Fuel for Allis Chalmers B.

Anonymous-0

Well-known Member
Hi everyone, I am brand new to this whole tractor ownership thing. Can anyone tell me what is the best fuel to run my 1940 Allis Chalmers B on? I can get access to real gasoline that does not have any of that rotten ethanol junk in it, but the non-ethanol stuff they sell by me in 92 octane. Will that high of an octane rating be too hot for the engine? Do I need to buy a lead additive and add lead to the gas since they did not make unleaded gas back in 1940? OR, am I fine just running the thing on the regular unleaded 87 octane with 10% ethanol which is what they commonly sell around here. Any advice you can give me would be greatly appreciated. Thanks, David.
 
I run 89 oct 10% ethanol in everything I have. My WC, WD, and 3 lawnmowers don't mind a bit. Many will say the old tractor engines don't need the lead as they don't run hot enough or high RPM or something to need the lubricant for the exhaust valves. Odds are, she's had hardened valve seats put in at some point along the way. Cheapest gas you can find now is better than what it had to burn when it worked for a living.
AaronSEIA
 
Back when that tractor was made the gas they had and used in them was a lot worse then what we have today. Run the cheapest stuff you can find and it will be just fine
 
(quoted from post at 22:24:31 06/14/13) Back when that tractor was made the gas they had and used in them was a lot worse then what we have today. Run the cheapest stuff you can find and it will be just fine

I have run 87 octane for the past 15 years without incident. I used to put in some lead additive early on, but finally got out of the habit.
 
You guys are the BEST! Thank you all so much for the awesome responses and for putting my mind at ease that I am not doing anything to ruin my nice little tractor.
 
I guess I am the odd ball here but I run non ethanol gas in all my non road stuff from my boat to my tractors. With the price of gas and the comments here I may have to reconsider. But I only use the tractors every 2 or 3 weeks.
 
not a thing wrong with gasohol just a bunch of old wives tales. ran it in everything since I started blending it in the 1970's, you don't need to spend the money on lead additives
 
The octanes available in the 40s were much lower than anything available now - so don't sweat that. If its a 40, it should be a BE engine as opposed to the later CE engines. It could have even been set up for Kerosene/Distillate - look for a K suffix on the motor S/N as opposed to a G suffix. Motor s/n is most likely steel stamped into edge of left side of motor flange where it mounts to transmission. Even the late (1950's) CE engines should have no issues with octane.

As to alcohol - I have to disagree with those that say its not a problem. It can be dealt with, but anything rubber in the fuel system may be a problem. I have had fuel sediment bowl gasket swelling problems as well as valve packing problems. And yes, I verified it was alcohol related. Put a new old stock rubber gasket in gas for 2 days - no change. Put same gasket in gasahol and it swelled significantly overnight.

Other significant issue with all fuels is long term storage - issue is more severe with alcohol - read the instruction manual on your ATV or Lawn Mower or Boat Motor. The more recent ones are more tolerant, but they still have issues. Water absorption is less of an issue in dryer climates, but in high humidity or significant temperature changes, you can have condensation & rust. Seafoam is one additive I use in my ATV when I can not get Alcohol free gas, there are others at Walmart or Home Depot.
 
I don't doubt that alcohol in gas can be some issue. I had nothing but trouble one summer with water separating out of my WD gas tank. Because the cap was missing all summer. Keeping water out of the tank will keep the water out of the ethanol IN the tank. I know my WC will sit from October to April with e10 in the tank and fire and run on the 4th pull in April and all of my mowers sit from Oct to April and do the same thing. Ethanol has been around in some form for at least 30 years. If the gasket and hose makers can't make rubber compounds to stand up to it in 30 years, they need to quit.
AaronSEIA
 
Does off road gas you have delivered to you own storage tank have ethanol? I have a friend that does that and it is much cheaper. I also have had moisture issues but I think alot of that is because of where the equipment was and the time of year. I would use whatever you are most comfortable using.
 
Okay, I will fess up to the fact that I had my sediment bowl valve stem fail on me, but I figure that's because I bought a cheap replacement the first time. The more expensive one I have on there now isn't giving me any grief.
 
My B and CA get's all the old 87 octane, 2 cycle gas every spring, that has been sitting, in cans, and boat tanks, over the winter. They will burn anything gasoline. The truth is the 2 cycle gas does already have some Seafoam in it.
 

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