Cast and Forged Cranks

thepope540

Member
:
2003.5 Yellow Speed - Sold, Spicy - Sold, #639 Black Mica
I've done a lot of research (and gotten some VERY helpful info from the forum and its members) and found that the FSDE came with a cast crank from 98-late 99 in the US and that it then went to a forged unit. This is most likely old news to some. Now here is my question - Was the cast unit steel or iron? Please don't speculate because that doesn't really help me. If you can speak from experience or show some type of documentation that would be awesome. The reason I care is that I am replacing my engine and don't want get a used "weak" cast iron crank, but cast steel and forged steel aren't really any different in strength. Here are some rough tensile strength numbers from the American Society for Metals:

Cast iron 70,000-80,000 psi
Nodular iron 95,000 psi
Cast steel 105,000 psi
Factory Forgings 100,000-110,000 psi
5140 steel 115,000 psi
4130 steel 120,000-125,000 psi
4340 steel 140,000-145,000 psi
 
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