Aviation Gasoline

[Larry M.]

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:

I run a 50/50 mix of VP 110 octane leaded racing fuel and 93 octane non-ethanol gasoline. The car loves this cocktail mix and I have so far not experienced issues from corrosion. But I also have side pipes which do not collect liquid upon cooling etc.

If I use gas containing ethanol, I know it will pick up moisture/water vapor from the air in both the tank and carb. That is a given here in New Orleans. If i don't drive my car every 4-6 weeks, the clutch disc will bond to the flywheel/pressure plate due to the humidity.

In my previous life.........and a long long time ago.......I worked for one of the four US companies making tetraetyyl lead additives for gasoline. I am very familiar with how it was made and sold to the refineries during this time.

Larry

[Joe T.]

Re: Aviation Gasoline

Larry,

Your 50/50 mix sounds great. Thanks for the advice.

In my previous life....and a long time ago...I was a Nuclear Engineer.

Joe

[Duke W.]

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?

It's a matter of experimentation, but if you observed light detonation on 93 PON, blending in 25 percent avgas will probably eliminate it. If not increase the percent avgas.

Duke

[Ronald L.]

Re: Aviation Gasoline

Sunoco was selling 260 racing gas for about $9 last summer, but the leaded stuff has continued at the 100LL.

Having said that it only took one alcohol laced tank to ruin an original fuel sender, our cars were not made for it, nor were those of the late 70's either when gasohol was first introduced, tons of fuel lines, carbs and tanks came back on warranty.

[Jim D.]

Re: Aviation Gasoline

Sunoco was selling 260 racing gas for about $9 last summer, but the leaded stuff has continued at the 100LL.

Having said that it only took one alcohol laced tank to ruin an original fuel sender, our cars were not made for it, nor were those of the late 70's either when gasohol was first introduced, tons of fuel lines, carbs and tanks came back on warranty.

I find it interesting that the original sending units in my 60 & 65 work perfectly and have been soaked in nothing but the mandated E-10 for 40+ years. Also my 11:1 CR big block runs perfectly on 92 ethanol even with a modified advance curve that's much more aggressive than original. As usual, the internet B.S. rumors are alive and well.

[Ronald L.]

Re: Aviation Gasoline

Jim,
E10 mandated by whom? Please get the internet rumor regulation and understand that does not mean that every retailer MUST put 10% ethanol in every tank of gasoline. This was discussed here many years ago, and there is likely someone here that was in the petroleum business too.

However - I was there at GM doing the higher level failure analysis on higher profile warranty return claims, nuff said on rumors.

[Jim D.]

Re: Aviation Gasoline

Jim,
E10 mandated by whom? Please get the internet rumor regulation and understand that does not mean that every retailer MUST put 10% ethanol in every tank of gasoline. This was discussed here many years ago, and there is likely someone here that was in the petroleum business too.

However - I was there at GM doing the higher level failure analysis on higher profile warranty return claims, nuff said on rumors.

A fellow firefighter was an engineer in the petroleum industry for many years before he changed his career. He informed me of the real truth about E-10. There is soooooo much B.S. out there being posted. I read on one forum that E-10 put in a jar will turn into jelly within 6 months. That defies all Federal standards for gasoline. That's only one of many examples of mis-information out there. In my area, the Pacific Northwest, we've had nothing but E-10 since the late 70's. I've never had a gasoline caused issue in anything, from lawnmowers to supercharged big block Chevy's, not to mention all the boats I've owned that sat in water year round.

[Joe L.]

Re: Aviation Gasoline

I find it interesting that the original sending units in my 60 & 65 work perfectly and have been soaked in nothing but the mandated E-10 for 40+ years. Also my 11:1 CR big block runs perfectly on 92 ethanol even with a modified advance curve that's much more aggressive than original. As usual, the internet B.S. rumors are alive and well.

Jim------


I totally agree. In addition, GM has long-since approved the use of E10 in all of its gasoline powered vehicles, past and present.

[Larry M.]

Re: Aviation Gasoline

Years ago we had many failures of gas tank sending units in cars using modern fuel containing ethanol. The company was Shell, in Norco, Louisiana. The location for all these damages was mainly in the Gulf Coast. BUT, the issue was excessive sulfur compounds that entered the refinery gas storage tanks due to a breakdown in the refinery de-sulfur equipment. This created electrical issues with the sending units wiring.

