Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Alcohol fuels in MG's

Hi All

Since more and more US Gas is coming from the pumps with alcohol mixed in, I thought I would ask if there are any parts of the MG system that would not do well with alcohol.

Bruce Cunha

Funny you brought this up.
I work in a shop restoring vintage Italian cars, and we had a fiat 8V in last week that had a gas tank liner that was totally coming apart, we think this was due to the alcohol in the cas now (no more mtbe right).
I suspect the stuff could do the same if you have an old liner in your tank.
Don't know abou any other parts, but carbs would be something to keep an eye on.
Bill Mertz

Bruce, we run it on and off in the A, when I don't get a chance to gas up in a different county.In ten years no trouble yet, but it is a killer to your gas mileage, our MGC gets 28 mpg hyway on normal gas and drops to 20 mpg on "reformulated". It also goes bad quickly during storage.
John H


Please contact me off line. I am interested in what you have done to get 28 mpg on your C.


69 C in restoration
Larry Hallanger

Here in Michigan, I don't think we get anything that's not adulterated with 10% ethanol. Generally, like drinking it, ethanol does little harm, and may be good in some ways "in moderation". A 90/10 gas/ethanol blend is generally thought to be benign by the auto engineers.

The major issue is breaking down of rubber components. E85 rated cars (85% ethanol) replace all rubber with metal piping, e.g. An issue important to us is having the solution separate during long storage, for which a fuel stabilizer is helpful. This will occur due to all the ingredients used now in gasoline, so the usual storage options are 1) completely dry tank (causing other issues) or 2) completely full w/ stabilizer (cutting down oxidation, etc.)

In our storage facility we recently had an "incident" where a plastic fuel filter case cracked while a car was running. Luckily the extinguisher was nearby. This may have been related to the interaction of alcohol to the plastic (or just because of the plastic itself).

As always, when you change an input, some output is likely to change as well - not always to the best.
John Z

To run at 100% ethanol you'd need to do the following:
Fuel lines: rubber is right out, teflon would work very well. Alcohol requires steel hard lines, so I think we're ok on that front.
fuel pump: ethanol would likely break down the diaphragm in a year or two. Either a gear-driven or metal plate diaphragm pump would be needed.
Carb: Ethanol would definitely rot the usual rubber seal where the jet meets the bowl- even regular gasoline does that. A neoprene seal would be fine, and cork would probably also be ok. I don't know if the plastic of the jet tube itself would be attacked or not. A metering needle 20%-35% richer than standard across the range would be needed. Plastic floats and jets would need to be replaced with brass.
Timing/etc: Ethanol has a higher octane rating than modern gasoline, so if you were to run exclusively on ethanol you could have more aggresive timing and run at higher compression ratios - 12:1 wouldn't be beyond the pale.

Ethanol will dissolve a lot of the junk in your engine out - out of your fuel tank, lines, and the engine itself, which could cause rough running and fouled filters initially. It also doesn't provide any protection against valve recession, but this can be prevented by adding a touch of deisel fuel to every tank.

Adam Birnbaum

I'm also interested in what's required for ethanol, or E85, cause i've got the whole fuel system to build, except the new stock steel tank which is in place. I thought that alcohol would corrode regular steel, and that you'd need a stainless tank? If not, then all the better, but good to see, at least in the recent past, stainless replacement tanks are available. I might still run the fuel supply line in stainless though. Guess that 25 foot roll of aluminum fuel line I bought will go in the parts bin, though. With things going the way they are, I hope to be able to run E85 and gas, with fuel injection on my 4 litre Buick conversion. Interesting to see what aftermarket FI manufacturers, if any, have already planned ahead for reliable use with E85. Have to do some calling soon. Joe
Joe Ullman

This thread was discussed between 05/05/2006 and 10/05/2006

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.