My Pete rebuild

[Rawze]

(01-09-2022 )Nostalgic Wrote:  ...
I've read that crank ends under high torque has a lot of bend and twist, up to .050" Again, an area I really don't know much about, which is why I've been relying on Quickserve to check everything....

Yes. at 500+ horsepower and 2000+ ft.lb load on an engine crank..l there will be a lot of flex in it.. especially when cylinder #6 is on the down stroke. All of the play in the #7 main bearing alone (and about 1/3 in the #6 main), (minus the oil film) comes into play the most at this stage, and as such.. viscosity and bearing clearances are the 2 most very important factors on loading.

As far as a large amount like 0.050" on an ISX.. its likely doubtful .. on a guess, it would likely be roughly in the 0.014" - 0.018" range at the rear seal, given the closeness of the #7 main bearings to it, and less than that at the front, where there is only the loading of the valve train + viscosity of all the other journals to overcome.. Some distortion comes from overall "flex" loading .. but some also comes form the weak points in the crank journals where the oil rifle is drilled into them. I am only giving a "bulls#itters-sake" estimated guess, based on experiences with that type of thing... I really have never measured it. It really would surprise me if it were much more than this.