Auto Gas Users

[canav8]

A word of caution to those that are ignoring the Auto Gas restrictions in Cessna aircraft. Chevron is now adding Nitrogen to its fuels to help reduce emissions. Nitrogen is inert and does not burn so the amount of BTU's is reduced. It will increase fuel consumption and reduce power. Auto fuel producers have now been approved to mix 15% ethanol in fuel from corn. E85 flex fuel vehicles should not be affected but all the rest will probably play hell. Mogas users should not be effected yet. D

[Harold Holiman]

In our area most of the auto gas stations now post their gas contains no alcohol. (Some still post that their gas may contain up to 10% alcohol). However, when I was still flying, although my 180 was approved for auto gas, I did not use it because of the short "shelf life" of the auto gas.

[flyguy]

Having just made a 3000 mile+ trip in my '92 Fleetwood m/h powered by a fuel injected Ford 460. I was often puzzled by the apparent capricious actions of my fuel gauge. This Class A only has a 28 gallon tank! This means at best mpg it has a 200 mile range so it's easy to figure the mpg. What was puzzling was the mpg degradation of some fuels from name brand stations compared to others. The big mill didn't seem to mind the extra crap in the fuel and kept on roaring down the hiway but sucked more fuel down its injectors. I think it was a Chevron in Safford AZ that actually got me the worst mpg of the trip. Several stops I looked for a Phillips 66 that was reported ethanol free. I only found two on the trip and the mpg was just about the normal 7-8. On that tank from that Chevron the mpg went down to 5! Might have had that 'notrogen' HUH?

[blueldr]

Where in hell did you ever find a class A motor home powered with a gas loving Ford 460 and a dinky fuel tank like that? I used to have a 460 in my '78 3/4 ton PU and it really did love gas. It had plenty of power, but it got about 7 1/2 mpg towing or with a camper. It had about forty gallons between the two tanks.
I pulled out the 460 and installed a 5.7 liter Nissan diesel with a six speed stick and doubled my mileage. In addition, I built a custom fromt tank that carries 45 gallons and installed an after market rear tank that carries 42 gallons. Man, do I have range!
After all that work, the dirty bas----s raised the price of diesel fuel above gasoline, but it is still a lot cheaper than the 460.

[futr_alaskaflyer]

A word of caution to those that are ignoring the Auto Gas restrictions in Cessna aircraft. D

Eh? What's that ?

[marathonrunner]

Hey everyone, most autogas does not meet the specs of the Peterson STC anymore...more so in colder climates in winter. If you cannot afford Avgas, sell the bird. The damage done to your engine i.e. lack of lubrication to exhaust valves, increased heat and wear, does not make up the price difference between mogas and avgas. Look at a cylinder removed from an engine run on mogas and it is clean which means no lubrication. Look at one with avgs and it has deposits. Look at burned valves with a boroscope and you will see that it was most likely run on mogas. It really is not worth the supposed savings.

[blueldr]

In view of the above warning on the serious dangers of using mogas, I realize how incredibly fortunate I've been over all these many years since I started using it in Alaska back in 1947. Please understand that I wasn't using "civilian" mogas back in those days.
After all, Alaskan mogas was about fifty cents a gallon back then and eighty octane av gas was only about thirty two cents a gallon in Fairbanks. However, I had a real buddy who seemed to have an endless supply of mogas. His name was Sam. He had a huge motor pool and all the gas he could ever use. He was also my uncle and I worked for him. Civilian mogas had a road tax that was not on av gas.
I've used mogas for a good many thousands of hours without ever having any kind of problem with it. Just lucky, I guess.

[GAHorn]

In view of the above warning on the serious dangers of using mogas, I realize how incredibly fortunate I've been over all these many years since I started using it in Alaska back in 1947. Please understand that I wasn't using "civilian" mogas back in those days.
After all, Alaskan mogas was about fifty cents a gallon back then and eighty octane av gas was only about thirty two cents a gallon in Fairbanks. However, I had a real buddy who seemed to have an endless supply of mogas. His name was Sam. He had a huge motor pool and all the gas he could ever use. He was also my uncle and I worked for him. Civilian mogas had a road tax that was not on av gas.
I've used mogas for a good many thousands of hours without ever having any kind of problem with it. Just lucky, I guess.

