X in H serial #

I looked at a H today serial number 267338 x1
I looked at 243373 also with no X what does the X mean?

Thanks

x1 means gas engine with higher compression head etc. No X means it is a plain jane distillate or kerosene tractor(not sure if there is any difference there) with lower compression, originally designed to start on gas and then switch when warm to burn cheaper fuels.
Zach

The kerosene letter series tractors had a slightly lower compression ratio head (4.4 to 1) to the distillate tractors (4.7 to 1), the other bits, tanks, manifolds radiator shutters, were the same.

At some point, X1 became somewhat obsolete, as the gasoline only engine was standard, so the X1 wasnt used. Thats probably why your newer one doesnt have X1 after it.

Look at those serial numbers again. The newer one is the one with the X1. Your conclusion is correct, but it happened about 10 or more years later than these tractors.

TOM

DOH!! Looked at them backwards I guess! I was told around 47 - 48 gas engines were pretty much the standard, so X1 wasnt used, instead the code, sont recall it at the moment, was used for kerosene engines. I had a 48 M with the kerosene code on it.

(quoted from post at 05:18:05 06/29/11) DOH!! Looked at them backwards I guess! I was told around 47 - 48 gas engines were pretty much the standard, so X1 wasnt used, instead the code, sont recall it at the moment, was used for kerosene engines. I had a 48 M with the kerosene code on it.

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X1 remained the code for gas engines throughout production of the letter series Farmalls. I have a '49 with the X1 code on it, FBH399513X1. The kero code is X3, while the distillate code that was added much later is X17, prior to its addition, the absence of a code indicated distillate use, as that was the default, so to speak. I have 4 '40 models that are marked as such, FBH17867, 23075, 36586 and 40665. No codes on them at all, except for the last one, which is a special case in that it has the X1 code, but it was hand stamped to the left of the FBH, in the block where the letter 'H' normally appears by itself, indicating it was converted to gas at a later date, probably by a dealership. I also have a '41 model, FBH72515X6, which code indicated low speed gears, where the X6 code was also added by hand apparently at a later date, only it is in the correct location on the plate. That particular tractor does indeed have the low speed gear set in it, so again, probably converted by a dealership. The remainder of my H's (I have 10 in all) all have no codes on them, and all showed signs of having been original distillate tractors, though some were converted to gas in later years without the code being added to the plate. These were most likely done by the farmer himself or a jobber shop. I also have a '52 model M, FBK294174X1, where again the code looks to be hand stamped and is in the correct location. The only one I have not yet figured out, (admittedly I haven't researched much yet as I just bought it), is a '53 Super M sporting the number F34536J, with the 'J' appearing hand stamped. I don't yet know what the 'J' is supposed to stand for, and the 'F' is a bit of a mystery as well, as according to my guide books, the Super M was supposed to have 'SM' at the start of the serial number. This one has the 'SM' above it in the block indicating model. This is my first foray into the Super series tractors so I have a bit of learning to do on them.

TOM

I think the X's disappeared with the Super series. J means Rockford clutch, the F means it was built at the Farmall plant. The reason for the F is that 12541 SM's were built at Louisville, and have an L designation. Although the SM is called the serial prefix, it is painted and not stamped, so that's ok.