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IO-360 Auto Fuel?

M

mattsmith

Well Known Member
I am not close to flying but want to know if a IO-360 can use auto fuel? 8:7 is not that much more than 8:5 does it make that much deference? just wondering, see a lot of discussion on 320s and 8:5 compression 360.
 
Ethanol-free premium auto fuel works fine. When ethanol is involved you will need to consider the tolerance of your fuel system components.
 
I run premium autogas in my IO540, which is basically the same as your engine with two extra cylinders. The main concern as I understand is that it not be high compression cylinders. I think mine are 7.8:1. I use autogas in one wing tank and 100LL in the other. When I switch tanks to autogas I see a slight rise in EGT's and no change in CHT's. I run at 60% LOP which gives me about 150 Kts TAS at 10 gph. (RV 10). I live in Missouri which is supposed to have ethanol free gas for premium. I have never noticed a hiccup and may soon abandon the 100LL, which I use for TO's and landings. Easily $2 a gallon less and not really a problem for local use, I have my own hangar.
John Koonce
N 78 MU
 
testing

Not to sound like an old hen, but if you do run auto gas, please test every single batch you get from the pump for ethanol. I've got a friend who runs auto gas in his airplane and I cannot tell you how many times he has gotten a nasty surprise in the tester at the pump. Don't believe any stickers... or lack thereof. Even though he has the STC, we took apart his carb just to make sure the float was not changed to something it should not be somewhere along the line. I'm going to stay out of the av-gas auto gas debate. I run only 100ll but I'm not going to discourage anybody who wants to run auto gas... the label says experimental for a reason :)
Best
Brian Wallis
 
mattsmith said:
I am not close to flying but want to know if a IO-360 can use auto fuel? 8:7 is not that much more than 8:5 does it make that much deference? just wondering, see a lot of discussion on 320s and 8:5 compression 360.
Click to expand...

Please remember that running mogas carries more than just a detonation hazard. There is the vapor lock issue and storage issues to worry about. I ran premium mogas for 600 hours in a Cherokee without problems. I also suffered an engine out scenario, (twice) in a 172 using mogas. This is not just an engine suitability issue. It depends on the airframe installation as well. I would personally not run mogas in an RV, unless it had cooling air directed towards the mechanical fuel pump and preferably a cooling shroud around it. Also, sharp bends in fuel lines and 90 degree fittings should be avoided. There is much info on previous threads on VAF if you do a search. Vapor lock has brought down RV's. These issues can be managed, but be cautious and do your homework!
There is an added level of risk involved!
 
With the increase in avgas price, and the no-lead avgas EPA law coming into effect, many of us will be forced to accept mogas, ethanol or not.
Finding ways to live with ethanol blended mogas is not an option, we have to do it or flying will be too expensive for many of us. Nonethanol blended mogas is no longer available in the Pacific Northwet.
My RV-8 fuel system is being set up for ethanol blended mogas.
1) ethanol tolerant materials
2) high pressure fuel injection
3) fuel return line to fuel tank
4) heat shielded fuel system components
My actaul goal is to tolerate all fuels for spart ignited engines eventually:
Swiftfuel, Avgas, mogas, ethanol blended mogas, pure ethanol.
Every power engineer knows that you have to adapt to the available fuel, that's just the way it is.
 
Auto Gas in an IO-360

Is there anyone out there that is actually running ethonal based auto gas in an IO-360 with the Bendix Experimental fuel body? I know that Fast Eddie is using ethonal based gas in his O-360 (carbureted) with no issues. I'm about ready to start testing with a 50/50 mixture of ethonal based auto gas and 100LL in my RV-7A, but can't get any specific data on the tolerence level of the Bedix Experimental fuel body to ethonal.
So is there anyone who has already done this? If so, what octane gas are you running?
 
Also keep in mind that autogas is about 2.5% heavier per gallon, on average, and it has an initial boiling point of 86F, will lose 5% at 97F, 10% at 111F, and 20% at 133F. so keep it cool and fresh!
The initial boiling point and higher is what causes the vapor lock.
 
Fred.Stucklen said:
Is there anyone out there that is actually running ethonal based auto gas in an IO-360 with the Bendix Experimental fuel body? I know that Fast Eddie is using ethonal based gas in his O-360 (carbureted) with no issues. I'm about ready to start testing with a 50/50 mixture of ethonal based auto gas and 100LL in my RV-7A, but can't get any specific data on the tolerence level of the Bedix Experimental fuel body to ethonal.
So is there anyone who has already done this? If so, what octane gas are you running?
Click to expand...

FrankH on this forum is one guy I know of that uses mogas with ethanol which here is Oregon is supposed to be 10%. I have run quite a bit of 93 oct mogas ethanol free and experienced no problems other than a slight burp right after fueling with a hot engine. Currently there is only a 70 cent spread between mogas and 100LL here and it costs me that diff to go out of my way to get the mogas so will be going back to 100ll and will report if the burp goes away.
 
