This isn't right. Consider an engines heritage, it's lineage. On the first, the earliest one cylinder, The center line of the engine is based on the bore. And the piston pin is in the center of the bore. From day one, The centerline of an engine was the cylinder bore/pin as a starting point and for ease of calculations when other designs and drawings were required. (think of a multi-cylinder radial engine) Eventually, someone glued two basic 1 cylinders together in a v shape, It didn't change the fact that the original centerline is based off of the pin/bore. But for a time the crank was placed directly at the intersection of left and right angle/bores. Prior to Desaxe, the crank just happened to be centered on a north/south case. On Radial engines, the centerlins of all bores/pins intersect to a common point. In the earliest of 1 cylinder under Desaxe, the crank was offset to the pin centerline. -The plain of the crank moved left as opposed to a non Desaxe engine. Still, the centerline remained at the starting point of inertia, at the one cylinders piston and it's pin. Then someone Glued two Desaxe cylinders in a V and they moved the crank over based on original bore/pin. Observe, Two different 'as found' reference pics: Left; Standard bore/pin and crank on same plain/centerline - Typical Early Engine Design Right: Desaxe Offset crank as referenced from cylinder bore/pin-which is still centerline Note that downward thrust has already begun (with piston at TDC) with several degrees crank rotation already past TDC at/of crank.. Next in lineage is a 4 cylinder Desaxe, (or maybe a Model A Banger) Ford 9N -Crank is offset of center bore/pin by .20 inches (our reference point here, as is above pic, is still center of bore/pin) The true centerline is indicated by a long continuous vertical line through entire plain of engine/diagram. V8-60-The crankshaft is offset from bore/pin intersection by .200 inches 59AB-The crank is offset from bore/pin intersection by .265 inches Cam is given and is measured in 10,000s of an inch at .0242 offset. In this 1932 pic, Ford actually indicates/shows the true centerline which is intersecting the centerline(s) of the bore/pin of 45 and 315 degrees respectively. Crank is offset to the left by .265 inches of intersection/centerline. Although not indicated in this pic, The cam is offset .0242 from crank. It is a given that All engines are referenced from the bore centerline and probably even irregardless of today's offset piston pins. In the beginning, it was a one cylinder but soon advanced on to complicated V's and even into Radial engines with umpteen cylinders. but all this doesn't change the fact that motion/inertia starts at the piston/pin and/or center of the bore (and not at the crank as someone else has stated). *Caveat Emptor, I'm just gonna state for the record, this has been hotly debated in the forums over the years... (MSN Flathead forum 10-15 years ago?) Every technical drawing I have seen of Early 1 cylinder, Flathead V8 60, early, mid and late Flat V8, and Especially the Flathead 4 cylinder in the 9N tractor shows that the Technical centerline intersects exactly with that of the piston pins. That is to say that the piston Bores are the key factor in determining what is, or what is not center line. Centerline of a block shouldn't be thought of as (visual) centerline based on carb/intake/fuel pump/crank or other point/accessories because the early reference has not changed since the day they started worrying about things like "core shift". That being said, to us it really doesn't matter where you or I see the centerline of the block as being......... ===================================== The Desaxe principle. In our case, Offsetting the crank to one side increases the leverage of the rod compared to the degrees rotation/turn of the crank. (you in effect increase degrees of rotation down stroke and lessen degrees of rotation of upstroke), Resulting in a longer power stroke being applied. It also relieves some of the thrust applied as a side force of the piston to cylinder wall. Thirdly, it relieves a relatively equal amount of harmful thrust at the rod bearing. Most importantly, It changes at what degree the downward thrust is initially applied. Exerting downward thrust at TDC on an inline crank is inefficient (and destructive). Offsetting the crank (Desaxe) causes the downward thrust to be applied X degrees past the true TDC -centerline- of the crank. This increases efficiency which translates to more downward thrust being applied. (more power/more torque) In this comparison pic, all initial pressures are given as equal, all figures are based at Piston TDC. All examples starts out with 700psi flame/ignition translating to 600 psi at the piston.. ^^Observe the improvements (made by offsetting the crank in varying degrees) ^^ in psi measured at the crank. -Note also the observed angle of rod 90 degrees to the crank (angle B). 40, 38 and 22 degrees respectively. -Note that this is calculated by offsetting the crank both up and Sideways (I added a horizontal line across the cranks for comparative height at each given offset) -It's important to realize that The Desaxe principle doesn't just move the crank off centerline, it also adjusts it's horizontal plain/centerline as well. This would be done to maintain rod lengths both left and right. The last thing a guy should note is that the crank offset is determined by engine rotation. Reverse the rotation of the engine and you must offset the crank to the other side. ===================================== In our Flatheads with minimal crank offset, All these factors are small but based on the design, it equates to longer engine, bearing, piston skirt and cylinder wall life as well as it increases engine efficiency, hp, torque and even improves fuel economy. -A rough estimate of offsetting the crankshaft by .265 inches might equate to 1 or 3% in additional hp/torque. (very rough estimate). Maybe more.. The actual hp/torque would be a factor of how many degrees of downward stroke were added by offsetting the crankshaft .** inches (over and up) as opposed to bore/pin/centerline and I didn't do the math. When all is said and done, 1 or 3% doesn't sound like much but remember, This was free hp/torque when discovered, and there was an added fuel saving that comes with it, so it only made sense that Henry would be 'all in' on this principle since it costs no more to manufacture an engine on centerline versus an engine with crank offset to one side and upwards of bore. And If an added benefit of longer engine life were involved, then it seems to me it would be a no brainier. Further to this, perhaps cad/math doesn't equate because the true centerline(s) are not being factored? In which case, the figure of .168 @ 45 degrees right and 315 left have not entered into the equation?? -I don't know, neither me or my calculator do CAD. Honestly, it's just a guess as to why, given the fact that the specs on the drawings are reportedly accurate to 1/1000th's of an inch that the actual math doesn't work out when plugged thru a computer? ?? jmho, moe .
And some still do it...not really that noisy when cold either. Hell you can hardly hear it over the lifter noise.
Hey Gang - I went back awhile ago and reworked all my drawings (based on the actual blue-prints from the Ford archives). I've validated all dimensions - the geometry works. Anyway, for the intimate details - including the drawing with all dimensions, go to this old post: http://www.jalopyjournal.com/forum/...s-angles-and-validation.958100/#post-10780867 B&S
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