If YOU think pistons and rods are rotating MASS you need to go back to engine design 101!!!!!!!!!

 

They move in relation to the rotation of the crank shaft and contribute to inertial generated dynamic forces that act on the engine and ultimately produce vibration, so yes they are considered part of the reciprocating mass.

 

WOW i figured the guy just wanted the cliff notes. We could go crazy and discuss how cam profile, valve timing, length of rod, counter weight mass/diameter/ and where the weight is located on said flywheel but were gonna really go into some serious math/engineering that i dont think most here will get. (thats no disrespect) Then we could bring in what your gonna use it for, drag racing, road racing, high speed runs....it all changes what you do to said engine. way to much to get into without typing for a week!!! lol like whats been said short answer is YES!!!

 

 

"Weight is the measure of the earth's gravitational pull on an object. Mass is a measure of the amount of matter in an object. Put a vehicle on the moon and its weight changes; its mass does not. Inertia is a measure of an object's resistance to a change in direction or acceleration; mass affects inertia, weight does not, though the distinction matters little when drag racing on this planet. However, the more mass, the more inertia--and the more inertia, the more the resistance to acceleration."

--David Freiburger

 

Softy buddy we'll have to plan a a hook up weekend when our schedules allow and summer gets into swing and have this conversation over some fine malted beverages , this one is gonna go sideways fast in here .

 

Already has. Still not convinced.

 

I want to be that fly(Camera) on the wall. For that exchange.

Best of buds.....forget it. Nothing will happen.

Still would like to know how a few shaving of Kg, or Onces. From what part of the rod will aid performance?

 

The rod big ends are rotating mass, pistons and the top end of the rods are are NOT ROTATIONAL! There is a physical limit to how fast you can stop and start a PISTON and ROD top end and it relates to weight and piston speed.

here is a good explaination of the difference in ROTATIONAL MASS, and what is and what isn't "rotational".
P.S. you changed form ROTATIONAL to Reciprocating, those are two different things!!!


http://www.eatonbalancing.com/blog/2...ancing-part-1/

 

Plenty will happen , laughs , good conversation , female harassment and general male oriented nonsense ......... seriously .

While the tech speak aspects of what getting tossed around in here are true for the most part the reality of it is in a v twin long stroke engine like the beasts we love have lightening the rods ( what little can be done ) has no real street usable gain . Your going that far into one it's a motor thats gonna see the drag strip or salt flats . You'll get the gains at the outer rim of the rpm ranges Joe Blow average owner fears to go .