billet cranks

[kilroy be here]

how far undersize can you safely turn a billet crank (Bryant) without getting into "soft" material?? I was told you could take a large journal rod crank and just turn it down to small journal size since it is a billet . they claim the crank is the same hardness all the way through. doesn't sound quite right to me though.

[Spbulldog]

That's kinda what makes something billet....it's machined from 1 solid chunk of steel or aluminum or whatever. So the hardness is the same throughout.

[Spbulldog]

With something forged or cast its molded then "case hardened" which makes it harder on the outside

[kilroy be here]

so you don't think turning a 2.100 journal to 2.000 or 1.888 would be out of the question??

[Spbulldog]

so you don't think turning a 2.100 journal to 2.000 or 1.888 would be out of the question??

I can't say it WONT be a problem because you're taking a lot of material off. And less material is always gonna mean less strength but as far as it being the same hardness all way thru ...it will be

[perfconn]

Main trouble is where will your oil holes be when you turn it down?

[kilroy be here]

that's only .050 to .060 deep. I don't think the oil holes will move that much (?) I see what you mean though

[Spbulldog]

that's only .050 to .060 deep. I don't think the oil holes will move that much (?) I see what you mean though

From 2.100 to 1.888 is .212 you're removing. That's .106 per side in a circle That's almost 1/16 inch per side. That's a pretty good amount of material

[kilroy be here]

ya would be .050 going to 2.000 from 2.100 but ya your math is right I didn't figure it for the Honda rods don't think the oil holes will move sideways enough to hurt(?)

[SLM98]

I have ground several Bryant cranks from 2.100 to the 1.8888 however in each case i increased the stroke. They were 3.300-3.335 stroke that I increased to 3.480-3.500. I had them nitrated after. All worked out fine.

[kilroy be here]

I have a 3.325 Bryant that I want to take down from 2.100 to 2.000 because I got a set of rods that fits my combo for super cheap. I wont be changing stroke length so I don't think ill be messing with the oiling passages hardly at all, just a normal chamfering job. do you think they need the nitriding after they are ground or just your personal preference?

[SLM98]

Look at the oil holes if they arent close to the radius it will work out fine. I like to nitrate after makes for a slicker surface

[Brian Gray]

taking the rod journals down is no issue. you can go to 1.880 with 0 problems. nitride is not even a concern with high quality bearings . and the oil holes will not be any issue either.

[kilroy be here]

thanks for all the replies!!!!

[Krooser]

I have a SBM cast crank being ground right now from the stock 2.125 down to 2.0… three crank grinders have told me I will not have any problems. I built an early Hemi a few years ago and the rods were ground .060 under…. forged steel.