is a 4130 "forged steel" crankshaft a stong piece? i dont know much about gradeing of metals and was just wondering if it were strong, i found a brand new crank for 300 bucks just wondering if it was worth it or not? thanks

 

4130 is lower grade steel than 4340 and is weaker. I'll give you the descriptions of the two alloys in my metals catalog and let you decide.

4130 - General puprose allow. Low in cost with a nominal .3% carbon, .95% chromium, and 20% molybdenum. Offers good strength and toughness for mederately stressed parts.

4340 - highly alloyed steel, nominally 1.80% nickel, .80% chromium, .25% molybdenum - assuring deep hardness when oil quenched, with high strength characteristics attained throughout the section. Used for heavily stressed parts operating under heavy-duty conditions.

In other words, if you can, get the 4340 forged crank. I don't know how the 4130 compares to a cast crank but I would doubt there is a whole lot of strength difference.

 

You could try a 5140 crank. They are stonger then a 4130 but cheaper then a good cro-moly 4340.