Spun bearing question

ch1ll said

You need to be careful about choosing a machine shop to recondition your crank. I believe that mopar cranks have the bearing surfaces induction hardened and that hardness only goes so deep.

Back in the day when this engine was popular, most machine shops had an inventory of reconditioned cranks and just swapped them out. Good bye to those days.

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They are what is called "tufftried" (sp). It is a chemical pickeling process. It only hardens the crank a few ten thousands of an inch (.000x) deep. Once the crank is "cut" the tufftriding is gone. There were very few shops "back in the day" that could do it. Now I know of none. I have a 170 slant six crank that is standard size, and hard chrome plated so I could run a hard bearing without scoring the crank or pounding out the bearing. The crank was done by Lunati in the mid '70's, and I used a tri metal bearing instead of Babbitt.