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Old 06-26-2014, 10:24 AM   #203
Bruce Lancaster
Senior Member
Join Date: May 2010
Location: Madison, NJ
Posts: 5,230
Default Re: Boring a flathead

On the offset...I have an ancient Ford produced engineering text with an explanation from the horse's mouth...the book is moderately common, and likely your local library could get a copy via interlibrary loan. I just replaced my copy because Flatdog had the old one and was reading it about the time of his death. Did not want to bug the family at such a time!
Anyway, the offset crank is referred to as the "Desaxe principle", which might help in hunting patents or early papers.
I can understand about 50% of the book until it moves into heavy math, it would be a much better read for someone like JWL!
Some excerpts: "...the axis of the cylinder is offset from the centre line of the crankshaft...The principle object of this offset is to diminish the obliquity of the connecting rod during the power stroke. so that the mean thrust of the piston on the cylinder walls during this stroke when the bearing loads are greatest, is reduced."
This moves on into the differences between upward and downward movement vs pin position, influence on real stroke, etc., moving into math that takes me into screaming nightmares of analytical algebra and geometry in the 10th grade.
It also gets into determination and definition of TDC in these things, really explaining why it is not nearly as simple as a dial indicator topping out...
For those who read such stuff:

"An Elementary Text Book of Automobile Engineering", 1935, Facilities department, Ford Motor Company Limited, Dagenham/Essex.
Note that the A&B Fords and the little four banger made in England all also were offset.
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