Broke forged connecting rods?
11-11-2004, 12:59 AM
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Broke forged connecting rods? I've been wondering for a now how much power forged rods can take, how much difference is there really in strength between say Eagle and Lunati or Lunati and Oliver.
And if you do break a eagle rod, would a oliver rod have saved the engine or do you have serious problems that would have caused that rod to break too? Does predetonation / bad tuning cause forged rods to break or just too much power?
And if you do break a eagle rod, would a oliver rod have saved the engine or do you have serious problems that would have caused that rod to break too? Does predetonation / bad tuning cause forged rods to break or just too much power?
11-11-2004, 01:24 AM
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There is a difference in the metals that make them up, as well as the design, I beam to H beam etc. Where one material may have more resistance to the vertical impact (the torque from controlled combustion forcing it downward) another may have more lateral resistance and there is resistance to fatigue as well, aluminum are not great for longevity, but are light as hell, thus spin up faster.
Detonation, or predetonation puts the force from the uncontrolled combustion, when the piston is still moving up, and thus creates a substantial amount of force thru the rotating assembly at the same time causing harmonic distortions which can cause "stress fractures" in the grain of the metal, much like a runners leg with stress fractures. The fractures eventually weaken the rod, piston, crank etc until it snaps.
So, yes there is a difference not only in material, but design and either can be weakened by improper tuning, or being out of balance (causes a lot bad vibes!). You dont see Aluminum rods in a DD, or Powdered "cracked" steel rods in a dragster. Each level of performance has a tolerance, street strip forged, or factory/ Dragsters Alum & Ti./ Exotic high revving (hyper gerbil machines) some also use Ti etc...
*edited in * Forgot, Quality, like no **** right. The process in which the metals are formed, forged, cold, pressed, stamped etc also has pro & cons. I am not totally up to date as I would like to be, but basically each different process will have a unique benefit, like forging increases strength by heat tempering, and there is billet, taking a solid pieve and maching it out to spec, reducing imperfections.
Hope this helps!
Charlie
Detonation, or predetonation puts the force from the uncontrolled combustion, when the piston is still moving up, and thus creates a substantial amount of force thru the rotating assembly at the same time causing harmonic distortions which can cause "stress fractures" in the grain of the metal, much like a runners leg with stress fractures. The fractures eventually weaken the rod, piston, crank etc until it snaps.
So, yes there is a difference not only in material, but design and either can be weakened by improper tuning, or being out of balance (causes a lot bad vibes!). You dont see Aluminum rods in a DD, or Powdered "cracked" steel rods in a dragster. Each level of performance has a tolerance, street strip forged, or factory/ Dragsters Alum & Ti./ Exotic high revving (hyper gerbil machines) some also use Ti etc...
*edited in * Forgot, Quality, like no **** right. The process in which the metals are formed, forged, cold, pressed, stamped etc also has pro & cons. I am not totally up to date as I would like to be, but basically each different process will have a unique benefit, like forging increases strength by heat tempering, and there is billet, taking a solid pieve and maching it out to spec, reducing imperfections.
Hope this helps!
Charlie
