the machine shop said the crank out of the used block i brought to them was very rusted and will need to be replaced. the crank i pulled out of my cracked block is scored up pretty bad and looks like it will need to be sleeved front and back. is it common to polish the surfaces of the crank? if they do that will i need oversized bearings? this is all very frustrating considering i was supposed to drive home to san diego in 2 weeks, but on the bright side, my engine will rebuilt top to bottom when im done!

 

hey-Hey!!!,
Check with Cummins on availability of undersize bearings and have the shop cut to fit what ever you can get quickly enough to get it done. Like if they've got .02" under, and it will take a week to get .01" under go to the -.02"...assuming this will clean it up. It is SOP in the land of gasoline engines...or at least it used to be.
cheers,
Douglas

 

I haven't actually bought them, but have heard undersize cummins bearings are extra expensive.

Maybe look into a usable crank, or different brand bearings. Federal Mogul didn't charge any extra for the undersize ones.

Yeah polishing is the norm. Kind of like the opposite of honing a cylinder, you want a nice smooth bearing surface.

 

"redlinear" on ebay probably has like 4 cranks. he parts out whole cummins engines all the time.

 

What's a little rust gonna hurt? The polishing should remove all of it from the all the journals. Unless, it's no longer surface rust.

 

Yea I wouldnt worry bout a little surface rust. Now if it is pitted that is a different story.