Octane value in the sixties

[Michiel]

I know that in the sixties, when my car was made , a variety of fuels was available, like standard, extra premium et cetera. But to get an idea, what were the octane ratings/values of these fuels. Is there a contributor with an excellent memory amongst us?

[Myrtles Man]

Friday 17th March 1967

Star grading of petrol was introduced in the UK based on a British Standard set of octane ratings. Under this system one star was the lowest grade, 2 star was 92 octane, 3 star 95 octane 4 star 98 octane and 5 star 101 octane. The lower end was for the low tuned/low compression older design of engine, the middle range for more modern higher compression engines and five star was for large, fast and powerful engines. Most cars would run happily on three star petrol (assuming the timing was set correctly) but most motorists seemed to believe that four star was ‘better’. Most stations offered two, three, four and five star grades.

(Lifted from 365 Days of Motoring website - Google is your friend)

[Michiel]

So maybe my humble automobile was always driven with 95 octane fuel at the time... same as modern E10

[rocco]

I don't think 3-star fuel is the same as E10 is it?

The old star rating would have contained lead for a start. I'm not sure whether they also contained ethanol back then though.

[Michiel]

No, with regard to ignition settings. But that's another topic

[geoberni]

I don't think 3-star fuel is the same as E10 is it?

The old star rating would have contained lead for a start. I'm not sure whether they also contained ethanol back then though.

A lot of petrol contained ethanol. There's loads about it online. But nobody got uptight about it like now, possibly because the amount of alcohol additive wasn't published.
At one point, early 1920s, ethanol was used instead of lead as an anti-knock additive.

Take a look at this timeline and you can see where the different corporate giants of the day had an influence.
The 1920s and 30s are particularly interesting.

https://en.wikipedia.org/wiki/Timeline_of_alcohol_fuel

In the UK, one of the biggest sellers of ethanol blend post-WWII was Cleveland Discol; brought out by ESSO in 1958, the brand disappeared in the early 70s. TV Advert here from 1966:
https://youtu.be/4uEqqlqqf4Q

[rocco]

Very interesting stuff, thanks.

I've never learned as much on any other forum, I'm so glad this place exists and appreciate all the info. from everyone.

[Guildbass]

My '66 Rover 2000TC had a factory sticker on the rear screen which advised '5 Star petrol only' which was (I believed at the time) 100 octane. The 'super' in the local BP garage has 99' written on the pump.
4 star was 98 octane I seem to remember.
As far as I'm aware no fuel in the seventies in yhe UK had ethanol in any appreciable amounts which is one reason why barn finds dating back from the 70's and 80's often still have usable fuel tanks. In around 2005 I acquired a 1978 Honda Dream 250 which had been stored with fuel in since '82 and the tank interior was shiny metal.
Octane level has no direct bearing on the percentage of ethanol.

[Classiccars]

Yes damn good forum isn't it.Whst would we do without those in the know I have mo idea.

[geoberni]

A lot of 'fake news' circulates about alcohol, i.e. ethanol and fuel, like it's a new thing.
It's been used since the 1930s as it was originally an 'anti-knock' additive before lead was adopted.
Personally I think there were competing commercial interests involved, a bit like VHS v Betamax in the 1980s, Betamax was better quality while VHS could record longer....
See this article from Motor Sport in March 1934: https://www.motorsportmagazine.com/arch ... n-engines/

ALCOHOL FUEL FOR HIGH COMPRESSION ENGINES
Final couple of sentences...

Thus for every gallon of alcohol fuel manufactured, only 75% of it (the alcohol content is roughly 25%) is subject to the 8d. petrol tax. And so, although alcohol is expensive to manufacture, this cost is counterbalanced by the saving on petrol tax, and the companies mentioned above are able to sell their fuel at a competitive price.

So why are people getting so hyped up about 10%?

Cleveland Discol was sold in the UK until 1973, when ESSO who then owned the brand, changed all the Cleveland filling stations to ESSO ones.