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two very odd questions

T

Tharpo

Member
My pards and I have a 160 horse RV4 ( hi-comp LYC) . We've been told, and I've read too, that it would not like M0-gas very much. Well...a local "expert" has told one of us that a blend of 30% 100LL and 70% Ethanol free 100 octane mo-gas would be alright in this engine. Looking for other's opinions.Also I saw a post the other day that said 6061-T6 lost half it's strength if welded.....anybody know what would the loss be,if any, with 2024T-3?
Blessings
Tharpo
 
anybody know what would the loss be,if any, with 2024T-3?
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2024 is not considered to be weldable period, and it sure wouldn't be T3 afterwards. I tried it. They're right.
 
Personnally,

I'd like to know where you find ethanol free 100 octane mo-gas!
 
Ethanol free mo-gas

Sorry, Mel but it's a long way from Texas.....I live in Mississippi. I know of two stations right now.
Tharpo
My apologies....got the octane ratings twisted up.... should have been 86 or 92( if I remember correctly), but it is ethanol free.
Tharpo
 
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I guess I don't understand.....

If you guys have unleaded (I assume it's unleaded) 100 octane gas in Mississippi, why are we having so much trouble finding a replacement for 100LL?
 
Mel said:
If you guys have unleaded (I assume it's unleaded) 100 octane gas in Mississippi, why are we having so much trouble finding a replacement for 100LL?
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Unfortunately avgas octane ratings and automotive gas octane ratings are not measured in quite the same way, so you can't directly compare them. The same fuel would get a higher reported octane rating if it was sold for automotive use than if it was sold as avgas. So, 100 octane automotive gas would be something less than 100 if it was sold as avgas. Lots more info in this Wikipedia article.
 
I have a 160 hp O-320 that was put on our 9A when it had over 850 hours on it. It was from a plane destroyed by hurricane Charlie. The owner said he had never had a single drop of 100ll in his tanks, running only 93 octane non-ethanol mo gas. I have never seen a cleaner engine, and everything about it checked out fine, and still does after about 400 more hours of 100ll. This is just a data point and not absolute, but I would not be afraid of good mo gas. I just can't find it in Indiana.

Bob
 
There are ways to remove the alcohol, and premium gas supposedly has lower percentages of alcohol. Somewhere theres a list of gas stations that have ethenol free gas.
 
Once again: If you remove the alcohol, you will lower the octane rating. As stated above, car gas is rated by the RON (road octane number) plus MON (motor octane number) divided by 2. It gives you a higher octane number than an equivalent avgas rating. Detonation is not your friend. I've actually seen one engine blow the guts out of a couple spark plugs. God knows what it was doing to the internal parts. one of the actual smart guys on here may be able to give better numbers, but I wouldn't run over 8.5:1 on 90UL.
 
Additives

aerhed said:
Once again: If you remove the alcohol, you will lower the octane rating. As stated above, car gas is rated by the RON (road octane number) plus MON (motor octane number) divided by 2. It gives you a higher octane number than an equivalent avgas rating. Detonation is not your friend. I've actually seen one engine blow the guts out of a couple spark plugs. God knows what it was doing to the internal parts. one of the actual smart guys on here may be able to give better numbers, but I wouldn't run over 8.5:1 on 90UL.
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Agreed- I would not run in higher compression engines unless an adequate additive was used to boost the octane rating.
 
There are a lot of old wives tales regarding mogas that are propagated by people who have no experience with it. In my 180hpC/S RV-6 I ran 87 octane with ethanol for nearly 1000 hours. I kept the boost pump on at all times.
 
mo-gas

I can't find anything higher than 89 octane ethanol free gasoling around north Florida. I blend it half and half with 100LL and have no problems at all. My engine has 9 to 1 compression pistons and I would feel safe running it on 93 octane ethanol free if I could find it somewhere. You have to be careful about detonation.....it will ruin your pistons.
 
It's a Gas...

Tharpo,
I ran MoGas in my 150HP RV4 for 10 years before Ethanol. I upgraded to a WD 0-320 with 10.4:1 Airboat racing pistons, rods and rings and still ran Ethanol free MoGas laced with CD3 (lead additive) and Marvel Mystery Oil. Both additives come from the Wal Mart Aviation Dept. I also ran my HR2's IO540 C4B5 on it once in awhile with no issues. My Airboat engine builder sees lots of engines come through his shop run very hard on various fuels, the most popular here being 75/25 Mogas/100LL. He said the only "blown engines" he has built were ran out of oil or submerged. A testament to properly built Lycomings.

My current RVX has a low comp 0-320 ND but runs great on MoGas, I found a local station with Ethanol Free 93 octane right now costing $3.83 a gallon. I used this site to find the location. http://pure-gas.org/

See Ya!
Smokey
 
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Mo-gas..No M0-gas

Thanks to you all:
Gotta love this stuff.....real world stuff I mean. My partner already fueled the plane with a 30% av to mo-gas mixture, and he said I'm elected to do the "test flight". I decided to not go over the 150 horse threshold on the(other) four I'm building mainly because of my Scotch ancestry, but it's good to know there are like minded folks around. Sometimes, I confess, I get bogged down with analysis....did I spell that right?
Blessings
Tharpo
 
O-320 (160 HP), 8.50:1 Pistons - Mogas no prob since 500+ hrs

Tharpo,

the RV-4 I have has the O-320 (160 HP) with 8.50:1 Pistons and me and the previous owner are running Mogas with no prob since 500+ hrs. In Germany we still have Ethanol free Mogas with an European ROZ of 98 which is ca. 94 after US specs as far as I know.

However as I am going to the UK where is no Mogas available I top up the tanks up with ca. 20 - 25 US gals Avgas every couple of weeks but I don´t think that matters really. As well I agressively lean while being on the ground and I don´t get any lead fouling on the sparks, too.

Just my 2 cents - you milage may/will vary, Heinz
 
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