THE USE OF ETHANOL (E10) FUELS IN MG’s.

At the June KYMG meeting, which was a technical question evening, the issue of whether we could use petrol with an ethanol content, currently in the State set at 10%, in our MG’s. 

The MG F owners present had been using unleaded with E10 fuel with no noticeable side effects (MGF’s have injector fuel systems), but the older MG owners were not too sure. No one had a definite view either way.

Co-incidentally after the meeting I came across a readers “Letter of the Month”  in the April 2008 issue of “Safety Fast” the official publication of the MG Car Club in the U.K. which may help clarify this issue.

The writer, Lawrie Brown, states he earns his living dealing with corrosion problems, and has some direct experience of the problems experienced in Brazil with the use of ethanol in cars.

He goes on to say

“Ethanol is a useful octane improver, and can tolerate much higher compression ratios without causing detonation and pinking. It does produce a lot of steam in the exhaust systems, but so doe’s petrol, and while this is a major cause of corrosion of exhaust systems, it is unlikely that ethanol will be any worse than petrol.

The big problem with ethanol is that it will easily dissolve water. This can mean that corrosion of fuel pipes, and indeed any part of the fuel system will be accelerated. In my opinion, the E10 fuels will cause very little trouble in this way.

E85, on the other hand is similar to the fuels used regularly in Brazil, where rapid and disastrous corrosion has been experienced. On a typical carburettor it will not be the steel bits that corrode, it will be the carburettor body itself, which is made of zinc and will suffer serious corrosion. At one time in Brazil carburettors were not lasting 12 months!

As nearly all the classic MG’s use carburettors with zinc diecast bodies I would earnestly advise owners not to use the so called biofuels. The problem in Brazil has been tackled by switching to fuel injection, and by designing fuel systems that are resistant to corrosion, but on cars built 10 years or more years ago biofuels were not

an issue, so the fuel systems did not have to resist corrosion except from the outside.”

In the latest July/August edition of the RAA’s SA Motor in their article “Under the Pump” they also review Biofuels, and conclude:

-Ethanol has 30 per cent less energy than petrol, which increases fuel consumption by 3%.

-Ethanol loves water and will absorb it readily so the fuel system on your car would need to be able to tolerate water.

As a general rule, modern cars can use E10 while vehicles older than 10 years shouldn’t, because of the potential effect on the rubber & steel components.

I hope this helps clarify the issue of biofuels in our MG’s.  Check the fuel pump whenever you fill up, for if ethanol is part of the fuel it should be clearly marked as containing E10 or ethanol.  BP for instance is phasing in the E10 into their standard unleaded fuel.  (They have to upgrade their entire distribution system to tolerate ethanol due to its ability to readily absorb water.)

I personally run both by MG’s on premium unleaded 98 RON from either BP, Mobil, or Shell which do not contain any ethanol. MG’s were originally designed to run on 96 RON.

If you only use your MG on weekends, imagine what the residual water absorbed by the ethanol could be doing to your fuel lines and carburettors whilst your MG sits peacefully in the garage between drives.

Cheers

Fred Neild

Editors note.

I ran a tank of E10 in Jo’s Midget and it didn’t run well at all, my view is that modern fuel injected cars use an oxygen sensor in the exhaust system which monitors the gas and via closed loop feedback automatically adjusts the fuel and timing by the computer to compensate for the different air/fuel mixture.

Our MGs don’t have this system and therefore don’t run properly when the carburettors and timing are set for normal petrol and then E10 is introduced.

 I use E10 all the time in my Falcon without any problem.

Laurie Houghton