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Running Mogas/Autofuel in a IO 360 ?

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.
 
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 🐍.
Many threads on this subject if you do a search.
 
How clean are the pistons & valves?
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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M1B with 8.5 standard compression, SDS engine control.
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!
 
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