FredG Posted November 7, 2015 Report Share Posted November 7, 2015 I guess the 912 is so different from all other horizontally opposed, pushrod, four cycle, gasoline powered engines equipped with a wet clutch that one motor oil, and only one motor oil, can be recommended for use in it. Roger, neither Rotax, nor other manufacturers of car and motorcycle engines have to "test and keep up with varying oil MFG's changing formulas." Oils must meet industry standards. That's how it works, as you know. The current Aeroshell Sport PLUS 4 is API SL rated and JASO MA rated (a motorcycle designation, suitable for wet clutch applications). That information is available from the Aeroshell webpage. So, really, Rotax doesn't have to keep track of all those oils. It can (and I strongly suspect it does) design engines (e.g., bearing clearances, operating oil pressure and oil temperature, etc) to work well with motor oil manufactured to industry standards. It is what other engine manufacturers do. Link to comment Share on other sites More sharing options...
Roger Lee Posted November 7, 2015 Report Share Posted November 7, 2015 HI FredG, Rotax just SIMPLIFIED when they RECOMMENDED Aeroshell. Aeroshell not only meets that minimum spec, but more. Oil specs are only minimums and may still not be suitable for some higher performing engines. Just because it meets the minimum standard doesn't mean you should use it. Think how an oil formula might change if Mobile One only made one oil for only one engine instead of trying to fit everyone's needs. Rotax doesn't have the time or the money to keep up with all the oils in the world. It isn't just the US. We are only one user. Oil MFG's don't alert anyone that their specs have changed. Mobile One here in the US is a slightly different formula here than other places in the world it is MFG. How could anyone be expected to keep up. There are oil that Rotax definetly recommends to stay away from. Like Castorol and there are others. Aeroshell was targeted solely for this engine and tested for hundreds of thousands of hours over the years. Nothing overtly special about the Rotax engine other than it does have a pressed crankshaft, old technology flat tappet lifters that need additives that overhead cam and roller bearing engines don't need. It fires on every stroke of the piston and not just the regular compression stroke. They have nickelsil cylinders that most don't have, they have armored valves you can't do a valve job on that I haven't seen anywhere else, they have a gearbox with an overload clutch and Bellville washers most don't have, the cylinders don't ever get honed, it's considered a high rev engine that Cont. and Lycomings aren't. The cylinder heads are the only thing that coolant cools and not other parts of the engine like most water cooled engines. The engine and gearbox share the same oil that usually only our motorcycles do. For me there has been millions of dollars and millions of hours put into this engine by people a whole lot smarter and with cooler tools than mine so listening to them instead of E.F. Hutton pays. Rotax recommends Aeroshell because it knows how it was engineered and engineered with just that engine in mind. They left all the other oils for you to find out if they meet the standard. Doing somethings outside the safe box is okay sometimes and sometimes not. It's up to each person to decide if he wants in the crap game or likes to just watch and keep his money. I have seen a lot of damaged Rotax engines over the years with those total cost probably into the hundreds of thousands of dollars. Rotax is not in the engine business, they are in the parts business and do quite well thanks to many craps players. Link to comment Share on other sites More sharing options...
FastEddieB Posted November 7, 2015 Report Share Posted November 7, 2015 I have seen a lot of damaged Rotax engines over the years with those total cost probably into the hundreds of thousands of dollars. Just curious... ...how often could you see obvious lubrication failure as the cause of the damage, and what were the signs? Link to comment Share on other sites More sharing options...
Tom Baker Posted November 7, 2015 Report Share Posted November 7, 2015 You're claiming it's no longer approved? Note, approved vs recommended. What I'm saying is that Mobil 1 racing 4T is no longer listed in the current Rotax publication for suitable operating fluids. Link to comment Share on other sites More sharing options...
N456TS Posted November 7, 2015 Report Share Posted November 7, 2015 Roger, neither Rotax, nor other manufacturers of car and motorcycle engines have to "test and keep up with varying oil MFG's changing formulas." Oils must meet industry standards. That's how it works, as you know. The current Aeroshell Sport PLUS 4 is API SL rated and JASO MA rated (a motorcycle designation, suitable for wet clutch applications). That information is available from the Aeroshell webpage. So, really, Rotax doesn't have to keep track of all those oils. It can (and I strongly suspect it does) design engines (e.g., bearing clearances, operating oil pressure and oil temperature, etc) to work well with motor oil manufactured to industry standards. It is what other engine manufacturers do. Well stated and good points. These engines are about the simplest in the world. But, wow, they sure worked the advertising for the Aeroshell. It fires on every stroke of the piston and not just the regular compression stroke. Umm, each cylinder fires on 2 of the 4 cycles. It's a waste spark ignition. Despite that, it has no bearing on oil choice. The tech that this engine is based on isn't new....(Maybe new to the aviation). This is why it's kinda funny all this talk of only one oil can be used. I would love to see any data showing that a non-Aeroshell approved oil was the cause of premature failure. I could see someone incorrectly breaking in their engine using full synthetic. But past that?... How did all those engines meeting or exceeding TBO do it prior to SI-912-016R8? Link to comment Share on other sites More sharing options...
