I was told by an old long time T owner that the early T's (the brass units) put out 22 H.P.
He seemed to believe that they had a slightly higher compression ratio. Apparently there was too many issues with poor quality gasoline that Henry had them reduce the compression ratio which resulted in lowering the H.P. output to 20.
Anyone heard of this? Or is this an Urban Legend?
They did detuned them several ways. Royce has vast knowledge in this area. I think they might have wanted to slow people down some.
Ford reduced compression ratio and changed the camshaft specs in the summer of 1912 due to bad gasoline quality. The 1912 and earlier engines were rated at 20 - 22 horsepower.
See the listing on the Encyclopedia at: http://www.mtfca.com/encyclo/E.htm#eng3 "Cylinder Heads." It shows they decreased the compression ratio several times and also that they increased it after the high head came out and then decreased it yet again. Note the "date of change" is the date on the Factory drawing or change card and NOT necessarily the date it was changed in production.
Date of Factory Change
03-14-11 T401C Increased compression space by 3/32"
07-17-14 T401C Added 3/32 to bottom of head, increases all top to bottom dimensions and lowers compression.
05-17-17 T401C Redesigned — High Head — Changes ASAP, Use Up Old Stock.
09-25-18 T401C Reduced height of combustion chamber 1/16"
05-18-26 T401C Reduced height of combustion chamber 3/32"
And about a month later they put it back like it had been.
06-22-26 T401C Increased height of combustion chamber 3/32".
If you scroll up on that same page you find the valve timing for 1909 listed and then 1912 the change along with the comment: VALVE TIMING
Revised during 1912, and typical through 1927.
Hap l9l5 cut off