Originally posted by 3400-95-Modified
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Wide parting lines indicate a forged crank and narrow lines are normally cast. During the forging process, there is a lot of extra material that is squeezed out of the dies and later cut off in a trimming operation. The mold for the casting process shuts off pretty good and therefore doesn't create a big parting line.
Kind of hard to tell from that pic but it looks forged. The 3900 crank appears to be forged.
The quickest pics that I found are here... http://forums.godragracing.com/viewt...c0ec190e8e2898
Hope this clears things up a little.
Edit: Let me add that the cast steel cranks are considerably stronger that the cast iron cranks.
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