FredG Posted November 7, 2015 Report Share Posted November 7, 2015 Roger, do you really think this is true? "Aeroshell was… tested for hundreds of thousands of hours over the years." Do you mean Aeroshell has been used for hundreds of thousands of hours or do you mean it was "tested" for hundreds of hundreds of thousands of hours? I doubt it was actually tested in 100 engines for over 1000 hours each. Also, I'm not buying how special these engines are. As if Nikasil, pressed crankshafts, and flat tappets haven't been around for decades. Finally, "millions of hours" put into this engine? Do you think that more than 100 Rotax engineers have spent over 10,000 hours each just working on the 912? I'd be very surprised. Link to comment Share on other sites More sharing options...
N456TS Posted November 7, 2015 Report Share Posted November 7, 2015 What I'm saying is that Mobil 1 racing 4T is no longer listed in the current Rotax publication for suitable operating fluids. Ugh! My brain is broken. Everything kept getting merged. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted November 7, 2015 Report Share Posted November 7, 2015 This is why it's kinda funny all this talk of only one oil can be used. I would love to see any data showing that a non-Aeroshell approved oil was the cause of premature failure. I could see someone incorrectly breaking in their engine using full synthetic. But past that?... How did all those engines meeting or exceeding TBO do it prior to SI-912-016R8? I think you are misstating some people's positions, either intentionally or unintentionally. Nobody has said "only one oil can be used." What we are saying, is that there is currently one recommended oil for the 912-series engines, though other oils *might* be suitable. Note the difference between "suitable" and "recommended." Since no other oil is recommended, and Rotax provides no technical data on what a different, suitable oil might look like, use of any other oil is, as Roger elegantly described, "a crapshoot." For the sake of argument, let's say that a lubrication failure occurs in your engine, leading to extensive damage, and you are using something other than Aeroshell Sport +4 (ASS+4). Perhaps your alternative oil is superior in all aspects to ASS+4. Regardless of that fact, do you think Rotax would be more inclined to: A ) Applaud your superior choice and grant you a complete warranty repair. or B ) Point to the fact you are using an oil outside their recommendation and deny a warranty claim? I know which I'd bet on. In the end it's not really even about using the best, most optimal engine oil in the Universe...it's about accepting that Rotax knows more about their engines than any user/owner does, and accepting their recommendations, both for engine life and warranty reasons.* One other point: If these engines were so old-school and similar to other air-cooled airplane engines, we'd be using a heavier non-synthetic ashless dispersant oil as is used in Continentals and Lycomings. If we did that our engines would grenade in short order. * The above consists entirely of my opinion, and I respect others' right to choose anything from Mobile One to bacon run-off grease for use in their own engine. Link to comment Share on other sites More sharing options...
N456TS Posted November 7, 2015 Report Share Posted November 7, 2015 Well, I'll at least try to be polite... Rotax can't deny a claim because you use non-aeroshell unless the oil specifically was the cause of the oil. If you have evidence of anything, please post. Any failures? If so, who determined the source of failure?...and the qualifications of this person? Link to comment Share on other sites More sharing options...
FlyingMonkey Posted November 7, 2015 Report Share Posted November 7, 2015 Are you saying I have not been polite? There is nothing impolite in my response. I'm guessing that if you use a product outside manufacturer's recommendations, you open yourself to warranty questions, at least. Link to comment Share on other sites More sharing options...
gbigs Posted November 7, 2015 Report Share Posted November 7, 2015 Here is the Service Instruction for Rotax "Selection Of Suitable Operating Fluids", dated 4-2015. Text in the bulletin of note applicable to this conversation are: 1. If possible, operate the listed engine types using unleaded or low-lead fuel. (AVAGS 100 LL is not considered low leaded in this context.) 2. Additives under the names of Decalin and Alcor TCP which aid the scavenging of lead deposits have not been tested by BRP-Powertrain. Field experience shows that these products have no detrimental effect on the engine, when used in the recommended manner. 3. AVGAS 100LL places greater stress on the valve seats due to its high lead content and forms increased deposits in the combustion chamber and lead sediments in the oil system. 4. Keep the motor oil temperature below 120 °C (250 °F) over most of the operating period 5. When operating with unleaded fuels or MOGAS and when engine oil temperatures often exceed 120 °C (250 °F) use of a high quality full synthetic oil is recommended. The 'recommended oil' Aeroshell is required when burning AVGAS because it is a semi-synthetic. But does say for better temperature control and when burning the 'recommended' MOGAS a high quality full synthetic is 'recommended.' Rotax SI Ops Fluids 4-2015.pdf Link to comment Share on other sites More sharing options...
N456TS Posted November 8, 2015 Report Share Posted November 8, 2015 Give us one good reason why you shouldn't be polite anyway. I'm sorry, at what point wasn't I? Are you saying I have not been polite? Yes, your accusations. You guys are too much. If you want to follow the facts, go a head. If you want to follow Rotax's advertising, good for you. MrMorden, If you've got any evidence of any damage or abnormal wear, I would still love to see it. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted November 8, 2015 Report Share Posted November 8, 2015 Accusations? What have I accused anyone of?!? I already said the issue is not damage, it is following recommendations for support and warranty. If you don't see that, I can't help you. Like I said, run bacon grease in your engine if you want, you paid for it. No skin off my nose. Link to comment Share on other sites More sharing options...
