Aviation Gasoline

[Joe T.]

I am currently running Aviation 100-LL in my 427/425 HP 66 Corvette. The car along with the required advance runs fantastically. My question is, can this fuel harm my motor? I have heard pro's and con's. Some say it will cause a burn to the top of the pistons. I do not like 93 octane in the car. It does not perform as well as the 100-LL. Also, I am not a fan of octane booster. Any comments?

[Joe R.]

Re: Aviation Gasoline

The miracle of 110LL is that there is no residue when it evaporates so that sticky stuff is not in your carb or your Fuel Injection. Everyone should run 110LL in their Fuel Injection.
Developed for airplanes because nobody wants their carb sticking at 10,000 feet.

JR

[Don H.]

Re: Aviation Gasoline

Like JR said, it leaves no residue and works great. I have been running it in my F.I. cars for well over 30 years with GREAT success (John D also recommends it). I can't address what it does in big blocks but can't imagine it causing problems. Good luck, Don H.

[Rich G.]

[Joe L.]

Re: Aviation Gasoline

The miracle of 110LL is that there is no residue when it evaporates so that sticky stuff is not in your carb or your Fuel Injection. Everyone should run 110LL in their Fuel Injection.
Developed for airplanes because nobody wants their carb sticking at 10,000 feet.

JR

JR-------


If you look for 110LL aviation gasoline you'll be looking for a long time since none is now or has ever been made.

Now, if you mean 100LL, that's a different story. That has been and remains available. However, it's illegal to use it in an automotive application. Even its use in aviation is on shaky ground as it's technically illegal to use leaded fuel for any internal combustion engine. Aviation has been granted several successive EPA waivers of the leaded fuel ban because of the problems associated with developing a non-leaded fuel for aviation purposes. Folks using aviation fuel for automotive purposes provide the folks protesting the aviation fuel waivers an additional "arrow in their quill" to justify the cessation of such waivers. So, it's not in the best interests of the aviation community to provide such folks with that "arrow". As a pilot, I'm part of that aviation community and, thus, I do not support the use of aviation gasoline for automotive purposes.

I'll repeat something I've said before: lead in gasoline is great for increasing octane (the old-fashioned way) and protecting exhaust valve seats (when that's even necessary). It's BAD for everything else in the engine. The scavengers necessary for leaded fuel are hard on engines, especially fuel system parts.

The late John Lingenfelter once said "unleaded gasoline is the best thing that ever happened for performance". He was right.

[Larry E.]

Re: Aviation Gasoline

JR-------


If you look for 110LL aviation gasoline you'll be looking for a long time since none is now or has ever been made.

Now, if you mean 100LL, that's a different story. That has been and remains available. However, it's illegal to use it in an automotive application. Even its use in aviation is on shaky ground as it's technically illegal to use leaded fuel for any internal combustion engine. Aviation has been granted several successive EPA waivers of the leaded fuel ban because of the problems associated with developing a non-leaded fuel for aviation purposes. Folks using aviation fuel for automotive purposes provide the folks protesting the aviation fuel waivers an additional "arrow in their quill" to justify the cessation of such waivers. So, it's not in the best interests of the aviation community to provide such folks with that "arrow". As a pilot, I'm part of that aviation community and, thus, I do not support the use of aviation gasoline for automotive purposes.

I'll repeat something I've said before: lead in gasoline is great for increasing octane (the old-fashioned way) and protecting exhaust valve seats (when that's even necessary). It's BAD for everything else in the engine. The scavengers necessary for leaded fuel are hard on engines, especially fuel system parts.

The late John Lingenfelter once said "unleaded gasoline is the best thing that ever happened for performance". He was right.

Joe>I agree with you about 99.9% of the time. That being said you are wrong on this one.
100LL is the only viable way to go. There is simply no substitute unless you find me a time machine
where I can go back in time to buy the "old type gas" for our "old type cars". JMHO>Larry

[Larry M.]

Re: Aviation Gasoline

I’ve owned airplanes for 45 years and I run 100LL in my 68 L71. The only downside in the small airplane motors that were designed to run on 80 octane is there can be a lead build up on plugs and valves but using a lead scavenger like TCP solves that for the most part. The only downside to running in the car is the price! Currently $5.75 at my airport.

I have often wondered why there is no lead on the plugs in the car. Cylinder head temps are lower in cars than in the air cooled airplane engines and everybody says the best way to scavenge lead in the airplane is to keep the temps up, within specs.

Rich

Av gas contains TEF (tetraethyl lead fluid) which has TEL + lead scavengers already combined into the mix. For 100LL the lead scavenger is ethylene dibromide. For leaded automobile gas/racing fuel the lead scavengers are a mix of ethylene dibromide and ethylene dichloride.

When leaded gas is burned the lead is converted to lead oxide, lead chloride and lead bromide. These (mostly) exit the engine cylinders thru the exhaust. The water vapor in the combusted gasoline reacts with the bromides and chlorides to make hydrochloric acid and hydrobromic acid. These acids destroy metals in the exhaust system.

Mixing leaded fuels with ethanol containing gasoline is a recipe for problems in areas with high humidity, as the mix will tend to pull in water and corrode the fuel tank, lines, and carb. So be careful when using.

Larry

[Duke W.]

Re: Aviation Gasoline

My question is, can this fuel harm my motor? I have heard pro's and con's. Some say it will cause a burn to the top of the pistons.

