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0-360 and Mogas

pierre smith

Well Known Member
Mornin' everybody,
Man-oh-man, we're finally there!! Waiting on the inspector for our long-awaited sign-off.....WHEW, what a trip it has been (1 year and 9 months for our RV6A.)
How many of you guys/gals have run mogas in O-360s? Ours is a stock O-360 with a fresh self-done overhaul with yellow tagged everything. Any problems, comments,
Thanks, Pierre Smith
 
Mogas Burner

Pierre,

I use 91 octane, alcohol-free mogas in a 360 with 8.5:1 compression. This is common in spam cans that have the Peterson STC for mogas. 7:1 compression engines (like my 150 horse 320 in a 172) can use 87 octane, exemplified by all the aircraft with EAA STC's. You don't need an STC for an experimental; it's only that there's a world of mogas use in certificated aircraft having the same engine.

I suggest you go to both web sites and read up on the subject. Common practice is to break in a new engine on 100LL, then transition to mogas.

Best wishes for your new bird, and a squawk-free first flight.

John Siebold
 
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Mogas

We operate 4 different ACs with mogas, a C182, a T craft, homebuilt with Rotax (4 cycle) and Lycoming. In all case, mogas improved, fuel consumption, oil consumption increased plug life, and generally improved performance.
In the case of the C182, it's oil guzzling O470 Conti's consumption dropped to 12/13 gph on fuel and, oil dropped 1 qt/hr, and performnace is closest to factory specs. The engine has 1300 hrs. Plug life had increased, and the JPI anylizer is stable with mogas, while eratic with AV gas, in addition to using more fuel for cooling, odd when considering that the higher octane should burn cooler.
Lead does not lubricate as is a popular myth in aviation, in fact it does damage to any engine. Before unleaded gas, the auto industry average engine lige was less than 50K miles, as opposed to double with unleaded. With modern FADECs, 200,000 in autos is becoming more and more common.
In the case of the Rotax, AV gas makes the little engine unruly and runs inconstantly. Rotax recommends replacing oil freqhently if using AV gas. Spark plugs load easily as well and consumption rises.
Crop dusters and banner towers have been using it for years. One banner tower on our fiels dreads towing banners from a busy airport due to "wandering" eyes. On less populated fields, they use mogas. Reasons, better fuel economy, better plug life. and performance.
The T Craft was OH ed nearly 25 years ago, and running mogas from the first day after OH. Oil consumption for the little Conti is very low, plug life (and just signed off it's annual) look as if they were fairly new.
FWIW
 
Mogas

I also ran Mogas for many years in a C182 and a Tripacer with no issues. However, those were both high wing, gravity fed fuel systems. Comparing those aircraft to the RV series of low wing airplanes with fuel pumps is not relevant.
 
How and where does anybody get ethanol free auto fuel? Keep in mind that any STC is invalid when using ethanol fuels, also not all Cessna 182’s can use auto fuel.. I believe the U models are high compression and won’t tolerate it.

There are other things to consider when using auto fuels.. rubber in your mechanical fuel pump, rubber fuel lines.. ect..
 
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I get 92 octane alcohol free at local gas station in a 25 gallon fuel caddy. No issues with 30 year old fuel system. No, no impact on rubber, fuel pumps.

IF NOT RUNNING ALCOHOL FREE, THERE IS A CONCERN ABOUT ALCOHOL IMPACT ON FUEL SYSTEM. Use the search function here, lots of threads on subject…..a dead horse in my opinion.
 
How and where does anybody get ethanol free auto fuel? Keep in mind that any STC is invalid when using ethanol fuels, also not all Cessna 182’s can use auto fuel.. I believe the U models are high compression and won’t tolerate it.

There are other things to consider when using auto fuels.. rubber in your mechanical fuel pump, rubber fuel lines.. ect..

Here in boat country, many, many gas station/convenience stores sell ethanol-free 91 octane at the pump. I don’t know about other parts of the country, but it’s common here.