Millions of dollars in damages...........but not due to ethanol.

I have personally run many (many) tankfuls of 93 octane gas containing ethanol thru my 67 327/350 HP engine. No major issues or detonation, but the car really does not like this gasoline. A small pail of gas left out in the summer heat and humidity will become cloudy and eventually have a small water layer within an hour. So for the limited miles I put on the car each year, I indulge in a mix of VP 110 and 93 octane no ethanol (Exxon or Valero) from a local refinery in Chalmatte, Louisiana. Gas in the tank can go a year with no visible or mechanical issues on performance after this time.

FWIW.

Larry

[Richard G.]

Re: Aviation Gasoline

Larry;
"That is a given here in New Orleans. If i don't drive my car every 4-6 weeks, the clutch disc will bond to the flywheel/pressure plate due to the humidity."

I find this interesting as bonding the flywheel to the disc was something I worried about after leaving my new clutch installed for over 30 years with out moving. Started the 340HP up and had no issues with the clutch after all that time. I live in SW Washington State. Known for out rain but not the summer humidity.

[Joe T.]

Re: Aviation Gasoline

When you say 93 PON, Is that with ethanol? The highest non-ethanol I am aware of is 90, 100 LL and VP 110.

[Joe L.]

Re: Aviation Gasoline

When you say 93 PON, Is that with ethanol? The highest non-ethanol I am aware of is 90, 100 LL and VP 110.

Joe------

It depends where in the country you live. On the west coast, most pump premium is 91 octane and with 10% ethanol. On the east coast it's 93 octane and (mostly) 10% ethanol. High altitude areas of the country may have lower octane.

[Joe L.]

Re: Aviation Gasoline

Something else that I do not understand about this ethanol/gasoline "separation" issue. Ethanol is the only alcohol of the myriad of alcohols that is consumable by human beings. All the others are highly toxic. In order to make ethanol available for non consumption uses and to prevent its use for consumption, ethyl alcohol is "denatured". One of the most widely used denaturants for ethyl alcohol is gasoline. So, a small amount of gasoline is added to the alcohol to make it unsuitable for human consumption. The reason that gasoline is widely used for this is that when mixed with ethyl alcohol it is virtually impossible to separate the two. There is no phase separation that will occur no matter how long the denatured alcohol is on the shelf or in storage. There is no way to "filter out" the gasoline from the ethyl alcohol. There is not even a way to remove the gasoline by distillation. I expect the exact same thing to be the case when 10% ethanol is added to gasoline. So, I really do not understand these various "separation" reports.

[Duke W.]

Re: Aviation Gasoline

Most gasolines sold in the USA have 10 percent ethanol. Since ethanol is an octane booster, the blends that come out of the refineries are less than what's posted on the pump, and the posted octane is achieved when the ethanol is blended in by the distributor. 90 PON non-ethanol is likely straight from the refinery with no added ethanol, so it is lower octane than the highest E10 brands.

In your second sentence you compare three different gasolines that use DIFFERENT octane rating methods. An explanation and how to approximately convert one to another in order to make an apples to apples comparison is in my tuning seminar.

Duke

[Duke W.]

Re: Aviation Gasoline

Something else that I do not understand about this ethanol/gasoline "separation" issue.

In not sure what percentage of ethanol you can blend with gasoline before separation occurs, but that's really not the issue. Ethanol laced fuel absorbs moisture more readily than straight gasoline. Again, I'm not sure what percent water can be held in solution in E10, but at some point with enough water buildup the water-ethanol blend will separate and drop to the bottom of the tank. At that point the car may not start. If it's an old car that is sitting, corrosion mechanisms will start.

Water absorption is not much of an issue in modern cars with sealed fuel systems, however, vintage cars with fuel bowls vented to the atmosphere and "vented" fuel tanks will absorb moisture, especially if constantly exposed to condensing humidity such as parking them outside and not driving them much. It's pretty much a one way trip. Once moisture gets in the system it's there to stay unless the fuel is drained or consumed by use.

This should not be an issue with most vintage cars since they are usually garaged, and I have always recommended that a vintage car should be driven at least through one full tank of fuel per year, and if it's stored during the winter months, it should be filled with fresh fuel just prior to storage. Follow these "rules" and you will not likely have major fuel system problems assuming it's currently in good working order

Duke