IO-320 and Mogas

[Horace Blok]

This is always a "hot" subject and one that can raise the blood pressure.

One of the posters refers to fuel injected motors. Only the Conti IO 470 passed the tests. The Bendix injection did'nt. I don't want to put you off Simon. I know of many lads that fly their non type certified aircraft (RVs) on Mogas with no issues whatsoever. Here in South Africa we too are lucky enough not to have Ethanol in our fuels (yet). By law - the fuel companies are allowed to blend up to 2% but thankfully don't.

A useful thread can be found here (The first few posts won't interest you too much):

http://www.avcom.co.za/phpBB3/viewtopic.php?f=1&t=78297

Vapour Lock is usually an airframe issue - hence two STCs are sold by either EAA or Petersens - one for engine and the other for the airframe.

[tacchi88]

We have mogas with E10, and have noticed only improvement in plug life, both fuel and oil reduction, on two airplanes, with certified and experimental engine, 1200 cumulatively. No vapor lock nor even an indication of it.

[WVM]

Originally Posted by PH-SCP

Hello guys,

I have the opportunity to buy a low time Lycoming IO-320-B1A engine for my RV-9. However, based in Europe I do not want to run my airplane on AvGas, it's just getting too expensive.

I am looking for advise whether or not it is possible to feed an IO-320-B1A engine with MoGas which in our part of the world has an octane number of 98 and is still available without ethanol/methanol from certain providers such as Esso.

Your 2 cents are most welcome

Hi,

Sorry for reopening this old post, but I am in the same situation as you were two years ago. I am living in Belgium, planning to put a IO-320-B1A in an RV9. I want to know what you finally did related to this subject. All information is welcome. Thank you!

[paul330]

A lot depends on your local regulations. Look at the latest SI1070 from Lycoming and see what types are approved for Mogas.

Apart from the vapour lock issues, you also have to worry about ethanol. I'm not sure how many places in Europe (if any) you can still get Mogas without ethanol.

There's also UL91 and 91/96UL available at various places in Europe which may be a little cheaper.

[smokyray]

Originally Posted by PH-SCP

Hello guys,

I have the opportunity to buy a low time Lycoming IO-320-B1A engine for my RV-9. However, based in Europe I do not want to run my airplane on AvGas, it's just getting too expensive.

I am looking for advise whether or not it is possible to feed an IO-320-B1A engine with MoGas which in our part of the world has an octane number of 98 and is still available without ethanol/methanol from certain providers such as Esso.

Your 2 cents are most welcome

Simon,
I grew up working alongside my IA Dad who used 100% MoGas in our family's 57' Cessna 182 for over 30 years. Never had a problem, ever.
I operated my Harmon Rocket with an IO-540 C4B5 and electronic ignition/Bendix F.I. for 5 years/700 hours primarily on 91 octane non ethanol MoGas readily available here in FL.
Here is some data and techniques/lessons learned.

My Dos Centavos...

1. I always mix Marvel Mystery Oil into the MoGas per recommendations on the container. It provides upper cylinder lubrication.
2. I never stored MoGas for later use, always recent purchases. It breaks down over time.
3. Boost Pump on below 1000' AGL period. This includes ground operations, taxi, etc. The cold fuel circulation is key to avoiding Vapor Lock.

4. Hot starts: Boost Pump on 10 seconds prior to engaging starter. Once prop is spinning and the Electronic ignition fires, full rich. As I said above, leave BP on throughout ground ops.

5. Longer run up in summertime. It's always summer here in FL so I would perform a standard run up then a 30 second run at 1500 RPM to insure cold fuel had reached the engine.

Conclusion: MoGas can not only be safely employed in airplanes, I believe it will be the only fuel available in 10 years.

V/R
Smokey

FAA MoGas Certified engine approval list: http://www.autofuelstc.com/approved_...airfames.phtml

Great article on MoGas use:http://generalaviationnews.com/2011/...0-mogas-myths/


PS:Van actually included drawings in my original RV4 plans from 1989 showing a fuel routing system for MoGas use to avoid vapor lock!

PSS:Two current fuel injection systems manufacturers willingly approve MoGas in their systems, Airflow Performance and Silverhawk(Bendix clone). The FAA STC approval list of certified engines approved to use MoGas doesn't include any "IO" engines, mainly because Bendix wouldn't approve their injections systems for MoGas. The real truth is nobody tested an IO to get enough data for the STC...

[N427EF]

Simmon,

With very little modification to the fuel delivery system you can easily operate on mogas with or without ethanol.
Fuel injection is your friend when it comes to mogas because of higher fuel pressure and if you use the Airflow performance fuel injection you will have an injection system actually approved by the the manufacturer for use with almost any kind of fuel.
What will and will not be approved in Belgium I cannot tell you but mogas E10 has worked for me now going 200 plus hours over a 2 year period.
I have tested extensively especially on hot days to be sure no vapor lock issues lurk in my system.
I cannot report a single occurrence of anything but smooth engine operation in any condition but especially in temperatures over 100F. I can't think of any other tests I could perform to proof the system is vapor lock proof with mogas/ethanol.

[dsmith1055]

A client tried to run non ethanol mogas in an IO- 320 in a 7KCAB Citabria. It ran fine in winter. As soon as wx began to warm up (above 80F) It got vapor lock. Boost pump did not help. Peterson Aviation advised there was no STC on the IO-320 Bendix fuel injection system due to vapor lock issues. This particular plane had been carbureted when the STC was issued and was changed back to the Bendix system. The owner thought the STC was still applicable. I suggest you contact Peterson for advice.

[10 G]

what is the maximum compression ratio that allows mogas?

[N427EF]

A lot of certified engines had type certificates for mogas with compression ratios of 8:1 or less.

2 things to remember when setting up for lower octane gas:
Detonation and Vapor lock.

Compression ratio generally speaking has the greatest effect on detonation when using low octane gas as well as efficient cooling etc.

Vapor lock happens in a poorly designed fuel system where boiling of fuel is allowed to occur.

[AK4x4]

Lycoming approves the IO-320-B1A for operation on 93 octane (R+M/2) Premium unleaded. See Lycoming service instruction 1070S for details.