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Python

Active Member
Hi, does anyone have any experience ( not opinion) in running Mogas/Autofuel ( nil ethanol) in a 180hp parallel valve IO 360, I’ve noticed some models ARE on the approved list from Lycoming. Thanks in advance 🐍.
 
The local Indiana/Indianapolis area has Landmark (Farm Bureau?) has 90 octane non alcohol gasoline. I run it in my IO-360 PV 180 hp engine. I retard the timing 2 degrees to get a larger detonation margine, but I have friends who run the full data tag timing (25 degrees) and so far no one has had any problems.

Cautions: do not carry over winter blend into the warmer late spring temperatures. It is alright to carry over summer blend into the winter. I would say I do use 25 or maybe 30% 100LL because thats what is available on XC's. Almost all my flights are LOP mixture. I've run this way for near 1000 hours.
 
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PS: I did remove the gascolator. The theory being; it was a place to boil fuel and cause problems. I have a large screen fillter ahead of the boost pump, to catch any debreas coming from the fuel tanks. I sump any potential water from the wing tank drains.
 
Lots of people on this forum run mogas in their io-360. Considerations are compression, timing, fuel system compatibility, and ethanol content.

I've burned all kinds of mogas both with and without ethanol and the only problems I have seen is occasional low vapor pressure (use boost pump to avoid it) and fuel cap gasket swelling (changed them to Viton). I did get a service notice from Andair that they needed to do an upgrade on the fuel pump due to mogas incompatibility, but that was after I had already run a few hundred hours on mogas.

From time to time I use 100LL when mogas is not available, or very inconvenient.

Once flying, I can't perceive any difference. It might be interesting to throw all my data into a statistical analysis engine to see if it can detect any differences - perhaps Savvy or Flysto will add this someday.
 
Python said:
Hi, does anyone have any experience ( not opinion) in running Mogas/Autofuel ( nil ethanol) in a 180hp parallel valve IO 360, I’ve noticed some models ARE on the approved list from Lycoming. Thanks in advance 🐍.
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Many threads on this subject if you do a search.
 
gasman said:
How clean are the pistons & valves?
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They look almost new - very low deposits, I run obsessively lean of peak. With just over 2000 hours on the engine my compressions are still 78 and 79, and I burn a quart of oil in about 25 hours.

A couple samples from my annual a few months back, but these are typical.

HKHJ9062.JPG

OVDV1469.JPG

I still have a lot of crosshatching visible.

BRDY4830.JPG
 
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airguy said:
M1B with 8.5 standard compression, SDS engine control.
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Thx. 8 1/2 to one seems like the limit, I’m not sure it would work well with 9:1 and certainly not above that. That’s a nice set-up you have and the pics and your results tell the story. It’s nice and clean in there.👍.

I’ve been working (slowly) towards switching over to auto gas bc like you, I know that lead is the enemy. My Bonanza has low compression and is already approved (with a cheap and easy STC) and my biplane - even though a high performance airplane - was built with 8.5:1 pistons. Still burning 100LL in both of them but a change is coming soon!
 
I have always been paranoid about vapor lock in the IO-360 so I have ran exclusively 100LL in mine. I may consider filling up one tank and giving it a try in cruise after reading this thread.
 
nitrohog said:
I have always been paranoid about vapor lock in the IO-360 so I have ran exclusively 100LL in mine. I may consider filling up one tank and giving it a try in cruise after reading this thread.
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Vapor pressure is a problem. There are multiple ways to solve it, search here is your friend.
If you are running standard bendix injection, remove the engine driven fuel pump and install a pair of electrics (in parallel for safety), run the pressure up to 40-45 psig using a Borla regulator referenced to manifold pressure. That will keep any vapor bubbles from forming upstream of the servo, but you can still get them downstream. Now change out the standard .028 orifices in the injector body to .024 and it will raise the pressure in the servo-to-injector line to stop the bubbles there as well. The higher fuel pressure is required to be able to make full flow rate through the smaller injectors. The Bendix system will happily tolerate the higher pressure, I tested mine to 55 and ran it at 45 for just over 800 hours.

Or install SDS.
 
airguy said:
Vapor pressure is a problem. There are multiple ways to solve it, search here is your friend.
If you are running standard bendix injection, remove the engine driven fuel pump and install a pair of electrics (in parallel for safety), run the pressure up to 40-45 psig using a Borla regulator referenced to manifold pressure. That will keep any vapor bubbles from forming upstream of the servo, but you can still get them downstream. Now change out the standard .028 orifices in the injector body to .024 and it will raise the pressure in the servo-to-injector line to stop the bubbles there as well. The higher fuel pressure is required to be able to make full flow rate through the smaller injectors. The Bendix system will happily tolerate the higher pressure, I tested mine to 55 and ran it at 45 for just over 800 hours.

Or install SDS.
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Good info here. FYI, I and many others run .024 restrictors and 25 PSI is more than adequate. In fact, they still operate down to the 12-14 PSI range like the 028's. Clearly the higher pressure you run is far superior for avoiding vapor and a great idea. Just wanted to clear up the required part.
 
Has an IO360-M1B and ran 91 Octane autogas and never had a problem. And the difference was night and day on the spark plugs. The engine was quite happy. The only time I exercised additional caution was in the spring when some tanks hadn't switched to the summer blend and the temperatures were warming. But other than that, it was all good, especially on the bottom line.
 
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