Duane Jefts Posted November 8, 2015 Report Share Posted November 8, 2015 If one runs bacon grease in your engine at high temps you might create some "hard lard' and that might "fowl" your engine. If this occurs then one must use ground up "rooster comb" as an additive to "de fowl" the engine. Just a thought. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted November 8, 2015 Report Share Posted November 8, 2015 But I bet an engine running bacon grease smells delightful. Link to comment Share on other sites More sharing options...
FredG Posted November 8, 2015 Report Share Posted November 8, 2015 The following two statements are made on page 2 of Rotax SI-912-016R8 (16 April 2015): "Use only oil which is classified by ROTAX standard (RON)!" and "Use the recommended motor oils tested and released by BRP-Powertrain according to section 3.2 of this SI." Note that the recommended "motor oils" are Aeroshell Sport Plus4. Although the SI is somewhat inconsistent in other sections, I don't see much room for use of oils that are not "recommended" in those two statements. Link to comment Share on other sites More sharing options...
gbigs Posted November 8, 2015 Report Share Posted November 8, 2015 The following two statements are made on page 2 of Rotax SI-912-016R8 (16 April 2015): "Use only oil which is classified by ROTAX standard (RON)!" and "Use the recommended motor oils tested and released by BRP-Powertrain according to section 3.2 of this SI." Note that the recommended "motor oils" are Aeroshell Sport Plus4. Although the SI is somewhat inconsistent in other sections, I don't see much room for use of oils that are not "recommended" in those two statements. Oh the inconsistencies are the point. Some interpretation is required. There is no question the SI says Mogas is preferred (and 100LL is allowed by not recommended). They also specifically say Decalin is fine and that if you use Mogas exclusively you can use a full synthetic oil - they don't say which one. In the recommended oil section the assumption is that you are using leaded gas. Link to comment Share on other sites More sharing options...
Doug G. Posted November 8, 2015 Report Share Posted November 8, 2015 Where does it say Decalin is "fine"? (What does that mean?) Page reference please. Link to comment Share on other sites More sharing options...
Anticept Posted November 12, 2015 Report Share Posted November 12, 2015 Decalin is acknowledged in http://docusearch.flyrotax.com/files/pdf/d06038.pdf. I don't say approved because it's not, but nor is it prohibited. Link to comment Share on other sites More sharing options...
Doug G. Posted November 12, 2015 Report Share Posted November 12, 2015 Yup, didn't see the word "fine" in there anywhere. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted November 12, 2015 Report Share Posted November 12, 2015 Decalin is acknowledged in http://docusearch.flyrotax.com/files/pdf/d06038.pdf. I don't say approved because it's not, but nor is it prohibited. Looking at section 5.2 of that document, they advise following the manufacturers recommendations, which is almost-sorta-kinda like saying it might be okay. I also saw in that document that the 80hp 912 models can run on 87 octane mogas. I didn't know that, that is one pretty good reason for using the 80hp engine, especially out in the hinterlands where high octane fuel might be scarce. Link to comment Share on other sites More sharing options...
Anticept Posted November 12, 2015 Report Share Posted November 12, 2015 80 hp models also use less gph. Link to comment Share on other sites More sharing options...
FastEddieB Posted November 12, 2015 Report Share Posted November 12, 2015 But I bet an engine running bacon grease smells delightful. I just asked Jake, and he said that he, for one, would not mind at all... Link to comment Share on other sites More sharing options...
FlyingMonkey Posted November 12, 2015 Report Share Posted November 12, 2015 Eddie, it might be a great way to get canines acclimated to air travel! Link to comment Share on other sites More sharing options...
andyb Posted January 7, 2016 Author Report Share Posted January 7, 2016 Lets see, 50 hours times 5 gal / hour = 250 gallons times 30% = 75 gallons. How about 50 hours or 75 gallons of avgas which ever comes 1st? Exception would be 75 gallons of avgas before 25 hours, then 25 hours is the limit. I have an old cheap fuel trailer but it does have both a bonding cable and a ground. Belated response, but I don't think that will work. After 30 hours, for example, at 5 gallons per hour, 30% would be only 45 gallons of avgas, at which time you'd need to change the oil. Right? Also, I'd think that what's relevant is how much avgas passes thru the engine, not what goes into the tanks. Immediately post-oil change, having 34 gallons that is a 90/10 avgas/mogas mix would have a much different outcome, in terms of how much avgas had passed through, than 10/90. Arguably I'm being precise on something that doesn't require precision, but if the decision is at 25 hours has passed, when >30% avgas has passed thru the engine the oil needs to be changed, I don't see a way to calculate it accurately other than what I've done. Love to be wrong! If someone can show me how, I'll attach the Excel file. Andy Link to comment Share on other sites More sharing options...
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