Okay i was wondering if it is worth it to shotpeen the stock ls rods or shoud i get after market. what about pistons? do i do them too. Does the itr and ctr come shotpeened already? I’m running N/a right now and revving about 8 k on the ls motor. Later i plan to go turbo. How much does it cost to get the rods and pistons shotpeened?
SHOTPEENING is the process of firing small pellet sized BB’s at a very high speed at the rod. OEM rods are necissarily shotpeened, but are normally able to withstand higher horsepower levels due to better craftsmanship/design. Around here in N.CAl, shotpeening typically run about $150-200.
Shot peening also helps raise the fatigue stress level the object can take meaning it will be able to take on higher loads. Won’t be as brittle as the non shot peened.
About the use of aftermarket rods on OEM pistons. Please look up under the Hybrid forum. Lots of info there.
Shot peening does not increase the strength of the material it just reduces or lessens the possibility of fracture at stress risers! Its like drilling a hole at the end of a crack, it does not make the part stronger it just reduces the possibility of fracture because the sheer planes in the crystal structure of the material have been interrupted.
Originally posted by DB2-R81
Shot peening does not increase the strength of the material it just reduces or lessens the possibility of fracture at stress risers! Its like drilling a hole at the end of a crack, it does not make the part stronger it just reduces the possibility of fracture because the sheer planes in the crystal structure of the material have been interrupted.
I thought that even when tempering an object it increases the stress levels as well right? or am I in the wrong thought process here? Doesn’t shot peening promote the strength of the surface of the object by the idea of ‘pushing the molecules’ closer together and helping them bond with each other?
Well, shotpeening does not make the rods “stronger” per say. But it does reduce the chance of fracture or cracks at stress risers (sharp points). By removing the sharp points the stress is more evenly distributed across the surface of the rod, allowing it to handle more abuse without fear of fracture. I hope this makes sense.
Think of a diamond, one of the hardest natural materials known, but hit it or put stress on it in the right area and it will fracture quite easily because of the organised structure of the diamond crystal. Rearrange the crystal lattice of a material and randomize the bond between its electrons and you increase the strength between grain boundaries. Kind of like putting two bricks together, they will slide against each other quite easily, put some cement between them and they will stay in place but the bricks don’t get any stronger just stay together better.
Ok, I must be boarded here is a better one. Think about “Lego”, if the blocks were smooth they wouldn’t stay together very well but because they have little interlocking nubs, the bonds between them become very strong when you assembly them together. Again the blocks themselves are not any stronger.
Those are some good analogies Marc…nice job 
Cool! Thanks for the knowledge! Nice to learn something new! That made it a lot easier to understand. I’m kinda more a hands on guy where I need examples! But thanks for clearing that up!
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