Octane and Ferguson

Bill Brox

Member
Hello tractorfriends.

Does anyone know the lowest octane rating that would work on a TE or TEA 20 ? I know the TEA 20 with 80 mm engine had 5.7:1 in compression. Today we have a high octane rating on all our gas, but what about in the late 40ties around here and there.
The later Ferguson 35 (UK built) had 6.6:1 in compression, maybe they needed a higher octane on the fuel.

I am just curious about it, if someone knows.


Bill
 

An interesting question Bill , of course a TED will run on a kerosene and petrol mix quite happily at 50:50 ratios and much lower as well . kerosene having a zero octane . An 85mm TEA will also run on this mixture when hot , I know because I needed to resort to putting a gallon or two into a friends TEA when he ran out of fuel . It ran with really no discernible difference from straight petrol . So I suppose you are effectively halving the octane of the petrol you are using.
I smile when new enthusiasts tell me that they only ever put high octane premium unleaded fuel into their Fergusons .
 
(quoted from post at 22:30:22 01/15/16)
An interesting question Bill , of course a TED will run on a kerosene and petrol mix quite happily at 50:50 ratios and much lower as well . kerosene having a zero octane . An 85mm TEA will also run on this mixture when hot , I know because I needed to resort to putting a gallon or two into a friends TEA when he ran out of fuel . It ran with really no discernible difference from straight petrol . So I suppose you are effectively halving the octane of the petrol you are using.
I smile when new enthusiasts tell me that they only ever put high octane premium unleaded fuel into their Fergusons .

Ï wonder if I have heard that Norway had 70 octane gas / petrol for tractors up and well into the 60ties, maybe early 70ties too.
But, if this was intended for the TED, or if it was intended for regular TEA 20 and similar I have no idea about. I just came to think of it.


Bill
 
In the US, octane is labeled as the average octane determinations by the Research Method and the Motor Method. The Motor Method is more representative of real engine conditions and is lower than the Research Method rating. Someone settled the argument on what to use by arbitrarily using the average of the two. the general difference between the two for normal SI fuels is 10-12 units. That implies that an 85 R+M/2 fuel would have an Research Methos rating of 90-91 and a Motor Method rating of 79-80.

Here in the US, unleaded regular is generally 85-87 average octane rating and IIRC premium fuel is rated at 93 octane. The limited data I have been able to find suggests that going from CR 6 to CR 7 increases octane requirements by 10 Research Method units. This is very simplistic number since engine design variables, rpm, fuel/air ratio, spark timing, etc, are factors which affect this number. None the less the regular unleaded fuel with a R+M/2 = 85 appears to closely match the requirements for 6.6 CR. I seem to recall hearing that the typical fuels of the pre-emission control era had a Research Method Octane rating of 80 and that goes along with these numbers. It also indicates that the octane requirements have not changed much with time. This is most likely due to the use of modern engine design, manufacturing methods, and electronically controlled fuel injection and ignition timing. Modern cars use knock sensors as an input to change ignition timing and can thus run on the edge of knocking for best performance. Our tractors use conservative ignition timing to avoid knock. So if you get a low grade fuel, retarding the timing somewhat will keep you out of knock.

That"s probably more than you wanted to hear about this.
 
Not at all too much information. I am aware of that the US and Europe have different ways of measuring gas, in the US Ron+Mon/2 is used as far as I know, while in Europe they used Ron only.... and it is nothing wrong with either of the methods, just that they give different figures and you have to be aware of it and act accordingly.

The 70 octane I remember from Norway they used for tractors might be just regular gas with low octane rating, and that means it would have had a lower rating here in the US.

If you do nothing else, just take out gas from crude oil, no additives, no nothing, what rating would that be here in the US ?


Bill
 
Gas is a blend of hydrocarbons so it will be made according to the ASTM specs for spark ignition motor fuel so that the end product has R+M/2 of 85-87 for regular unleaded fuel and 93 for premium with the additive package included. Some places sell a mid range fuel with R+M/2 of 89-90.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top