What is Ethanol Doing to Our MGAs?
This is a subject that is generating much interest lately in the UK, especially with the increase in Ethanol content from 5% to 10% in 2013.
The Federation of British Historic Vehicle Clubs is closely monitoring developments in this area and you can keep up to date with this and other issues through its website. Fellow MGA owner, Peter Tipping, has had some adverse experience with these modern fuels and has provided some notes which he would like to share with us all.
Three years ago I rebuilt the engine in my MGA1600. At the time I discovered it had the standard dished pistons but was fitted with a ‘67 MGB head with its larger combustion chamber. Amongst other things this was one factor which explained the total lack of power I had experienced since owning it.
It was recommended by Bob West that flat top pistons were fitted to restore the compression ratio. Incidentally, I also discovered at this time that the block had been bored out so many times it was actually fitted with 1600MkII pistons and con rods! So my 1588cc engine, with all new pistons, shells, camshaft, camshaft followers, etc., finished up with a capacity of 1685cc!
With the cylinder head ‘unleaded’, additives were not needed, but I now found that the unleaded 95 octane fuel made it run very hot with the necessarily very retarded ignition and the run-on was horrid on shut-down. Colder plugs were no good either.
The only answer was to try some 99 octane ‘V-power’ stuff. As I worked off the old fuel and finished running-in I could bring the timing up to where it should be again, it ran cooler and now I think the performance is as good as when new – certainly good for way over 90!
So problem solved. Then this ethanol issue came up that petrol could contain up to 5% of the stuff and that higher percentages will attack brass, cork, rubber, aluminium, lead, zinc and its alloys. A worry as the “A” has all of these, as will most old cars.
Searching around the net I discovered that V-power has the full 5% and remember I’ve been using it for 3 years now. So that’s fine, we are told that 5% is OK…. or is it?
Recently I whipped off the fuel sender unit as the gauge was misbehaving badly. The sender unit body on the “A” is of course of the diecast zinc-alloy type. Previously when I had repaired the innards, I had used a cork gasket for the steel cover which gives access to the coil. So, here we have cork and a casting certainly containing zinc, aluminium and most probably lead too.
As the sender unit came out of the tank it was immediately noticeable that the casting was really being got at. It was looking too clean and very light in colour with an etched look about it – so this 5% is doing something!
What had caused the original gauge reading problem was the expansion of the cork gasket onto the internal thin bare wire, which passes from the top of the coil to the bottom terminal. At certain fuel levels the wire would touch the wiper which gives the required variable resistance. The cork gasket had expanded so much it had in fact split. The remedy was simple, remove the gasket’s centre and put it all back together again. No real problem and I now have my meaningful and normally inaccurate gauge back again! Well – it’s a tradition isn’t it..!
Just for the record I have, had to replace leaking SU cork jet seals (this petrol removes paint too!). The inside of the SU’s are also now looking too ‘clean’ and the brass floats show different colours above and below the fuel level …and incidentally they are held together with solder containing lead..!
Apologies if this all seemed a bit long winded but I thought it might be relevant to some other MGAs. It would seem, as things stand, we really don’t want anything over this 5% ethanol when 2013 comes around…
Submitted by Peter Tipping