How can you tell if a crankshaft has been hard chromed? I think the mains on my 392 crank have been. They're nice and shiney, while the rod journals had dome surface rust on them. Thanks. Bugman Jeff
If you can't see a bond point between chrome and shank it's a job. Baiscally if it's absolutely oil free and not oxidizing it's probably chrome. Plus held to the light chrome generally has a bluish hue to it. Any actual test I know would damage it. Having rust on the surface is not a good indicator if it is light yellowish brown rust. Chrome is porous and cannot rust, but rust can work through it and appear on the surface from substrata, or even from too much iron in the plating tanks, but that normally is low enough to actually help strengthen chrome. My old man used to have rods tipped with stellite. That looked like chrome too. just to confuse the issue.
I saw a 350 Olds diesel crank that had been sitting out in the weather. The whole thing was rusty except for the hard-chromed eccentric part on the front. Still nice and shiny. I also have seen hard chromed cranks and other parts, and the parts that are not chromed will start oxidizing but the chrome will not.
We used to use Hard Chrome shafts for making hydraulic cylinders.That stuff is HARD. A file won't mark Hard Chrome. Under real close examination,Chrome is smooth while a polished surface will still have small lines in it. And depending on the light,the color is just slightly different.
The Jalopy Journal