Does that help explain why my inheritance from our Uncle Sam is now so worthless?

Marathonrunner... I can tell from your helpful and otherwise intelligent posts that you are no dummy and you mean well in advising folks to stay away from modern mogas. I agree in that advice.
However, when we offer such advice ... quoting "facts" which are illogical and simply wrong... detracts from the credibility of the source.
There is no benefit in "deposits" in the upper cylinders, and lead does not "lubricate" valves.
(I have challenged the so-called "experts" who write in certain aviation publications to show me their source which discusses when engines were suffering valve failures and that the solution was found by adding lead to gasoline. I am still waiting for that documentation.)
The only reason tetraethyllead is in gasoline is to raise apparent octane numbers and those levels of anti-detonation characteristics are not required in our 145 hp Continentals. (If WalMart can offer me "Additech" for a few cents per gallon at their gaspumps...why the heck can't the avgas pumps offer me "lead"...or not??? I want ordinary avgas without the lead.

[mike roe]

Please, if you have not already done it, access Pure-Gas.org
>> <http://pure-gas.org/> and sign the petition to the EPA to try to make
>> ethanol free mogas available to owners of planes, boats, old tractors,
>> lawn mowers, etc.
>> I updated my source of ethanol free mogas here in Raymondville, TX and
>> scanned the over 3,000 comments provided by the signers.
>> To date there are 3875 petition signers with the organization's goal of
>> 10,000. I signed on Nov 9, 2010 and was somewhere around the 500th to
>> 600th signer, so it is picking up steam. However, scanning the
>> comments, most were from boat, tractor, and small engine
>> owners/operators with a few antique auto owners and very few aircraft
>> owners.
>> We need every owner of the EAA or Peterson STC to sign the petition and
>> it will go well over the 10,000 signatures. EPA may well ignore us as
>> do most government entities, but we can't change the outcome if we don't
>> try.

The above was copied from the Stinson Yahoo site. If you believe in using it in your aircraft or not I would reccomend signing the petition. 100LL days are numbered. Also as a after thought if you run mogas(as I do) I would reccomend changing your strainer to carb fuel hose every 3-4 years. One of the problems we have is the tanker that carrys non-ethanol today could carry ethanol gas tomorrow. So you could get a mixture. Never think because the pump says non ethanol you dont have to test it.

[marathonrunner]

As a tech rep for TCM for many years, we had experts from other fields come to the factory for seminars. One petroleum engineer had a presentation and informed us that in order to increase octane ratings while decreasing lead content, they had to include additives like toluene and other such chemicals. While increasing the octane rating they act as solvents and detract from the lubrication and octane rating that lead provided. In actuality it is a combination of many things that contribute to mogas not being a good fuel for aircraft. The tolerences are wider. Heat is the main problem with valve issues. Decreasing lubrication and increasing octane with solvents and leaning agressively are the main reasons for exhaust valve difficulties.

I worked with many operators who used their aircraft on a daily basis...read air taxi. They had high powered Continentals that were geared and turbocharged and had TBO increases from their FSDOs because of the way they operated and maintained their aircraft. Cooling is of utmost importance and baffling is approximately one third of your cooling. Fuel is approximately another third. If you lean your engine aggressively you are decreasing your cooling. If you have baffling in poor condition you are decreasing your cooling. With increased heat the exhaust valve is going to fail or have difficulties. Your EGT probe is usually 3 inches or more from where the actual heat is concentrated. That is at the valve and guide. When it dissipates to where the probe is you do not have an accurate indication of the heat that is at the valve and guide. Auto fuel does not meet the strict standards that AVgas is subjected to in these times. If you read the Peterson STC you will see that it has some very definite standards that modern mogas does not comply with anymore. Add to that the fact that alchohol is added in winter and you have more problems. One of which is the amount of moisture it will absorb prior to releasing it into the system.

