I keep asking this question to people and i keep getting different answers. I jsut want to feel at ease with spending the extra money for my long rod engine. Ok here it is:

If you have 2 motors that have the identical bore and stroke and also the same power output which combination would be the most likely to break a rod.

engine 1. deck plate block with a longer rod

engine 2. standard block with a standard rod.

Heres what im trying to get at. Obvously the longer something is it is weaker than if it were shorter. Would Engine 1 with the longer rod and the better r/s ratio be stronger than Engine 2 with the shorter rod with the worse r/s ratio?

 

that's something to think about

 

When designing vertical I-Beams for steel construction buildings, we take this into account. There is a load limit determined by the "slenderness ratio". Too much loading and the longer beam deflects first.

Stand a wood ruler on edge and push down on it. Then take one of the pieces anfter it breaks and push down on that. Same deal.

So based off this fact alone, the shorter rod is stronger.

EDIT: Wouldn't you necessarily have a longer stroke though?


[Modified by asdewq, 5:10 PM 1/9/2003]

 

I would think that if the rod is longer, and the width of the rod is the same on each motor, the longer rod would be weaker. There must be some physice people on here though.....

 

Yeah there has to be some phisics here to think about. The reason im thinking that the longer rod might have a chance is that it the force may be applied at a better angle at some degrees of rotation that may snap a shorter rod because the shorter rod should have a different position in the cylinder at the same time of combustion. I dont know where are all the smart people.