5-speed swap...a rumor I once heard

[GutlessSupreme]

Connecting rods don't stretch; its that simple.

 

If you're in high school physics, then no, they don't stretch.

 

Once you're neck deep into machine dynamics and mechanics of materials, then yes, they do stretch.

 

I don't particularly plan on giving an engineering lesson here, and I will say right off the bat that the probability of an engine dying because a manual transmission was swapped is unlikely. But I will say this: nothing is completely rigid.

 

Everything flexes to a degree, and as velocity increases with the same/greater input power (combustion), you bet your ass that stretching and deformation of components will increase. Some things stretch elastically and return to their original shape/size, some things stretch past yield strength and become permanently deformed. And then some things stretch past their ultimate tensile strength and catastrophic failure occurs.

 

I'm not saying our rods are especially susceptible to this or anything. Everything depends on the modulus of elasticity and ultimate tensile strength of the materials used and on the power created by combustion.

 

Could a ridge near the top of the combustion chamber be hit if the RPMs were suddenly increased past their normal operating region? Possibly. The effects would be worse on a well-worn engine, where the cylinder would be it's pristine, original shape and diameter above the piston's normal range of travel, but slightly bored and oval-shaped where it usually operates.

 

Could the change in vibrations and harmonics between having the auto tranny attached vs having the manual tranny attached have damaging consequences? Again, possibly, on a well-worn engine. Not everything is perfectly balanced in high production parts.

 

Either of these reasons could potentially lead to an engines demise, but probably not one that wasn't on it's way out anyway.

[RobertISaar]

but probably not one that wasn't on it's way out anyway.

 

winner, winner; chicken dinner.

 

thats how the game is played folks.

 

and: forged rods from the factory FTW.