I know of several people that sumped their tanks and then had water disipate and clog the screens to the point of engine failues. In all cases they were able to land safely and rectify the problem. I hesitated to get back into this autogas forum as there are many very strong opinions both for and against. Again I have to say that if you cannot afford avgas then sell the bird. Auto gas also does bad things to rubber components in aircraft fuel systems. Yes I do know they have made parts now that are compatible with auto fuel. I just don't believe the cost benefits are worth the headaches and potential problems.

[ginbug92b]

The autogas STC was the best thing that ever happened to the recreational flyer. All you "Pros" can say and think what you want but the 80 oct engines run better and are more trouble free on car gas than 100LL. There are many people that love to fly but don't make $100,000 a year and during the 1980's and 90's car gas was 1/2 the price of 100LL. It's a shame that the BIG LIE "global warming / climate change" people are in power and started this alcohol in the gas crap. It's really sad that you have an elitist attitude when you say that if we don't use avgas we should get out of flying.

[blueldr]

ginbug92b,
Right on! You said what I wish I could have come up with.
These auto fuel naysayers all have the "Straight Information" but I've never found one whose experiences were personal. They've never even tried it since they're convinced of the danger.
My experience is personal and I've been gathering it for over sixty years in which I've never had problem one. Why back in the days of the "Non Skids", right after WWII, a lot of them surreptitiously filled some of their tanks on DC-3s and C-46s with mogas to use during cruise when the power was pulled back. Those engines were designed to operate on 87 octane.
I am not one trying to gather ratings, but I am an A&P, ATP, and Flight Engineer on the old recips.
I can't immagine anyone *** enough to tell me that if I don't want to pay the price of 100LL av gas that I should get out of flying after spending over sixty-five years at it.

[marathonrunner]

Guys, I am not trying to be elitist or to tell you to get out of flying if you cannot afford avgas. I am saying that the mogas now is not the same as what you used in th 1940's or even the 1970s. You do need to research what is going on with mogas and I think you will see that there are some very major issues with its use, vapor lock detonation, etc. If it works for you go ahead and use it. It does not meet what the orginal Peterson STC spells out. Do the research.

[GAHorn]

Please, let's all remember we are ALL AMONG FRIENDS here ...and we all want to keep it that way.

NO outright attacks on persons...and keep in mind that opinions are only that. (except mine, of course.)

It is true that "in the good-old days" we had better mogas than we do today.
I believe it's also true that ethanol is not a new fuel and is not the monopoly of "earth-warmers" etc.. (Henry Ford himself
spent quite a bit of time and money fighting DuPont and Standard oil in support of ethanol instead of leaded gasoline...but big oil and chemical companies won the marketing argument....same folks who poo-poo global-warming and environmental concerns as today.)

Unfortunately ... I think everyone can agree that the commonly-available mogas down at the corner gas-pump ain't what it should be, nor is it priced where it is affordable. As both mogas and avgas become more and more expensive...the benefits of using mogas become less and less advantageous.
The statement about mogas "used to be" 1/2 the price of avgas is no longer true. I pay $2.89 for mogas at the Exxon station and I paid $3.84 for avgas at Nacogdoches TX just yesterday. It simply ain't worth another carburetor ($1500) and fuel selector valve (ouch!) rebuild to me ...simply to save a buck-a-gallon on fuel, expecially when I fly less than 100 hrs a year. (I ain't no 6-digit salary guy or retired-on-natural-gas-well-royalties either....and THATs why I can't afford to repair the damage modern mogas does to my equipment or my neighbor's corn-field when I land in it due to engine failure and the insurance company figures out the mogas in my tanks ain't the mogas on my STC certificate.)

As Miles says, "Your mileage may differ." But...to be truthful.... my family better not be onboard or beneath when your plan falls flat. If you're flying a certificated airplane on modern mogas...you're operating illegally and, in my personal opinion, me and my lawyer will not be happy about it. If you think the money you save on fuel will allow you to afford that....then have at it.

[canav8]

Since I started this thread, I wanted to warn all that were still using Auto gas Unleaded, not Mogas from the airport, The automolbile gas Unleaded has the nitrogen enrichment. It will have less power output from the same ounce of Avgas or Mogas. Please be advised that I am already seeing the nitrogen autogas at the filling stations in Las Vegas. I have never had a problem running auto fuel in the past but this recent addition to the fuel has my alarm bell ringing. Doug