That's a myth. It will do more harm than leaded mogas from days past, and 100 LL Avgas has less TEL that premiums from the sixties. You say you "do not like" 93 PON. Why? Does it detonate? It's equivalent to 97-98 RON from the sixties in terms of detonation resistance. If it does detonate on 93 PON as little as a 25 percent blend of 100LL may quell it.

The other issue with modern pump gas is the distillation curve, which is lower in the bottom and midrange boiling points than avgas, so vapor lock and percolation problems are more likely with mogas.

Duke

[Gary S.]

Re: Aviation Gasoline

Interesting discussion here about aviation gas, especially the part where it is is/is not legal in automotive applications. One day a week I work at an air museum and, just on a whim, asked the fuel truck guy if I could buy some 100LL for my 1972 LT-1. "Of course, either call me and I truck it right over or next time we refuel the plane, I will sell you some". Now, I know that the 72s and later don't need lead but is this any better or worse than premium pump gas for my 72? The airplane likes it but we would love to get some of the old stuff with more lead (115/145 maybe?) in it to allow the radial engines to develop full power. Can't do that with 110LL.

[Larry E.]

Re: Aviation Gasoline

[QUOTE=Gary Schisler (21316);858306]Interesting discussion here about aviation gas, especially the part where it is is/is not legal in automotive applications.

Yes this is a myth. Our local airport indicates the only thing they can not do is to fill the car "AT THE PUMP". You have to buy it in
gas cans. I thought I was one of very few that bought this product and they told me you would not believe how many people buy
this product not for airplane use. Yes it is expensive but face it our old Corvettes are not for everyday use. Of course>JMHO>Larry

[Joe L.]

Re: Aviation Gasoline

[QUOTE=Larry Evoskis (16324);858312]

Interesting discussion here about aviation gas, especially the part where it is is/is not legal in automotive applications.

Yes this is a myth. Our local airport indicates the only thing they can not do is to fill the car "AT THE PUMP". You have to buy it in
gas cans. I thought I was one of very few that bought this product and they told me you would not believe how many people buy
this product not for airplane use. Yes it is expensive but face it our old Corvettes are not for everyday use. Of course>JMHO>Larry

Larry-----

The guy at the airport is correct. It's only illegal for him to dispense the avgas into an automobile. As far as I know, it's not illegal for him to dispense it into a container since, presumably, it could thereafter be used to fuel an aircraft. However, it is illegal for any person to thereafter dispense that aviation fuel into any non-aviation application. So, the illegality remains; it's just a question of who is performing the illegal act.

As far as the lead goes, it will soon be a moot point because there soon will not be any leaded aviation fuel, anyway. The big concern for the aviation community is that this occurs before an approved, unleaded fuel is available. If that occurs it will ground most of the general aviation fleet with the exception of those using Jet-A or those models which can obtain an STC to use non-ethanol automotive fuel.

When the unleaded aviation fuel is finally available, presumably it will be legal to use it for any purpose since it will not contain lead. However, to me, "tethering" a car to a source of aviation gasoline, now or in the future, is not something I would EVER do.

[Domenic T.]

Re: Aviation Gasoline

As to lead build up on the plugs, I have cleaned aviation plugs for over 50 years. Because aviation engines do not have valve seals, the burn't oil also gets confused with the lead build up.
Try and take the lead out of aviation fuel! Law suits galore. Especially when the first engine problem causes a accident, related or not to the fuel. removing the lead would be a lawyers delight.
I think/hope that when aviation fuel went from the normal leaded fuel to LL was a compromise to make the law makers happy.
The plugs seem to have the same build up as they did with the older fuel that had more lead.
I think that myth of burning pistons and valves may have some validity. Our fathers and grandfathers in WWII said when they ran out of fuel for the jeeps they used the high octane aviation fuel and that caused damage. They may not have been mechanics, but they recognized damage. Well one possible answer was that the engine timing. The higher octane fuel as was said by a veteran motor pool mechanic of WWII, burns slower and therefore is still burning while going past the exhaust valve. Maybe advancing the timing would have solved that, but I think the drivers had a bit more to worry about.
I try to obey the law, but wounder what would cause more pollution, the effect of to days fuel in a older engine, or a engine running great on Avgas.
We have to live with to days fuel but the very few using avgas is not going to make the sky fall.

Dom

[Joe T.]

Re: Aviation Gasoline

Very interesting Larry. I was thinking of mixing 100LL with 93 containing ethanol. Only because of piston and valve burning damage and gasket leaks. Those so called problems with 100LL seem to be very opinionated. Tough to get all the facts. At this point I will continue with 100LL. Thanks..

[Joe T.]

Re: Aviation Gasoline

Thanks Duke. The reason for not using 93 pump gas is the car has a better overall performance with 100LL. Had very, very little detonation with 93 pump gas. It's kind of I want the best of, without causing harm to my motor and fuel system. Is it your advice that 75% 93 pump gas and 25% 100LL will meet that objective?

[Joe T.]

Re: Aviation Gasoline

Thanks Larry. I tend to agree with you also. I am only trying to get all the facts from all of those that have knowledge and experience on this important subject. It's what we feed our motor.. Now, that can have good or bad long term effects.. I want to continue with the good. Now that may be straight 100LL or 75% 93 Pump Gas and 25% 100LL??? We have many different opinions on this subject.