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LenNH
02-26-2008 14:49:56
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Re: Fuel economy of an F-20 both gas and distillite in reply to Scott Rukke, 02-20-2008 13:58:12
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The lower costs are obvious, and so is the extra time it takes to save the money. I "grew up" on a 10-20. My father had been using gasoline in his tractors at least from the early 30s. One time, I decided to see what it was like to use kerosene in this tractor. I guess everybody is familiar with the routine: Drain oil down to the lowest petcock on the side of the crankcase, then refill to the top petcock. Kerosene and distillate appear to condense in the cylinders and the remaining liquid drips down the cylinder walls and dilutes the oil. This was supposed to be every 10 hours, and would certainly be an extra cost that is not calculated in the fuel savings.
You were supposed to stop the tractor either by shutting the fuel off (leaving the carb empty), or by shutting off the kerosene/distillate valve and letting the engine stop on gasoline. Minor pain. If you somehow stopped the engine on kerosene or distillate, it wouldn't start for love nor money if it was allowed to cool off. In this case, you had to drain the carb (little valve on the side) and then turn on the gas.
After starting on gas, you pulled up a curtain over the radiator, or on later model tractors, shut a kind of venitian blind attached to the radiator. When you were pretty sure the engine was hot enough (steam coming from the radiator cap, or if there was a heat indicator, when the needle pointed to a temperature you knew would work)--then you could shut off the gas valve and turn on the kerosene or distillate. Get right to work, because if the motor cooled down at all, it would spit and sputter until it got hot again. You could keep it fairly warm while idling if you pulled that curtain back up. I did this only once, and vowed I'd never do it again, and I never did.
One thing that appears not to have been tested here is a low-compression engine--10-20, F-20 and the like, all sold as "kerosene" or "kerosene/distillate" tractors--using gasoline. I expect there would be a certain amount of power wastage when these engines burned gas. Their compression ratio was in the 4:1 range. I believe that even in the 30s, engines designed only for gasoline (F-12, for example) had a ratio in the 6:1 range.
One of the things we don't think about today is the retard lever that all the "old" tractors had. On kerosene, you could sometimes get knocking ("detonation" today), which you could hear, and which could destroy a piston if allowed to go on too long. If you heard the "spark knock," you retarded the spark. In fact, lots of cars right up until the beginning of the 30s had a "spark lever," used just for this purpose (and to save the driver's arm if he had to crank the engine). When automatic spark advance came out, the spark lever disappeared. I remember my father's '32 Chevy ton-and-a-half, which still had a little pull knob to retard the spark--a kind of "just in case" which we always used. A kickback could break the spring of the Bendix drive on the starter. Sometimes when the battery was low, we had to crank the old Chevy, and again, the retard button was a safety feature.
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