I was running 93 UL exclusively until Florida mandated ethanol. We still have a few gas stations that still carry it. I always test it to insure no ethanol.
Right now I mix it 2:1, 100LL:93UL. I short term store it for topping off only.
The price spread here right now is about $1.25. When it get's below $1, I don't bother.
 
Fuel leakage

Hello Gents/Gals

Did any of you experienced fuel leaks after using mogas for an extended period of time??
I just finally fixed a nasty fuel leak that just wouldn't go away and since that I haven't used mogas at all.. I was wondering if PRC/Proseal could be intolerate to mogas...any ideas??

Over here the differnce in price between Premium mogas vs 100LL is about $1.75/gal...

Thanks

Bruno
[email protected]
 
I don't get it? So much fear about ethanol on what it "might" do! I was filling up my cans the other day and the station owner came out and was making small talk while he was cleaning up around the pumps. I asked him if then had to make any major changes to their equipment due to the use of ethanol? He said they were asked to change one O-ring at the top of their hoses as it might be made of natural rubber, he didn't change his and said he hasn't had the first leak. I have been running with auto fuel for years, and now with the "evil ethanol" and I am having no issues. Maybe it's just me but I tend to find more issues when I am forced to buy 100LL on a trip.

Mike
 
I ran auto fuel in a O-360 for a long time.

But I have switched to Av Gas now because of the ethanol additive. It really confuses the capacitance type fuel senders.

Politics has trumped technology, economics, and common sense.
 
MikeF said:
Maybe it's just me but I tend to find more issues when I am forced to buy 100LL on a trip.

Mike
Click to expand...

Do you mind elaborating on what issues you find with 100LL?

Other than maybe having your mags timed better for the Mogas I can't think of any issues there could be.

I definately prefer to run airport mogas, or auto fuel in my C-140 but those are different reasons than an RV engine would have.

Thanks
Mark
 
RV-4 said:
I was wondering if PRC/Proseal could be intolerate to mogas...any ideas??
Click to expand...

I ran ethanol free mogas in one tank of my RV-6A (O-360, carb) for a few hundred hours. I had problems with icing on the mogas side (winter), and with a white residue that would clog the aux fuel filter on that tank (again, only on the mogas side).

I finally decided it wasn't worth the cost savings, and switched to 100% avgas several years ago. When I quit using mogas the white residue stopped appearing in the fuel filter, and no more icing problems.

My tanks were QBs, circa 1996 delivery.
 
RV Wannabe said:
Do you mind elaborating on what issues you find with 100LL?

Other than maybe having your mags timed better for the Mogas I can't think of any issues there could be.

I definately prefer to run airport mogas, or auto fuel in my C-140 but those are different reasons than an RV engine would have.

Thanks
Mark
Click to expand...

I tend to find a bit of rusty water at times with 100LL, maybe old in ground tanks not sure. The lead build up on the spark plugs requires cleaning more often and maybe it's in my head but I think my engine just runs better.

Mike
 
Ethanol and Bendix

Fred.Stucklen said:
Is there anyone out there that is actually running ethonal based auto gas in an IO-360 with the Bendix Experimental fuel body? I know that Fast Eddie is using ethonal based gas in his O-360 (carbureted) with no issues. I'm about ready to start testing with a 50/50 mixture of ethonal based auto gas and 100LL in my RV-7A, but can't get any specific data on the tolerence level of the Bedix Experimental fuel body to ethonal.
So is there anyone who has already done this? If so, what octane gas are you running?
Click to expand...
Fred
Try a forum search for "Airflow Performance" and "ethanol", lots of information has been posted. Make sure you get o and the a in the right spot, search works better :D
 
I believe that it was more politics than anything.

Alcohol is not good for metal. I used it to race years ago and it always left a chalky white residue that needed to be cleaned the next week if not sprayed with a lubricant and wiped off after a race. The chalky white residue made the injection system throttle shaft rough and difficult to move if left uncleaned. It would haul potatoes though.

I don't want any in my airplane.
 
Politics

DanH said:
Politics....it made a huge farm lobby very happy.
Click to expand...

Are we going to opine on politics or talk about airplanes?

My understanding is this forum is for flying and building. If it's also about slamming farmers (I resemble that remark;), then I've got lots to say on the topic. Not being thin skinned here, I'll happily dive into it, I just don't think taking things in the political direction is what the forum is about, so thus far I've refrained.

With all due respect here, what are the guidelines moderators?

best
Stan
(out for a week on the main Salmon)
 
Last edited:
My friend on his RV-10 for 540 engine put in plunger
a compression ratio 7.
Some lost power.
Fills 95 auto petrol and very pleased.
He lives in Ukraine.
 
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