How to tell if something is forged or not?

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There is and has been a rumor going around that the connecting rods in Nissan vehicles have all been forged since the early 80's. My question is this... Is there a way to tell if a connecting rod is forged by inspecting it? Maybe cut it in half? Try to bend it? Heat it up? Anything?What would a cast con. rod do vs a forged con. rod in any of the above situations?I have a connecting rod from a 96 Nissan pathfinder that I am willing to do whatever to if I can find out. I just don't know what I should do.
Reply:I might be wrong but as far as I know ALL connecting rods in modern IC engines are forged.  As well as the cranks, axles, and almost any highly stressed part,  pistons and blocks excluded.
Reply:Parting lines can be a good clue, google 'parting lines forging versus casting'. Quality of a casting or forging obviously varies but unmachined surfaces, particually edges, can also be a clue as intricate details can be easily cast whereas details on forgings are generally less sharply defined
Reply:Start with comparing parting lines.Cast iron throws less sparks when ground on.As for "all are forged"  Pontiacs, with the excheption of really old ones like 1963 and earlier and some high performance ones - Ram Air IVs etc. were all cast iron.  Coupled with long stroke motors like the 455, they had a maximum practical rpm of 5500 - and even then it was common to have slight rod knock after a while.  On those motors, $400 would buy you aftermarket rods that were 10x as reliable.I gotta ask why it matters.  With the exception of Pontiac, if you are building a motor where cast rods aren't strong enough, switching to factor steel ones is maybe only a hair better.  Rather then spending all the money on machining a set of rods, buy some aftermarket ones.  I know at one time to resize both ends, shot peen, install new rod bolts etc. was $80.  I imagine its significantly more now.  A set of V-8 aftermarket rods is like $450.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:most modern production connecting rods are powdered metal. some are cast iron,and a few are forged.the vast majority of cranks are cast.
Reply:Originally Posted by con_fuse9I gotta ask why it matters.  With the exception of Pontiac, if you are building a motor where cast rods aren't strong enough, switching to factor steel ones is maybe only a hair better.  Rather then spending all the money on machining a set of rods, buy some aftermarket ones.  I know at one time to resize both ends, shot peen, install new rod bolts etc. was $80.  I imagine its significantly more now.  A set of V-8 aftermarket rods is like $450.
Reply:forged has a higher pitch ring when hit, compared to a duller ring from cast iron. powdered metal is in between. its also easier to file down cast iron than forged is, due to less density from cast iron. i used to build racing engines before and hitting the counterweights on a crank with a hammer was a sure way of telling. cant really do that with a connecting rod though.Ranger 305gMillermatic 140 AutosetDewalt Chopsaw2 grindersMy Fists
Reply:you could cut the rod in half down the middle - polish the cut - and then stain the polished facewith the iron solution used to etch circuit boards.  That may allow you to see the if the grainstructure follows the shape of the part.   A lot of work though.......  hitting it with a hammer would be quicker if you had a cast one to compare the pitch to ....Tim
Reply:Originally Posted by DiabolicZSomething about orange sparks vs. red sparks.
Reply:Cast iron has a large mount of graphite in it.  Filings from cast iron will turn you fingers black when rubbed between your fingers.  This is a good way to distinguish between cast iron and cast steel.