View Full Version : Rod to Stroke ratio;

02-12-2010, 10:20 AM
Respected motor head Smokey Y. stated that a2.2 to 1 was ideal y yhe also wished con rods could be infinite. Engine desgin perameters don't alway's allow for this .If you can't reach the ideal what we can do is exployt the positives minimze the weaknesses. The positive start around TDC a piston attached to a long hangs around TDC in actual time and crank degress keeping the combustion chamber smaller longer.Ashort rod engine's piston at 20 degress is farther down the cylinder making for less potent charge might as well open up the exhaust valve early start scavenged that exhaust .Remwember this after the inishel pop the explotion is chacing the piston not pushing it.At BDC it's the opposite L/R piston move quickley after 90 degree's good stuff for the intake stroke the quick drop in pressure is sustained longer because of quick piston speed at this part of the stroke giving the intke charge lot's of momentom which can leed to over 100% volemetric effientce.And the LR.will deliver it more effientley with less side load on piston."Any information right or wrong is food for thought"