Posted by Dan Shockley on Saturday, July 05, 2003 at 10:09AM :
In Reply to: Spun rod bearing journal easy fix? posted by David Sherman on Friday, July 04, 2003 at 4:12PM :
First of all, it sounds like you had a blown head gasket, causing the over heating. With a diesel, generally, blue smoke= oil, white smoke=water and black smoke=excess fuel. If I had to guess, that would be my guess.
To answer your question about the crank you will need to know if the crank got hot enough to temper the journal. If there is any discoloration, that is one indication, but really hardness needs to be compared with the other journals. If it is softer than the other journals this is called a soft-spun journal. When the bearing is seizing, it heats up enough that it anneals the case of the journal. In addition, the crank will no longer be straight. When the journal is stress relieved by this heating, the crank distorts significantly. In a diesel engine, this crank will not survive if reused as is. You will have to have the crank salvaged. At the diesel engine remanufacturing facility that I work for, we stress relieve, straighten, rough grind, nitro-carburize and final grind and polish. Running the distorted crank can do significant damage to other engine components included causing a "ventilated block"!!
Good luck,
Dan
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