Just got this email from a gearhead friend & fellow MGA owner; since some of you drive cars from the Good Old Days I thought I would pass it along:

I have warned many times about trying to avoid using any form of ethanol mix (I call it corn gas) in our older cars. Several of you have questioned my warning. You need to find a copy of Auto Weeks August 28th issue and read Denise McCluggage

 

I've heard the same about the economy of ethanol and the mpg it yields. I've not heard of it ruining an engine in two tankfuls (or any tankfulls for that matter). What does it do?

 

Ethanol has more oxygen in it than gasoline, so it is a less energy-dense fuel. Which means that yes, your mpg will go down the more ethanol you mix in.

All cars manufactured in the US (and I think worldwide) today are rated to be safely used with up to 15% ethanol. Many can run on 100% ethanol. Older cars have issues, though. Ethanol is a solvant for many petrochemicals, including older rubber and plastic fuel lines and seals.

The engine itself shouldn't have trouble per se, it is the fuel delivery system that has to be made ethanol-ready.

 

Years ago, during the fuel crisis of the 1970s that was what people said the danger of ethanol or an ethanol mix was. It was supposed to somehow "dry out" the rubber and plastic fuel lines and cause them to fail. I never knew if that was true or not.

 

[QUOTE=ralper,Sep 14 2006, 08:43 PM] Years ago, during the fuel crisis of the 1970s that was what people said the danger of ethanol or an ethanol mix was.

 

The other problem with Ethanol is that it is higher octane than gasoline. It's energy density is actually similar, but the issue is that you need at least a 14:1 compression ratio to run pure ethanol efficiently. The standard 8:1 to 10.5:1 in most cars will not cut it. That is what E85 is for. It allows a 9:1 car run mostly ethanol, with a little gas to "kick it off." If you were to increase compression in a vehicle to 14:1, it would run pure ethanol with similar mileage number to gasoline. Of course, then you could not run gasoline in it without it knocking horribly and destroying the engine.

Hope this helps.

 

Mike,
Isn't there a potential problem of metal corrosion or rusting of metal components in using ethanol? I read that somewhere.

 

The last I read was that 10% ethanol lowers mpg about 3%, and it does slightly raise the octance. I don't know anything about E85 and or its effects. However, wasn't the damage to fuel systems in old cars primarily attributed to the use of methanol for several years before it was discontinued, many years ago? I've also read though that perhaps ethanol should not be used in old car fuel systems, although they did not provide data on specific effects or problems. I know that use of 10% ethanol gas has had devastating effects and lunched the engines on old boats that had fiberglass gas tanks. I most often try to avoid it, but I have noticed that you cannot depend on the pumps being labeled. Supposedly, that used to be an advertisement meant to entice environmentalists but now is considered to be detrimental to sales. Except for the major brands, most off brand and discount stations are using ethanol, eg. Speedway, Imperial, Sterling, Duke, Racetrack, etc.

 

Not that I know of. But I'm not a chemist. I have some limited education on alternative fuels as part of my job, but not a whole lot on ethanol because it is not suitable for use in airplanes. The energy density per unit volume is not high enough, and so the range of the airplanes would be impacted.

It does mix with water while gas does not. That could be an issue for contaminated tanks and the like.

 

From looking into this in the 80's

Ethanol and Methanol