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What oil to use

E

Ex Bonanza Bucko

Well Known Member
What brand oil do you use in your RV12's Rotax?

I will be operating with about 50% Avgas 100LL. The Rotax docs say that a "semi synthetic" oil is needed for that. They also say that motorcycle oil is one choice.

So I'm looking for input about that and also about Delcon as a lead scavenger.

Also what brand and label coolant do you use?

Thanks,

EBB
 
100LL, Ethanol free and Decalin

I've been running a mix of 100 LL and 90 octane Ethanol free to get the required 93 octane. I add Decalin and also use the Aeroshell Sport mentioned above. This is for the Rotax 912S in my Kitfox. I change the oil every 30 hours.

Vic
 
Here is a good place to learn a little about the oils we can and or should use.

This is a blog on the Rotax website and at the bottom has a good oil study article from a test lab.

http://www.rotax-owner.com/rotax-blog/item/8-oils-a-fluid-discussion

I would highly recommend reading both articles.

You must use a motorcycle oil because our crankcase and gearbox share the same oil and that dictates certain additives that car oils do not have using the additive ZDDP.

If you want to skip all this and keep life simple then Aero Shell Sport Plus 4 is a good choice. I have heard that a re-formulation of that oil is coming with an increase of ZDDP.

Using 100LL you need to use a semi synthetic to help suspend the lead. You only need 91 oct. for the 912ULS. If you can get away from 100LL I would stay away completely around your home field flights and the small amount of 100LL you might use during cross country's won't be any big deal compared to the engines life time. 100LL is not good for your engine so if you have a choice stay away. If you use 100LL then Decalin should be a staple for you.
 
Vic, I think you have a typo. 91 Octane needed, not 93. There was a typo in one of Van's manuals for awhile. The auto premium fuel you see everywhere is typically labelled 91. You won't find 93.
 
90 Octane

Only 90 Octane Ethanol free is available around here so I mix it 3:1 with 100LL.

Vic
 
vic syracuse said:
Only 90 Octane Ethanol free is available around here so I mix it 3:1 with 100LL.

Vic
Click to expand...

I add a little octane boost, about half of what the product recommends rather than add 100 LL.

There is a Service Instruction regarding approved fluids for the ROTAX. Everyone who flies behind a ROTAX should have a copy of that handy.
 
Before using any octane booster you should read the several test studies done on them. Some are junk, but there are 2-3 standouts. One is king, but these can add a significant amount to your fuel cost.
 
Does anyone have a feel for how much difference there is between 90 octane (non ethanol super unleaded) and 91 octane?

Jim
 
I just buy premium and don't obsess about the octane label. After all that's the highest you are going to get at the pump. So far (160 hrs) that philosophy seems to work.
 
I wonder if those independent stations really get or have 93 despite the label. I thought they got leftover offloads from a variety of suppliers on a route or from terminals with spot market availability. Seems if a major refiner was sending a truck around with 93 on it, their branded stations would say so. But also, a major is always going to have an octane slightly higher than the label to avoid a pesky class action lawsuit. It's a quality spec that they can't "go under."
 
Last edited:
roger lee said:
...... but these can add a significant amount to your fuel cost.
Click to expand...

Uh, really? Not so. With only E0 90 octane available in this part of the country, the only option is octane boost or 100 LL. With a cost difference of over a $1/gallon on a 20 gallon fill up, I have plenty of money to pay for the 10 ounces octane boost AND I avoid all the problems with adding lead to my engine. Sounds like the right thing to do to me, but maybe I'm missing something.
 
Does Van's say to avoid Ethanol for the -12? All of our planes with 912/914's are fine with Ethanol. The reason we avoid Ethanol in the Lycomings in general is because of the fuel system, not the engine. Don't get me wrong. I wish there was no Ethanol. I'm just saying that I haven't seen any Rotax instructions not to use it. When I went through the service class at Lockwood they said Ethanol is fine. Lead us bad. If using lead use TCP or equivalent, and the more you use lead the more often you change the oil.

On oil, we always use Aeroshell Sport as mentioned. If no lead, that's 3-4 quarts every 100 hrs.
 
Hi Jesse,

Rotax has in writing that 10% ethanol is fine. Down in South America they use up to 23% so for the engine it isn't a concern. It should be a concern for your hoses either or all our cars would be sitting on the side of the road. So for most people the ethanol question boils down to whether the fuel tanks are okay with ethanol. So it is what Vans has to say. people with ethanol susceptible tanks have used products like Kreme Wiess or other tank coatings very successfully. lead is bad, you got that right. I'll use ethanol fuel long before 100LL. The manual says 100 hr. oil changes, but very few actually go that long. Most classes teach 50 hrs. on 91 oct. and 25 for 100LL. The 100LL change time is in the Rotax SB's. I don't have a single client and have met only a hand full of people that actually wait 100 hrs. to change the oil.
 
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