Rb Series Cranks

[carl h]

question at hand is what are the standard rb cranks made out of?

cast? forged? chizzled out by some japanese sweatshop worker forced to gind them with nothing but bits of rocks?

trying to figure this out as there is a current war building over this topic on one of the stateside rb related forums.....

[Fitzpatrick Speed Works]

They are cast iron, that is then heat treated (toughened) and nitrided!!!!

Edited November 20, 2005 by Fitzpatrick Speed Works

[proengines]

They are definately steel, not cast iron.

[Warpspeed]

Definitely steel, and definitely forged.

I have an RB26 crank in front of me right at this moment.

[Fitzpatrick Speed Works]

They are steel sorry, I dont believe they are forged, I guess it depends on your process of forging and the different understading of it??? Is there any way to prove a theory either way, be interesting to know. Forged for me means heated metal pressed into a shape???

I have a snapped rb20 crank and the metal is a little pourass like you see on something that is cast, infact the look of it looks like die cast thats the texture for those who understand, maybe that was due to the way it broke??? Now that I think about it I dont really know why I thought it was iron maybe cause it looks cast, momentary brain failure i guess, haha!!!

[SteveL]

maybe that was due to the way it broke???

<{POST_SNAPBACK}>

Most likely. Nissan only uses forged steel cranks, and I'd be very surprised if they are nitrided.

[carl h]

sooooo whats the definative answer.......?

[Fitzpatrick Speed Works]

definative answer from mr science, a friend of mine that is a scientist but also likes nissans. As Greg said, they are forged mild steel, temper toughened (hardened), then machined and nitrided.