What I don’t know is if the vapor pressures, storage methods, etc — the things that Lycoming delineates as “airworthiness” — would make such pump gas something I’d want to use in my airplane. So far, absent Lycoming’s blessing, the answer is “no”. (For me).
 
Clearly a timeless topic . . . .

How and where does anybody get ethanol free auto fuel? Keep in mind that any STC is invalid when using ethanol fuels, also not all Cessna 182’s can use auto fuel.. I believe the U models are high compression and won’t tolerate it.

There are other things to consider when using auto fuels.. rubber in your mechanical fuel pump, rubber fuel lines.. ect..

Ethanol is added/mixed with the gasoline before/as it flows into the tank delivery truck. It is up to the local gas station (op lims permitting) as to whether they offer ethanol/alcohol free fuel. There is/was a clear viscous sticky "lubricant" also added to the mix. I don't know what it is/was.

Ethanol is shipped by tankers (rail/truck), not pipelines.

You might find an independent station near the airport and convince them to sell the fuel you desire.
 
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Be careful with ethanol free

If you’re planning on using ethanol free, buy a tester, they should be available at aircraft spruce. Also pay attention to the pump you’re getting it from. Some pumps use a single hose for all the different grades of gasoline, some use an individual hose for each grade. There may be residual ethanol fuel in the hose. Though I usually use 100LL, when using mogas, as a general rule that I came up with, I’ll admit without much thought, I’ll put 2 gallons into whatever vehicle I’m at the station with before filling up cans for the airplane, just to purge any ethanol gas out of the lines. I’ve never detected any ethanol in fuel when testing it afterwards.
 
The engine itself (normally aspirated) does not care about ethanol, it will happily eat that stuff. As noted earlier in this thread however, the REST of the fuel system does care about it. High compression and turbocharged engines are the exception here, they require special care and feeding.

STC'd aircraft require ethanol-free. New-build EAB can be built without any rubber in the fuel system (substitute Viton/Teflon for O-rings and seals) and then you're good. If you buy a used EAB you can certainly revamp the fuel system to eliminate the rubber components, but that's a task for an experienced wrench-turner, not a rookie. Higher fuel system pressures can eliminate the high vapor pressure issues with mogas and autogas.

I won't say it's easy, but it certainly CAN be done - I'm closing in on 1000 hours running 91E10 in my IO360 at altitudes normally in the high teens for cruise and I've had it up to FL210. I am burning, quite literally, automotive premium fuel from Walmart. I can do 100F summer day hotstarts and direct max-power climbs into the teens with zero fuel issues.

CAUTION - jacking around with your fuel system is not advised. It's the quickest way I know to become a glider pilot. Don't do it unless you are sure of what you are doing. If you are not sure, then FIND OUT the answers to your questions before you go there.
 
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Does anyone make Mogas formulated for longer term storage? That is my biggest concern. Many aircraft don’t fly often enough to keep auto fuel fresh and within it’s designed storage limits. Combine old fuel with a high heat day and perhaps ignition timing that has slipped a bit and bad things can happen.
 
Question to Pierre??

Are you asking for experiences with or without ethanol??
Ethanol free 91 octane is relatively rare in most parts of the country where as 91E10 is available everywhere. Both work in the experience of many users but for the sake of keeping this thread on track, let us know what sort of mogas you want to use??
Opinions and experiences vary widely, see my tag line.
 
Does anyone make Mogas formulated for longer term storage? That is my biggest concern. Many aircraft don’t fly often enough to keep auto fuel fresh and within it’s designed storage limits. Combine old fuel with a high heat day and perhaps ignition timing that has slipped a bit and bad things can happen.

I've been burning 87 unleaded gas in our C182 for the 500 hrs SMO. I pour 11 oz. of Sta-bil in the 55 gallon drum before filling it with the 87 unleaded gas. It has sat for up to three months during down time with no issues at all - both in the wing tanks and in the drum.
 
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