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It only becomes an issue when you cut away all the factory hardening which is good to about .015-.017" I've said this before too and told you the same thing on the phone a couple times now, right?
With .010 the hardening is still there, with .020 it is pretty much ground away. AS I said before, one more time, once the crank wears into to soft steel beneath the hardened surface, the cranks wear poorly. That is why Nissan hardened them in the first place! They were trying to build rugged and durable engines.
There are definitely still .std and .010 cranks around- I'm sure some guys right here on the forum have them.
Yes, most Datsun cranks are boat anchors once they are cut to .020 or beyond. In part that is because you have to nitride BEFORE turning, so if you don't do it BEFORE it is cut to .020, and then you harden it, you are going to .030. Most pro builders will say "you are really better of finding a better crank" at that point!
They also know that the difference between the hardened surface and the fairly soft core steel is about 50% bearing/crank life! Meaning the hardened crank will run about twice as long as a soft crank. And again, I did point out that it is often the thrust surface that fails on the roadster crank once you are through the hardening.
The specific knowledge came from decades of building roadster engines - literally. NOT just one or two engines! The hardness depths were determined years ago on race cranks in the 80's (specifically during Bob Studdard's D-prod engine program at Sunbelt).
My advice is simple and free, if you have to run .020, get it nitrided before it gets turned-and it will work fine for a long time.
If you have a non-nitrided crank at .020 or .030, you are really better off shopping around for another crank IF you want crank life and durability consistent with a Nissan factory crank. If not, it doesn't matter.
We are glad to help anyone out if we can. Thank you for calling today Pat, for the sake of the forum, it’s probably better if we talk real-time rather than going back and forth here. Thanks again.
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