the oil would do an excellent job, burn clean, and provide excellent lube at all operating temperatures.

30,000 kilometers on your scoot is impressive. Ours is pushing 22,000 miles. We'll take look at the piston in a few months and post some pics. I'll be surprised if there's anything unusual. Honestly, I think that unless you really abuse these engines, longevity is more about regular maintenance than the type of oil you use. We'll see.

Thanks for the nice exchange & cheers.

No issue whatsoever with what you are doing. However, don't confuse API TC with being a standard developed for "Rotax type" engines. The origins of the myths arose because Rotax found that a standard for water cooled marine applications did not address the needs of their marine engines. API T series standards predate the Rotax embroglio, and are not just for "high output" engines. As I noted earlier, this one unique issue just spread out across the entire 2T community, to include ultra-light aircraft applications.

There are a variety of "racing oils", for example, that do not hold an API certification. In such cases, you have the manufacturer's word that they will perform well. With a published "standard" you are assured how that performance was measured. If you trust the manufacturer, then go for it.

I have a bigger problem with "designer oil" labels that make claims that their oil "exceeds" API service specs, without providing a sound basis for the value of same. For example, a claim that the oil has "more" or "better acid neutralizers". Fact is that acids are either neutralized or they aren't. The API spec for acid neutralization calls for the oil to handle the amount of acid producing combustion byproducts that a reasonably healthy engine can produce, and then some. Engine manufacturers will fine tune things by specifying the change interval to ensure an oil change before the neutralizing additive is fully consumed. An engine producing more acid related combustion byproducts has bigger problems than the acid produced. In short, there is no measurable benefit in having more or better acid neutralizers than API spec, but it sure sounds good that the designer oil can neutralize more acid, or do it "better". However, since this falls into the legal realm of "sales puffery", it's allowable.

If a lab sample shows acid in crankcase oil, the prescribed initial diagnostic is a compression test, dynamic and static, not questioning the oil itself. Too much blow by is the most common cause.

My all time favorite was the major oil company that created a new "label" (I'll call it "Platimum") for it's top of the line oil when the API released a more stringent service rating for gasoline engine motor oils. They proudly stated that in their "never ending quest for best protection" or something like that, their newly developed "Platinum" had X% more this and Y% more that, etc than the oils pictured in the ad, "Even better than our own excellent Gold Oil". What they chose not to mention was that all the oils depicted were an earlier API service category, and all the increases were simply "Platinum" complying with the minimums of the newer spec. The ad was immediately challenged by the other oils companies depicted, and the FTC did rule in their favor.

Standards can be misused and are. They can also be misunderstood.

Sure there are plenty of snake oil sellers out there making some pretty wild claims. I don't think that's the case here. We're using a premium product by a reputable company with a proven track record. And and other things being equal, I'd rather buy from a smaller local enterprise than one of the large multi-national conglomerates, but that's a different issue and we'll save it for another thread.

Cheers.